Steam turbine generator system arranged at high position and low position

Abstract

The invention provides a steam turbine generator system arranged at a high position and a low position, which at least comprises a high-position shaft system arranged at an elevation position close to an inlet header and an outlet header of a superheater and a reheater, a high-pressure cylinder, an intermediate-pressure cylinder, a generator, a low-pressure cylinder, a generator and a condenser, wherein the low-pressure cylinder, the generator and the condenser are arranged on a low-position shaft system; the communicating pipe is connected with the steam exhaust end of a medium-pressure cylinder and the steam inlet end of a low-pressure cylinder on the high-position shaft system, the valve is arranged at the steam inlet end of the low-pressure cylinder, and further, the communicating pipe in front of the steam inlet valve of the low-pressure cylinder enters a heating heat exchange station through a heating valve and a pipeline. By adjusting the heat supply valve and the low-pressure cylinder steam inlet valve, more flexible heat supply steam use adjustment can be realized. By means of the low-pressure cylinder steam inlet valve, steam entering the low-pressure cylinder can be adjusted according to specific seasons and loads, so that commissioning and removing functions of the low-pressure cylinder and a low-position shaft system and adjustment of the steam inlet amount and heating steam pressure maintaining in the heating season are achieved, then the optimal all-season and full-load operation working condition is achieved, and the purposes of saving energy and reducing consumption are achieved.

Description

Technical Field

[0001] The invention relates to a high-low position arranged steam turbine generator system, belonging to the field of thermal power generation. Background Art

[0002] In recent years, on the one hand, with the increase of steam parameters and reheat times, the length of high-temperature and high-pressure steam pipelines is relatively long, the investment is large, and it brings pipeline pressure loss and heat loss, affecting the economic efficiency of the unit. On the other hand, with the continuous development of new energy such as wind energy and solar energy, thermal power has been transformed into a supporting and regulating energy source. In order to ensure the safe power supply and power quality of the power grid, coal-fired thermal power units have to take on the main role of peak load regulation, and it is normal for large thermal power units to operate frequently at low load conditions.

[0003] Generally, under the design conditions, the flow of the steam turbine can maintain the best efficiency. However, once it deviates from the design conditions, such as in summer conditions, due to the high circulating water temperature and high unit back pressure, the volume flow of the low-pressure cylinder exhaust steam drops significantly, resulting in an increase in the residual speed loss. In particular, when the unit is in low-load operation, the actual volume flow of the low-pressure cylinder exhaust steam is seriously less than that of the design conditions, resulting in a relatively large increase in the exhaust residual speed loss of the low-pressure cylinder and a significant decrease in efficiency. Similarly, in winter conditions, when the unit is running at high load, the exhaust area of ​​the low-pressure cylinder is often insufficient, causing back pressure blockage problems, resulting in insufficient effective enthalpy drop of the low-pressure cylinder, thereby affecting the economy of the unit.

[0004] The design of existing large-scale thermal power generation steam turbines often takes into account the average performance throughout the year. The design operating conditions are all designed according to the average back pressure. The summer and winter conditions that deviate from the design conditions have to sacrifice a certain degree of economy. Otherwise, if designed according to winter conditions, the summer conditions will deviate more seriously from the optimal conditions and the efficiency will be lower. Similarly, if designed according to summer conditions, the low-pressure cylinder will be seriously blocked in the winter conditions, seriously affecting the effective use of low back pressure.

[0005] At present, the existing large units are generally equipped with 1 to 3 low-pressure cylinders. The larger the unit capacity or the lower the design back pressure, the more low-pressure cylinders there are. This is because the length of the last-stage blades of the existing low-pressure cylinders is limited. In order to increase the exhaust area of ​​the low-pressure cylinders, more low-pressure cylinders will be used. For current steam turbine manufacturers, the shaft system is usually arranged in the order of high, medium, and low-pressure cylinders. If the number of cylinders is large and a single-axis design is still adopted, the large expansion difference between the dynamic and static flow parts will become an important obstacle. For example, for a single-axis secondary reheat unit with low back pressure, three low-pressure cylinders need to be set, and the total number of cylinders reaches 6.

