CN105822368B - Starting bypass system and starting method of combined cycle extraction condensing and back pressure unit - Google Patents

Abstract

A start-up bypass system and start-up method for a combined cycle extraction condensing and back pressure unit, which mainly includes: an extraction condensing steam turbine unit, a back pressure steam turbine unit, a condenser, the extraction condensing type steam turbine unit and a back pressure unit The capacity of the waste heat boiler configured for the compression steam turbine unit is the same, and the extraction condensing steam turbine unit is equipped with a condenser with a capacity of 100% of the steam capacity of the waste heat boiler; The device can accommodate the amount of steam generated when the back pressure steam turbine unit is started; the extraction condensing turbine unit is provided with three bypasses, including a 100% gas turbine load high pressure bypass of the extraction condensing unit, and a 100% gas turbine load bypass of the extraction condensing unit. The load medium pressure bypass and the 100% gas turbine load low pressure bypass of the extraction condensing unit; the back pressure steam turbine unit is equipped with a back pressure machine 10% Pressure bypass, back pressure machine 15% gas turbine load medium pressure bypass and back pressure machine 100% gas turbine load low pressure bypass.

Description

A start-up bypass system and start-up method of a combined cycle condensate extraction and back-pressure unit

technical field

The invention relates to a start-up bypass system and a start-up method of a combined cycle condensate extraction and back pressure unit, which is suitable for a "one-to-one" gas-steam combined cycle unit and belongs to the technical field of gas-steam combined cycle.

Background technique

my country is in the process of adjusting the energy structure, and vigorously develops gas-steam combined cycle technology. This technology not only produces electric energy, but also uses low-quality waste heat after power generation for heating, which greatly improves energy utilization and has a good social impact. efficiency, energy saving benefits and environmental benefits.

The back pressure unit does not have a condenser, and it needs to exhaust steam to the air when it is started alone. The exhaust steam to the air will cause noise pollution to the environment and have a negative impact on the lives of surrounding residents; loss.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a combined cycle condensate extraction system with reasonable structure, compact structure, convenient use, reduction of noise pollution, recovery of working fluid, and joint start-up of condensate extraction and back pressure units. And the start-up bypass system and start-up method of the back pressure unit.

The object of the present invention is accomplished through the following technical scheme, a start-up bypass system of a combined cycle condensing and back pressure unit, which mainly includes: an extraction condensing type steam turbine unit, a back pressure type steam turbine unit, a condenser, The extraction condensing steam turbine unit has the same waste heat boiler capacity as the back pressure steam turbine unit, and the extraction condensing steam turbine unit is equipped with a condenser with a capacity of 100% of the waste heat boiler steam; the extraction condensing steam turbine unit In the maximum steam extraction condition, the condenser can accommodate the amount of steam generated when the back pressure steam turbine unit is started; the extraction condensing steam turbine unit is equipped with three bypasses, including the 100% gas turbine load high pressure of the extraction condenser Bypass, condensing unit 100% gas turbine load medium pressure bypass and condensing unit 100% gas turbine load low pressure bypass;

The back pressure steam turbine unit is provided with four bypasses in total, including a high pressure bypass for 10% of the gas turbine load of the back pressure machine, a medium pressure bypass for 10% of the gas turbine load of the back pressure machine, and a medium pressure bypass of 15% of the gas turbine load for the back pressure machine. Medium pressure bypass and back pressure machine 100% gas turbine load low pressure bypass.

The 100% gas turbine load high-pressure bypass of the condensing unit according to the present invention is drawn from the main steam pipe in front of the main steam valve of the condensing unit, and is connected to the high-pressure bypass interface of the condenser through the bypass valve to reduce temperature and pressure; The 100% gas turbine load medium-pressure bypass of the extraction condenser is drawn from the medium-pressure steam pipe in front of the medium-pressure main steam valve, and is connected to the condenser medium-pressure bypass interface through the bypass valve to reduce temperature and pressure; The 100% gas turbine load low-pressure bypass of the condenser is led from the low-pressure steam pipe in front of the low-pressure main steam valve, and is connected to the low-pressure bypass interface of the condenser through the bypass valve to reduce temperature and pressure.

