Device and Method for Improving Reheat Steam Temperature in a Thermal Power Plant by Reheat-Regeneration Hybrid Mode

Abstract

The present invention provides a device and method for increasing the temperature of reheated steam in a thermal power plant by means of a reheating and regenerative hybrid mode. The device includes: using a first electric control valve to adjust the flow rate of the high-pressure steam entering the pressure matcher in the second first-stage extraction steam pipeline; after the high-pressure steam and the low-pressure steam enter the pressure matcher, the ratio between the high-pressure steam and the low-pressure steam is adjusted through the pressure automatic control system of the pressure matcher, so that after the pressure of the mixed steam in the pressure matcher is higher than the steam pressure in the mixing heater, it is sprayed into the mixing heater; using the outlet temperature automatic control system of the mixing heater to adjust the flow rate at the outlet of the pressure matcher, and further adjusting the temperature of the mixed steam. The device and method for increasing the temperature of reheated steam in a thermal power plant by means of a reheating and regenerative hybrid mode provided by the present invention solve the defect that the transformation of the existing boiler equipment reduces the temperature of the hot reheated steam, thereby reducing the overall efficiency of the thermal power unit.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal power plant equipment, and particularly to a device and method for improving the temperature of reheated steam in a reheating and regenerative hybrid mode in a thermal power plant. Background Art

[0002] Under the major policies of "carbon peak and carbon neutrality" in the country and the general background of "three reforms in tandem" in the power industry, energy conservation and consumption reduction have become the primary technical indicators for the survival of thermal power units. The efficiency improvement transformation of thermal power enterprises has become a common demand. The steam flow path transformation technology of steam turbines and the low-nitrogen burner transformation technology belong to the national energy-saving and environmental protection technology popularization projects commonly adopted. Thanks to the development of steam turbine design and manufacturing technology in just over a decade, the thermal consumption rate of steam turbines can generally be increased by 100 - 300 kJ / kWh after the steam flow path transformation. However, after the steam flow path transformation of the high-pressure cylinder, an obvious problem arises. With the unchanged output parameters, the improvement of the high-pressure cylinder efficiency will inevitably affect the reduction of the exhaust parameters, especially the exhaust parameter temperature of the high-pressure cylinder can be reduced by 2 - ˚C. At the same time, due to the core idea of the low-nitrogen burner transformation being to reduce the temperature in the furnace combustion zone, the furnace flame is elongated, the temperature in the reheater area of the upper furnace wall increases, the cooling effect in the high-temperature reheater area decreases, and desuperheating water has to be injected to control the safety of the tube wall temperature. However, this also causes a decrease in the temperature of the reheated steam. To meet the design value requirements of the reheated steam temperature under the condition of reduced cooling capacity, it is necessary to increase the heat transfer area and reduce the heat load per unit area. Since many factors need to be considered in the transformation of boiler equipment, it is difficult to increase the area of the reheater. Therefore, the heat provided by the reheater remains unchanged as the original design. With the unchanged flow rate of the cold reheat steam, the final temperature of the hot reheat steam is equal to the temperature of the cold reheat steam plus the steam temperature rise in the reheater. Therefore, the temperature of the cold reheat steam decreases significantly due to the decrease in the exhaust temperature of the high-pressure cylinder. With the unchanged steam temperature rise in the reheater, the temperature of the hot reheat steam will decrease. According to the consumption difference analysis of a general 300 MW unit, a 10˚C decrease in the reheated steam temperature will increase the power supply coal consumption of the unit by 0.79 g / kWh. Calculated based on an annual power generation of 1.5 billion kWh, 1185 tons of standard coal need to be consumed more. Calculated at a standard coal unit price of 1000 yuan, the production cost increases by 1.185 million yuan.

