阅读说明：本技术 一种低温工质超临界气轮机或膨胀机及使用方法 (Low-temperature working medium supercritical gas turbine or expander and use method thereof ) 是由 翁志远 于 2019-03-29 设计创作，主要内容包括：本发明实施例提供一种低温工质超临界气轮机或膨胀机及使用方法,属于一种特殊用途的气轮机或膨胀机。所述气轮机主蒸汽管道输入的气体,温度需明显高于低温工质的临界温度；所述气轮机排气管道输出的乏汽,温度须达到或略微高于所述低温工质的临界温度；所述气轮机的工况区域,始终都处在所述低温工质的临界温度以上。所述气轮机排气管道连接乏汽回热器,令低温液体泵输出的低温液体冷凝临界温度的高温乏汽；另外,本发明实施例还提供一种采用气轮机外缸体进行轴端密封的技术方法,以解决气轮机或膨胀机等旋转机械转轴两端泄漏难题,尤其是昂贵的低温工质；所述气轮机或膨胀机具有结构紧凑、体积较小、成本低、扭矩力大等优势。(The embodiment of the invention provides a low-temperature working medium supercritical gas turbine or an expander and a using method thereof, belonging to a gas turbine or an expander with special application. The temperature of the gas input by the main steam pipeline of the gas turbine is obviously higher than the critical temperature of the low-temperature working medium; the temperature of the exhaust steam output by the exhaust pipeline of the gas turbine needs to reach or be slightly higher than the critical temperature of the low-temperature working medium; the working condition area of the gas turbine is always above the critical temperature of the low-temperature working medium. The exhaust pipeline of the gas turbine is connected with a waste steam heat regenerator, so that low-temperature liquid output by the low-temperature liquid pump is condensed to high-temperature waste steam at critical temperature; in addition, the embodiment of the invention also provides a technical method for sealing the shaft end by adopting the outer cylinder body of the gas turbine so as to solve the problem of leakage at two ends of a rotating shaft of a rotating machine such as the gas turbine or an expander and the like, particularly expensive low-temperature working media; the gas turbine or the expander has the advantages of compact structure, small volume, low cost, large torque force and the like.)

1. The low-temperature working medium supercritical gas turbine is characterized by comprising an equipment input end, an equipment body and an equipment output end; the high-pressure gas working medium input by the input end of the device is a low-temperature liquid meson with the boiling point temperature lower than zero degrees centigrade under the standard atmospheric pressure, and the high-pressure gas comprises but is not limited to high-pressure carbon dioxide gas, ammonia gas, methane gas, nitrogen gas, high-pressure air, hydrogen gas and helium gas;

the temperature of the high-pressure gas input by the input end of the low-temperature working medium supercritical gas turbine is obviously higher than the critical temperature of the low-temperature working medium; the temperature of the dead steam discharged from the output end of the low-temperature working medium supercritical gas turbine is required to reach or be slightly higher than the critical temperature of the low-temperature working medium;

the exhaust pipeline of the low-temperature working medium supercritical turbine is connected with an exhaust steam heat regenerator, so that extremely low-temperature liquid output by a low-temperature liquid pump condenses high-temperature exhaust steam which is exhausted by the exhaust pipeline of the low-temperature working medium supercritical turbine and has the temperature reaching the critical temperature of the low-temperature working medium;

the low-temperature working medium supercritical turbine applies work by utilizing the temperature energy of the high-temperature and high-pressure gas working medium input by the input end of the low-temperature working medium supercritical turbine and the enthalpy difference between the exhaust steam which is exhausted by the output end of the low-temperature working medium supercritical turbine or the expander and has the temperature reaching the critical temperature of the low-temperature working medium; the working condition area of the low-temperature working medium supercritical gas turbine or the expansion machine is always above the critical temperature of the low-temperature working medium;

the low-temperature working medium supercritical gas turbine or the expansion machine belongs to a high-pressure gas turbine machine and comprises but is not limited to a gas turbine, a pneumatic machine, a gas turbine expansion machine and a gas screw rod expansion machine;

the low-temperature working medium supercritical gas turbine or the expander is made of low-temperature resistant materials including but not limited to austenite low-temperature steel and ferrite low-temperature steel.

2. The low-temperature working medium supercritical gas turbine or expander according to claim 1, further comprising a shaft seal system adopting a highly closed structure of a gas turbine or expander cylinder, wherein the low-temperature working medium supercritical gas turbine or expander is composed of a stationary part and a rotating part; the gas turbine or the expander cylinder body shaft seal system comprises an input end shaft seal system and an output end shaft seal system; the input end shaft seal system of the low-temperature working medium supercritical gas turbine or the expander comprises an input end cylinder body, an input end bearing, a bearing seat, an input end rotating shaft and a main steam pipeline; the input end bearing and the bearing seat comprise a supporting bearing and a thrust bearing;

a heat insulation shell is arranged outside the input end bearing and the bearing seat; the insulated shell is divided into an upper insulated shell and a lower insulated shell; the lower heat insulation shell is arranged in a lower cylinder at the position of the bearing at the input end and the bearing seat and is tightly combined with the lower cylinder of the gas turbine or the expander; said input end bearing and bearing housing mounted in said lower insulated housing within said turbine or expander lower cylinder;

the lower heat insulation shell and the upper heat insulation shell are provided with flanges, and the lower heat insulation shell and the inner cavity of the upper heat insulation shell form a closed heat insulation space through the fastening of the flanges and bolts; the input end rotating shaft, the input end bearing, the bearing seat and lubricating oil are sealed in a heat insulation space formed by the heat insulation shell;

the heat insulation shell wraps the contact position of the input end rotating shaft, and a heat insulation shell seal is further arranged, and the heat insulation shell seal prevents bearing lubricating oil in the heat insulation shell from leaking outwards from the heat insulation shell seal.

3. The supercritical turbine or expander with low temperature working medium according to claim 2, wherein the upper and lower heat-insulating shells of the heat-insulating shell are fastened by the flange and the bolt, and a sealed heat-insulating space is formed inside the upper heat-insulating shell, and a lubricating oil injection hole is provided at the top of the upper heat-insulating shell, so that lubricating oil is injected into the heat-insulating space of the bearing and the bearing seat;

the heat insulation shell also comprises a lubricating oil output pipeline, a lubricating oil filter, a lubricating oil cooler and a lubricating oil pump which are connected with the heat insulation shell; the constant-temperature lubricating oil output by the lubricating oil pump is conveyed to the bearing and the bearing seat in the heat insulation shell through a lubricating oil input pipeline;

the lubricating oil filter, the lubricating oil cooler and the lubricating oil pump are arranged outside a cylinder body of the low-temperature working medium supercritical gas turbine or the expansion machine or inside the cylinder body of the low-temperature working medium supercritical gas turbine or the expansion machine, and a heat exchange pipeline is required to exchange heat with the outside to ensure constant temperature of the lubricating oil when the lubricating oil filter, the lubricating oil cooler and the lubricating oil pump are arranged inside the cylinder body;

a lubricating oil temperature probe, a lubricating oil pressure probe, a lubricating oil quantity probe and a pressure probe inside the cylinder body of the gas turbine or the expander are also arranged in the cylinder body of the low-temperature working medium supercritical gas turbine or the expander;

the low-temperature working medium supercritical gas turbine or the expansion machine is characterized in that a shaft seal is further arranged between a main steam pipeline and an input end of the heat insulation shell, an input end reserved space or a pipeline is further arranged between the heat insulation shell and the shaft seal, the input end reserved space or the pipeline is arranged in the lower cylinder, lubricating oil leaked from the sealing position of the heat insulation shell is stored, and the leaked lubricating oil is discharged through a first pipeline valve.

4. The low-temperature working medium supercritical gas turbine or expander according to claims 2-3, wherein the output end of the low-temperature working medium supercritical gas turbine or expander comprises a gas turbine or expander exhaust duct, an output end cylinder, an output end bearing and bearing seat, a coupling and a generator; the output end bearing, the bearing seat, the coupling and the generator are all hidden and arranged inside an output end cylinder body of the low-temperature working medium supercritical gas turbine or the expander;

the input end of the low-temperature working medium supercritical gas turbine or the expander and the output end of the low-temperature working medium supercritical gas turbine or the expander are hidden and arranged in the cylinder body of the low-temperature working medium supercritical gas turbine or the expander, and shaft seals at two ends of the rotating shaft are carried out by utilizing the high tightness of the cylinder body of the low-temperature working medium supercritical gas turbine or the expander, so that the low-temperature working medium is prevented from leaking from the shaft seals at two ends of the rotating shaft of the low-temperature working medium supercritical gas turbine or the expander.

5. The use method of a low-temperature working medium supercritical gas turbine or expander comprises the low-temperature working medium supercritical gas turbine or expander according to claims 1-4, and is characterized by comprising a low-temperature liquid storage tank, a low-temperature liquid pump, a low-temperature pipeline of an exhaust steam heat regenerator, a main heat exchanger, the low-temperature working medium supercritical gas turbine or expander and a high-temperature pipeline of the exhaust steam heat regenerator which are sequentially communicated; the outlet of the high-temperature pipeline of the exhaust steam heat regenerator is connected with the low-temperature liquid storage tank to form a closed loop; the low-temperature working medium supercritical gas turbine or the expander is connected with generator equipment;

the main steam pipeline at the input end of the low-temperature working medium supercritical gas turbine or the expander is communicated with the outlet pipeline of the main heat exchanger; the exhaust pipeline at the output end of the low-temperature working medium supercritical gas turbine or the expander is communicated with the inlet of the high-temperature pipeline of the exhaust steam heat regenerator;

the low-temperature liquid power generation working medium stored in the low-temperature liquid storage tank is a low-temperature liquid meson with the boiling point temperature lower than zero centigrade under the standard atmospheric pressure, and comprises but is not limited to carbon dioxide, ammonia, methane, liquid nitrogen, liquid air, liquid hydrogen and liquid helium; the low-temperature liquid storage tank is arranged independently or is arranged together with the dead steam heat regenerator;

the main heat exchanger is main equipment for exchanging heat with a heat source, and comprises any one or combination of a boiler, a waste heat boiler, a heat exchange device, a cooler, a condenser, a flue gas heat exchanger, an air duct heat exchanger, an air heat exchanger, a hot water heat exchanger, an industrial waste gas and waste liquid heat exchanger, an equipment cooling heat exchanger and a geothermal heat exchanger.

