阅读说明：本技术 一种热电机组给水旁路及变主再热汽温宽域调整系统 (Thermoelectric generator set feed water bypass and variable main reheat steam temperature wide-range adjusting system ) 是由 许朋江 王东晔 高庆 范庆伟 居文平 黄嘉驷 马汀山 于 2020-12-08 设计创作，主要内容包括：本发明公开了一种热电机组给水旁路及变主再热汽温宽域调整系统,该系统通过增设高压加热器旁路调整阀(3),以减小汽轮机各级抽汽量,降低锅炉入口水温,同时通过增设主蒸汽温度调整阀(1)和再热蒸汽温度调整阀(2)对主蒸汽温度和再热蒸汽温度进行宽域调整,大幅提升汽轮机供热抽汽流量,从而使供热能力增加的同时,达到电负荷调节能力大幅提升的目的。这一技术具有降低机组能耗水平且可以和现有供热相关技术兼容的特性。(The invention discloses a thermoelectric unit feed water bypass and main reheating steam temperature wide-range adjusting system, which reduces the steam extraction amount of each stage of a steam turbine and reduces the water temperature of a boiler inlet by additionally arranging a high-pressure heater bypass adjusting valve (3), and meanwhile, the main steam temperature and the reheating steam temperature are adjusted in a wide range by additionally arranging a main steam temperature adjusting valve (1) and a reheating steam temperature adjusting valve (2), so that the heat supply steam extraction flow of the steam turbine is greatly improved, and the purpose of greatly improving the electric load adjusting capacity is achieved while the heat supply capacity is increased. This technique has the characteristic of reducing the energy consumption level of the unit and of being compatible with existing heating-related techniques.)

1. A wide-range adjusting system for a feed water bypass and main-variable reheat steam of a thermoelectric unit is characterized by comprising a high-pressure heater (4), wherein a high-pressure heater bypass adjusting valve (3) is additionally arranged in a bypass system of the high-pressure heater (4), independent temperature adjusting water is led out from an inlet of the high-pressure heater (4), a main steam system with a main steam temperature adjusting valve (2) connected to a boiler (5) is additionally arranged to form a main steam normal temperature adjusting system, and a reheat steam system with a reheat steam temperature adjusting valve (1) connected to the boiler (5) is additionally arranged to form a reheat steam normal temperature adjusting system.

2. The thermoelectric power unit feed water bypass and main reheat steam temperature wide range adjustment system as claimed in claim 1, wherein the main steam normal temperature adjustment system is led out from the inlet of the high pressure heater (4) to the main steam system of the boiler (5), and a main steam temperature adjustment valve (2) is provided to further reduce the feed water flow rate entering the high pressure heater (4) so as to reduce the steam inlet flow rate of the high pressure heater.

3. The system for adjusting the temperature range of the feed water bypass and the main reheat steam of the thermoelectric power unit as claimed in claim 1, wherein the reheat steam thermostat system is independently a reheat steam system led from an inlet of the high pressure heater (4) to the boiler (5), and is provided with the reheat steam thermostat valve (1) or is adjusted by the reheat steam critical attemperation water carried by the thermoelectric power unit.

4. The thermoelectric generator set feed water bypass and main reheat steam temperature range adjusting system as claimed in claim 1, wherein the inlet of the high pressure heater bypass adjusting valve (3) additionally arranged on the high pressure heater (4) bypass is connected with the feed water inlet of the high pressure heater (4), the outlet is connected with the feed water outlet of the high pressure heater (4), and the two are in parallel connection.

5. The thermoelectric generator set feed water bypass and main reheat steam temperature wide-range adjustment system as claimed in claim 1, wherein the feed water flow passing through the high pressure heater (4) is adjusted by adjusting the high pressure heater bypass adjustment valve (3), and then the flow of steam entering the high pressure heater is adjusted to reduce the feed water temperature.

6. The thermoelectric generator set feed water bypass and main reheating steam temperature wide-range adjusting system as claimed in claim 1, wherein the main steam temperature and the reheating steam temperature are adjusted by the main steam temperature adjusting valve (2) and the reheating steam temperature adjusting valve (1), so as to adjust the main steam flow and the reheating steam flow, achieve the purposes of adjusting the extraction steam flow of the high-pressure heater (4) and adjusting the main steam, the reheating steam parameters and the flow, and achieve thermoelectric decoupling and guarantee the heating capacity improvement.

7. The thermoelectric power unit feed water bypass and main reheat steam temperature wide-range adjustment system as claimed in claim 1, wherein the system comprises a plurality of high-pressure heaters (4) arranged in series.

