TCA water supply system of gas-steam combined cycle waste heat boiler

Abstract

The utility model relates to a TCA water supply system of a gas-steam combined cycle waste heat boiler, and belongs to the technical field of boiler equipment. The device comprises a condensate water pipeline and a low-pressure water supply pipeline, a high-pressure water supply pump is arranged on the low-pressure water supply pipeline, the inlet end of the low-pressure water supply pipeline is connected with a low-pressure steam pocket, and the outlet end of the low-pressure water supply pipeline is connected with the water supply inlet end of a TCA cooler; the inlet end of the condensate water pipeline is connected with the condensate pump, and the outlet end of the condensate water pipeline is connected with the inlet end of the high-pressure feed pump; under the condition that the operation requirement of the TCA cooler is completely met, a TCA pump and corresponding valve groups and pipelines are omitted on the condensate water pipeline, so that the configuration cost of the system is reduced, the occupied space of the system is reduced, the control logic of the system is simplified, and the economical efficiency of the whole unit is improved.

Description

Technical Field

[0001] The utility model relates to a TCA water supply system for a gas-steam combined cycle waste heat boiler, belonging to the technical field of boiler equipment. Background Art

[0002] As the country's requirements for air quality become higher and higher, especially the emphasis on PM2.5 indicators, the use of clean energy and the realization of low pollution emissions, high-efficiency gas-steam combined power generation units are becoming more and more widely used. Not only large-capacity, high-parameter combined cycle units have been favored by many users, but even small-scale combined cycle distributed energy station projects have also been booming with their advantages of energy saving, environmental protection, rapid investment and construction, and high efficiency of generator sets. The boiler adapts to the peak-shaving operation and rapid start-up of the unit. The operation effect of the waste heat boiler directly affects the efficiency of the combined cycle generator set. Therefore, the safety and economic operation of the waste heat boiler have received great attention.

[0003] When the gas turbine is in normal operation, the turbine rotor and the turbine blades exposed to high-temperature combustion gas are cooled by air cooling. The cooling air is extracted from the compressor exhaust port, cooled by the TCA cooler, and then sent to the turbine rotor and (or) blades. The flow rate and temperature of the cooling air on the TCA cooler depend on the operating state of the gas turbine. To meet the different operating states of the gas turbine, the air temperature at the cooling air outlet on the TCA cooler and the water temperature of the cooling water must meet the following requirements:

[0004] During the start-up phase of the gas turbine (from the start-up (ignition) of the gas turbine to full speed and no-load), the air temperature at the outlet of the TCA cooler should be lower than 100°C, so the water temperature at the cooling water inlet of the TCA cooler needs to be maintained below 60°C;

[0005] After the engine reaches full speed and no-load, the TCA cooler outlet air temperature will be adjusted during the trial operation phase. To avoid water accumulation inside the cooling air pipeline due to air dew point, the TCA cooler outlet air temperature should be higher than 90°C.

[0006] In view of the above operating requirements of TCA cooler, the existing TCA water supply system is as follows: Figure 1As shown, at the initial start-up of the unit, the feed water inlet 6 uses another condensate pipe 1 connected to the condensate pump 3, and draws a condensate from the outlet of the condensate pump 3 and sends it to the feed water inlet 6 after the TCA pump 9 increases the head; when the unit is operating normally, the feed water inlet 6 of the TCA cooler is connected to the low-pressure feed water pipe 2, and the low-pressure feed water from the low-pressure drum 5 is sent to the feed water inlet 6 through the high-pressure feed water pump 4. During the operation of the unit, in the start-up stage of the engine, the TCA pump 9 is running, and the condensate from the condensate pump 3 (water temperature is about 30-40℃) provides cooling feed water for the TCA cooler, so that the outlet air temperature of the TCA cooler is lower than 100℃; when the engine reaches full speed and no-load, the TCA pump 9 is turned off, and the low-pressure feed water from the low-pressure drum 5 (water temperature is 180℃) provides cooling feed water for the TCA cooler, which can increase the outlet air temperature of the TCA cooler to above 90℃.

