阅读说明：本技术 一种两级透平气悬浮orc发电系统及控制方法 (Two-stage turbine gas suspension ORC power generation system and control method ) 是由 李健 杨晨辉 于 2020-06-23 设计创作，主要内容包括：本发明涉及一种两级透平气悬浮ORC发电系统及控制方法,包括循环连接的蒸发器、膨胀发电机组、冷凝器、工质泵与蒸发器；膨胀发电机组包括高压级透平、气悬浮轴承发电机以及低压级透平；高压级透平出口与低压级透平入口连通；蒸发器为组合式满液蒸发器；蒸发器的预热段出口与膨胀发电机组的发电机之间通过供液冷却管路与其旁路相连；蒸发器的蒸发段出口与膨胀发电机组之间通过进气管路及其旁路相连。本发明中采用的膨胀机为两级透平气悬浮膨胀机,实现无油运行结构简单,发电效率高；膨胀机配有旁通管路和控制阀门,有效保护膨胀机并且两级透平对称布置其结构受力平衡且两级透平串联设计适用于ORC高膨胀压比工况,系统发电效率更高。(The invention relates to a two-stage turbine gas suspension ORC power generation system and a control method, wherein the two-stage turbine gas suspension ORC power generation system comprises an evaporator, an expansion generator set, a condenser, a working medium pump and an evaporator which are connected in a circulating manner; the expansion generator set comprises a high-pressure stage turbine, a gas suspension bearing generator and a low-pressure stage turbine; the outlet of the high-pressure stage turbine is communicated with the inlet of the low-pressure stage turbine; the evaporator is a combined full liquid evaporator; the outlet of the preheating section of the evaporator is connected with a generator of the expansion generator set through a liquid supply cooling pipeline; an outlet of an evaporation section of the evaporator is connected with the expansion generator set through an air inlet pipeline and a bypass thereof. The expander adopted in the invention is a two-stage turbine gas suspension expander, so that the oil-free operation is realized, the structure is simple, and the power generation efficiency is high; the expander is provided with a bypass pipeline and a control valve, the expander is effectively protected, the two stages of turbines are symmetrically arranged, the structural stress of the expander is balanced, the two stages of turbines are in series connection, the expander is suitable for the working condition of ORC (organic Rankine cycle) with high expansion pressure ratio, and the system power generation efficiency is higher.)

1. A two-stage turbine gas suspension ORC power generation system comprises an evaporator (1), an expansion generator set, a condenser (7), a working medium pump (8) and the evaporator (1) which are connected in a circulating mode; the method is characterized in that:

the expansion generator set comprises a high-pressure stage turbine (4), a gas suspension bearing generator (6) and a low-pressure stage turbine (5); the outlet of the high-pressure stage turbine (4) is communicated with the inlet of the low-pressure stage turbine (5);

the evaporator (1) is a combined full liquid evaporator (1); an inner partition plate with liquid equalizing holes is arranged in the inner cavity of the combined flooded evaporator (1) to divide the evaporator (1) into an upper part and a lower part which are communicated, the upper part is a flooded evaporation section, and the lower part is a working medium preheating section;

the outlet of the preheating section of the evaporator (1) is connected with a generator of the expansion generator set through a liquid supply cooling pipeline; the liquid supply cooling pipeline comprises an evaporator (1) preheating section outlet, a pressure stabilizing pump electromagnetic valve (12) and a pressure stabilizing pump (11) which are connected in sequence; the liquid supply cooling pipeline also comprises a bypass liquid supply cooling pipeline which is connected with a pressure stabilizing pump electromagnetic valve (12) and a pipeline where the pressure stabilizing pump is arranged in parallel; the bypass liquid supply cooling pipeline comprises a pressure stabilizing pump bypass electromagnetic valve (13); the pressure stabilizing pump electromagnetic valve (12) and the pressure stabilizing pump bypass electromagnetic valve (13) are in an interlocking state;

an air inlet pipeline is arranged between an outlet of an evaporation section of the evaporator (1) and the expansion generator set; the air inlet pipeline comprises an evaporation section outlet of the evaporator (1), an air inlet valve (2) and a high-pressure turbine air inlet which are connected in sequence; the air inlet pipeline also comprises a bypass pipeline of the air inlet pipeline; and the bypass path of the air inlet pipeline comprises an evaporation section outlet of the evaporator (1), a bypass valve (3) and an outlet of the low-pressure turbine which are sequentially connected.

2. A two stage turbine gas suspended ORC power generation system according to claim 1, wherein: the expansion generator set is an integrated generator set, wherein the gas suspension bearing generator is a variable-speed permanent magnet generator; the rotor in the variable-speed permanent magnet generator rotates along with the rotating shaft; two ends of the rotating shaft are respectively provided with impellers to form two turbines; the outlet pipe of one of the turbines is connected with the inlet pipe of the other turbine, and a high-pressure stage turbine (4) and a low-pressure stage turbine (5) are correspondingly formed.

