TWI842860B - Condenser pre-pressurization system can improve the power generation efficiency of thermal power plant steam turbines - Google Patents

Abstract

A condenser pre-pressurization system for improving the power generation efficiency of a steam turbine in a thermal power plant is used in a steam turbine in a thermal power plant. The steam turbine uses steam as a power source and converts the thermal energy of the steam into mechanical work to drive the generator of the thermal power plant. After the pressurized steam passes through the steam turbine and drives the steam turbine, the steam will form exhaust steam and be discharged to the outside through the exhaust end of the steam turbine; the condenser pre-pressurization system includes a booster pump system, including an inlet end, an outlet end, and at least one booster pump; the inlet end is connected to the exhaust end of the steam turbine; the exhaust steam discharged from the exhaust end of the steam turbine is input from the inlet end to the at least one booster pump for pressurization and then output from the outlet end; the outlet end of the booster pump system is connected to a condenser; the condenser is used to condense the pressurized exhaust steam from the booster pump system into water.

Description

Condenser pre-boosting system that can improve the power generation efficiency of steam turbines in thermal power plants

The present invention relates to a booster system used in a steam turbine of a thermal power plant, and in particular to a condenser pre-boosting system that can improve the power generation efficiency of the steam turbine of a thermal power plant.

In a thermal power plant, the main core equipment for power generation is the steam turbine, which uses the characteristic of the steam turbine to convert the thermal energy of steam into mechanical work to generate electricity. Usually, a condenser is equipped on the exhaust side of the steam turbine. In addition to condensing the exhaust steam of the steam turbine into water for reuse in the boiler, the condenser can also form and maintain a vacuum at the exhaust of the steam turbine. The steam turbine and the condenser are connected by a pipeline. The vacuum of the condenser will directly affect the efficiency of the generator. The reason is that after the pressurized steam passes through the steam turbine and drives the steam turbine to rotate, it will lose power and form exhaust steam. At this time, the back pressure (vacuum) generated by the condenser will directly affect the exhaust steam removal speed and the work efficiency of the steam turbine, and directly affect the power generation efficiency of the steam turbine.

At present, the exhaust steam of the steam turbine of the thermal power plant is usually input into the condenser in the form of natural pressure difference migration. In order to improve the power generation efficiency of the steam turbine, the common method is to try to reduce the back pressure value of the condenser to maximize the pressure difference between the steam turbine and the condenser to accelerate the migration of steam and improve the power generation efficiency of the steam turbine. For some large-scale power generating units, within a certain range, for every 1KPa increase in vacuum, the coal consumption per kilowatt-hour may be reduced by 3 grams.

However, since the condensers of thermal power plants basically use water as the condensing medium, and these media need to rely on cold sources obtained from nature (water or air from rivers, lakes, and seas) for cooling, the water temperature in the condenser will be affected by the natural temperature and water temperature due to seasonal changes. As we all know, the saturated vapor pressure of water is related to temperature. Therefore, thermal power plants cannot always keep the condenser vacuum near the optimal vacuum required by the generator design. This means that the working vacuum of the generator is not near the optimal vacuum that is most conducive to improving coal combustion efficiency most of the time during the year.

There is usually a vacuum system at the back end of the common condenser in thermal power plants, and most of them are large water ring pumps or other forms of systems. A few still retain steam vacuum pump systems or water jet pump vacuum systems. After the above vacuum system forms a vacuum state in the condenser (for a short time, usually not more than 2 hours), it is only used to maintain the vacuum degree of the condenser, that is, to continuously extract the non-condensable gas in the condenser during continuous operation, and increase the vacuum volume of these vacuum pumps to avoid the vacuum degree from decreasing due to water ingress of non-condensable gas. However, in terms of increasing vacuum and reducing back pressure, due to the influence of factors such as excessive water and its low-pressure accelerated evaporation characteristics, increasing the vacuum pump unit's vacuum capacity often has a small effect on improving the vacuum degree of the condenser.

Therefore, this case hopes to propose a new condenser pre-pressurization system that can improve the power generation efficiency of the steam turbine in the thermal power plant to solve the above-mentioned technical defects.