The 10% gas turbine load high pressure bypass of the back pressure machine according to the present invention is led from the main steam pipe in front of the back pressure machine main steam valve. The pipeline behind the valve of the bypass is connected to the high-pressure bypass interface of the condenser; the medium-pressure bypass of the 10% gas turbine load of the back pressure machine is drawn from the medium-pressure steam pipe in front of the medium-pressure main steam valve, and is reduced by the bypass valve. After temperature and decompression, connect the pipeline behind the valve of the 100% gas turbine load medium pressure bypass of the extraction condenser, and connect to the condenser medium pressure bypass interface; the 15% gas turbine load medium pressure bypass of the back pressure machine The pipeline is drawn from the exhaust pipe of the back pressure machine, and after the bypass valve reduces the temperature and pressure, it is connected with the pipeline after the 100% gas turbine load medium pressure bypass of the condensing machine and the 10% gas turbine load medium pressure bypass valve of the back pressure machine After being merged into a main pipe, it is connected to the medium-pressure bypass interface of the condenser; the 100% gas turbine load low-pressure bypass of the back pressure machine is drawn from the low-pressure steam pipe in front of the low-pressure main steam valve, and the temperature is reduced by the bypass valve. After compression, it merges with the pipeline behind the 100% low-pressure bypass valve of the extraction condenser to form a main pipe, and then connects to the low-pressure bypass interface of the condenser.

A method for starting the bypass system of the combined cycle extraction and back pressure unit as described above, the method for starting includes the following steps:

a) The pumping condensing unit is first started through the 100% gas turbine load high, medium and low pressure bypass, and the bypass valve is closed after reaching a stable operating condition;

b) The extraction condensing unit extracts steam for heat supply to the outside, and maintains stable operation after gradually reaching the maximum extraction condition;

c) The waste heat boiler of the back pressure unit starts to run. When the parameters of back pressure machine running are not reached, the main steam generated by the waste heat boiler is discharged into the condenser through the back pressure machine 10% gas turbine load high-pressure bypass. When the parameters meet the back pressure machine After the compressor has changed the parameters, the main steam enters the back press, and the high pressure bypass of the back press is turned off at 10% of the gas turbine load;

d) After the back pressure unit runs, the exhaust pipe simultaneously produces steam that does not meet the heating conditions. At this time, the electric gate valve of the exhaust pipe is closed, and the exhaust steam is discharged into the condensate through the 15% gas turbine load medium pressure bypass of the back pressure machine. When the exhaust steam of the back pressure machine meets the requirements of the heating parameters, close the medium pressure bypass of the back pressure machine at 15% of the gas turbine load;

e) The low pressure steam generated by the waste heat boiler of the back pressure unit is discharged into the condenser through the low pressure bypass of the back pressure machine with 100% gas turbine load before reaching the rated parameters. When the rated parameters are reached, the low pressure steam enters the waste heat boiler and the back pressure is turned off 100% gas turbine load low pressure bypass. The beneficial effects of the present invention are reflected in several aspects: first, through the setting of the bypass system for the start-up of the combined cycle condensate-back pressure unit, the noise pollution caused by the exhaust steam to the air is solved when the back pressure machine is started alone; Second, the bypass-condenser-waste heat boiler circuit is used to recover the working fluid; third, the safe start-up of the back-pressure machine is guaranteed, which meets the start-up characteristics of the extraction condensing-back-pressure unit to the greatest extent.

Description of drawings

Fig. 1 is a schematic flow diagram of the start-up bypass system of the combined cycle condensate extraction and back pressure unit according to the present invention.

detailed description

The present invention will be described in detail below in conjunction with accompanying drawing: As shown in Fig. 1, the start-up bypass system of a kind of combined cycle extraction condensing and back pressure unit of the present invention, it mainly comprises: extraction condensing type steam turbine unit 1, The back pressure steam turbine unit 2 and the condenser 3, the extraction condensing steam turbine unit 1 and the back pressure steam turbine unit 2 are equipped with the same waste heat boiler capacity, and the extraction condensing steam turbine unit 1 is equipped with a capacity of 100% waste heat The steam condenser of the boiler; when the extraction condensing steam turbine unit is in the maximum steam extraction condition, the condenser can accommodate the steam generated when the back pressure steam turbine unit 2 starts; the extraction condensing steam turbine unit 1 There are three bypasses in total, including high-pressure bypass 4 with 100% gas turbine load of the condensing machine, medium-pressure bypass 5 with 100% gas turbine load of the condensing machine, and low-pressure bypass 6 with 100% gas turbine load of the condensing machine;

The back-pressure steam turbine unit 2 is provided with four bypasses in total, including a high-pressure bypass 7 of 10% of the gas turbine load of the back-pressure machine, a medium-pressure bypass 8 of 10% of the gas turbine load of the back-pressure machine, and a 15% of the gas turbine load of the back-pressure machine. Gas turbine load medium pressure bypass 9 and back pressure machine 100% gas turbine load low pressure bypass 10.