3. A control method of a two-stage turbine gas-suspended ORC power generation system, controlling a two-stage turbine gas-suspended ORC power generation system according to any one of claims 1 to 2, characterized in that: the method comprises the following steps:

the method comprises the following steps: the system starts to operate, the air inlet valve is in a closed state, the bypass valve is in an open state, the liquid working medium is heated and evaporated after the heat source enters the evaporator, and the liquid working medium firstly enters the condenser through the bypass valve to be condensed; detecting the temperature and the pressure of a gaseous working medium at an outlet of an evaporator, detecting the temperature and the pressure of a working medium in a condenser, obtaining enthalpy values of the working medium at the outlet of the evaporator and the working medium at the outlet of the condenser through the temperature and the pressure, calculating to obtain enthalpy difference between the working medium at the outlet of the evaporator and the working medium at the outlet of the condenser, calculating theoretical generated energy at the moment according to the enthalpy difference and a flowmeter, comparing the generated energy with preset starting generated energy of an expander, and if the generated energy is more than or equal to the starting generated energy of the expander, opening an air inlet valve, closing a bypass valve, enabling a working medium;

step two: detecting the working medium air pressure at the outlet of the working medium pump, and if the value of the compressed air pressure is higher than the preset air pressure of the cooling pipeline, opening the electromagnetic valve of the pressure stabilizing pump and closing the bypass electromagnetic valve of the pressure stabilizing pump; if the air pressure is lower than the preset air pressure of the cooling pipeline, closing the electromagnetic valve of the pressure stabilizing pump, opening the bypass electromagnetic valve of the pressure stabilizing pump, and pressurizing through the pressure stabilizing pump to keep the pressure obtained by the air suspension bearing stable;

step three: when the system is stopped, the flow of the heat source is reduced, the heat exchange capacity of the evaporator is reduced, the temperature and the pressure of the organic working medium entering the expansion machine are gradually reduced, when the generated energy is lower than a preset stop power generation value, the bypass valve is opened from a closed state, the air inlet valve is closed from an open state, the organic working medium at the outlet of the evaporator directly enters the condenser to be condensed until the heat source stops entering the evaporator, and the system is completely stopped.

Technical Field

The invention relates to the technical field of industrial waste heat recovery and clean energy, in particular to a two-stage turbine gas suspension ORC power generation system and a control method.

Background

The Organic Rankine Cycle (ORC) is a technology for realizing Rankine cycle power generation by adopting a low-boiling-point organic working medium (such as a refrigerant) and completing the phase change of the organic working medium by utilizing a heat source with a lower temperature. The liquid organic working medium is heated by low-temperature waste heat in an evaporator (sometimes called a waste heat exchanger) to generate high-temperature high-pressure gas, the high-temperature high-pressure gas is expanded by an expander to drive a generator to generate electric energy, the low-temperature low-pressure gaseous working medium after passing through the expander is cooled into liquid in a condenser, and the liquid is pressurized by a refrigerant pump and sent back to the evaporator to complete a cycle. The ORC waste heat power generation technology has the problems of low cycle efficiency, less generated energy, high operation and maintenance cost and long investment return period. The expansion generator is a key device for restricting the performance of an ORC unit, and the expansion generator mainly comprises two types, namely a screw machine and a centripetal turbine expander. The screw machine can run at low speed to directly drive the power frequency generator to generate power, and the centripetal turbine rotates at high speed and drives the power frequency motor to generate power after being decelerated by the gear box.

Disclosure of Invention

1. The technical problem to be solved is as follows:

the invention aims to provide a two-stage turbine gas suspension ORC power generation system, wherein an expansion generator set adopts a static pressure gas bearing, so that the friction loss is lower, and the power generation efficiency is high; by adopting a two-stage turbine structure, the working condition of high expansion ratio is practical, and the system efficiency is higher; the air inlet structure adopts a bypass loop to realize the protection of the expansion machine; the liquid supply cooling pipeline is provided with a pressure stabilizing pump with a bypass, and the on-off is controlled by an electromagnetic valve to ensure the stable pressure supply of the gas suspension bearing.

2. The technical scheme is as follows:

a two-stage turbine gas suspension ORC power generation system comprises an evaporator, an expansion generator set, a condenser, a working medium pump and an evaporator which are connected in a circulating manner; the method is characterized in that: the expansion generator set comprises a high-pressure stage turbine, a gas suspension bearing generator and a low-pressure stage turbine; and the outlet of the high-pressure stage turbine is communicated with the inlet of the low-pressure stage turbine.