[0003] Under the major national policies of "carbon peak and carbon neutrality" and the background of the "three-way linkage" in the power industry, the deep peak shaving capacity of units has become another important technical indicator pursued by thermal power units. Currently, in regions with rapid development of new energy, affected by the large uncertainties in the maximum consumption of power grids and the power generation of new energy sources such as wind power and photovoltaic power that basically depend on the weather, the power grid requires that pure condensing thermal power units should have the deep peak shaving capacity in the range of 100 - 30% THA operating conditions, and some advanced units have reached below 15%. However, the currently operating units adopt a relatively economical sliding parameter operation mode. Below a load rate of 50 - 40%, affected by the efficiency of the high-pressure cylinder of the steam turbine under off-design conditions, the design value of the reheat steam temperature drops by 25 - 30 °C compared with full load, and this deviation may be even greater in actual operation. Under deep peak shaving conditions, in order to minimize coal consumption, the main steam temperature still maintains the THA design value during operation. Therefore, the difference between the inlet steam temperature of the high-pressure cylinder and the inlet steam temperature of the intermediate-pressure cylinder may exceed 30 °C. As is well known, mainstream large steam turbine units all adopt the combined layout of high-pressure and intermediate-pressure cylinders. When the deviation between the main steam temperature and the reheat steam temperature is large, the turbine shaft and cylinder body in the cross-over steam seal area will be in an extremely complex thermal stress state, posing certain safety risks.

[0004] In summary, the transformation of existing boiler equipment has reduced the hot reheat steam temperature, thereby resulting in a reduction in the overall efficiency of thermal power units. In order to meet the deep peak shaving capacity of the units, the currently operating units adopt a relatively economical sliding parameter operation mode. When the deviation between the main steam temperature and the reheat steam temperature is large, the turbine shaft and cylinder body in the cross-over steam seal area will be in an extremely complex thermal stress state, having certain safety risk defects. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a device and method for improving the reheat steam temperature in a reheat and regenerative hybrid mode in a thermal power plant to solve the problems raised in the above background technology.

[0006] [[ID=]

[11] ]According to the first aspect of the present invention, there is provided a device for improving the reheat steam temperature in a reheat and regenerative hybrid mode in a thermal power plant, including: a boiler, a steam turbine, a pressure matcher, and a mixing heater. The boiler and the steam turbine are connected through a main pipeline. The steam turbine is provided with a first extraction steam pipeline for the first stage and a first extraction steam pipeline for the third stage. A second extraction steam pipeline for the first stage is provided on the first extraction steam pipeline for the first stage. A third motorized stop valve, a second check valve, and a first motorized regulating valve are provided on the second extraction steam pipeline for the first stage. A second extraction steam pipeline for the third stage is provided on the first extraction steam pipeline for the third stage. A sixth motorized stop valve, a fourth check valve, and a second motorized regulating valve are provided on the second extraction steam pipeline for the third stage. Both the second extraction steam pipeline for the first stage and the second extraction steam pipeline for the third stage are connected to the pressure matcher. A mixing heater is provided on the high-pressure exhaust steam pipeline between the boiler and the steam turbine. The pressure matcher and the mixing heater are connected through a first pipeline;

[0007] The first electric control valve regulates the flow rate of the high-pressure steam entering the ejector steam of the pressure matcher in the second first-stage extraction steam pipeline, and the second electric control valve regulates the flow rate of the temperature-regulating steam of the low-pressure steam entering the pressure matcher in the second third-stage extraction steam pipeline.

[0008] Optionally, a first electric stop valve, a first check valve, and a second electric stop valve are provided on the first first-stage extraction steam pipeline. The first check valve is located between the first electric stop valve and the second electric stop valve, and a first three-way pipe is provided between the first check valve and the second electric stop valve.

[0009] Optionally, the first first-stage extraction steam pipeline is communicated with the second first-stage extraction steam pipeline through a first three-way pipe. The second check valve is located between the third electric stop valve and the first electric control valve, and the first electric control valve is arranged close to the pressure matcher.