The 100% gas turbine load high-pressure bypass 4 of the condensing unit according to the present invention is drawn from the main steam pipe in front of the main steam valve of the condensing unit, and is connected to the high-pressure bypass interface of the condenser 3 through the bypass valve to reduce temperature and pressure ; The 100% gas turbine load medium-pressure bypass 5 of the extraction condenser is drawn from the medium-pressure steam pipe in front of the medium-pressure main steam valve, and is connected to the condenser 3 medium-pressure bypass interface through the bypass valve for temperature reduction and decompression; The 100% gas turbine load low-pressure bypass 6 of the extraction condenser is drawn from the low-pressure steam pipe in front of the low-pressure main steam valve, and is connected to the low-pressure bypass interface of the condenser 3 through the bypass valve for temperature and pressure reduction.

The 10% gas turbine load high-pressure bypass 7 of the back pressure machine according to the present invention is led from the main steam pipe in front of the back pressure machine main steam valve, and connected to the 100% gas turbine load of the condensing machine after the temperature and pressure reduction of the bypass valve The pipeline behind the valve of the high-pressure bypass 4 is connected to the high-pressure bypass interface of the condenser 3; the medium-pressure bypass 8 of the 10% gas turbine load of the back pressure machine is led out from the medium-pressure steam pipe in front of the medium-pressure main steam valve, and passed through After the bypass valve reduces temperature and pressure, it is connected to the pipeline behind the valve of the 100% gas turbine load medium pressure bypass 5 of the extraction condensing unit, and connected to the condenser 3 medium pressure bypass interface; the back pressure machine 15% The gas turbine load medium pressure bypass 9 is drawn from the exhaust pipe of the back pressure machine, and after the bypass valve reduces temperature and pressure, it is connected with the 100% gas turbine load medium pressure bypass 5 of the extraction condensing machine, and the 10% gas turbine load of the back pressure machine After the pipes behind the valve of the load medium pressure bypass 8 merge into a main pipe, they are connected to the medium pressure bypass interface of the condenser 3; The steam pipe is led out, after the temperature and pressure reduction of the bypass valve, it merges with the 100% low-pressure bypass 6-valve pipeline of the condensing machine to form a main pipe, and then connects to the low-pressure bypass interface of the condenser 3.

A method for starting the bypass system of the combined cycle extraction and back pressure unit as described above, the method for starting includes the following steps:

a) The pumping condensing unit is first started through the 100% gas turbine load high, medium and low pressure bypass, and the bypass valve is closed after reaching a stable operating condition;

b) The extraction condensing unit extracts steam for heat supply to the outside, and maintains stable operation after gradually reaching the maximum extraction condition;

c) The waste heat boiler of the back pressure unit starts to run. When the parameters of back pressure machine running are not reached, the main steam generated by the waste heat boiler is discharged into the condenser through the back pressure machine 10% gas turbine load high-pressure bypass. When the parameters meet the back pressure machine After the compressor has changed the parameters, the main steam enters the back press, and the high pressure bypass of the back press is turned off at 10% of the gas turbine load;

d) After the back pressure unit runs, the exhaust pipe simultaneously produces steam that does not meet the heating conditions. At this time, the electric gate valve of the exhaust pipe is closed, and the exhaust steam is discharged into the condensate through the 15% gas turbine load medium pressure bypass of the back pressure machine. When the exhaust steam of the back pressure machine meets the requirements of the heating parameters, close the medium pressure bypass of the back pressure machine at 15% of the gas turbine load;

e) The low pressure steam generated by the waste heat boiler of the back pressure unit is discharged into the condenser through the low pressure bypass of the back pressure machine with 100% gas turbine load before reaching the rated parameters. When the rated parameters are reached, the low pressure steam enters the waste heat boiler and the back pressure is turned off 100% gas turbine load low pressure bypass.