6. The use method of the low-temperature working medium supercritical gas turbine or the expander according to claim 5, characterized in that, in order to control and limit the evaporation of the low-temperature liquid power generation working medium in the low-temperature liquid storage tank, the low-temperature liquid storage tank is further provided with a cooling device of the low-temperature liquid power generation working medium, and the cooling device comprises a low-temperature liquid storage tank, a compressor, a heat exchanger and a throttling and pressure reducing device which are sequentially communicated; the outlet of the throttling and pressure reducing device is connected with the low-temperature liquid storage tank to form a closed loop;

the heat exchanger is heat exchange equipment for releasing heat energy, is arranged between the outlet of the compressor and the throttling and pressure reducing device, and is used for replacing and releasing the heat energy generated by the gas compressed by the compressor into a low-temperature power generation working medium output by the low-temperature liquid pump or into a power generation working medium between the outlet of a low-temperature pipeline of the exhaust steam heat regenerator and the main heat exchanger; or into the air and cold water in the environment;

the throttling and pressure reducing device comprises a throttling valve, a stop valve, an expansion valve or an expansion machine device with the throttling and pressure reducing functions; expander devices are preferred.

7. The use method of the low-temperature working medium supercritical turbine or the expander according to the claims 5-6, characterized in that the exhaust steam heat regenerator is further provided with a cooling heat dissipation system and/or a heat pump system; the function of the device is to control the temperature rise of the working medium at the outlet of the high-temperature pipeline of the exhaust steam heat regenerator, thereby reducing the evaporation capacity of the low-temperature liquid working medium in the low-temperature liquid storage tank;

the heat pump system consists of a heat pump compressor, a condenser, a throttling device and an evaporator which are sequentially communicated; the evaporator is arranged at the high-temperature end of the exhaust steam heat regenerator and close to the low-temperature pipeline of the exhaust steam heat regenerator, and the heat energy of the high-temperature end of the exhaust steam heat regenerator and the high-temperature part of the low-temperature pipeline of the exhaust steam heat regenerator is transferred to a low-temperature working medium between the outlet of the low-temperature pipeline of the exhaust steam heat regenerator and the main heat exchanger by a heat pump or is released into cold air or cold water in the environment.

8. The low-temperature working medium supercritical temperature gas turbine or expander and the use method thereof according to claims 5-7, characterized in that the low-temperature working medium stored in the low-temperature liquid storage tank is any one or more of liquid carbon dioxide, ammonia gas, natural gas, methane, ethane, air, oxygen, nitrogen, argon, hydrogen, helium and refrigerant purities;

the low-temperature working medium supercritical gas turbine or expander, the exhaust steam heat regenerator, the main heat exchanger, the low-temperature liquid storage tank, the low-temperature liquid pump, the compressor, the heat exchanger, the throttling and pressure reducing device, and a heat pump compressor, the condenser, the throttling device and the evaporator of the heat pump system; the low-temperature components and the corresponding connecting pipelines of the equipment are low-temperature resistant materials, including but not limited to austenite low-temperature steel and ferrite low-temperature steel;

the low-temperature equipment and the corresponding connecting pipeline are also wrapped by a heat insulating layer; the thermal insulation layer has good thermal insulation performance and comprises vacuum thermal insulation, aerogel, foam materials, fiber materials, glass wool and high-silicon cotton;

the low-temperature equipment is characterized by also comprising a cold box, wherein the cold box is made of a high-temperature heat-insulating material and is used for placing the low-temperature equipment in the cold box; the cold box is also provided with an isolation; the cold box is insulated from the external environment by a highly insulated enclosure, and the insulation is again insulated and isolated from the cryogenic equipment at different temperatures.

9. A process for a low-temperature working medium supercritical gas turbine or an expander and a using method thereof is suitable for the low-temperature working medium supercritical gas turbine or the expander and the using method thereof according to any one of claims 1 to 8; the method comprises the following steps:

for example, the low-temperature liquid working medium stored in the low-temperature liquid storage tank is liquid nitrogen or liquid air with the boiling point temperature lower than-190 ℃ under the standard atmospheric pressure, the low-temperature liquid working medium is pressurized by the low-temperature liquid pump, so that the pressure of the low-temperature liquid power generation working medium reaches more than 0.5Mpa, and the low-temperature liquid power generation working medium flows through a low-temperature pipeline of an exhaust steam heat regenerator and is conveyed to the main heat exchanger, such as a waste heat boiler, for heating; the temperature of the heat source reaches above 0 ℃; the low-temperature liquid power generation working medium absorbs the energy of the heat source, forms high-pressure gas after gasification, and inputs and drives the low-temperature working medium supercritical gas turbine or the expander to rotate at a high speed to do work; outputting mechanical energy or driving a generator to rotate at a high speed to output electric energy;

the temperature of the exhaust steam output by the low-temperature working medium supercritical gas turbine or the expansion machine is required to reach the critical temperature of nitrogen or air to be higher than-146 ℃, and the latent heat of vaporization is 0; condensing high-temperature exhaust steam which is output by the low-temperature working medium supercritical turbine or the expander and has the temperature reaching the critical temperature with liquid nitrogen or liquid air which is output by the low-temperature liquid pump and has the temperature below-190 ℃ to fully exchange heat in the exhaust steam heat regenerator, wherein the high-temperature exhaust steam loses heat energy and is condensed into low-temperature liquid nitrogen or liquid air, and returning the low-temperature liquid nitrogen or liquid air to the low-temperature liquid storage tank for later use;

liquid nitrogen or liquid air stored in the low-temperature liquid storage tank is pressurized by the low-temperature liquid pump and is conveyed into a low-temperature pipeline of the exhaust steam heat regenerator at the temperature of below-190 ℃, the liquid nitrogen or the liquid air is subjected to sufficient heat exchange with the high-temperature pipeline of the exhaust steam heat regenerator to absorb high-temperature exhaust steam heat energy discharged by the low-temperature working medium supercritical gas turbine or the expander, the temperature of the high-temperature exhaust steam heat energy reaches the critical temperature above-146 ℃, the low-temperature liquid power generation working medium output by the low-temperature liquid pump is raised to be close to the critical temperature, the temperature is about-148 ℃, and the heat exchange temperature difference of a metal pipe wall is above 0.5 ℃; and the steam is conveyed to the main heat exchanger from the outlet of the low-temperature pipeline of the exhaust steam heat regenerator, such as a waste heat boiler, for continuous heating; high-pressure gas is formed to be input and drive the low-temperature working medium supercritical gas turbine or the expander to rotate at a high speed to do work, and mechanical energy is output or a generator is driven to output electric energy; the circulation is continuously carried out;

in addition, the temperature of the liquid output by the high-temperature pipeline of the steam exhaust heat regenerator is higher due to the heat exchange temperature difference existing on the metal pipe wall of the steam exhaust heat regenerator, and the temperature of the low-temperature liquid stored in the low-temperature liquid storage tank is continuously increased after the low-temperature liquid is returned to the low-temperature liquid storage tank, so that a part of the low-temperature liquid working medium is evaporated and lost, the low-temperature liquid working medium is less and less, and the low-temperature liquid working medium is required to be continuously supplemented to the low-temperature liquid storage tank;

in order to avoid and reduce the occurrence of the condition, the low-temperature liquid storage tank is also provided with a cooling device of a low-temperature liquid working medium, and the cooling device comprises the low-temperature liquid storage tank, a compressor, a heat exchanger and a throttling and pressure reducing device which are sequentially communicated; the output port of the throttling pressure reduction device is connected with the low-temperature liquid storage tank to form a closed loop;

in the low-temperature liquid storage tank, the evaporated low-temperature working medium gas is introduced into the inlet of the compressor through a pipeline; the temperature is increased after being compressed by the compressor and is conveyed to the heat exchanger; the heat exchanger is heat exchange equipment for releasing heat energy, is arranged at the outlet of the compressor, and releases heat energy generated by compressing gas by the compressor into a low-temperature working medium output by the low-temperature liquid pump or a power generation working medium between the outlet of a low-temperature pipeline of the exhaust steam heat regenerator and the main heat exchanger through heat exchange; or into cold air or water in the environment;

the gas compressed by the compressor loses heat energy and is condensed into low-temperature liquid, and the low-temperature liquid returns to the low-temperature liquid storage tank after the pressure of the low-temperature liquid is reduced by the throttling and pressure reducing device;

the low-temperature liquid stored in the low-temperature liquid storage tank is gasified to absorb a large amount of vaporization heat, the compressor continuously operates to compress a large amount of latent vaporization heat energy carried by the gas, and the generated high-temperature and energy are continuously replaced and released into a low-temperature working medium output by the low-temperature liquid pump through the heat exchanger or released into a power generation working medium between a low-temperature pipeline outlet of the exhaust steam heat regenerator and the main heat exchanger for power generation; or into cold air and cold water in the environment; the temperature is continuously reduced in such a way of continuous circulation.

Technical Field

The invention provides a low-temperature working medium supercritical gas turbine or expander and a using method thereof, belonging to the machinery of a gas turbine and the related technical field. The steam turbine generally refers to a steam turbine, and the power generation working medium of the embodiment of the invention is not filled with water, so that the steam turbine is changed into a gas turbine, including but not limited to a gas turbine, a pneumatic engine, a gas turbine expander, a gas screw expander and other similar gas turbine mechanical equipment; besides the gas turbine, other gas turbine mechanical equipment is generally a small gas turbine, the cost is relatively high, and the practical application is relatively few; the gas turbine can be large-sized and can also be made into small-sized equipment, and is more popular in application; accordingly, embodiments of the present invention will be described with emphasis on conventional gas turbine plants, as well as other gas turbine plants.