[0010] Optionally, a fourth electric stop valve, a third check valve, and a fifth electric stop valve are provided on the first third-stage extraction steam pipeline. The third check valve is located between the fourth electric stop valve and the fifth electric stop valve, and a second three-way pipe is provided between the third check valve and the fifth electric stop valve.

[0011] Optionally, the first third-stage extraction steam pipeline is communicated with the second third-stage extraction steam pipeline through a second three-way pipe. The fourth check valve is located between the sixth electric stop valve and the second electric control valve, and the second electric control valve is arranged close to the pressure matcher.

[0012] According to the second aspect of the present invention, there is provided a method for increasing the temperature of the reheated steam in a reheating and regenerative hybrid mode of a thermal power plant. The method for increasing the temperature of the reheated steam by using the device for increasing the temperature of the reheated steam in the reheating and regenerative hybrid mode of the thermal power plant includes:

[0013] Step 1, regulating the flow rate of the high-pressure steam entering the ejector steam of the pressure matcher in the second first-stage extraction steam pipeline by using the first electric control valve, and regulating the flow rate of the temperature-regulating steam of the low-pressure steam entering the pressure matcher in the second third-stage extraction steam pipeline by using the second electric control valve;

[0014] Step 2, after the high-pressure steam and the low-pressure steam enter the pressure matcher, regulating the ratio between the high-pressure steam and the low-pressure steam through the pressure automatic control system of the pressure matcher, so that after the pressure of the mixed steam in the pressure matcher is higher than the steam pressure in the mixing heater, it is sprayed into the mixing heater;

[0015] Step 3, regulating the outlet flow rate of the pressure matcher by using the outlet temperature automatic regulation system of the mixing heater, and further regulating the temperature of the mixed steam, so that the temperature of the mixed steam plus the temperature of the high-pressure extraction steam is equal to the temperature of the cold reheat steam.

[0016] Optionally, before step 1, it further includes:

[0017] The mixed heating steam flow rate, mixed heating steam enthalpy value and mixed heating steam temperature are calculated based on the known high exhaust steam flow rate, high exhaust steam enthalpy value and cold reheat steam enthalpy value.

[0018] Optionally, the formulas for calculating the mixed heating steam flow rate and the mixed heating steam enthalpy are as follows:

[0019] (1);

[0020] (2);

[0021] Combine (1) and (2);

[0022] in, For high exhaust steam flow, is the high exhaust steam enthalpy value, is the cold reheat steam enthalpy, is the mixed heating steam flow rate, is the enthalpy of mixed heating steam.

[0023] Optionally, the injection steam flow rate is calculated based on the known mixed heating steam enthalpy value, mixed heating steam flow rate, injection steam enthalpy value and temperature control steam enthalpy value. , and temperature-controlled steam flow The formula is as follows:

[0024] (3);

[0025] (4);

[0026] Combine (3) and (4);

[0027] in, is the enthalpy of mixed heating steam, is the mixed heating steam flow rate, is the enthalpy of the injected steam, is the enthalpy of the temperature-controlled steam, is the injection steam flow rate, The steam flow rate for temperature control.