8. The thermoelectric generator set feed water bypass and main reheating steam temperature wide-range adjusting system as claimed in claim 1, wherein the system can achieve adjustment of main steam temperature within 0-130 ℃.

Technical Field

The invention belongs to the field of power station boilers and steam turbine systems, and particularly relates to a wide-range adjusting system for a feed water bypass and main reheating steam temperature of a thermoelectric unit.

Background

In order to solve the problem of new energy consumption and improve the electric load adjusting capacity of the thermal power generating unit, the method is a key target for flexibility modification of the thermal power generating unit. The thermal load and the electrical load are limited by the coupling characteristic of the thermal load and the electrical load are simultaneously increased and decreased in the operating mode of fixing the electricity by heat, and the adjusting performance is poor. When the heating and heat supply unit operates in winter, the electric load is in a relatively high state and is difficult to be adjusted downwards, so that difficulty is caused to new energy consumption. The contradiction of heat and power supply and insufficient heat supply are common problems of the cogeneration units. The method realizes thermoelectric decoupling and improves the electric load adjusting capacity of the heat supply unit, and is an urgent problem to be solved by the current cogeneration unit.

The existing thermoelectric decoupling technology has certain limitations in different degrees, the bypass heat supply technology and the main and reheat steam direct heat supply technology have strong electric load adjusting capacity, but can cause the unit energy consumption level to be greatly increased, and the temperature and pressure reduction amplitude is large (taking a subcritical unit as an example, the main steam pressure is reduced from 16.7MPa to 0.1-0.5MPa, and the temperature is reduced from 535 ℃ to less than or equal to 200 ℃) and the system reliability is low; the low-pressure cylinder optical axis heat supply technology can greatly reduce the electric load of the unit, but the thermoelectric coupling property is further increased, and the electric load regulation capacity is further reduced; the low-pressure cylinder zero-output technology has strong electric load adjusting capacity, but has the problems of discontinuous electric load adjustment and the like. And the transformation technology has a large transformation range, part of the technologies can not be shared, and the mutual compatibility is not strong.

Disclosure of Invention

The invention aims to provide a thermoelectric unit feed water bypass and main-variable reheat steam temperature wide-range adjusting system, which has a novel technology which can guarantee and increase heat supply capacity, improve electric load adjusting capacity, reduce unit energy consumption level and is compatible with the existing heat supply related technology, and solves a series of problems in the existing thermoelectric decoupling technology.

In order to achieve the purpose, the invention adopts the following technical scheme:

a thermoelectric unit feed water bypass and main-variable reheat steam temperature wide-range adjusting system comprises a high-pressure heater, wherein a high-pressure heater bypass adjusting valve is additionally arranged in a bypass system of the high-pressure heater, independent temperature adjusting water is led out from an inlet of the high-pressure heater, a main steam temperature adjusting valve is additionally arranged and connected to a main steam system of a boiler to form a main steam normal temperature adjusting system, and a reheat steam temperature adjusting valve is additionally arranged and connected to the reheat steam system of the boiler to form a reheat steam normal temperature adjusting system.

The invention is further improved in that the main steam normal temperature adjusting system is led out from the inlet of the high-pressure heater to the main steam system of the boiler, and a main steam temperature adjusting valve is arranged to further reduce the flow rate of feed water entering the high-pressure heater, so that the flow rate of steam entering the high-pressure heater is reduced.

The invention is further improved in that the reheat steam normal temperature adjusting system is independently led out from the inlet of the high-pressure heater to the reheat steam system of the boiler, and is provided with a reheat steam temperature adjusting valve or is adjusted by the reheat steam emergency temperature reducing water carried by the unit.

The invention is further improved in that the inlet of the high-pressure heater bypass adjusting valve additionally arranged on the high-pressure heater bypass is connected with the high-pressure heater feed water inlet, the outlet of the high-pressure heater bypass adjusting valve is connected with the high-pressure heater feed water outlet, and the high-pressure heater bypass adjusting valve are in parallel connection.

The invention is further improved in that the water supply flow passing through the high-pressure heater is adjusted by adjusting the high-pressure heater bypass adjusting valve, so that the steam flow entering the high-pressure heater is adjusted, and the water supply temperature is reduced.

The invention has the further improvement that the main steam temperature and the reheat steam temperature are adjusted through the main steam temperature adjusting valve and the reheat steam temperature adjusting valve, the main steam flow and the reheat steam flow are adjusted, the purposes of adjusting the steam extraction flow of the high-pressure heater and adjusting the parameters and the flow of the main steam and the reheat steam are realized, the thermoelectric decoupling is realized, and the heat supply capacity is improved.