Background

In 1882, the first single-stage impulse turbine was designed and manufactured by the swedish engineer laval, and the turbine is a rotating machine which takes steam as power and converts the heat energy of the steam into mechanical work, and is the most widely applied prime mover in modern thermal power plants. The steam turbine has the advantages of large single machine power, high efficiency, long service life and the like, and is widely applied to power stations, ship navigation and large-scale industry.

In order to improve the power and the efficiency of steam turbine equipment, the improvement is continuously carried out for more than 100 years, the air inlet temperature and the air inlet pressure are continuously improved, the power of the steam turbine reaches 1200MW at most from a low-pressure steam turbine to a high-pressure steam turbine and then from a subcritical steam turbine to a supercritical steam turbine, the air inlet temperature reaches 650 ℃, and the pressure reaches 25 MPa; the exhaust temperature of the low pressure cylinder of the straight condensing steam turbine is as low as 30-45 ℃, the exhaust pressure is as low as 10-13kPa, and people can obtain the maximum enthalpy difference and power generation output by continuously increasing the inlet temperature and pressure of the steam turbine and reducing the exhaust temperature and pressure of the steam turbine as far as possible.

The temperature of the exhaust steam output by pure condensing turbine equipment applied to the existing power station is far lower than the boiling point temperature of water (as low as about 30 ℃), so that the aim is to improve the power generation efficiency and output as much as possible, but the direct result is that a great amount of low-grade exhaust steam latent heat cannot be recycled.

For example: the steam inlet heat content of a certain high-pressure steam turbine is about 3433kJ/kg, only about 837kJ/kg of the heat is used for doing work, about 126kJ/kg of heat is contained in condensed water, and about 2240kJ latent heat energy per kilogram of water is taken away by cooling water of a cooling system, so that the heat occupied by the latent heat of dead steam is about 2-3 times of the utilized heat; this is a very significant loss and waste. The latent heat of a large amount of low-grade dead steam generated by the method needs to be cooled by a large amount of water or air, so that the method is not energy-saving and is not economical.

The applicant finds that in order to obtain more power generation output, the temperature and pressure of inlet air are continuously improved, and the temperature and pressure of exhaust steam are reduced as much as possible, the temperature of the exhaust steam of the existing large power station is far lower than the standard boiling point, the exhaust pressure is mostly negative vacuum pressure, the extremely large low-grade latent heat energy formed in the exhaust steam cannot be utilized while obtaining more power generation output, the exhaust steam can be condensed into water only by releasing latent heat, and meanwhile, a series of problems that the lengths of a last-stage blade and a next-stage blade of a steam turbine are increased, the volume of the steam turbine is huge, the tail end of the steam turbine needs to maintain high vacuum, the last-stage blade is easy to be corroded by condensed water and the like are caused, the invention aims to solve the problems.

Water is generally used as a working medium for power generation, most of waste heat power generation is also used as a power generation working medium, and the power generation efficiency is very low; for low-temperature waste heat power generation, an organic working medium ORC Rankine cycle with the boiling point temperature of about 15 ℃ is adopted, and the hot water power generation at the temperature of more than 80 ℃ can be realized; for a low-temperature power generation working medium with the boiling point temperature lower than 0 ℃ under the standard atmospheric pressure, the low-temperature power generation working medium is still in a research stage at home and abroad, and for technicians doing power generation work, the storage of the low-temperature power generation working medium is a difficult point, the boiling point of the extremely low-temperature power generation working medium is far lower than the environmental temperature, a low-temperature meson in equipment is gasified when placed in the environment, and high-pressure gas formed cannot be reused and used for power generation; in addition, the biggest difficulty is that the low-temperature exhaust steam is reduced into liquid after the gas turbine does work, which is the biggest pain point.

Generally, after a traditional steam turbine works, latent heat energy in exhaust steam is released into cold water or cold air in the environment by a cooling tower, but the exhaust steam temperature of a low-temperature power generation working medium is far lower than the environment temperature, and under the normal condition, extremely low-temperature gasification latent heat cannot be released into the cold water or the cold air in the environment, so that reduction cannot be realized, and Rankine cycle cannot be performed any more. If a compressor is used for compressing dead steam or a heat pump is used for transferring latent heat of the dead steam to the ambient temperature and releasing the heat to cold water or cold air in the environment, the cost is too high; the electric energy output by power generation is probably not enough for the electric energy consumed by the compressor and the heat pump system, so that the economic value is not high and the cost is too high.

In addition, the cylinder body of the steam turbine or the expander is still, the rotating speed of the rotor of the steam turbine or the rotor of the expander is very high, shaft sealing needs to be carried out between the rotating shaft rotating at high speed and the stationary cylinder body, otherwise, high-pressure gas input by the steam turbine leaks along the rotating shaft of the steam turbine, and the leakage pressure is very high. The steam turbine needs a shaft seal system, and the traditional steam turbine needs a tooth-shaped steam seal, a Brabender steam seal, a honeycomb steam seal, a brush steam seal, a flexible tooth steam seal and an elastic tooth steam seal; although the high-pressure air inlet end is provided with the shaft seal, the leakage of steam through the shaft seal cannot be avoided; the leakage rate of a large turbine can reach more than 10 tons per hour.

In the self-sealing system, in the starting and stopping processes of the steam turbine, the high-pressure end shaft seal has no steam, new steam subjected to temperature reduction and pressure reduction needs to be introduced and sent into the high-pressure end shaft seal and the low-pressure end shaft seal simultaneously, the system is combined with the self-sealing system after reaching about 80% of load, and the whole shaft seal system is quite complex. The rest small amount of air leakage is discharged to the atmosphere through the signal tube after passing through a plurality of shaft sealing sheets, and the quality of the shaft seal operation can be monitored by observing the steam bleeding condition of the signal tube during operation. Especially, the cost of low-temperature organic working media is as high as about 10 ten thousand per ton, so the leakage cost of the shaft seal is quite expensive.

In addition, the traditional steam turbine adopts steam as a power generation working medium, high-pressure steam drives an impeller and a rotor of the steam turbine to rotate at a high speed through a nozzle, and mechanical energy is output or a generator is driven to rotate at a high speed to output electric energy; the low-temperature power generation mesons such as high-pressure carbon dioxide, high-pressure nitrogen, high-pressure air and the like enter the input end of the gas turbine, the impeller on the rotor of the gas turbine is blown through the nozzle, the impeller and the rotor of the gas turbine can be driven to rotate at high speed, the nozzle and the impeller of the gas turbine do not distinguish whether the input is high-pressure steam, high-pressure carbon dioxide gas, high-pressure air and high-pressure nitrogen, and the impeller of the gas turbine can rotate as long as the high-pressure gas drives the nozzle and the; the same is true of the expander.

The same applies to other gas turbine mechanical devices, such as pneumatic machines, gas turbo expanders, single screw expanders, twin screw expanders, etc., which are generally applied to small-sized power generation devices, and the specific body structure is slightly different from that of a gas turbine, but basically the same and the same, and the rotors of the gas turbine and the expander rotate at high speed regardless of the gas as long as the gas is supplied at high pressure. It should be noted that, the traditional steam turbine and expander adopt common temperature or high temperature resistant material (high temperature resistant steel material), after the low temperature working medium steam turbine or expander does work, the temperature of the output exhaust steam is reduced to below zero (such as high pressure nitrogen, after the steam turbine does work, the temperature of the output exhaust steam is probably lower than minus 100 ℃), some steel materials of the common steam turbine are not low temperature resistant, the conditions of embrittlement, cracking and the like are likely to occur, obviously, the allowable conditions are not allowed, the solution is to adopt low temperature resistant material, including but not limited to austenite low temperature steel and ferrite low temperature steel, select low temperature resistant material and adjust according to the characteristics of the material at low temperature.

The same as the low-temperature working medium supercritical gas turbine, the tail of the original equipment needs to be cut off, and only the part higher than the critical temperature is reserved for the gas turbine equipment such as the low-temperature working medium supercritical expander, the pneumatic machine, the screw expander and the like, so that the equipment volume is smaller and the driving force is strong; for the embodiment of the present invention, the modification method and the using method are the same as those of the gas turbine, and the size of the gas turbine equipment can be changed, so that the embodiment of the present invention mainly describes the gas turbine, and other gas turbine equipment is the same as that of the gas turbine, and thus redundant description is not repeated.

Compared with an organic working medium ORC Rankine cycle with the boiling point temperature of about 15 ℃, the low-temperature working medium supercritical gas turbine provided by the embodiment of the invention adopts lower-temperature power generation working media such as carbon dioxide with lower boiling point, liquid air, liquid nitrogen and the like, and can realize waste heat power generation at lower temperature (which can be as low as 10 ℃); meanwhile, the cost of CO2, liquid air and liquid nitrogen per ton is only about hundreds of RMB, and is much lower than the cost of about 10 ten thousand organic working media. In order to solve the problems, the applicant continuously researches and explores for over twenty years, and finally finds a high-efficiency low-cost low-temperature working medium condensation technology and a new technology for preventing shaft seal leakage of a low-temperature working medium gas turbine or an expander.

Disclosure of Invention

The storage problem of the extremely low-temperature liquid, including but not limited to the storage of liquid carbon dioxide, liquid methane LNG, liquid nitrogen, liquid air, even liquid hydrogen and liquid helium, can be solved well by using a low-temperature liquid storage tank and a vacuum technology, which are already mature technologies.