[0028] Device and method for increasing reheat steam temperature through a reheating and regenerative hybrid mode of a thermal power plant. The boiler and the steam turbine are connected through a main pipeline. The steam turbine is provided with a first extraction steam pipeline for the first stage and a first extraction steam pipeline for the third stage. A second extraction steam pipeline for the first stage is provided on the first extraction steam pipeline for the first stage, and a second extraction steam pipeline for the third stage is provided on the first extraction steam pipeline for the third stage. Both the second extraction steam pipeline for the first stage and the second extraction steam pipeline for the third stage are connected to a pressure matcher. A mixing heater is provided on the high-pressure extraction steam pipeline between the boiler and the steam turbine. The pressure matcher and the mixing heater are connected through a first pipeline. An electric control valve is used to adjust the injection steam flow of the high-pressure steam in the second extraction steam pipeline for the first stage entering the pressure matcher, and a second electric control valve is used to adjust the temperature control steam flow of the low-pressure steam in the second extraction steam pipeline for the third stage entering the pressure matcher. After the high-pressure steam and the low-pressure steam enter the pressure matcher, the ratio between the high-pressure steam and the low-pressure steam is adjusted through the pressure automatic control system of the pressure matcher, so that the pressure of the mixed steam in the pressure matcher is higher than the steam pressure in the mixing heater, and then it is sprayed into the mixing heater. The outlet temperature automatic control system of the mixing heater is used to adjust the flow rate at the outlet of the pressure matcher, and then the temperature of the mixed steam is adjusted, so that the temperature of the mixed steam plus the high-pressure extraction steam temperature is equal to the cold reheat steam temperature. Therefore, this application ensures that the reheat steam temperature after adding the cold reheat steam temperature and the actual reheat steam temperature rise meets the requirements of the unit. By optimizing the heat source, without modifying the equipment on the boiler side, through the method of reheating and regenerative hybrid heating, the reheat steam temperature is increased. On the one hand, the overall efficiency of the thermal power unit is improved, and on the other hand, the problem of excessive temperature difference between the main and reheat steam during deep peak shaving is solved, which improves the operating safety of the steam turbine. Therefore, the present invention solves the defects that the transformation of the existing boiler equipment reduces the temperature of the hot reheat steam, thereby reducing the overall efficiency of the thermal power unit, and in order to meet the deep peak shaving capacity of the unit, the current operating unit adopts a more economical sliding parameter operation mode, so that when the deviation between the main steam temperature and the reheat steam temperature is large, the large shaft and cylinder body of the steam turbine in the overbridge steam seal area will be in an extremely complex thermal stress state, posing a certain safety risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 FIG. is a schematic structural diagram of a device for increasing reheat steam temperature through a reheating and regenerative hybrid mode of a thermal power plant according to the present invention;

[0030] Figure 2 FIG. is a logic block diagram of a method for increasing reheat steam temperature through a reheating and regenerative hybrid mode of a thermal power plant according to the present invention.

[0031] LIST OF REFERENCE NUMERALS:

[0032] 10. Boiler; 20. Steam turbine; 21. First-stage extraction steam pipeline; 210. First electric globe valve; 211. First check valve; 212. Second electric globe valve; 22. First three-stage extraction steam pipeline; 220. Fourth electric globe valve; 221. Third check valve; 222. Fifth electric globe valve; 23. Second first-stage extraction steam pipeline; 230. Third electric globe valve; 231. Second check valve; 232. First electric control valve; 24. Second three-stage extraction steam pipeline; 240. Sixth electric globe valve; 241. Fourth check valve; 242. Second electric control valve; 30. Pressure matcher;; 40. Mixing heater; 50. Main pipeline; 60. High-pressure exhaust steam pipeline; 70. First pipeline. Detailed implementation mode

[0033] To make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0035] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0036] Referring to Figures 1 to 2 , the present invention provides a device and method for improving the temperature of reheated steam in a reheating and regenerative hybrid mode in a thermal power plant, which can solve the problems that the transformation of existing boiler equipment reduces the temperature of hot reheated steam, thereby reducing the overall efficiency of the thermal power unit, and in order to meet the deep peak shaving capacity of the unit, the current operating unit adopts a more economical sliding parameter operation mode, so that when the deviation between the main steam temperature and the reheated steam temperature is large, the turbine shaft and cylinder body in the overbridge steam seal area will be in an extremely complex thermal stress state, posing a certain safety risk.