Therefore, the purpose of the present invention is to solve the above-mentioned problems in the known technology. The present invention proposes a condenser pre-pressurization system that can improve the power generation efficiency of the steam turbine of the thermal power plant. A booster pump system is added between the steam turbine and the rear condenser. The mechanical exhaust mechanism of the booster pump system is applied to change the natural exhaust mode of the exhaust steam in the original steam turbine to forced exhaust, and the exhaust speed of the steam turbine can be increased, which is equivalent to reducing the back pressure of the condenser, thereby improving the power generation efficiency of the steam turbine, thereby saving the unit coal consumption required for the steam turbine to generate electricity, and achieving the purpose of improving the power generation efficiency of the steam turbine of the power plant. And the power generation efficiency of the power plant is no longer affected by the ambient temperature, vacuum leakage and the size of the vacuum pump, so that the generator is in an optimized state and is not affected by the natural ambient temperature. Each booster pump in the booster pump system of this case can be connected in series, in parallel, or in multiple series and then in parallel according to the needs, which can maximize the migration speed of the exhaust steam. The biggest difference between this case and the vacuum system composed of the power plant system in the known technology and the existing transformation technology is that the booster pump system is directly installed between the turbine and the condenser, rather than the method used in the market to increase the condenser vacuum to indirectly improve the turbine power generation efficiency. Therefore, the application of the structure of this case can effectively avoid the characteristics of the condenser being affected by the cooling water temperature and leakage rate, and can more directly and efficiently make the system vacuum not affected by the season, and always stabilize in the range with the highest turbine power generation efficiency.

In order to achieve the above-mentioned purpose, the present invention proposes a condenser pre-pressurization system that can improve the power generation efficiency of the steam turbine of the thermal power plant. The system is used in the steam turbine of the thermal power plant. The steam turbine uses steam as power and converts the heat energy of the steam into mechanical work to drive the generator of the thermal power plant. The steam turbine has an exhaust end. After the pressurized steam passes through the steam turbine and drives the steam turbine, the steam will lose power and form exhaust steam, which is discharged to the outside through the exhaust end. The condenser pre-pressurization system includes a booster pump system, including an inlet end, an outlet end, and a booster pump system. end, and at least one booster pump; the inlet end of the booster pump system is connected to the exhaust end of the steam turbine via an input pipeline; each booster pump includes an inlet end and an exhaust end; the exhaust steam discharged from the exhaust end of the steam turbine is input from the inlet end to the at least one booster pump for boosting and then output from the outlet end; and a condenser includes an input end, and the outlet end of the booster pump system is connected to the input end of the condenser via an output pipeline; the condenser is used to receive the boosted exhaust steam from the booster pump system and condense the boosted exhaust steam into water.

The following description will provide a better understanding of the features and advantages of the present invention. Please refer to the attached figures while reading.

1: Steam turbine

2:Transmission pipeline

3: Booster pump

4: Condenser

5: Booster pump system

6: Vacuum system

7: Soda separator

11: Exhaust end

21: Input pipeline

22: Output pipeline

31: Intake end

32: Exhaust end

33: Valve

41: Input port

42: Output terminal

51: Entrance end

52:Exit port

71: Circulating fluid heat exchanger

81: Drive motor

82: Controlling agency

91: Cooling mechanism

92: Pressure sensor

93: Temperature sensor

Figure 1 shows a schematic diagram of the component combination of this case.

The component assembly schematic diagram in Figure 2 shows the multiple booster pumps in this case connected in series.

The component assembly schematic diagram in Figure 3 shows that multiple booster pumps in this case are connected in series, in which the vacuum system is connected to a steam-water separator.

The component combination diagram in Figure 4 shows that multiple booster pumps in this case are connected in series, with the condenser connected to a steam-water separator.

The component assembly schematic diagram in Figure 5 shows the parallel connection of multiple booster pumps in this case.

The component assembly schematic diagram in Figure 6 shows that multiple booster pumps in this case are connected in parallel, and the vacuum system is connected to a steam-water separator.

The component assembly schematic diagram in Figure 7 shows that multiple booster pumps in this case are connected in parallel, with the condenser connected to a steam-water separator.

The schematic diagram of the component combination in Figure 8 shows the type of multiple booster pumps in this case forming multiple sets of booster pumps connected in parallel.

Figure 9 shows a block diagram of the booster pump, related electrical components, and detection control circuit in this case.

The following is a detailed description of the structural composition of this case, the effects and advantages it can produce, and a preferred embodiment of this case with the help of diagrams.

Please refer to Figures 1 to 9, which show the condenser pre-pressurization system of the present invention that can improve the power generation efficiency of the steam turbine in a thermal power plant, including the following components:

A steam turbine 1 has an exhaust end 11. After the pressurized steam passes through the steam turbine 1 and drives the steam turbine 1, the steam will lose power and form exhaust steam, which is discharged to the outside through the exhaust end 11. Generally, the steam turbine 1 is a steam turbine used for power generation in a thermal power plant. The steam turbine 1 uses steam as power and converts the thermal energy of the steam into mechanical work to drive the generator of the thermal power plant.