[0006] Considering the above-mentioned existing steam turbine designs, it is difficult to take into account other operating conditions in order to ensure the optimal design conditions, such as low-load operating conditions of the unit in summer or high-load operating conditions of the unit in winter, as well as the problem of excessive differential expansion caused by the use of conventional shafting arrangements. The technical personnel in this field are committed to developing a steam turbine system that can shorten the high-temperature and high-pressure steam pipeline, reduce pipeline investment and pressure loss, thereby improving the economy of the unit. At the same time, it can also control the gap between the dynamic and static low-pressure cylinders, and achieve a low blocking back pressure when the unit is fully loaded in winter, and maintain a high operating efficiency when the unit is under low load in summer, so as to achieve the optimal full-season and full-load operating conditions and achieve the purpose of energy saving and consumption reduction. In addition, it can also take into account the flexible heating needs. Summary of the invention

[0007] To achieve the above-mentioned purpose, the present invention provides a high-low arrangement of a steam turbine system, the system at least comprising a high-pressure cylinder, an intermediate-pressure cylinder and a generator on a high-position shaft system, and a low-pressure cylinder and a generator and a condenser on a low-position shaft system; and a connecting pipe connecting the exhaust end of the intermediate-pressure cylinder on the high-position shaft system with the steam inlet end of the low-pressure cylinder, and a valve arranged on the steam inlet end of the low-pressure cylinder, characterized in that the high-position shaft system is arranged at an elevation position close to the inlet and outlet manifolds of a superheater and a reheater, the valve on the steam inlet end of the low-pressure cylinder is arranged close to the inlet of the low-pressure cylinder, the exhaust steam of the high-pressure cylinder on the high-position shaft system enters the intermediate-pressure cylinder after one reheating, the exhaust steam of the intermediate-pressure cylinder enters the low-pressure cylinder through the valve on the steam inlet end of the low-pressure cylinder, and the exhaust steam of the low-pressure cylinder enters the condenser.

[0008] The valve on the steam inlet end of the low-pressure cylinder can be used to adjust the steam entering the low-pressure cylinder, thereby realizing the commissioning and cutting-off functions of the low-level shaft system. Specifically, the low-pressure cylinder on the low-level shaft system can be commissioned and cut off according to the unit load and seasonal conditions. For example, when the load is low in summer, the low-pressure cylinder and the generator on the low-level shaft system are cut off. Conversely, when the load is high in winter, the low-pressure cylinder and the generator on the low-level shaft system are commissioned.

[0009] Further, it is characterized in that the intermediate pressure cylinder of the high-level shaft system is divided into intermediate pressure cylinder one and intermediate pressure cylinder two, the exhaust steam of the high-pressure cylinder on the high-level shaft system enters the intermediate pressure cylinder one after one reheating, the exhaust steam of the intermediate pressure cylinder one enters the intermediate pressure cylinder two after two reheating, and the intermediate pressure cylinder two enters the low-pressure cylinder through the valve on the steam inlet end of the low-pressure cylinder.

[0010] The low-pressure cylinder of the low-position shaft system may be one or more; the exhaust steam of the low-pressure cylinder enters the condenser.

[0011] A clutch is arranged between the multiple low-pressure cylinders on the low-position shaft system. When operating in summer or / and low-load conditions, one of the low-pressure cylinders of the low-position shaft system can be completely cut off by the clutch, thereby avoiding the air blowing loss of the low-pressure cylinder.

[0012] Furthermore, it is characterized in that the exhaust of the medium-pressure cylinder or the second medium-pressure cylinder on the high-position shaft system and before the valve (referred to as the low-pressure cylinder steam inlet valve) at the steam inlet end of the low-pressure cylinder leads out a pipeline and enters the heating heat exchange station through a heating valve, and the heating valve is arranged at a three-way position close to the lead-out. Through the heating valve and the valve on the steam inlet end of the low-pressure cylinder, more flexible adjustment of heating steam can be achieved, that is, the steam inlet amount in the heating season is controlled and the regulation of the heating steam pressure is maintained, thereby achieving the optimal operating conditions of all seasons and full load, and achieving the purpose of energy saving and consumption reduction.