The evaporator is a combined full liquid evaporator; the inner cavity of the combined flooded evaporator is internally provided with an internal clapboard with liquid equalizing holes to divide the evaporator into an upper part and a lower part which are communicated, the upper part is a flooded evaporation section, and the lower part is a working medium preheating section.

An outlet of the preheating section of the evaporator is connected with a generator of the expansion generator set through a liquid supply cooling pipeline; the liquid supply cooling pipeline comprises an evaporator preheating section outlet, a pressure stabilizing pump electromagnetic valve and a pressure stabilizing pump which are connected in sequence; the liquid supply cooling pipeline also comprises a bypass liquid supply cooling pipeline which is connected with the pressure stabilizing pump electromagnetic valve and a pipeline where the pressure stabilizing pump is arranged in parallel; the bypass liquid supply cooling pipeline comprises a pressure stabilizing pump bypass electromagnetic valve; the pressure stabilizing pump electromagnetic valve and the pressure stabilizing pump bypass electromagnetic valve are in an interlocking state. An air inlet pipeline is arranged between an outlet of an evaporation section of the evaporator and the expansion generator set; the air inlet pipeline comprises an evaporation section outlet of the evaporator, an air inlet valve and a high-pressure turbine air inlet which are connected in sequence; the air inlet pipeline also comprises a bypass pipeline of the air inlet pipeline; and the bypass path of the air inlet pipeline comprises an evaporation section outlet of the evaporator, a bypass valve and an outlet of the low-pressure turbine which are connected in sequence.

Furthermore, the expansion generator set is an integrated generator set, wherein the gas suspension bearing generator is a variable-speed permanent magnet generator; the rotor in the variable-speed permanent magnet generator rotates along with the rotating shaft; two ends of the rotating shaft are respectively provided with impellers to form two turbines; the outlet pipe of one turbine is connected with the inlet pipe of the other turbine, and a high-pressure stage turbine and a low-pressure stage turbine are correspondingly formed.

A control method of a two-stage turbine gas suspension ORC power generation system comprises the following steps:

the method comprises the following steps: the system starts to operate, the air inlet valve is in a closed state, the bypass valve is in an open state, the liquid working medium is heated and evaporated after the heat source enters the evaporator, and the liquid working medium firstly enters the condenser through the bypass valve to be condensed; detecting the temperature and the pressure of gaseous working media at an outlet of an evaporator, detecting the temperature and the pressure of the working media in a condenser, obtaining enthalpy values of the working media at the outlet of the evaporator and the working media at the outlet of the condenser through the temperature and the pressure, calculating to obtain enthalpy difference between the working media and the working media at the outlet of the condenser, calculating theoretical generated energy at the moment according to the enthalpy difference and a flowmeter, comparing the generated energy with preset starting generated energy of an expander, if the generated energy is more than or equal to the starting generated energy of the expander, opening an air inlet valve, closing a bypass valve, enabling working media gas to firstly enter a high-pressure stage.

Step two: detecting the working medium air pressure at the outlet of the working medium pump, and if the value of the compressed air pressure is higher than the preset air pressure of the cooling pipeline, opening the electromagnetic valve of the pressure stabilizing pump and closing the bypass electromagnetic valve of the pressure stabilizing pump; if the air pressure is lower than the preset air pressure of the cooling pipeline, closing the electromagnetic valve of the pressure stabilizing pump pipeline, opening the bypass electromagnetic valve of the pressure stabilizing pump, and pressurizing through the pressure stabilizing pump to keep the pressure obtained by the air suspension bearing stable.

Step three: when the system is stopped, the flow of the heat source is reduced, the heat exchange capacity of the evaporator is reduced, the temperature and the pressure of the organic working medium entering the expansion machine are gradually reduced, when the generated energy is lower than a preset stop power generation value, the bypass valve is opened from a closed state, the air inlet valve is closed from an open state, the organic working medium at the outlet of the evaporator directly enters the condenser to be condensed until the heat source stops entering the evaporator, and the system is completely stopped.

3. Has the advantages that:

(1) the expansion machine adopted in the invention is a two-stage turbine gas suspension expansion machine, the ORC system realizes oil-free operation, the structure is simple, and the power generation efficiency is high; two stages of turbines of the expansion machine are symmetrically arranged on two sides of the generator, and the stress of the structure is balanced; the two-stage turbine series design of the expansion machine is suitable for the working condition of ORC high expansion pressure ratio, and the system has higher power generation efficiency.

(2) The evaporator is a combined evaporator integrating a liquid storage tank, a preheater and the evaporator, so that the complexity of the system is greatly simplified, the unit size is reduced, and the cost is reduced.

(3) The expander bypass pipeline is arranged to realize the protection of the expander in the starting and stopping state; and a combined full-liquid evaporator with a liquid storage function is used for simultaneously supplying liquid to a liquid cooling pipeline to cool the motor and supply pressure to the air suspension bearing.