A booster pump system 5 includes an inlet port 51, an outlet port 52, and at least one booster pump 3. The inlet port 51 of the booster pump system 5 is connected to the exhaust port 11 of the steam turbine 1 via an input pipeline 21. Each booster pump 3 includes an inlet port 31 and an exhaust port 32. The exhaust steam discharged from the exhaust port 11 of the steam turbine 1 is input from the inlet port 51 to the at least one booster pump 3 for boosting and then output from the outlet port 52. The booster pump 3 is a roots vacuum pump, a centrifugal pump, a turbine, a jet pump, or a gas moving power device with a large suction volume, etc., which can promote the gas migration speed. Therefore, by mechanically extracting the exhaust steam output by the steam turbine 1 through the at least one booster pump 3, the purpose of forced exhaust can be achieved.

As shown in FIG1 , the at least one booster pump 3 may be a single booster pump 3.

The at least one booster pump 3 can also be a plurality of booster pumps 3, wherein the plurality of booster pumps 3 can be connected in series or in parallel. As shown in FIG2 , the plurality of booster pumps 3 are connected in series to increase the pressure difference. The corresponding intake ends 31 and exhaust ends 32 of two adjacent booster pumps 3 are connected to each other via a delivery pipeline 2 to distribute the total pressure increase or pressure drop in the booster pump system 5 to the booster pumps 3 of each stage, thereby sharing the heat generated by the need to compress the air, maintaining the stable operation of each booster pump 3, and avoiding jamming due to overheating.

As shown in FIG5 , the multiple booster pumps 3 are connected in parallel, wherein the air intake ends 31 of all booster pumps 3 are connected in parallel to the input pipeline 21, and the air exhaust ends 32 of all booster pumps 3 are connected in parallel to the output pipeline 22, so as to increase the total air extraction volume of the booster pump system 5.

As shown in FIG8 , the multiple booster pumps 3 can also form multiple groups of booster pumps 3 in parallel, and the corresponding intake ends 31 and exhaust ends 32 of two adjacent booster pumps 3 in each group are connected in series via the delivery pipeline 2, and the input pipeline 21 is connected in parallel to the corresponding intake ends 31 of the multiple groups of booster pumps 3, and the output pipeline 22 is connected in parallel to the corresponding exhaust ends 32 of the multiple groups of booster pumps 3, so that the exhaust steam migration speed can be maximized.

A condenser 4 includes an input end 41, and the outlet end 52 of the booster pump system 5 is connected to the input end 41 of the condenser 4 via an output pipeline 22. The condenser 4 is used to receive the pressurized exhaust steam from the booster pump system 5 and condense the pressurized exhaust steam into water. The condenser 4 can be a water condenser, an air condenser, or other types of condensers, etc.

The present case may also include a vacuum system 6, wherein the condenser 4 further includes an output port 42 connected to the vacuum system 6, and the vacuum system 6 is used to extract the non-condensable gas in the condenser 4, so that a vacuum is formed inside the condenser 4.

As shown in FIG. 3 and FIG. 6 , the present invention may further include a steam-water separator 7, which may be connected to the vacuum system 6. The steam-water separator 7 is used to separate the steam-water mixture output by the vacuum system 6 into air and liquid water. The liquid water is input into the steam-water separator 7 and formed into working water with a suitable water temperature by the circulating liquid heat exchanger 71 and is input back to the vacuum system 6 to serve as the working circulating liquid required for the operation of the vacuum system 6.

As shown in Figures 4 and 7, the present invention may also not configure the vacuum system 6, but directly connect the steam-water separator 7 to the output end 42 of the condenser 4, and the steam-water separator 7 separates the steam-water mixture output by the condenser 4 into air and liquid water.

A valve 33 is installed at the air inlet end 31 of each booster pump 3 to close the corresponding booster pump 3 when necessary, so as to disconnect it from the operation of the entire booster pump system 5, thereby improving the reliability and controllability of the booster pump system 5.

Each of the booster pumps 3 forms a channel (not shown in the figure), so even if a booster pump 3 is stopped, the exhaust steam can still pass through the unused booster pump 3, so the steam turbine 1 will not be unusable and there will be no safety hazards to the original system.

Figure 9 shows a block diagram of the electromechanical components of each booster pump 3, which is mainly used to display the relevant electrical components and detection control circuits.