[0013] It should be noted that the heating valve is arranged near the three-way position of the lead-out and before the low-pressure cylinder steam inlet valve. The advantage is that, on the one hand, when the low-pressure cylinder is completely cut off, the exhaust steam of the medium-pressure cylinder or the medium-pressure second cylinder all enters the heating heat exchange station, which can avoid the "blind section" of the pipeline where no flow occurs, and maintain the hot standby state of the low-pressure cylinder steam inlet pipeline. On the other hand, it reduces the harmful volume between the high-level machine shaft system and the heating steam exchange station, avoiding the steam backflow from the heating heat exchange station to the high-level machine shaft system.

[0014] The high-low-position steam turbine optimization configuration system of the present invention can achieve the following technical effects:

[0015] 1. The technical solution of the present invention, since the high-level shaft system is arranged at the elevation position close to the inlet and outlet manifolds of the superheater and reheater, the main steam pipeline, the primary cold re-pipeline, and the primary hot re-pipeline (for the secondary reheat unit, it also includes the secondary cold re-pipeline and the secondary hot re-pipeline) can be greatly shortened, effectively reducing the pipeline investment, while reducing the pipeline pressure loss and heat dissipation loss, thereby improving the unit economy. In addition, for the double reheat unit, especially for the unit with low back pressure and need to set up 3 low-pressure cylinders, the scheme can reduce the number of cylinders of a single shaft system, and the relative expansion difference between the cylinder and the rotor (referred to as the expansion difference) is relatively small, that is, the gap between the dynamic and static low-pressure cylinders can be made relatively smaller, so that higher cylinder efficiency can be obtained, and the short shaft system is also conducive to the span arrangement of the entire plant. For the high-level arrangement of the high-level shaft system, the weight and length of the cylinder of the high-level shaft system itself directly affect the investment of the plant. Therefore, controlling the length and weight of the high-level shaft system can control the investment of the plant as a whole.

[0016] 3. Since the low-pressure cylinder and generator of the low-level shaft system can be put into operation or cut off by the valve on the connecting pipe according to the changes in the unit load and season (or back pressure), it is possible to maintain a low blocking back pressure under high-load conditions in winter, and to relatively reduce the residual speed loss of the low-pressure cylinder in operation when the unit is operating at low load in summer, thereby achieving the optimal full-season and full-load operating conditions and achieving the purpose of energy saving and consumption reduction.

[0017] 4. The technical case of the present invention is to exhaust steam from the intermediate pressure cylinder (or intermediate pressure cylinder 2) of the high-level shaft system to the steam inlet of the low-pressure cylinder of the low-level shaft system, and then set the steam to the heating heat exchange station, and set an adjustment valve on the steam inlet pipeline to the heating heat exchange station. Through the adjustment valve and the low-pressure cylinder inlet steam inlet valve on the low-level shaft system, more flexible adjustment of heating steam can be achieved. Compared with the conventional single shaft system that directly uses the intermediate pressure cylinder exhaust steam as the steam for the heating heat exchange station, but cannot cut off the low-pressure cylinder, when the unit load is reduced or the heating steam consumption increases, the conventional method can only be to "hold back the pressure" through the regulating valve at the steam inlet end of the low-pressure cylinder to meet the heating steam demand, so the throttling loss is large, which has a great impact on the economy of the entire unit. The technical solution of the present invention can achieve the cutting of a single low-pressure cylinder or two low-pressure cylinders through the cooperation of the low-pressure cylinder inlet steam inlet valve and the clutch, thereby achieving the optimal economy of the unit.