(4) The liquid supply cooling pipeline is provided with a pressure stabilizing pump with a bypass, so that the system can stably run under the working condition of large heat source fluctuation.

Drawings

FIG. 1 is a connection diagram of the overall structure of the present invention;

FIG. 2 is a schematic diagram of the modular flooded evaporator of the present invention.

Detailed Description

As shown in fig. 1 to fig. 2, a two-stage turbine gas suspension ORC power generation system comprises an evaporator, an expansion generator set, a condenser, a working medium pump and an evaporator which are connected in a circulating manner; the method is characterized in that: the expansion generator set comprises a high-pressure stage turbine, a gas suspension bearing generator and a low-pressure stage turbine; and the outlet of the high-pressure stage turbine is communicated with the inlet of the low-pressure stage turbine.

The evaporator is a combined full liquid evaporator; the inner cavity of the combined flooded evaporator is internally provided with an internal clapboard with liquid equalizing holes to divide the evaporator into an upper part and a lower part which are communicated, the upper part is a flooded evaporation section, and the lower part is a working medium preheating section.

An outlet of the preheating section of the evaporator is connected with a generator of the expansion generator set through a liquid supply cooling pipeline; the liquid supply cooling pipeline comprises an evaporator preheating section outlet, a pressure stabilizing pump electromagnetic valve and a pressure stabilizing pump which are connected in sequence; the liquid supply cooling pipeline also comprises a bypass liquid supply cooling pipeline which is connected with the pressure stabilizing pump electromagnetic valve and a pipeline where the pressure stabilizing pump is arranged in parallel; the bypass liquid supply cooling pipeline comprises a pressure stabilizing pump bypass electromagnetic valve; the pressure stabilizing pump electromagnetic valve and the pressure stabilizing pump bypass electromagnetic valve are in an interlocking state. An air inlet pipeline is arranged between an outlet of an evaporation section of the evaporator and the expansion generator set; the air inlet pipeline comprises an evaporation section outlet of the evaporator, an air inlet valve and a high-pressure turbine air inlet which are connected in sequence; the air inlet pipeline also comprises a bypass pipeline of the air inlet pipeline; and the bypass path of the air inlet pipeline comprises an evaporation section outlet of the evaporator, a bypass valve and an outlet of the low-pressure turbine which are connected in sequence.

Furthermore, the expansion generator set is an integrated generator set, wherein the gas suspension bearing generator is a variable-speed permanent magnet generator; the rotor in the variable-speed permanent magnet generator rotates along with the rotating shaft; two ends of the rotating shaft are respectively provided with impellers to form two turbines; the outlet pipe of one turbine is connected with the inlet pipe of the other turbine, and a high-pressure stage turbine and a low-pressure stage turbine are correspondingly formed.

A control method of a two-stage turbine gas suspension ORC power generation system comprises the following steps:

the method comprises the following steps: the system starts to operate, the air inlet valve is in a closed state, the bypass valve is in an open state, the liquid working medium is heated and evaporated after the heat source enters the evaporator, and the liquid working medium firstly enters the condenser through the bypass valve to be condensed; detecting the temperature and the pressure of gaseous working media at an outlet of an evaporator, detecting the temperature and the pressure of the working media in a condenser, obtaining enthalpy values of the working media at the outlet of the evaporator and the working media at the outlet of the condenser through the temperature and the pressure, calculating to obtain enthalpy difference between the working media and the working media at the outlet of the condenser, calculating theoretical generated energy at the moment according to the enthalpy difference and a flowmeter, comparing the generated energy with preset starting generated energy of an expander, if the generated energy is more than or equal to the starting generated energy of the expander, opening an air inlet valve, closing a bypass valve, enabling working media gas to firstly enter a high-pressure stage.

Step two: detecting the working medium air pressure at the outlet of the working medium pump, and if the value of the compressed air pressure is higher than the preset air pressure of the cooling pipeline, opening the electromagnetic valve of the pressure stabilizing pump and closing the bypass electromagnetic valve of the pressure stabilizing pump; if the air pressure is lower than the preset air pressure of the cooling pipeline, the electromagnetic valve of the pressure stabilizing pump is closed, the bypass electromagnetic valve of the pressure stabilizing pump is opened, and the pressure obtained by the air suspension bearing is kept stable through pressurization of the pressure stabilizing pump.

Step three: when the system is stopped, the flow of the heat source is reduced, the heat exchange capacity of the evaporator is reduced, the temperature and the pressure of the organic working medium entering the expansion machine are gradually reduced, when the generated energy is lower than a preset stop power generation value, the bypass valve is opened from a closed state, the air inlet valve is closed from an open state, the organic working medium at the outlet of the evaporator directly enters the condenser to be condensed until the heat source stops entering the evaporator, and the system is completely stopped.