The booster pump 3 is connected to a drive motor 81, and the drive motor 81 is connected to a control mechanism 82, and the drive motor 81 is controlled by the control mechanism 82 to drive the booster pump 3. The control mechanism 82 can control the drive motor 81 in a variable frequency manner, and adjust the performance of the booster pump 3 according to the variable frequency characteristics. Variable frequency starting can maintain the safe and stable operation of the booster pump 3. Low frequency operation can save energy deeply, and high frequency operation can give full play to the boosting performance of the booster pump 3. By using variable frequency to adjust the operating speed of the booster pump system 5, the boosting degree can be increased or decreased, and the vacuum degree of the system can be adjusted within a wider range, so that the vacuum degree of the system is under the optimal vacuum condition required by the generator throughout the year, thereby preventing the generator from being affected by climate, seasons and weather, and improving the working efficiency of the generator throughout the year.

Each booster pump 3 is also connected to a cooling mechanism 91, and the cooling mechanism 91 is used to input cooling water into the booster pump 3 for cooling.

Each booster pump 3 is also equipped with a pressure sensor 92 and a temperature sensor 93. The pressure sensor 92 is used to detect the pipeline pressure of the booster pump 3, and the temperature sensor 93 is used to detect the temperature of the booster pump 3. The pressure sensor 92 and the temperature sensor 93 are connected to the control mechanism 82. The pressure value and temperature value detected by the pressure sensor 92 and the temperature sensor 93 are transmitted to the control mechanism 82 to control the drive motor 81 and the cooling mechanism 91 to protect the booster pump 3 from running stably.

The booster pump system 5 of this case can be supported by a fixed bracket (not shown in the figure). This structure is well known in the art and its details will not be described in detail.

The advantage of this case is that a booster pump system is added between the steam turbine and the rear condenser. The mechanical exhaust mechanism of the booster pump system is applied to change the natural exhaust mode of the exhaust steam in the original steam turbine to forced exhaust, which can increase the exhaust speed of the steam turbine, which is equivalent to reducing the back pressure of the condenser, thereby improving the power generation efficiency of the steam turbine, thereby saving the unit coal consumption required for the steam turbine to generate electricity, and achieving the purpose of improving the power generation efficiency of the power plant steam turbine. The power generation efficiency of the power plant is no longer affected by the ambient temperature, vacuum leakage and the size of the vacuum pump, so that the generator is in an optimized state and is not affected by the natural ambient temperature. The booster pumps in the booster pump system of this case can be connected in series, in parallel, or in multiple series and then in parallel according to the needs, which can maximize the migration speed of the exhaust steam.

The biggest difference between this case and the vacuum system composed of power plant systems in the prior art and existing transformation technologies is that a booster pump system is directly installed between the steam turbine and the condenser, rather than the method on the market (including the condenser vacuum energy-saving system previously invented by the inventor) of using vacuum acquisition equipment such as a mechanical pump or steam pump after the condenser to increase the condenser vacuum to indirectly improve the turbine power generation efficiency. Therefore, the application of the structure of this case can effectively avoid the characteristics of the condenser being affected by the cooling water temperature and leakage rate, and can more directly, more significantly and more efficiently make the system vacuum not affected by the season, and always stabilize in the range with the highest turbine power generation efficiency.

In summary, the humanized and considerate design of this case meets the actual needs. Its specific improvement of existing deficiencies is obviously a breakthrough in the known technology, and it does have the effect of enhancing the effectiveness, which is not easy to achieve. This case has not been published or disclosed in domestic and foreign literature and markets, and it has complied with the provisions of the Patent Law.

The above detailed description is a specific description of a feasible embodiment of the present invention, but the embodiment is not used to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the technical spirit of the present invention should be included in the patent scope of this case.

1: Steam turbine

3: Booster pump

4: Condenser

5: Booster pump system

6: Vacuum system

7: Soda separator

31: Intake end

32: Exhaust end

33: Valve

41: Input port

42: Output terminal

51: Entrance end

11: Exhaust end

21: Input pipeline

22: Output pipeline

52:Exit port

71: Circulating fluid heat exchanger

Claims (13)