A further development of the invention is that the system comprises a plurality of high-pressure heaters arranged in series.

The invention is further improved in that the system can realize the adjustment of the temperature of the main steam within 0-130 ℃.

The invention has at least the following beneficial technical effects:

1. the water supply flow through the high-pressure heater is adjustable, so that the steam extraction flow of each heater is adjustable, the steam flow through the steam turbine cylinder body is indirectly adjustable, and the purpose of adjusting the heat supply steam extraction flow is finally achieved. Generally, the flow of the heating steam can be increased by 20-30% at most. Thereby realizing the purpose of heat supply and capacity increase.

2. Through the main steam normal temperature regulating system and the reheat steam normal temperature regulating system, the temperature of main and reheat steam can be regulated within a wide range (the regulation range of the later case is 0-130 ℃), the power generation power change caused by the through-flow steam flow change of the steam turbine in item 1 is avoided, meanwhile, the regulation of the power generation of the steam turbine generator set is realized through the large-amplitude regulation of the main reheat parameters, and the thermoelectric load decoupling is realized.

3. The feed water flow through the high-pressure heater is adjustable, so that the feed water temperature entering the boiler is reduced, the smoke temperature is reduced, the boiler efficiency is improved, and the heat energy utilization potential of the unit is further dug deeply.

4. It is worth to say that when the invention is used for a non-heat supply unit, the heat return depth of the unit is reduced, and no steam extraction utilization facility is provided, so that the heat loss of the steam turbine exhaust is greatly increased, and the overall energy consumption level of the unit is greatly increased. When the steam turbine is used for a heat supply unit, because a large amount of through-flow steam extraction of the steam turbine is extracted, the steam exhaust flow is basically fixed, and when the main and reheat steam parameters are reduced, the steam exhaust parameters are reduced, on the contrary, the heat loss of the steam turbine can be directly reduced, and the energy utilization efficiency is improved. The main principle that the technology plays a role in energy conservation is that the No. 3 is added in the technology.

5. For the steam extraction heat supply unit or the low-pressure cylinder zero-output unit, the flow rate of the through-flow steam entering the low-pressure cylinder is basically fixed (generally 0-200 t/h), after the technology is used, the flow rate of the steam entering the low-pressure cylinder is unchanged, but the temperature of the steam is reduced, a cooling effect can be achieved on high-temperature points generated by local blast friction and the like of the low-pressure cylinder, and then the operation safety of the unit is improved.

Drawings

FIG. 1 is a schematic diagram of a thermoelectric power unit feed water bypass and main reheat steam temperature wide-range adjusting system according to the present invention;

description of reference numerals:

reference numeral 1 denotes a reheat steam temperature adjusting valve, 2 denotes a main steam temperature adjusting valve, 3 denotes a high-pressure heater bypass adjusting valve, 4 denotes a high-pressure heater, and 5 denotes a boiler.

Detailed Description

The following embodiments are given as examples of the present invention, and it should be noted that the present invention is not limited to the following embodiments, and all equivalent changes based on the technical solutions of the present invention are within the protection scope of the present invention.

According to the technical scheme, as shown in fig. 1, the thermoelectric generator set water supply bypass and main-variable reheat steam temperature wide-range adjusting system provided by the invention realizes thermoelectric decoupling and improves the electric load adjusting capacity.

A plurality of high-pressure heaters 4 are connected in series; the inlet of the high-pressure heater bypass adjusting valve 3 is connected to the inlet of the high-pressure heater 4, and the outlet is connected to the outlet of the high-pressure heater 4. A main steam temperature regulating valve 2 is additionally arranged, the inlet of the main steam temperature regulating valve is connected with the inlet of a high-pressure heater 4, and the outlet of the main steam temperature regulating valve is connected with a main steam system of a boiler 5. A reheat steam temperature control valve 1 is added, and an inlet thereof is connected to an inlet of the high pressure heater 4, and an outlet thereof is connected to the reheat steam of the boiler 5 (the reheat steam temperature control system may not be provided in some cases).

A thermoelectric unit feed water bypass and main reheat steam temperature wide-range adjusting system comprises the following implementation modes:

1. the high-pressure heater bypass adjustment valve 3 is connected in parallel to the high-pressure heater 4, and has an inlet connected to an inlet of the high-pressure heater 4 and an outlet connected to an outlet of the high-pressure heater 4. The water supply flow through the high-pressure heater is continuously adjustable within the range of 0-100%, so that the heat supply extraction flow is adjusted. When the water supply flow passing through the high-pressure heater is less, the steam extraction of the steam turbine is less, the heat supply extraction can be greatly increased, and the final increment can reach 20-30%.