The invention aims to provide a low-temperature working medium supercritical gas turbine and a using method thereof, and the applicant researches and discovers that the last-stage blade and the next-last-stage blade of the gas turbine are simplified and optimized, the working condition area and the working area of gas turbine equipment are always higher than the critical temperature of a power generation working medium, the temperature of exhaust steam discharged by the gas turbine reaches the critical temperature of the power generation working medium, the latent heat of the exhaust steam is 0, the latent heat is changed into sensible heat, and the condensation of the exhaust steam can be realized by using a low-temperature liquid working medium output by a low-temperature liquid pump. Compare traditional steam turbine equipment, not only retrench the volume, reduce the too big cracked probability that causes the flutter of traditional steam turbine blade moreover, improved the efficiency and the reliability of gas turbine equipment to can also reduce the cost of gas turbine. Through the synergistic effect of the gas turbine equipment, the low-temperature liquid pump, the exhaust steam heat regenerator and the like, a high-efficiency power generation system is realized, and the cost of the gas turbine equipment and the investment cost of a power station can be reduced while the power generation efficiency is improved.

The embodiment of the invention is realized as follows:

in a first aspect, embodiments of the present invention provide a low-temperature working medium supercritical gas turbine or an expander and a use method thereof, where the low-temperature working medium supercritical gas turbine or the expander is divided into an equipment input end, an equipment body, and an equipment output end; the high-pressure gas working medium input from the input end of the device is a low-temperature meson with the boiling point temperature lower than zero degree centigrade under the standard atmospheric pressure;

the temperature of the high-pressure gas input from the input end of the low-temperature working medium supercritical gas turbine or the expander is required to be obviously higher than the critical temperature of the low-temperature working medium; the temperature of the exhaust steam discharged from the output end of the low-temperature working medium supercritical gas turbine or the expander needs to reach the critical temperature of the low-temperature working medium;

furthermore, the output end of the low-temperature working medium supercritical turbine or the expander is connected with a steam exhaust heat regenerator, so that extremely low-temperature liquid output by a low-temperature liquid pump is condensed, and high-temperature steam exhaust which is discharged from the output end of the low-temperature working medium supercritical turbine or the expander and has the temperature reaching the critical temperature of the low-temperature working medium is condensed; the low-temperature working medium supercritical turbine or expander uses the enthalpy difference between the high-temperature gas working medium input by the input end of the low-temperature working medium supercritical turbine or expander and the exhaust steam which is exhausted by the output end of the low-temperature working medium supercritical turbine or expander and has the temperature reaching the critical temperature of the low-temperature working medium to do work;

further, the temperature of the gas input from the input end of the low-temperature working medium supercritical gas turbine or the expander needs to be obviously higher than the critical temperature of the low-temperature working medium; the temperature of the exhaust steam discharged from the output end of the low-temperature working medium supercritical gas turbine or the expander needs to reach or be slightly higher than the critical temperature of the low-temperature working medium; the temperature of the exhaust steam output by the exhaust pipeline of the gas turbine or the expansion machine also comprises a temperature range near a critical temperature point (the critical temperature is extremely accurate data and cannot be actually achieved, so the temperature near the critical temperature point is required to be included); the temperature of the exhaust steam output by the exhaust pipeline of the gas turbine or the expansion machine is lower than the critical temperature, latent heat exists in the exhaust steam, the latent heat cannot be regenerated and can only be released, and therefore the effective thermal efficiency is reduced; when the temperature of the exhaust steam output by the exhaust pipeline of the gas turbine or the expansion machine is higher than the critical temperature, the latent heat is 0, but if the temperature is higher than the critical temperature too much, the effective work is reduced, the equipment cost is increased, and the optimal condition is that the temperature of the exhaust steam is slightly higher than the critical temperature of the low-temperature power generation working medium.

Furthermore, the low-temperature working medium supercritical gas turbine or the expander applies work by utilizing the enthalpy difference between the high-temperature high-pressure gas which is input by the input end and has the temperature obviously higher than the critical temperature of the low-temperature working medium and the exhaust steam which is exhausted by the low-temperature working medium supercritical gas turbine or the expander and has the temperature reaching or slightly higher than the critical temperature of the low-temperature working medium; the working condition area and the operation area of the low-temperature working medium supercritical gas turbine or the expansion machine are always above the critical temperature of the low-temperature working medium.

Furthermore, the low-temperature working medium supercritical gas turbine or the expander is made of low-temperature resistant materials including but not limited to austenite low-temperature steel and ferrite low-temperature steel;

furthermore, the low-temperature working medium supercritical gas turbine or expander belongs to mechanical equipment of a high-pressure gas turbine, and includes but is not limited to a gas turbine, a pneumatic machine, a gas turbine expander and a gas screw expander.

In a second aspect, an embodiment of the present invention further provides a shaft seal system that adopts a highly sealed structure of a cylinder body of a gas turbine or an expander, where the low-temperature working medium supercritical gas turbine or expander is composed of a stationary part and a rotating part; the gas turbine or the expander cylinder body shaft seal system comprises an input end shaft seal system and an output end shaft seal system;

the input end shaft seal system of the low-temperature working medium supercritical gas turbine or the expander comprises an input end cylinder body, an input end bearing, a bearing seat, an input end rotating shaft and a main steam pipeline; the input end bearing and the bearing seat comprise a support bearing and a thrust bearing;

furthermore, a heat insulation shell is arranged outside the input end bearing and the bearing seat; the insulated shell is divided into an upper insulated shell and a lower insulated shell; the lower heat insulation shell is arranged in a lower cylinder at the position of the bearing at the input end and the bearing seat and is tightly combined with the lower cylinder of the gas turbine or the expander; said input end bearing and bearing housing mounted in said lower insulated housing within said turbine or expander lower cylinder;

further, the lower heat insulation shell and the upper heat insulation shell are provided with flanges, and the lower heat insulation shell and the upper heat insulation shell are fastened through the flanges and bolts to form a closed heat insulation space in the inner cavity of the lower heat insulation shell and the inner cavity of the upper heat insulation shell; the input end rotating shaft, the input end bearing, the bearing seat and lubricating oil are sealed in a heat insulation space formed by the heat insulation shell;

furthermore, the heat insulation shell wraps the contact position of the input end rotating shaft, a heat insulation shell seal is further arranged, and the heat insulation shell seal prevents bearing lubricating oil in the heat insulation shell from leaking outwards from the heat insulation shell seal.

Preferably, the upper heat-insulating shell and the lower heat-insulating shell of the heat-insulating shell are fastened through the flange and the bolt, a closed heat-insulating space is formed inside the upper heat-insulating shell, and a lubricating oil injection hole is formed in the top of the upper heat-insulating shell, so that lubricating oil is injected into the heat-insulating space of the bearing and the bearing seat;

the heat insulation shell also comprises a lubricating oil output pipeline, a lubricating oil filter, a lubricating oil cooler and a lubricating oil pump which are connected with the heat insulation shell; constant-temperature lubricating oil output by the lubricating oil pump is delivered to the bearing and the bearing seat in the heat insulation shell through a lubricating oil input pipeline;

optionally, the lubricating oil filter, the lubricating oil cooler, and the lubricating oil pump are disposed outside a cylinder of the low-temperature working medium supercritical gas turbine or the expander, or disposed inside the cylinder of the low-temperature working medium supercritical gas turbine or the expander (disposed inside and required to have a pipeline to exchange heat with the outside); optionally, a lubricating oil temperature probe, a lubricating oil pressure probe, a lubricating oil quantity probe, and a pressure probe inside the cylinder of the gas turbine or the expander are also arranged in the cylinder of the low-temperature working medium supercritical gas turbine or the expander;

preferably, a shaft seal is further arranged between the main steam pipeline of the low-temperature working medium supercritical gas turbine or the expander and the input end heat insulation shell, an input end reserved space or pipeline is further arranged between the heat insulation shell and the shaft seal, the input end reserved space or pipeline is arranged in the lower cylinder, lubricating oil leaked from the sealing position of the heat insulation shell is stored, and the leaked lubricating oil is discharged through the first pipeline valve.

Further, the output end of the low-temperature working medium supercritical gas turbine or the expander comprises a gas turbine or expander exhaust pipeline, an output end cylinder body, an output end bearing, a bearing seat, a coupling and a generator; preferably, the output end bearing, the bearing seat and the generator of the low-temperature working medium supercritical gas turbine or the expander are hidden in an output end cylinder body of the low-temperature working medium supercritical gas turbine or the expander;

preferably, the input end of the low-temperature working medium supercritical gas turbine or expander and the output end of the low-temperature working medium supercritical gas turbine or expander are both arranged in a cylinder body of the low-temperature working medium supercritical gas turbine or expander, and the two ends of the rotating shaft are sealed by using the high-tightness structure of the cylinder body of the low-temperature working medium supercritical gas turbine or expander, so as to prevent the low-temperature working medium from leaking from shaft seals at two ends of the rotating shaft of the low-temperature working medium supercritical gas turbine or expander.

In a third aspect, in order to better explain the practicability, novelty and creativity of the low-temperature working medium supercritical gas turbine or expander equipment and to better understand, the embodiment of the present invention further provides a use method of the low-temperature working medium supercritical gas turbine or expander equipment; the method specifically comprises the following steps:

the system comprises a low-temperature liquid storage tank, a low-temperature liquid pump, a low-temperature pipeline of an exhaust steam heat regenerator, a main heat exchanger, a low-temperature working medium supercritical gas turbine or an expander and a high-temperature pipeline of the exhaust steam heat regenerator which are sequentially communicated; the outlet of the high-temperature pipeline of the exhaust steam heat regenerator is connected with the low-temperature liquid storage tank to form a closed loop;

further, a main steam pipeline at the input end of the low-temperature working medium supercritical gas turbine or the expansion machine is communicated with an outlet pipeline of the main heat exchanger; an exhaust pipeline at the output end of the low-temperature working medium supercritical gas turbine or the expander is communicated with a high-temperature pipeline inlet of the exhaust steam heat regenerator;

further, the low-temperature liquid power generation working medium stored in the low-temperature liquid storage tank is a low-temperature liquid meson with the boiling point temperature lower than zero degrees centigrade under the standard atmospheric pressure, and the low-temperature liquid power generation working medium includes but is not limited to carbon dioxide, ammonia, methane, liquid nitrogen or liquid air; the low-temperature liquid storage tank is arranged independently or is arranged together with the dead steam heat regenerator;

optionally, the main heat exchanger is a main device for exchanging heat with a heat source, and includes any one or more combinations of a boiler, a waste heat boiler, a heat exchange device, a cooler, a condenser, a flue gas heat exchanger, a hot water and waste liquid heat exchanger, and a geothermal heat exchanger.