[0037] A device for improving the temperature of reheated steam in a reheating and regenerative hybrid mode in a thermal power plant provided by the present invention includes a boiler 10, a steam turbine 20, a pressure matcher 30 and a mixing heater 40. The boiler 10 and the steam turbine 20 are connected through a main pipeline 50. The steam turbine 20 is provided with a first extraction steam pipeline 21 for the first stage and a first extraction steam pipeline 22 for the third stage. A second extraction steam pipeline 23 for the first stage is provided on the first extraction steam pipeline 21 for the first stage, and a second extraction steam pipeline 24 for the third stage is provided on the first extraction steam pipeline 22 for the third stage. Both the second extraction steam pipeline 23 for the first stage and the second extraction steam pipeline 24 for the third stage are connected to the pressure matcher 30. A mixing heater 40 is provided on the high-pressure extraction steam pipeline 60 between the boiler 10 and the steam turbine 20. The pressure matcher 30 and the mixing heater 40 are connected through a first pipeline 70.

[0038] An apparatus and method for increasing the temperature of reheated steam in a reheating and regenerative hybrid mode in a thermal power plant. Through a boiler 10, a steam turbine 20, a pressure matcher 30, and a mixing heater 40, the boiler 10 and the steam turbine 20 are connected through a main pipeline 50. The steam turbine 20 is provided with a first extraction steam pipeline 21 for the first stage and a first extraction steam pipeline 22 for the third stage. A second extraction steam pipeline 23 for the first stage is provided on the first extraction steam pipeline 21 for the first stage, and a second extraction steam pipeline 24 for the third stage is provided on the first extraction steam pipeline 22 for the third stage. Both the second extraction steam pipeline 23 for the first stage and the second extraction steam pipeline 24 for the third stage are connected to the pressure matcher 30. A mixing heater 40 is provided on the high-pressure extraction steam pipeline 60 between the boiler 10 and the steam turbine 20. The pressure matcher 30 and the mixing heater 40 are connected through a first pipeline 70. And use a first electric control valve 232 to adjust the injection steam flow of the high-pressure steam in the second extraction steam pipeline 23 for the first stage entering the pressure matcher 30, and use a second electric control valve 242 to adjust the temperature-regulating steam flow of the low-pressure steam in the second extraction steam pipeline 24 for the third stage entering the pressure matcher 30. After the high-pressure steam and the low-pressure steam enter the pressure matcher 30, the ratio between the high-pressure steam and the low-pressure steam is adjusted through the pressure automatic control system of the pressure matcher 30, so that the pressure of the mixed steam in the pressure matcher 30 is higher than the steam pressure in the mixing heater 40, and then it is sprayed into the mixing heater 40. Use the outlet temperature automatic control system of the mixing heater 40 to adjust the flow rate at the outlet of the pressure matcher 30, and then adjust the temperature of the mixed steam, so that the temperature of the mixed steam plus the high-pressure extraction steam temperature is equal to the cold reheat steam temperature. Therefore, this application ensures that the reheated steam temperature after adding the cold reheat steam temperature and the actual reheated steam temperature rise meets the requirements of the unit. By optimizing the heat source, without modifying the equipment on the boiler side, through the method of reheating and regenerative hybrid heating, the temperature of the reheated steam is increased. On the one hand, the overall efficiency of the thermal power unit is improved, and on the other hand, it solves the problem that the temperature difference between the main steam and the reheated steam is too large during deep peak shaving, which improves the operating safety of the steam turbine. Therefore, the present invention solves the defects that the transformation of the existing boiler equipment reduces the temperature of the hot reheated steam, which in turn leads to a reduction in the overall efficiency of the thermal power unit, and in order to meet the deep peak shaving capacity of the unit, the current operating unit adopts a more economical sliding parameter operation mode, when the deviation between the main steam temperature and the reheated steam temperature is large, the turbine shaft and the cylinder body in the overbridge steam seal area will be in an extremely complex thermal stress state, and there are certain safety risks.