[0018] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 is a system schematic diagram of a specific embodiment of the present invention;

[0020] Markings in the figure: 1--high-pressure cylinder; 2--medium-pressure cylinder; 3--generator on the high-level shaft system; 4, connecting pipe; 5--valve; 6--low-pressure cylinder; 7--generator on the low-level shaft system; 8--condenser; 9--valve; 10--heating and heat exchange station; 11--clutch. DETAILED DESCRIPTION

[0021] Example 1

[0022] like Figure 1As shown, it is the first specific embodiment of a high-low arrangement steam turbine generator system of the present invention. It mainly includes a high-pressure cylinder, a medium-pressure cylinder and a generator on the high-level shaft system, and two low-pressure cylinders and a generator on the low-level shaft system. The unit adopts a single reheating method, that is, the exhaust steam of the high-pressure cylinder enters the medium-pressure cylinder after one reheating, and the exhaust steam of the medium-pressure cylinder enters the two low-pressure cylinders on the low-level shaft system through the valve at the steam inlet end of the low-pressure cylinder. Among them, the high-level shaft system is arranged at an elevation position close to the inlet and outlet manifolds of the superheater and reheater, for example, at an elevation of 65 to 85 meters (the elevation positions of the inlet and outlet manifolds of the superheater and reheater of different types of power plant units will have certain differences); while the low-pressure cylinder and the generator on the low-level shaft system are arranged at a conventional low position, for example, 17 meters, and the condenser is arranged at the 0-meter layer. Since the high-pressure cylinder and the medium-pressure cylinder are arranged at high positions, the main steam pipeline, the primary cold re-pipeline and the primary hot re-pipeline can be greatly shortened. This can shorten the length of these high-temperature and high-pressure pipelines, reduce pipeline investment and pressure loss, and thus improve the economy of the unit.

[0023] Since two low-pressure cylinders are arranged in the low-position shaft system, a clutch is also provided between the two low-pressure cylinders. In this way, the steam intake of the low-pressure cylinder can be adjusted through the valve at the steam inlet end of the low-pressure cylinder according to load and seasonal changes. Even in conjunction with the clutch, one or even two of the low-pressure cylinders can be completely cut off to achieve optimal economy at full load and in all seasons.

[0024] Example 2

[0025] like Figure 2 As shown, it is a second specific embodiment of a high-low arrangement steam turbine generator system of the present invention. It mainly includes a high-pressure cylinder, a medium-pressure cylinder 1, a medium-pressure cylinder 2 and a generator on the high-position shaft system, and a low-pressure cylinder and a generator on the low-position shaft system. The unit adopts a double reheating method, that is, the exhaust steam of the high-pressure cylinder enters the medium-pressure cylinder 1 after one reheating, and the exhaust steam of the medium-pressure cylinder 1 enters the medium-pressure cylinder 2 after the second reheating, and the exhaust steam of the medium-pressure cylinder 2 enters the low-pressure cylinder on the low-position shaft system through the valve on the connecting pipe. Among them, the high-position shaft system is arranged at an elevation position close to the inlet and outlet headers of the superheater and reheater, for example, 65 to 85 meters (the elevation positions of the inlet and outlet headers of the superheater and reheater of different types of power plant units will have certain differences); while the two low-pressure cylinders and the generator on the low-position shaft system are arranged according to the conventional low position, for example, 17 meters, and the condenser is arranged at the 0-meter layer. Since the high-pressure cylinder, medium-pressure cylinder 1 and medium-pressure cylinder 2 are all arranged at high positions, the main steam pipeline, primary cooling re-pipeline, primary hot re-pipeline, secondary cooling re-pipeline and secondary hot re-pipeline can be greatly shortened, which reduces pipeline investment and pressure loss, thereby improving the economy of the unit.

[0026] Compared with the first embodiment, the high-position shaft system has one more cylinder, and a double reheating method is adopted. The switching of the low-pressure cylinder of the low-position shaft system is the same as that of the first embodiment, and will not be repeated here.