In a fourth aspect, in order to control and limit evaporation of a low-temperature liquid power generation working medium in the low-temperature liquid storage tank, the low-temperature liquid storage tank is further provided with a cooling device for the low-temperature liquid power generation working medium, and the cooling device comprises the low-temperature liquid storage tank, a compressor, a heat exchanger and a throttling and pressure reducing device which are sequentially communicated; the outlet of the throttling and pressure reducing device is connected with the low-temperature liquid storage tank to form a closed loop;

furthermore, the heat exchanger is a heat exchange device for releasing heat energy, is arranged between the outlet of the compressor and the throttling and pressure reducing device, and is used for replacing and releasing the heat energy generated by the compressed gas of the compressor into a low-temperature power generation working medium output by the low-temperature liquid pump or a power generation working medium (used for acting and generating power) between the outlet of a low-temperature pipeline of the exhaust steam regenerator and the main heat exchanger; or the heat exchange is easier with cold air or cold water in the environment when the standard boiling point of the low-temperature power generation working medium is relatively high, and the heat exchange is more favorable for the energy conservation of the compressor when the heat exchange is directly released into the cold air and the cold water in the environment;

optionally, the throttling and depressurizing device includes a throttle valve, a stop valve, an expansion valve, or an expander device having a throttling and depressurizing function;

in a fifth aspect, in order to control and limit the temperature rise of the working medium at the outlet of the high-temperature pipeline of the exhaust steam heat regenerator, the exhaust steam heat regenerator is further provided with a cooling heat dissipation system and/or a heat pump system; the function of the device is to control the temperature rise of the working medium at the outlet of the high-temperature pipeline of the exhaust steam heat regenerator, thereby reducing the evaporation capacity of the low-temperature liquid power generation working medium in the low-temperature liquid storage tank;

furthermore, the heat pump system consists of a heat pump compressor, a condenser, a throttling device and an evaporator which are sequentially communicated; the evaporator is arranged at the high-temperature end of the exhaust steam heat regenerator and close to the low-temperature pipeline of the exhaust steam heat regenerator, and the heat energy of the high-temperature end of the exhaust steam heat regenerator and the high-temperature part of the low-temperature pipeline of the exhaust steam heat regenerator is transferred to a low-temperature working medium between the outlet of the low-temperature pipeline of the exhaust steam heat regenerator and the main heat exchanger by the heat pump or is released into air or cold water in the environment (when the standard boiling point of a low-temperature power generation working medium is relatively high, the heat exchange with cold air or cold water in the environment is easier, and the energy conservation of the compressor is more facilitated by directly releasing the cold air or cold water.

In a sixth aspect, in an embodiment of the present invention, the low-temperature working medium stored in the low-temperature liquid storage tank is any one or a combination of more of liquid carbon dioxide, ammonia, natural gas, methane, ethane, air, oxygen, nitrogen, argon, hydrogen, helium, and a pure refrigerant;

further, the low-temperature working medium supercritical gas turbine or expander, the exhaust steam heat regenerator, the main heat exchanger, the low-temperature liquid storage tank, the low-temperature liquid pump, the compressor, the heat exchanger, the throttling and pressure reducing device, and a heat pump compressor, a condenser, a throttling device and an evaporator of a heat pump system; the low-temperature components and the corresponding connecting pipelines of all the devices are made of low-temperature resistant materials, including but not limited to austenitic low-temperature steel and ferritic low-temperature steel;

furthermore, the low-temperature equipment and the corresponding connecting pipeline are wrapped by a heat insulating layer; the thermal insulation layer has good thermal insulation performance and comprises vacuum thermal insulation, aerogel, foam materials, fiber materials, glass wool and high-silicon cotton;

further, the device also comprises a cold box, wherein the cold box is made of a high-heat-insulation material, and the low-temperature equipment is placed in the cold box for heat insulation; the cold box is also provided with an isolation; the cold box is insulated from the external environment by a highly insulated enclosure, and the insulation is again insulated and isolated from the cryogenic equipment at different temperatures. The storage problem of the cryogenic liquid can be well solved by using a cryogenic liquid storage tank and a vacuum technology, and the storage problem is mature.

In a seventh aspect, in the small gas turbine and other devices such as the low-temperature working medium supercritical expander, the pneumatic machine, and the screw expander provided in the embodiment of the present invention, low-temperature resistant materials (including but not limited to austenite low-temperature steel and ferrite low-temperature steel) are also required to be adopted, and the tail of the original device is cut off, and only the part above the critical temperature is reserved; the temperature of the high-pressure gas input from the input end of the low-temperature working medium supercritical gas turbine equipment is required to be obviously higher than the critical temperature of the low-temperature working medium; the temperature of the dead steam discharged from the output end of the low-temperature working medium supercritical gas turbine equipment is required to reach or be slightly higher than the critical temperature of the low-temperature working medium;

furthermore, the output end of the low-temperature working medium supercritical gas turbine equipment is connected with a steam exhaust heat regenerator, so that extremely low-temperature liquid output by a low-temperature liquid pump condenses high-temperature steam exhaust which is discharged from the output end of the low-temperature working medium supercritical gas turbine equipment and has the temperature reaching or slightly higher than the critical temperature of the low-temperature working medium; the working condition area and the operation area of the low-temperature working medium supercritical gas turbine equipment are always above the critical temperature of the low-temperature working medium.

The dead steam discharged from the output end of the gas turbine equipment needs to reach the critical temperature of the low-temperature power generation working medium, and for the embodiment of the invention, the modification method and the use method are the same as those of the gas turbine; the equipment volume is smaller, and the driving is strong; the gas turbine can be large or small, the universality is higher, the technology is mature, the cost is lower, and the quantity of other gas turbine equipment on the market is less, so that the gas turbine is mainly described in the embodiment of the invention, other equipment is the same, and redundant description is not repeated.

Further, the low-temperature working medium supercritical expander, the pneumatic machine and the low-temperature working medium supercritical gas turbine belong to a gas turbine machine, and only the specific structure of the equipment body is slightly different; in the embodiment of the invention, the input end, the output end, the pipeline connecting method, the using method and the parameters of the low-temperature working medium supercritical expansion machine are completely the same as those of the low-temperature working medium supercritical turbine, so that the low-temperature working medium supercritical expansion machine also belongs to the scope provided by the embodiment of the invention;

in an eighth aspect, embodiments of the present invention provide a process for a low-temperature working medium supercritical gas turbine or expander and a method of using the same, which are useful, novel, and inventive, and facilitate better understanding; the method specifically comprises the following steps:

for example: the low-temperature liquid working medium stored in the low-temperature liquid storage tank is liquid nitrogen (or liquid air) with the boiling point temperature lower than-190 ℃ under the standard atmospheric pressure, the pressure of the low-temperature liquid power generation working medium is increased to more than 0.5Mpa by the pressurization of the low-temperature liquid pump, the low-temperature liquid power generation working medium flows through a low-temperature pipeline of an exhaust steam heat regenerator and is conveyed to the main heat exchanger (such as a waste heat boiler) for heating, and the temperature of a heat source is more than 0 ℃; the low-temperature liquid power generation working medium absorbs the energy of the heat source, forms high-pressure gas after gasification, and inputs and drives the low-temperature working medium supercritical gas turbine or the expander to rotate at a high speed to do work; outputting mechanical energy or driving a generator to rotate at a high speed to output electric energy;

furthermore, the temperature of the exhaust steam output by the low-temperature working medium supercritical gas turbine or the expander needs to reach the critical temperature (-146 ℃ or above) of the low-temperature working medium (air or nitrogen), and the latent heat of vaporization is 0; condensing high-temperature exhaust steam output by the low-temperature working medium supercritical turbine or the expander and having the temperature reaching the critical temperature by using extremely low-temperature liquid (liquid nitrogen or liquid air with the temperature being lower than-190 ℃) output by a low-temperature liquid pump, wherein the high-temperature exhaust steam and the low-temperature liquid (liquid nitrogen or liquid air with the temperature being lower than-190 ℃) are subjected to sufficient heat exchange in the exhaust steam heat regenerator, the high-temperature exhaust steam loses heat energy and is condensed into low-temperature liquid nitrogen or liquid air, and the low-temperature liquid nitrogen or liquid air returns to the low-temperature liquid storage tank for later use;

further, the low-temperature liquid (liquid nitrogen or liquid air, the temperature is below-190 ℃) stored in the low-temperature liquid storage tank is pressurized by the low-temperature liquid pump, is conveyed into a low-temperature pipeline of the exhaust steam heat regenerator, and performs sufficient heat exchange with the high-temperature pipeline of the exhaust steam heat regenerator, so as to absorb the high-temperature exhaust steam heat energy which is exhausted by the low-temperature working medium supercritical turbine or expander and reaches the critical temperature (above (-146 ℃), the temperature of the low-temperature liquid power generation working medium output by the low-temperature liquid pump is raised to be close to the critical temperature (about-148 ℃, and has a metal pipe wall heat exchange temperature difference above 0.5 ℃), and is conveyed from the outlet of the low-temperature pipeline of the exhaust steam heat regenerator to the main heat exchanger (such as a waste heat boiler) for continuous heating; high-pressure gas is formed to be input and drive the low-temperature working medium supercritical gas turbine or the expander to rotate at a high speed to do work, and mechanical energy is output or a generator is driven to output electric energy; and the process is continuously circulated.