[0039] Refer to Figure 1 Optionally, a first electric stop valve 210, a first check valve 211, and a second electric stop valve 212 are provided on the first extraction steam pipeline 21 for the first stage. The first check valve 211 is located between the first electric stop valve 210 and the second electric stop valve 212, and a first three-way pipe is provided between the first check valve 211 and the second electric stop valve 212.

[0040] Among them, a first three-way pipe is provided between the first check valve 211 and the second motorized globe valve 212 to extract high-pressure steam.

[0041] Referring to Figure 1 , optionally, the first extraction steam pipeline 21 communicates with the second extraction steam pipeline 23 through the first three-way pipe. A third motorized globe valve 230, a second check valve 231, and a first motorized regulating valve 232 are provided on the second extraction steam pipeline 23. The second check valve 231 is located between the third motorized globe valve 230 and the first motorized regulating valve 232, and the first motorized regulating valve 232 is arranged close to the pressure matcher 30.

[0042] Among them, the first motorized regulating valve 232 is arranged to be matched with the pressure matcher 30 to adjust and control the injection steam flow rate of the high-pressure steam.

[0043] Referring to Figure 1 , optionally, a fourth motorized globe valve 220, a third check valve 221, and a fifth motorized globe valve 222 are provided on the first third-stage extraction steam pipeline 22. The third check valve 221 is located between the fourth motorized globe valve 220 and the fifth motorized globe valve 222, and a second three-way pipe is provided between the third check valve 221 and the fifth motorized globe valve 222.

[0044] Among them, the second three-way pipe is provided between the third check valve 221 and the fifth motorized globe valve 222 to extract low-pressure steam.

[0045] Referring to Figure 1 , optionally, the first third-stage extraction steam pipeline 22 communicates with the second third-stage extraction steam pipeline 24 through the second three-way pipe. A sixth motorized globe valve 240, a fourth check valve 241, and a second motorized regulating valve 242 are provided on the second third-stage extraction steam pipeline 24. The fourth check valve 241 is located between the sixth motorized globe valve 240 and the second motorized regulating valve 242, and the second motorized regulating valve 242 is arranged close to the pressure matcher 30.

[0046] Among them, the second motorized regulating valve 242 is arranged to be matched with the pressure matcher 30 to adjust and control the temperature-regulating steam flow rate of the low-pressure steam.

[0047] A method for increasing the temperature of reheated steam in a reheating and regenerative hybrid mode of a thermal power plant provided by the present invention. The method for increasing the temperature of reheated steam by using a device for increasing the temperature of reheated steam in a reheating and regenerative hybrid mode of a thermal power plant includes:

[0048] Step 1, using the first motorized regulating valve 232 to adjust the injection steam flow rate of the high-pressure steam entering the pressure matcher 30 in the second extraction steam pipeline 23, and using the second motorized regulating valve 242 to adjust the temperature-regulating steam flow rate of the low-pressure steam entering the pressure matcher 30 in the second third-stage extraction steam pipeline 24;

[0049] Step 2: After the high-pressure steam and the low-pressure steam enter the pressure matching device 30, the ratio between the high-pressure steam and the low-pressure steam is adjusted by the pressure automatic control system of the pressure matching device 30 so that the pressure of the mixed steam in the pressure matching device 30 is higher than the steam pressure in the mixing heater 40, and then the mixed steam is sprayed into the mixing heater 40;

[0050] Step three, use the outlet temperature automatic adjustment system of the mixing heater 40 to adjust the outlet flow of the pressure matcher 30, and then adjust the temperature of the mixed steam so that the mixed steam temperature plus the high exhaust steam temperature is equal to the cold reheat steam temperature.

[0051] The present application reasonably selects the first stage extraction steam of the steam turbine with higher pressure as the power steam source, selects the third stage extraction steam of the steam turbine with higher superheat as the low-pressure steam source, modulates the heating steam with a pressure higher than the cold reheat steam by a certain value and a temperature higher than the cold reheat steam by a certain value through the pressure matcher 30, and uses this mixed steam as the heat source, reasonably designs the mixing heater 40, and finally achieves the reasonable increase of the reheat steam temperature by adjusting the flow rate and temperature, and finally realizes that the hot reheat steam temperature reaches or exceeds the design requirement.