2. A main steam temperature regulating valve 2 is additionally arranged, the inlet of the main steam temperature regulating valve is connected with the inlet of a high-pressure heater 4, and the outlet of the main steam temperature regulating valve is connected with a main steam system of a boiler 5, so that a normal main steam temperature reducing system is formed. The system is commonly used in the heat supply period, and the temperature of main steam can be adjusted within a wide range (about 100 ℃) (the adjustment range of the later case is 0-130 ℃). By wide-range adjustment of the temperatures of the main steam and the reheated steam, the heat supply is guaranteed, meanwhile, the power generation load of the unit can be adjusted, and the thermoelectric decoupling effect is achieved.

3. A reheat steam temperature adjusting valve 1 is additionally provided, and an inlet thereof is connected to an inlet of the high pressure heater 4, and an outlet thereof is connected to reheat steam of the boiler 5 (the reheat steam temperature adjusting system may not be provided as the case may be), thereby constituting a normal reheat steam temperature reducing system. The reheat steam temperature adjustable range is the same as the main steam and the adjustment strategy is the same as in clause 2.

The following application cases are specified:

1. case application background: taking a certain 300MW subcritical cogeneration unit as an example, the combined heat and power generation unit is provided with three stages of high-pressure heaters which are arranged in series, wherein an inlet is connected with a boiler feed pump, an outlet is connected with a boiler, the feed water flow is 977.2t/h under the heat supply working condition, the feed water temperature rises from 171.2 ℃ to 278.4 ℃, and the temperature rises to 107.2 ℃. Rated main steam parameters are 16.7MPa, 538 ℃ and 977.2t/h, and rated reheat steam temperature is 538 ℃. The heat supply steam is extracted by the steam exhaust (five-stage steam extraction) of the intermediate pressure cylinder, the steam extraction parameters are 0.43MPa, 256 ℃ and 550t/h, the steam is cooled into water after heat supply, the temperature is 104 ℃, and the heat supply load is 388.07 MW. The unit generates 219MW of load.

2. The invention is modified as follows: a bypass regulating valve of a high-pressure heater is additionally arranged, the bypass valve is fully opened under the maximum operation working condition, the water temperature at the inlet of the high-pressure heater is 171.2 ℃, feed water entering a boiler directly enters the boiler through the bypass regulating valve, and the temperature is still 171.2 ℃. The main steam flow is adjusted by a main steam temperature adjusting valve, the adjusting range is 100 ℃, and the stable working condition after 90 ℃ adjustment is adopted in the calculation of the scheme. The temperature of the reheated steam is adjusted by a reheated steam temperature adjusting valve, the adjusting range is 130 ℃, and the stable working condition after 120 ℃ adjustment is adopted in the calculation of the scheme.

3. The operation parameter change after the invention is adopted: the main steam parameters are 16.7MPa, 448 ℃ (reduced by 90 ℃), 904t/h (ensuring that the coal burning quantity is unchanged and the evaporation quantity is reduced by about 73.2t/h), and the rated reheat steam temperature is 418 ℃ (reduced by 120 ℃). The heat supply steam is extracted from the steam exhaust (five-stage steam extraction) of the intermediate pressure cylinder, the steam extraction parameters are 0.43MPa, 168.2 ℃ (the steam extraction temperature is reduced by 87.8 ℃), and 696.9t/h (the steam amount is increased by 146.9t/h), the steam is cooled into water after heat supply, the temperature is 104 ℃, and the heat supply load is 455.63 MW. The unit power generation load is 190 MW.

4. The improved effect after the invention is adopted is as follows:

(1) the feed water temperature is greatly reduced, the boiler exhaust gas temperature is reduced, the exhaust gas loss is reduced, and the boiler thermal efficiency is improved by 0.83 percentage points (92% to 92.83%).

(2) The low-pressure cylinder inlet steam flow is unchanged (102t/h), the inlet steam parameters are reduced (from 253.3 ℃ to 158.6 ℃), so that the low-pressure cylinder exhaust steam flow is basically unchanged (98t/h), the exhaust steam parameters are greatly reduced (the exhaust steam enthalpy is reduced from 2606.9kJ/kg to 2512.4kJ/kg), and the exhaust steam heat loss is reduced. The comprehensive furnace effect influences that the coal consumption of the unit power generation is reduced by 15.46 g/kWh.

(3) The heat supply capacity of the unit is improved by 67.56MW (the heat supply area can be increased by 168.9 ten thousand square meters), the heat supply capacity is improved by 17.41%, and the electromechanical load regulation capacity is improved by 9.07%.