[0007] However, this TCA water supply system has the following disadvantages: the TCA pump, valve group and connecting pipe of the condensate pipeline 1 not only need to occupy a large production site, but also the configuration cost of the unit is high, so the economy of the unit is poor. Summary of the invention

[0008] The utility model mainly solves the technical problem of poor unit economy caused by high system configuration cost in the prior art, and provides a TCA water feed system for a gas-steam combined cycle waste heat boiler with low configuration cost.

[0009] The utility model aims to solve the above-mentioned technical problems mainly through the following technical solutions: the utility model comprises a condensate pipeline and a low-pressure water supply pipeline, a high-pressure water supply pump is arranged on the low-pressure water supply pipeline, the inlet end of the low-pressure water supply pipeline is connected to the low-pressure steam drum and the outlet end is connected to the water supply inlet end of the TCA cooler, and is characterized in that a regulating valve is arranged on the condensate pipeline, the inlet end of the condensate pipeline is connected to the condensate pump and the outlet end is connected to the inlet end of the high-pressure water supply pump, a thermometer is arranged at the inlet end of the high-pressure water supply pump, the water temperature change at the inlet end of the high-pressure water supply pump is monitored by the thermometer and controlled by adjusting the condensate flow rate of the condensate pipeline by the regulating valve.

[0010] Preferably, the water temperature change rate at the inlet end of the high-pressure water supply pump is lower than 50°C / min.

[0011] The utility model has a simple structure and has the following advantages:

[0012] In the utility model, the condensate pipeline is connected between the condensate pump and the inlet end of the high-pressure feed water pump, and a regulating valve is arranged on the condensate pipeline to regulate and control the condensate flow rate, and a temperature measuring instrument for monitoring the water temperature is arranged at the inlet end of the high-pressure feed water pump. During the start-up phase of the engine, the condensate flow rate is increased by the regulating valve, and the condensate (water temperature is about 30-40°C) is sent to the TCA cooler through the high-pressure feed water pump to cool the cooling air, so that the outlet air temperature of the TCA cooler is lower than 100°C; as the engine load increases, the condensate flow rate is reduced by the regulating valve, and the condensate is mixed with the low-pressure feed water (about 180°C) from the low-pressure drum to increase the feed water temperature at the inlet end of the high-pressure feed water pump, so that the outlet air temperature of the TCA cooler is controlled above 90°C; after the engine reaches a certain speed, the outlet air temperature of the TCA cooler can be increased to a higher temperature above 90°C, at which time the condensate is cut off by the regulating valve, and the feed water sent to the TCA cooler is all provided by the low-pressure feed water from the low-pressure drum.

[0013] Therefore, while fully meeting the operating requirements of the TCA cooler, the utility model eliminates the TCA pump and the corresponding valve group and connecting pipes in the condensate water pipeline, thereby reducing the configuration cost of the system, reducing the site occupied by the system, and simplifying the control logic of the system, thereby improving the overall economy of the unit.

[0014] Furthermore, the water temperature change rate at the inlet of the high-pressure feed water pump is lower than 50°C / min. When the condensate flow is controlled by the regulating valve to adjust the water temperature change at the inlet of the high-pressure feed water pump, the temperature change at the inlet of the high-pressure feed water pump is monitored by a thermometer to control the water temperature change rate at the inlet of the high-pressure feed water pump to be lower than 50°C / min. This is conducive to improving the operating conditions of the high-pressure feed water pump, which can not only meet the operating requirements of the unit's long-term daily start and stop, but also avoid fatigue damage to the pump body of the high-pressure feed water pump due to repeated rapid changes in water temperature, thereby improving the service life of the high-pressure feed water pump and the stability of the operation of the water supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 It is a schematic diagram of the prior art;

[0016] Attached Figure 2 It is a schematic diagram of a preferred embodiment of the utility model.