[0027] Example 3

[0028] like Figure 3 As shown, it is the third specific embodiment of a high-low arrangement steam turbine generator system of the present invention. It mainly includes a high-pressure cylinder, a medium-pressure cylinder and a generator on the high-level shaft system, and a low-pressure cylinder and a generator on the low-level shaft system. The unit adopts a single reheating method, that is, the exhaust steam of the high-pressure cylinder enters the medium-pressure cylinder after one reheating, and the exhaust steam of the medium-pressure cylinder enters the low-pressure cylinder on the low-level shaft system through the valve on the connecting pipe. Among them, the high-level shaft system is arranged at an elevation position close to the inlet and outlet manifolds of the superheater and reheater, for example, at an elevation of 65 to 85 meters (the elevation positions of the inlet and outlet manifolds of the superheater and reheater of different types of power plant units will have certain differences); while the low-pressure cylinder and the generator on the low-level shaft system are arranged in a conventional low position, for example, 17 meters, and the condenser is arranged at the 0-meter layer. Since the high-pressure cylinder and the medium-pressure cylinder are arranged at high positions, the main steam pipeline, the primary cold re-pipeline and the primary hot re-pipeline can be greatly shortened. This can shorten the length of these high-temperature and high-pressure pipelines, reduce pipeline investment and pressure loss, and thus improve the economy of the unit.

[0029] In addition, steam for heating and heat exchange station is provided from the exhaust steam of intermediate-pressure cylinder of high-level shaft system to the steam inlet of low-pressure cylinder of low-level shaft system, and an adjustment valve is provided on the steam inlet pipeline to the heating and heat exchange station. By means of the adjustment valve and the steam inlet valve at the inlet of low-pressure cylinder on the low-level shaft system, more flexible adjustment of steam for heating can be achieved.

[0030] Furthermore, the heating valve is arranged near the three-way position of the lead-out and before the low-pressure cylinder steam inlet valve. The advantage is that, on the one hand, when the low-pressure cylinder is completely cut off, the exhaust steam of the medium-pressure cylinder or the medium-pressure second cylinder all enters the heating heat exchange station, which can avoid the "blind section" of the pipeline where no flow occurs, and maintain the hot standby state of the low-pressure cylinder steam inlet pipeline. On the other hand, it reduces the harmful volume between the high-level machine shaft system and the heating steam exchange station, avoiding the steam backflow from the heating heat exchange station to the high-level machine shaft system.

[0031] Example 4

[0032] like Figure 4As shown, it is the fourth specific embodiment of a high-low arrangement steam turbine generator system of the present invention. It mainly includes a high-pressure cylinder, a medium-pressure cylinder, a medium-pressure cylinder and a generator on the high-level shaft system, and a low-pressure cylinder and a generator on the low-level shaft system. The unit adopts a double reheating method, that is, the exhaust steam of the high-pressure cylinder enters the medium-pressure cylinder after one reheating, and the exhaust steam of the medium-pressure cylinder enters the medium-pressure cylinder after the second reheating, and the exhaust steam of the medium-pressure cylinder enters the low-pressure cylinder on the low-level shaft system through the valve on the connecting pipe. Among them, the high-level shaft system is arranged at an elevation position close to the inlet and outlet headers of the superheater and reheater, for example, 65 to 85 meters (the elevation positions of the inlet and outlet headers of the superheater and reheater of different types of power plant units will have certain differences); while a low-pressure cylinder and a generator on the low-level shaft system are arranged according to the conventional low position, for example, 17 meters, and the condenser is arranged at the 0-meter layer. Since the high-pressure cylinder, medium-pressure cylinder 1 and medium-pressure cylinder 2 are all arranged at high positions, the main steam pipeline, primary cooling re-pipeline, primary hot re-pipeline, secondary cooling re-pipeline and secondary hot re-pipeline can be greatly shortened, which reduces pipeline investment and pressure loss, thereby improving the economy of the unit.

[0033] Furthermore, the heating valve is arranged near the three-way position of the lead-out and before the low-pressure cylinder steam inlet valve. The advantage is that, on the one hand, when the low-pressure cylinder is completely cut off, the exhaust steam of the medium-pressure cylinder or the medium-pressure second cylinder all enters the heating heat exchange station, which can avoid the "blind section" of the pipeline where no flow occurs, and maintain the hot standby state of the low-pressure cylinder steam inlet pipeline. On the other hand, it reduces the harmful volume between the high-level machine shaft system and the heating steam exchange station, avoiding the steam backflow from the heating heat exchange station to the high-level machine shaft system.