Furthermore, the temperature of the low-temperature working medium (liquid air or liquid nitrogen) stored in the low-temperature liquid storage tank is higher due to the heat exchange temperature difference existing on the metal pipe wall of the exhaust steam heat regenerator, and the temperature of the liquid output by the high-temperature pipeline of the exhaust steam heat regenerator is continuously increased after the low-temperature working medium returns to the low-temperature liquid storage tank, so that a part of the low-temperature working medium is evaporated and lost, the low-temperature liquid working medium is less and less, and the low-temperature liquid working medium needs to be continuously supplemented to the low-temperature liquid storage tank;

further, in order to avoid and reduce the occurrence of the condition, the low-temperature liquid storage tank is also provided with a cooling device of a low-temperature liquid working medium, and the cooling device comprises the low-temperature liquid storage tank, a compressor, a heat exchanger and a throttling and pressure reducing device which are sequentially communicated; the output port of the throttling pressure reduction device is connected with the low-temperature liquid storage tank to form a closed loop;

further, in the low-temperature liquid storage tank, the evaporated low-temperature working medium gas is introduced into an inlet of the compressor through a pipeline; the temperature is increased after being compressed by the compressor and is conveyed to the heat exchanger; the heat exchanger is heat exchange equipment for releasing heat energy, is arranged at the outlet of the compressor, and releases heat energy generated by compressing gas by the compressor into a low-temperature working medium output by the low-temperature liquid pump or a power generation working medium between the outlet of a low-temperature pipeline of the exhaust steam heat regenerator and the main heat exchanger through heat exchange; or into cold air or water in the environment; further, the gas compressed by the compressor loses heat energy and is condensed into low-temperature liquid, and the low-temperature liquid returns to the low-temperature liquid storage tank after the pressure of the low-temperature liquid is reduced by the throttling and pressure reducing device;

further, the low-temperature liquid stored in the low-temperature liquid storage tank is gasified to absorb a large amount of vaporization heat, the compressor continuously operates to compress a large amount of latent vaporization heat energy carried by the gas, and the generated high-temperature and energy are continuously replaced and released into the low-temperature working medium output by the low-temperature liquid pump through the heat exchanger or released into a power generation working medium between an outlet of a low-temperature pipeline of the exhaust steam heat regenerator and the main heat exchanger for power generation; or into cold air and cold water in the environment; the temperature is continuously reduced in such a continuous circulation way.

The embodiment of the invention has the beneficial effects that:

the embodiment of the invention provides a low-temperature working medium supercritical gas turbine or an expander and a using method thereof, wherein the temperature of a working medium at the input end of a device of the low-temperature working medium supercritical gas turbine or the expander is obviously higher than the critical temperature of a power generation working medium; the working condition area of the low-temperature working medium supercritical gas turbine or expander equipment is not lower than the critical temperature of the power generation working medium all the time; the temperature of the exhaust steam discharged from the output end of the low-temperature working medium supercritical turbine or expander equipment needs to reach or slightly exceed the critical temperature (including the vicinity of a critical temperature point) of the power generation working medium, so that the latent heat of the exhaust steam output by the low-temperature working medium supercritical turbine or expander is 0, the latent heat is changed into sensible heat, and the high-temperature exhaust steam discharged by the low-temperature working medium supercritical turbine or expander is condensed by extremely low-temperature liquid output by a low-temperature liquid pump, so that the self-condensation of the system is realized;

compared with the traditional gas turbine or expander, the low-temperature working medium supercritical gas turbine or expander not only can be suitable for low-temperature working medium, but also greatly reduces the volume of equipment; the temperature of exhaust steam of the traditional gas turbine or expander needs to be reduced to be lower than the standard boiling point of a working medium by acting, so that the last-stage blade and the next-stage blade of the gas turbine are very long (the same expander is adopted), and the gas turbine or the expander is large in size, relatively high in material and manufacturing cost and large in size; the low-temperature working medium supercritical gas turbine or the expander is 'removed' from the position below the critical temperature point of the power generation working medium, the removed part is low in working medium density, the tail part and the position below the critical temperature of the gas turbine or the expander are removed, dead steam latent heat is not formed, and the volume, the weight and the manufacturing cost of the gas turbine or the expander are reduced.

In addition, the cylinder body of the gas turbine or the expander is stationary, the rotating speed of the rotor of the gas turbine or the rotor of the expander is very high, shaft sealing needs to be carried out between the rotating shaft rotating at high speed and the stationary cylinder body, otherwise high-pressure gas input by the gas turbine or the expander leaks along the rotating shaft of the gas turbine, and the leakage pressure is very high. The shaft seal system of the traditional steam turbine or expander comprises a tooth-shaped steam seal, a Brabender steam seal, a honeycomb steam seal, a brush steam seal, a flexible tooth steam seal and an elastic tooth steam seal; although the shaft seal is arranged, the steam can not be prevented from leaking out through the shaft seal; the leakage rate of the traditional large-scale steam turbine can reach more than 10 tons per hour.

Through years of research, the applicant finds that the bearing systems at the input end and the output end of the low-temperature working medium supercritical gas turbine or the expansion machine are hidden in the cylinder body of the low-temperature working medium supercritical gas turbine or the expansion machine, and the problem of leakage at two ends of the rotating shaft of the low-temperature working medium supercritical gas turbine or the expansion machine can be solved by using the high-tightness structure (up to 100 percent sealing) of the cylinder body of the gas turbine or the expansion machine; the rotating shaft sealing system provided by the embodiment of the invention is also suitable for other rotating mechanical equipment such as expanders, pneumatic machines, screw machines and the like, and the high-pressure gas input end and the high-pressure gas output end can also adopt the same sealing technology and method as those of the low-temperature working medium supercritical gas turbine or expander equipment, so that the near-zero leakage of the rotating shaft sealing system is realized and achieved, and the rotating shaft sealing system also belongs to the field.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts; this is easily done. For better illustration, the embodiment of the present invention only takes the low-temperature working medium supercritical gas turbine as an example, and other pneumatic machines and expansion machines are the same and different, and thus, the drawings and the detailed description are not repeated.

FIG. 1 is a schematic view of a low temperature nitrogen conventional turbine with bearings outside the cylinder, the turbine having exhaust steam temperature as low as the normal boiling point of nitrogen (-196 deg.C) for reference and comparison;

FIG. 2 is a schematic structural diagram of a turbine with a tail section of a conventional turbine "cut off" and an output end with exhaust steam temperature reaching a critical temperature of nitrogen (-146 deg.C);

fig. 3 is a schematic structural diagram of a gas turbine apparatus according to an embodiment of the present invention, in which an input end bearing, an output end bearing, and a generator are disposed in a cylinder of the gas turbine apparatus;

fig. 4 is a schematic structural diagram of a low-temperature working medium supercritical gas turbine in which an input end bearing, an output end bearing and a generator of a gas turbine device are all placed in a gas turbine cylinder body, and the exhaust steam temperature of the output end reaches the critical temperature of nitrogen (-146 ℃);

FIG. 5 is a schematic diagram of a method for using a low temperature working medium supercritical turbine (and expander) plant and the plant connections provided by an embodiment of the present invention;

FIG. 6 is a schematic diagram of a method for using a gas turbine (and an expander) with a cooling device for a cryogenic liquid storage tank according to an embodiment of the present invention, and the connection of the apparatus;

FIG. 7 is a schematic diagram of a method for using a gas turbine (and expander) with a cryogenic liquid storage tank cooling device and a waste steam regenerator heat pump system according to an embodiment of the present invention;

part of the low-temperature working medium supercritical gas turbine is shown in the figure:

(other related high-pressure gas turbine equipment and the gas turbine are only slightly different in equipment body and the same in modification of the characteristics of the embodiment of the invention, so that repeated description is not repeated) 20-a gas turbine main steam pipeline; 21-gas turbine exhaust duct; 101-a gas turbine shaft; 102-an insulating shell; 103-input end bearing and bearing seat; 104-a shaft seal; 105-a gas turbine equipment cylinder; 106-rotor impeller; 107-gas turbine diaphragm; 108-output shaft seal; 9-an output end heat insulation shell; 10-output end bearing and bearing seat; 11-a coupling; 12-a generator; 13-a third pipeline valve; 14-a third conduit outlet; 15-a second conduit outlet; 16-a second pipeline valve; 17-reserving space or pipeline at the output end; 18-reserving a heat insulation area at the output end; 19-reserving a heat insulation area at an input end; 22-insulating shell sealing; 23-reserving space or pipeline at the input end; 24-a first pipeline valve; 25-a first conduit outlet; 26-a lubricant output conduit; 27-a lubricating oil reservoir; 28-lube oil filter; 29-a lube oil cooler; 30-a lubricating oil pump; 31-a lubricating oil high pressure input pipeline; 32-output end heat insulation shell sealing;

usage of the gas turbine plant is illustrated in part by the following figures: 1-a cryogenic liquid storage tank; 2-a cryogenic liquid pump; 300-a dead steam regenerator; 301-low temperature pipeline of exhaust steam heat regenerator; 302-high temperature pipeline of exhaust steam regenerator; 4-a primary heat exchanger; 5-low temperature working medium supercritical gas turbine; 6-a generator; 7-a compressor; 303-a heat exchanger; 8-a throttling pressure reduction device; 500-heat pump compressor; 501-high temperature pipeline of condenser; 503-a throttling device; 504-evaporator

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not imply that the components are required to be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the embodiments of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

FIG. 1 is a schematic view of a low temperature nitrogen conventional turbine with bearings outside the cylinder, the turbine having exhaust steam temperature as low as the normal boiling point of nitrogen (-196 deg.C) for reference and comparison;

as shown in fig. 1, in a conventional gas turbine plant, bearings at both ends of a gas turbine rotating shaft 101, including an input end bearing and bearing housing 103, an output end bearing and bearing housing 10, a coupling 11 and a generator 12, are generally disposed outside a cylinder 105 of the gas turbine plant; shaft end sealing at two ends of a rotating shaft 101 of the gas turbine is realized by an input end shaft seal 104 and an output end shaft seal 108, and the traditional shaft seals comprise a tooth-shaped steam seal, a Braiden steam seal, a honeycomb steam seal, a brush steam seal, a flexible tooth steam seal and an elastic tooth steam seal; the leakage problem of the gas turbine still exists although the gas turbine is provided with a shaft seal, and the leakage amount of the traditional large-scale gas turbine can reach more than 10 tons per hour. The leakage is also large, especially the leakage of the shaft end steam seal is very painful due to the expensive low-temperature liquid working medium.