A condenser pre-pressurization system for improving the power generation efficiency of a steam turbine in a thermal power plant is used in a steam turbine in a thermal power plant. The steam turbine uses steam as a power source and converts the heat energy of the steam into mechanical work to drive the generator of the thermal power plant. The steam turbine has an exhaust end. After the pressurized steam passes through the steam turbine and drives the steam turbine, the steam will lose power and form exhaust steam, which is discharged to the outside through the exhaust end. The condenser pre-pressurization system comprises: a booster pump system, comprising an inlet end, an outlet end, and at least one booster pump; the inlet end of the booster pump system is connected to the exhaust end of the steam turbine through an input pipeline; each of the booster pumps comprises an intake end and an outlet end. exhaust end; the exhaust steam discharged from the exhaust end of the steam turbine is input from the inlet end to the at least one booster pump for boosting and then output from the outlet end; and a condenser includes an input end, and the outlet end of the booster pump system is connected to the input end of the condenser through an output pipeline; the condenser is used to receive the boosted exhaust steam from the booster pump system and condense the boosted exhaust steam into water; wherein the booster pump is connected to a drive motor, the drive motor is connected to a control mechanism, and the control mechanism controls the drive motor to drive the booster pump; each booster pump is also connected to a cooling mechanism, and the cooling mechanism is used to input cooling water into the booster pump for cooling. As described in Item 1 of the patent application scope, a condenser pre-boosting system capable of improving the power generation efficiency of a steam turbine in a thermal power plant, wherein the at least one boosting pump is a single boosting pump. As described in Item 1 of the patent application scope, the condenser pre-boosting system can improve the power generation efficiency of the steam turbine of the thermal power plant, wherein the at least one boosting pump is a plurality of boosting pumps, and the plurality of boosting pumps form a parallel type. As described in Item 1 of the patent application scope, the condenser pre-boosting system can improve the power generation efficiency of the steam turbine of the thermal power plant, wherein the at least one boosting pump is a plurality of boosting pumps, and the plurality of boosting pumps are connected in series to increase the pressure difference; wherein the corresponding air intake ends and exhaust ends of two adjacent boosting pumps are connected to each other via a transmission pipeline. As described in Item 1 of the patent application scope, a condenser pre-boosting system capable of improving the power generation efficiency of a steam turbine in a thermal power plant, wherein the booster pump is a gas pump capable of promoting the gas migration speed. As described in Item 1 of the patent application scope, a condenser pre-boosting system that can improve the power generation efficiency of a thermal power plant steam turbine, wherein the booster pump is selected from a Roots vacuum pump, a centrifugal pump, or a turbine, a jet pump, or a gas moving power device with a large suction volume. As described in Item 1 of the patent application scope, a condenser pre-boosting system that can improve the power generation efficiency of a steam turbine in a thermal power plant, wherein a valve is installed at the air inlet end of each booster pump to shut down the corresponding booster pump when necessary, so as to disconnect it from the operation of the entire booster pump system. As described in Item 1 of the patent application scope, a condenser pre-pressurization system that can improve the power generation efficiency of a thermal power plant steam turbine, wherein the condenser is a water-cooled condenser or an air-cooled condenser. As described in Item 1 of the patent application scope, the condenser pre-pressurization system that can improve the power generation efficiency of the steam turbine of the thermal power plant also includes a vacuum pumping system, wherein the condenser also includes an output end connected to the vacuum pumping system, and the vacuum pumping system is used to extract the non-condensable gas in the condenser so that a vacuum is formed inside the condenser. As described in Item 9 of the patent application, the condenser pre-pressurization system capable of improving the power generation efficiency of the steam turbine of a thermal power plant also includes a steam-water separator, wherein the vacuum system is connected to the steam-water separator, and the steam-water separator is used to separate the steam-water mixture output by the vacuum system into air and liquid water. As described in Item 1 of the patent application scope, the condenser pre-pressurization system capable of improving the power generation efficiency of the steam transmission machine of the thermal power plant also includes a steam-water separator, wherein the condenser also includes an output end connected to the steam-water separator, and the steam-water separator is used to separate the steam-water mixture output by the condenser into air and liquid water. As described in Item 1 of the patent application scope, the condenser pre-boosting system can improve the power generation efficiency of the steam turbine in the thermal power plant, wherein the control mechanism uses a variable frequency method to control the drive motor and adjusts the performance of the booster pump according to the variable frequency characteristics. As described in item 1 of the patent application scope, the condenser pre-boosting system that can improve the power generation efficiency of the steam turbine of the thermal power plant, wherein each boosting pump is also equipped with a pressure sensor and a temperature sensor; the pressure sensor and the temperature sensor are connected to the control mechanism; the pressure value and the temperature value detected by the pressure sensor and the temperature sensor are transmitted to the control mechanism to control the drive motor and the cooling mechanism to protect the boosting pump from running stably.

Images