[0017] Explanation of the reference numerals: 1. Condensate pipeline; 2. Low-pressure feed water pipeline; 3. Condensate pump; 4. High-pressure feed water pump; 5. Low-pressure steam drum; 6. Feed water inlet; 7. Regulating valve; 8. Thermometer; 9. TCA pump. DETAILED DESCRIPTION

[0018] The technical solution of the utility model is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0019] Embodiment 1: As attached Figure 2 As shown, the utility model comprises a condensate water pipeline 1 and a low-pressure water supply pipeline 2, a high-pressure water supply pump 4 is arranged on the low-pressure water supply pipeline 2, the inlet end of the low-pressure water supply pipeline 2 is connected to the low-pressure steam drum 5 and the outlet end is connected to the water supply inlet end 6 of the TCA cooler;

[0020] A regulating valve 7 is provided on the condensate water pipeline 1, the inlet end of the condensate water pipeline 1 is connected to the condensate pump 3 and the outlet end is connected to the inlet end of the high-pressure feed water pump 4;

[0021] A temperature measuring instrument 8 is provided at the inlet end of the high-pressure water supply pump 4;

[0022] The water temperature change at the inlet end of the high-pressure water supply pump 4 is monitored by a temperature measuring instrument 8 and the condensate flow rate of the condensate water pipeline 1 is controlled by adjusting the regulating valve 7;

[0023] The water temperature change rate at the inlet end of the high-pressure water supply pump 4 is lower than 50°C / min.

[0024] When the utility model is used, at the start-up stage of the combustion engine, the flow rate of the condensate pipeline 1 is increased through the regulating valve 7, and the condensate (water temperature is about 30-40°C) is sent to the water inlet end 6 of the TCA cooler through the high-pressure water pump 4 at the inlet end of the high-pressure water pump 4, and the water entering the TCA cooler is used to cool the cooling air, so that the outlet air temperature of the TCA cooler is lower than 100°C;

[0025] As the load of the engine increases, the condensate flow rate is reduced by regulating valve 7, so that the feed water temperature at the inlet end of the high-pressure feed water pump 4 is increased, and the outlet air temperature of the TCA cooler can be controlled above 90°C; after the engine reaches a certain speed, the outlet air temperature of the TCA cooler can be increased to a higher temperature above 90°C; when the low-pressure feed water (water temperature of about 180°C) from the low-pressure drum 5 fully meets the water temperature requirement of the TCA cooler for the feed water, the condensate is cut off by regulating valve 7, and the feed water sent to the feed water inlet end 6 is all from the low-pressure feed water of the low-pressure drum 5;

[0026] When the water temperature at the inlet of the high-pressure water pump 4 is adjusted by controlling the condensed water flow rate through the regulating valve 7, the temperature change at the inlet of the high-pressure water pump 4 is monitored by the thermometer 8, and the water temperature change rate is controlled below 50°C / min.

[0027] Of course, the above drawings and embodiments are only used to explain and illustrate the utility model, and cannot be used as an improper limitation of the utility model. Any technical solutions obtained by those skilled in the art making equivalent adjustments and changes based on the utility model fall within the protection scope of the utility model.

Claims

1. A TCA water supply system for a gas-steam combined cycle waste heat boiler, comprising a condensate water pipeline (1) and a low-pressure water supply pipeline (2), wherein the low-pressure water supply pipeline (2) is provided with a high-pressure water supply pump (4), the inlet end of the low-pressure water supply pipeline (2) is connected to a low-pressure steam drum (5) and the outlet end is connected to a water supply inlet end (6) of a TCA cooler, characterized in that: The condensate pipeline (1) is provided with a regulating valve (7); the inlet end of the condensate pipeline (1) is connected to the condensate pump (3) and the outlet end is connected to the inlet end of the high-pressure water supply pump (4); the inlet end of the high-pressure water supply pump (4) is provided with a thermometer (8); the change of water temperature at the inlet end of the high-pressure water supply pump (4) is monitored by the thermometer (8) and controlled by adjusting the condensate flow rate of the condensate pipeline (1) through the regulating valve (7).

2. A gas-steam combined cycle waste heat boiler TCA water supply system according to claim 1, characterized in that: The water temperature change rate at the inlet end of the high-pressure water supply pump (4) is lower than 50°C / min.

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