As shown in figure 1, the temperature of input gas of a low-temperature nitrogen working medium gas turbine of a traditional Rankine cycle is 50 ℃, steam does work in gas turbine equipment, the temperature is continuously reduced, when the temperature is reduced to a-146 ℃ critical temperature position marked in figure 1 (latent heat is 0, and latent heat above the critical temperature is 0), when the gas temperature is lower than the critical temperature of the nitrogen, latent heat begins to be formed in exhaust steam, and the latent heat stored in the nitrogen is increased along with the reduction of the temperature of the exhaust steam, the temperature of a gas turbine exhaust pipeline 21 is reduced to the-196 ℃ boiling point temperature of the nitrogen, the latent heat is also increased, and because the temperature of the exhaust steam is very low, the huge low-grade latent heat energy is difficult to release, the Rankine cycle is difficult to perform, and the main reason that low-temperature working medium power generation is difficult to realize is also.

FIG. 2 is a schematic structural diagram of a turbine with a tail section of a conventional turbine "cut off" and an output end with exhaust steam temperature reaching a critical temperature of nitrogen (-146 deg.C);

FIG. 2 shows the turbine of FIG. 1 with the same input end, the front half and the output end of the turbine body as the conventional turbine, but with the last-stage blades and the next-stage blades completely cut off, and the exhaust steam temperature output by the exhaust pipeline reaches the critical temperature of (-146 ℃ or higher), so the volume of the turbine equipment is greatly reduced;

in FIG. 2, the main steam pipeline 20 of the turbine still inputs high-pressure nitrogen (50 ℃), and the energy of the high-temperature and high-pressure nitrogen is converted into mechanical energy rotating at high speed through the turbine body to drive the generator 6 to output electric energy; after the temperature of the low-temperature working medium supercritical turbine is reduced to a critical temperature point marked as (-146 ℃) in figure 2, the low-temperature working medium supercritical turbine directly discharges high-temperature exhaust steam with the critical temperature of (-146 ℃) from an exhaust pipeline, latent heat is 0, the high-temperature exhaust steam is conveyed to a high-temperature pipeline of an exhaust steam heat regenerator 300 shown in figure 5 and exchanges heat with extremely low-temperature liquid nitrogen output by a low-temperature liquid pump 2, and the extremely low-temperature liquid nitrogen output by the low-temperature liquid pump is used for condensing the high-temperature exhaust steam.

Fig. 3 is a schematic structural diagram of a gas turbine apparatus according to an embodiment of the present invention, in which an input end bearing, an output end bearing, and a generator are disposed in a cylinder of the gas turbine apparatus;

in order to solve the problem of leakage at two ends of a rotating shaft of gas turbine equipment, the applicant discovers through research for over 20 years that the problem of leakage at two ends of the rotating shaft of the gas turbine equipment can be solved by hiding the input end and the output end of a gas turbine into a cylinder body of the gas turbine and using a highly-closed structure (up to 100 percent sealing) of the cylinder body of the gas turbine;

the rotating shaft sealing system provided by the embodiment of the invention can also adopt the same sealing technology and method as those of the gas turbine equipment for other rotating mechanical equipment, namely a high-pressure gas input end and a high-pressure gas output end, so that the near-zero leakage of the rotating shaft sealing system is realized and achieved, and the rotating shaft sealing system also belongs to the category.

As shown in fig. 3, the high pressure inlet 20 and the top line a to the left are intended to mean the input of the turbine installation; between the main steam pipeline 20 and the exhaust steam pipeline 21 is the turbine equipment body, as shown in the middle part B between the line A and the line C; the steam exhaust pipeline 21 and the top line C to the right are the output end of the gas turbine equipment;

in the turbine shown in FIG. 3, the insulated casing 102 comprises an upper insulated casing and a lower insulated casing (the lower insulated casing of the turbine shown in FIG. 3); the lower heat insulation shell is arranged at the position of an end bearing of the rotating shaft 101 of the gas turbine, is arranged in the lower cylinder body and is tightly combined with the lower cylinder body of the gas turbine cylinder body 105; the input end bearing and the bearing seat 103 are arranged in the lower heat insulation shell of the heat insulation shell 102, support the weight of the turbine rotating shaft 101, and limit the axial movement of the turbine rotating shaft 101 by a thrust bearing; the position where the heat insulation shell 102 contacts with the turbine rotating shaft 101 is provided with a heat insulation shell seal 22, and the heat insulation shell seal 22 prevents the bearing lubricating oil in the heat insulation shell 102 from leaking outwards from the heat insulation shell seal 22;

optionally, a shaft seal 104 is further disposed between the high-pressure gas inlet 20 and the input end, so as to prevent the high-temperature and high-pressure gas input from the main steam pipeline 20 from entering the heat insulation housing 102; optionally, an input end reserved thermal insulation area 19 is further disposed between the shaft seal 104 and the thermal insulation housing 102, so as to isolate and reduce the high temperature input by the high-pressure main steam pipeline 20, which affects the thermal insulation housing 102 and the input end bearing and bearing seat 103 therein, because the upper and lower thermal insulation housings of the thermal insulation housing 102 are of a closed structure, and the pressure is the same as the input pressure of the high-pressure air inlet 20, the high-pressure air input by the high-pressure air inlet 20 is difficult to enter the thermal insulation housing 102. Also shaft seal 104 and insulated housing seal 22; two heat insulation shell seals 22 can be arranged, so that high-temperature and high-pressure gas input by the main steam pipeline 20 can hardly enter the heat insulation shell seals, and meanwhile, lubricating oil in the heat insulation shell 102 can be prevented from being leaked out difficultly;

optionally, an input end reserved space or pipeline 23 is further provided between the insulation shell seal 22 and the input end reserved insulation area 19, the input end reserved space or pipeline 23 is isolated, and meanwhile, lubricating oil leaked from the insulation shell seal 22 is stored and discharged through a first pipeline valve 24 and a first pipeline outlet 25;

preferably, as shown in fig. 3, a lubricant oil output pipeline 26, a lubricant oil storage 27, a lubricant oil filter 28, a lubricant oil cooler 29, a lubricant oil pump 30 and a lubricant oil high-pressure input pipeline 31 connected with the heat insulation shell are further arranged outside the heat insulation shell 102 and the lower cylinder 105, and sufficient, clean and low-temperature (temperature-controllable) lubricant oil is delivered into the heat insulation shell 102 through the lubricant oil high-pressure input pipeline 31 and is provided for the input-end bearing and bearing seat 103, so that sufficient, clean and low-temperature lubricant oil is ensured; ensuring safe and stable operation of the input end bearing and bearing housing 103.

The lubricating oil storage 27, the lubricating oil filter 28 and the lubricating oil cooler 29 can be combined in an unlimited number, and lubricating oil is conveyed to the bearing and the bearing seat 103 in the heat insulation shell 102 through a lubricating oil pump 30 and a lubricating oil high-pressure input pipeline 31;

the lube oil filter 28, lube oil cooler 29 and lube oil pump 30 may be provided outside the cylinder 105 of the gas turbine apparatus (or inside the cylinder of the gas turbine);

when the lubricating oil cooler 29 is arranged inside the cylinder body, a pipeline is arranged in the lubricating oil cooler 29 and is communicated with the outside, the heat of the lubricating oil in the cylinder body is transferred to the outside of the cylinder body through the flow of the medium in the pipeline, and the lubricating oil returns to the inside of the cylinder body after being cooled by the heat exchanger.

Optionally, the input end and the output end of the gas turbine are both placed inside a cylinder body of the gas turbine equipment, and the shaft end of the rotating shaft 101 of the gas turbine is sealed by using a highly airtight structure (close to 100% sealing) of the cylinder body of the gas turbine, so that gas is prevented from leaking from shaft seals at two ends of the rotating shaft of the gas turbine. The output end of the gas turbine comprises the following embodiments: an output end bearing and bearing housing 10 disposed at a location remote from the output end shaft seal 108; optionally, an insulating region 18 is reserved at the output end; the bearing and the bearing seat 10 of the output end are arranged in the heat insulation shell 9 of the output end, the heat insulation shell 9 of the output end has the same structure as the input end and is divided into a lower heat insulation shell and an upper heat insulation shell, the lower heat insulation shell is tightly combined with the lower cylinder of the cylinder 105 of the gas turbine equipment, the upper heat insulation shell and the lower heat insulation shell of the output end are fastened through flanges and bolts, and a closed heat insulation space is formed inside the upper heat insulation shell and the lower heat insulation shell; optionally, a lubricating oil injection hole is formed in the top of the upper heat insulation shell, so that lubricating oil is injected into the heat insulation space between the bearing and the bearing seat;

preferably, the outlet thermally insulated housing 9 further comprises a lube oil outlet line 26 connected to the outlet thermally insulated housing 9, a lube oil reservoir 27, a lube oil filter 28, a lube oil cooler 29, and a lube oil pump 30; the low-temperature high-pressure lubricating oil output by the lubricating oil pump 30 is delivered into the output end heat insulation shell 9 through the lubricating oil input pipeline 31, so that sufficient, clean and low-temperature lubricating oil is provided for the output end bearing and the bearing seat 10, the output end bearing and the bearing seat 10 can be ensured to run safely and stably, the specific implementation is the same as that of the input end, and redundant description is omitted;

it should be noted that the output-side heat-insulating housing 9 and the rotating shaft 101 have two contact positions, and therefore, the output-side heat-insulating housing seals 32 have two contact positions, which are respectively arranged in contact with the rotating shaft 101 as shown in fig. 3; the output end heat insulation shell seal 32 prevents the bearing lubricating oil in the output end heat insulation shell 9 from leaking outwards from the output end heat insulation shell seal 32; the shaft end of the output end gas turbine rotating shaft 101 is also provided with a shaft coupling 11 for coupling with the rotating shaft of the generator 12, so that the generator 12 is convenient to overhaul and replace;

optionally, the output end reserved space or pipeline 17 is respectively arranged in the lower cylinder 105 at two sides of the output end heat insulation shell 9, stores the leaked lubricating oil from the output end heat insulation shell seal 32, and discharges the leaked lubricating oil through the second pipeline valve 16 and the third pipeline valve 13; the output side generator 12 generates electric power, which is led out through a terminal provided in the cylinder block 105 of the gas turbine equipment, and does not affect the sealing performance of the gas turbine.