Claims (2)

1. A start-up bypass system of combined cycle extraction condensing and back pressure unit, which mainly includes: extraction condensing type steam turbine unit (1), back pressure type steam turbine unit (2), condenser (3), described The extraction condensing steam turbine unit (1) and the back pressure steam turbine unit (2) are equipped with the same waste heat boiler capacity, and the extraction condensing steam turbine unit (1) is equipped with a condenser with a capacity of 100% of the waste heat boiler steam; When the extraction condensing steam turbine unit is in the maximum steam extraction condition, the condenser can accommodate the amount of steam generated when the back pressure steam turbine unit (2) starts; it is characterized in that the extraction condensing steam turbine unit (1) is There are three bypasses, including condensing unit 100% gas turbine load high pressure bypass (4), condensing unit 100% gas turbine load medium pressure bypass (5) and condensing unit 100% gas turbine load low pressure bypass ( 6); The back-pressure steam turbine unit (2) is provided with four bypasses in total, including a high-pressure bypass (7) for 10% of the gas turbine load of the back-pressure machine, and a medium-pressure bypass (8) for 10% of the gas turbine load of the back-pressure machine. , Back pressure machine 15% gas turbine load medium pressure bypass (9) and back pressure machine 100% gas turbine load low pressure bypass (10); The 100% gas turbine load high-pressure bypass (4) of the condensing unit is drawn from the main steam pipe in front of the main steam valve of the condensing unit, and is connected to the high-pressure side of the condenser (3) through the bypass valve for temperature reduction and decompression. Road interface; the 100% gas turbine load medium pressure bypass (5) of the extraction condenser is drawn from the medium pressure steam pipe in front of the medium pressure main steam valve, and is connected to the condenser (3) through the bypass valve for temperature reduction and pressure reduction Medium-pressure bypass interface; the 100% gas turbine load low-pressure bypass (6) of the extraction condenser is drawn from the low-pressure steam pipe in front of the low-pressure main steam valve, and is connected to the condenser (3 ) low-pressure bypass interface; The 10% gas turbine load high-pressure bypass (7) of the back pressure machine is drawn from the main steam pipe in front of the main steam valve of the back pressure machine, and connected to the condensing machine with 100% gas turbine load The pipeline behind the valve of the high-pressure bypass (4) is connected to the high-pressure bypass interface of the condenser (3); the medium-pressure bypass (8) of the back pressure machine with 10% gas turbine load is connected from the middle pressure main steam valve The pressure steam pipe is led out, and after the bypass valve reduces temperature and pressure, it is connected to the pipeline after the valve of the 100% gas turbine load medium pressure bypass (5) of the extraction condensing machine, and connected to the condenser (3) medium pressure bypass Interface; the 15% gas turbine load medium pressure bypass (9) of the back pressure machine is drawn from the exhaust pipe of the back pressure machine. Pressure bypass (5), back pressure machine 10% gas turbine load medium pressure bypass (8) After the valve pipes are merged into a main pipe, they are connected to the medium pressure bypass interface of the condenser (3); Compressor 100% gas turbine load low-pressure bypass (10) leads from the low-pressure steam pipe in front of the low-pressure main steam valve. Connect to the low-pressure bypass port of the condenser (3) after forming a main pipe. 2. a method for starting the bypass system of combined cycle extraction and back pressure unit as claimed in claim 1, characterized in that said method for starting comprises the steps: a) The pumping condensing unit is first started through the 100% gas turbine load high, medium and low pressure bypass, and the bypass valve is closed after reaching a stable operating condition; b) The extraction condensing unit extracts steam for heat supply to the outside, and maintains stable operation after gradually reaching the maximum extraction condition; c) The waste heat boiler of the back pressure unit starts to run. When the parameters of back pressure machine running are not reached, the main steam generated by the waste heat boiler is discharged into the condenser through the back pressure machine 10% gas turbine load high-pressure bypass. When the parameters meet the back pressure machine After the compressor has changed the parameters, the main steam enters the back press, and the high pressure bypass of the back press is turned off at 10% of the gas turbine load; d) After the back pressure unit runs, the exhaust pipe simultaneously produces steam that does not meet the heating conditions. At this time, the electric gate valve of the exhaust pipe is closed, and the exhaust steam is discharged into the condensate through the 15% gas turbine load medium pressure bypass of the back pressure machine. When the exhaust steam of the back pressure machine meets the requirements of the heating parameters, close the medium pressure bypass of the back pressure machine at 15% of the gas turbine load; e) The low-pressure steam produced by the waste heat boiler of the back pressure unit is discharged into the condenser through the low-pressure bypass of the back pressure machine with 100% gas turbine load before reaching the rated parameters, and when the rated parameters are reached, the back pressure machine is turned off at 100% gas turbine load Low pressure bypass.