[0034] Compared with Example 3, the high-level shaft system has one more cylinder, and a double reheating method is adopted to adjust the steam intake and heating steam of the low-pressure cylinder of the low-level shaft system, which is the same as Example 3 and will not be repeated here.

[0035] Example 5

[0036] like Figure 5 As shown, it is the fifth specific embodiment of a high-low arrangement steam turbine generator system of the present invention. The difference between this embodiment and embodiment 4 is that the low-position shaft system includes two low-pressure cylinders, and a clutch is arranged between the two low-pressure cylinders, so that the steam inlet adjustment and complete removal of the low-pressure cylinder of the low-position shaft system can be achieved. The rest is the same as embodiment 4 and will not be repeated here.

[0037] Example 6

[0038] like Figure 6 As shown, it is the sixth specific embodiment of a high-low arrangement steam turbine generator system of the present invention. The difference between this embodiment and embodiment 5 is that the high-position shaft system has one more cylinder, and a two-time reheating method is adopted to adjust the steam intake and heating steam of the low-pressure cylinder of the low-position shaft system, which is the same as embodiment 5 and will not be repeated here.

Claims

1. A high-low arrangement steam turbine generator system, characterized in that: The system at least includes a high-pressure cylinder, an intermediate-pressure cylinder and a generator on a high-level shaft system, and a low-pressure cylinder and a generator, as well as a condenser on a low-level shaft system; and a connecting pipe connecting the exhaust end of the intermediate-pressure cylinder on the high-level shaft system and the steam inlet end of the low-pressure cylinder, and a valve arranged on the steam inlet end of the low-pressure cylinder. It is characterized in that the high-level shaft system is arranged at an elevation position close to the inlet and outlet manifolds of the superheater and reheater, the exhaust steam of the high-pressure cylinder on the high-level shaft system enters the intermediate-pressure cylinder after one reheating, the exhaust steam of the intermediate-pressure cylinder enters the low-pressure cylinder through the valve on the steam inlet end of the low-pressure cylinder, and the exhaust steam of the low-pressure cylinder enters the condenser.

2. The system according to claim 1, characterized in that The intermediate pressure cylinder of the high-position shaft system is divided into intermediate pressure cylinder one and intermediate pressure cylinder two. The exhaust steam of the high-pressure cylinder on the high-position shaft system enters the intermediate pressure cylinder one after one reheating, and the exhaust steam of the intermediate pressure cylinder one enters the intermediate pressure cylinder two after two reheating. The intermediate pressure cylinder two enters the low-pressure cylinder through the valve at the steam inlet end of the low-pressure cylinder.

3. The system according to claim 1, characterized in that There is one low-pressure cylinder, and the intermediate-pressure cylinder on the high-position shaft system exhausts steam and is close to the valve at the steam inlet end of the low-pressure cylinder. A pipeline is led out and enters the heating heat exchange station through a heating valve. The heating valve is arranged at a three-way position close to the lead-out.

4. The system according to claim 2, characterized in that There is one low-pressure cylinder, and the two medium-pressure cylinders on the high-position shaft system exhaust steam and are close to the valve at the steam inlet end of the low-pressure cylinder. A pipeline is led out and enters the heating heat exchange station through a heating valve. The heating valve is arranged at a three-way position close to the lead-out.

5. The system according to claim 1, wherein: There are multiple low-pressure cylinders, and clutches are arranged between the multiple low-pressure cylinders.

6. The system according to claim 2, characterized in that There are multiple low-pressure cylinders, and clutches are arranged between the multiple low-pressure cylinders.

7. The system according to claim 5, characterized in that The exhaust steam of the intermediate pressure cylinder on the high-level shaft system is led out through a pipeline in front of the valve at the steam inlet end of the low pressure cylinder and enters the heating heat exchange station through a heating valve. The heating valve is arranged at a three-way position close to the lead-out.

8. The system according to claim 6, characterized in that The exhaust steam of the second medium-pressure cylinder on the high-level shaft system is led out through a pipeline in front of the valve at the steam inlet end of the low-pressure cylinder and enters the heating heat exchange station through a heating valve. The heating valve is arranged at a three-way position close to the lead-out.

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