The high-pressure main steam pipeline 20 of the gas turbine and the exhaust pipeline 21 of the gas turbine are fastened by adopting flanges and screws with excellent sealing performance, and leakage cannot occur, so that the gas turbine equipment provided by the embodiment of the invention has multiple sealing measures. It should be noted that the technology is relatively independent, and the technical solution provided by the embodiment of the present invention can also be applied to other products of rotating equipment, and therefore, the technical solution also belongs to the technical features provided by the embodiment of the present invention. The applicant also needs to gain approval when referring to these technical features.

Fig. 4 is a schematic structural diagram of a low-temperature working medium supercritical gas turbine in which an input end bearing, an output end bearing and a generator of a gas turbine device are all placed in a gas turbine cylinder body, and the exhaust steam temperature of the output end reaches the critical temperature of nitrogen (-146 ℃);

in fig. 4, the sealing performance (up to nearly 100%) of the system can reach nearly zero leakage as in fig. 3 by using the cylinder body of the gas turbine equipment for shaft end sealing; the low-temperature power generation working medium is close to zero leakage, so that the loss of the low-temperature power generation working medium with high cost can be reduced, and the overall power generation efficiency of the power generation system and the power system can be improved;

in addition, by comparing fig. 1 and fig. 4, in fig. 1, the temperature of the nitrogen gas which is input by the main steam pipeline 20 of the gas turbine is reduced after the nitrogen gas works; when the temperature is reduced to the critical temperature of the nitrogen (-146 ℃), the traditional gas turbine equipment still continues to work, the temperature is reduced to be below the standard boiling point of the nitrogen-196 ℃, as shown in the figure 1, the temperature is discharged from the gas turbine exhaust pipeline 21 after the temperature is reduced to-196 ℃, a large amount of latent heat is stored in exhaust steam, and the extremely-low-temperature latent heat cannot be released.

The low-temperature working medium supercritical gas turbine provided by the embodiment of the invention is greatly different from the traditional gas turbine equipment, as shown in fig. 4, when the temperature is reduced to the critical temperature (about-146 ℃ and latent heat of 0) of the power generation working medium nitrogen, the low-temperature working medium supercritical gas turbine provided by the embodiment of the invention does not continue to work, but is directly discharged through the exhaust pipeline 21 of the low-temperature working medium supercritical gas turbine, at the moment, the exhaust steam has no latent heat, the latent heat is 0, and the latent heat changes into sensible heat. Condensing high-temperature exhaust steam at critical temperature by using extremely low-temperature liquid nitrogen output by a low-temperature liquid pump; the low-temperature working medium supercritical gas turbine has the advantages of small volume, strong power and low cost;

FIG. 5 is a schematic diagram of a method for using a low-temperature working medium supercritical turbine (or expander) plant and the connection of the plant according to an embodiment of the present invention;

in fig. 5, the power generation working medium stored in the low-temperature liquid storage tank 1 is liquid nitrogen (about-196 ℃), the pressure is increased by the low-temperature liquid pump 2, the low-temperature liquid is conveyed to the main heat exchanger 4 (such as a condenser) through the low-temperature pipeline 301 of the exhaust steam heat regenerator 300 and heated to about 50 ℃, the low-temperature power generation working medium absorbs heat to form high-pressure gas, and the high-pressure gas is input to and drives the low-temperature working medium supercritical gas turbine (or expander) 5 to rotate at a high speed to do work; outputting mechanical energy or driving the generator 6 to rotate at high speed to output electric energy; the temperature of the dead steam discharged by the low-temperature working medium supercritical gas turbine (or expander) 5 reaches the critical temperature of nitrogen (about-146 ℃ or higher, the latent heat is 0, and latent heat becomes sensible heat), the liquid nitrogen with the temperature of below-196 ℃ output by a low-temperature liquid pump 2 is used for condensing the high-temperature dead steam with the temperature of above-146 ℃ into liquid nitrogen (about-190 ℃ or higher, and the metal wall has a heat exchange temperature difference of above 0.5 ℃) and returning the liquid nitrogen to the low-temperature liquid storage tank 1 for later use;

liquid nitrogen (below about-196 ℃) in a low-temperature liquid storage tank 1 is pressurized into the low-temperature pipeline 301 of the exhaust steam heat regenerator through a low-temperature liquid pump 2, and absorbs high-temperature exhaust steam heat energy (about-146 ℃) at the critical temperature output by the low-temperature working medium supercritical gas turbine (or expander) 5 into the high-temperature pipeline 302 of the exhaust steam heat regenerator, the liquid nitrogen temperature is raised to be close to the critical temperature (about-148 ℃ and above 0.5 ℃ of metal wall heat exchange temperature difference), the liquid nitrogen is conveyed into the main heat exchanger 4 from the outlet of the low-temperature pipeline 301 of the exhaust steam heat regenerator and is reheated to be above 50 ℃ to become high-temperature high-pressure nitrogen, the low-temperature working medium supercritical gas turbine (or expander) 5 is driven to rotate at a high speed and do work, mechanical energy is output or the generator 6 is driven to generate electricity and output, and the electricity is continuously; the working condition area of the low-temperature working medium supercritical gas turbine (or expander) 5 is always above the nitrogen critical temperature (-146 ℃).

FIG. 6 is a schematic diagram of a method for using a gas turbine (or an expander) with a cooling device for a cryogenic liquid storage tank according to an embodiment of the present invention, and an apparatus connection;

as shown in fig. 6, in order to control and limit evaporation of a low-temperature liquid power generation working medium in a low-temperature liquid storage tank 1 in the embodiment of the present invention, the low-temperature liquid storage tank 1 is further provided with a cooling device for the low-temperature liquid power generation working medium, and the cooling device comprises the low-temperature liquid storage tank 1, a compressor 7, a heat exchanger 303, and a throttling and pressure reducing device 8 which are sequentially communicated; the outlet of the throttling and pressure reducing device is connected with the low-temperature liquid storage tank 1 to form a closed loop;

further, the heat exchanger 303 is a heat exchange device for releasing heat energy, is arranged between the outlet of the compressor 7 and the throttling and pressure reducing device 8, and displaces and releases the heat energy generated by the gas compressed by the compressor 7 into the low-temperature power generation working medium output by the low-temperature liquid pump 2 or into the power generation working medium between the outlet of the low-temperature pipeline 301 of the exhaust steam heat regenerator and the main heat exchanger 4; or into cold air and cold water in the environment;

further, the heat energy generated by the compressor 7 compressing the gas is displaced and released into the low-temperature power generation working medium output by the low-temperature liquid pump 2; the low-temperature pipeline of the heat exchanger at the output end of the compressor 7 is arranged between the outlet of the low-temperature pipeline 301 of the steam exhaust heat regenerator and the main heat exchanger 4, or is arranged at the high-temperature end of the steam exhaust heat regenerator 300, or is the high-temperature part of the low-temperature pipeline 301 of the steam exhaust heat regenerator 300;

when the critical temperature of the low-temperature power generation working medium is obviously higher than the ambient temperature, preferably, the low-temperature pipeline of the heat exchanger 303 is arranged in cold water or cold air in the environment, and the heat energy generated by the compressed gas of the compressor 7 is directly released into the cold air and the cold water in the environment, so that the energy conservation of the compressor 7 and the quick cooling of the low-temperature working medium are facilitated;

the throttling and pressure reducing device 8 comprises a throttling valve, a stop valve, an expansion valve or an expansion machine device with the throttling and pressure reducing functions; preferably an expander device;

FIG. 7 is a schematic diagram of a method for using a gas turbine (or expander) with a cryogenic liquid storage tank cooling device and a waste steam regenerator heat pump system according to an embodiment of the present invention; the cooling device for the low-temperature liquid storage tank is the same as that in the figure 6, and redundant description is omitted;

in fig. 7, in order to control and limit the temperature rise of the working medium at the outlet of the high-temperature pipeline 302 of the steam exhaust heat regenerator in the embodiment of the present invention, the steam exhaust heat regenerator 300 is further provided with a heat pump system; the function of the device is to control the temperature rise of the outlet of the high-temperature pipeline 302 of the exhaust steam heat regenerator, thereby reducing the evaporation capacity of the low-temperature liquid power generation working medium in the low-temperature liquid storage tank 1;

the heat pump system is composed of a heat pump compressor 500, a condenser 501, a throttling device 503 and an evaporator 504 which are sequentially communicated; the evaporator 504 is arranged at the high-temperature end of the exhaust steam heat regenerator 300 and close to the exhaust steam heat regenerator low-temperature pipeline 301, and transfers the heat energy of the high-temperature end of the exhaust steam heat regenerator 300 and the high-temperature part of the exhaust steam heat regenerator low-temperature pipeline 301 into the low-temperature working medium between the outlet of the exhaust steam heat regenerator low-temperature pipeline 301 and the main heat exchanger 4 (the condenser high-temperature pipeline 501 exchanges heat with the condenser low-temperature pipeline 502, releases the heat energy generated by compressing the heat pump compressor 500 between the outlet of the exhaust steam heat regenerator low-temperature pipeline 301 and the main heat exchanger 4) or releases the heat energy into the air or cold water in the environment, so that the heat pump heat regenerator heat pump heat recovery system is suitable for low-temperature power generation working media with relatively high boiling points and directly releases the heat energy into the cold air and the cold.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.