[0052] Optionally, before step 1, the following steps are further included:

[0053] The mixed heating steam flow rate, mixed heating steam enthalpy value and mixed heating steam temperature are calculated based on the known high exhaust steam flow rate, high exhaust steam enthalpy value and cold reheat steam enthalpy value.

[0054] Optionally, the formulas for calculating the mixed heating steam flow rate and the mixed heating steam enthalpy are as follows:

[0055] (1);

[0056] (2);

[0057] Combine (1) and (2);

[0058] in, For high exhaust steam flow, is the high exhaust steam enthalpy value, is the cold reheat steam enthalpy, is the mixed heating steam flow rate, is the enthalpy of mixed heating steam.

[0059] Optionally, the injection steam flow rate is calculated based on the known mixed heating steam enthalpy value, mixed heating steam flow rate, injection steam enthalpy value and temperature control steam enthalpy value. , and temperature-controlled steam flow The formula is as follows:

[0060] (3);

[0061] (4);

[0062] Combine (3) and (4);

[0063] in, is the mixed heating steam enthalpy, is the mixed heating steam flow rate, is the enthalpy of injected steam, is the enthalpy of the temperature-controlled steam, is the injection steam flow rate, Thermostatic steam flow rate.

[0064] In summary, the device and method for improving the temperature of reheated steam in a reheating and regenerative hybrid mode provided by the present invention, through the boiler 10, the steam turbine 20, the pressure matcher 30 and the mixing heater 40, the boiler 10 and the steam turbine 20 are connected through the main pipeline 50. The steam turbine 20 is provided with a first extraction steam pipeline 21 for the first stage and a first extraction steam pipeline 22 for the third stage. A second extraction steam pipeline 23 for the first stage is provided on the first extraction steam pipeline 21 for the first stage, and a second extraction steam pipeline 24 for the third stage is provided on the first extraction steam pipeline 22 for the third stage. Both the second extraction steam pipeline 23 for the first stage and the second extraction steam pipeline 24 for the third stage are connected to the pressure matcher 30. A mixing heater 40 is provided on the high-pressure extraction steam pipeline 60 between the boiler 10 and the steam turbine 20. The pressure matcher 30 and the mixing heater 40 are connected through a first pipeline 70; and the first electric control valve 232 is used to adjust the injection steam flow of the high-pressure steam in the second extraction steam pipeline 23 for the first stage into the pressure matcher 30, and the second electric control valve 242 is used to adjust the temperature-regulating steam flow of the low-pressure steam in the second extraction steam pipeline 24 for the third stage into the pressure matcher 30; after the high-pressure steam and the low-pressure steam enter the pressure matcher 30, the ratio between the high-pressure steam and the low-pressure steam is adjusted through the pressure automatic control system of the pressure matcher 30, so that the pressure of the mixed steam in the pressure matcher 30 is higher than the steam pressure in the mixing heater 40, and then it is sprayed into the mixing heater 40; the outlet temperature automatic control system of the mixing heater 40 is used to adjust the flow rate at the outlet of the pressure matcher 30, and then the temperature of the mixed steam is adjusted, so that the temperature of the mixed steam plus the high-pressure extraction steam temperature is equal to the cold reheat steam temperature; therefore, this application ensures that the reheated steam temperature after adding the cold reheat steam temperature and the actual reheated steam temperature rise meets the requirements of the unit. By optimizing the heat source, without modifying the equipment on the boiler side, through the method of reheating and regenerative hybrid heating, the temperature of the reheated steam is increased. On the one hand, the overall efficiency of the thermal power unit is improved, and on the other hand, the problem of excessive temperature difference between the main steam and the reheated steam in the deep peak shaving of small units is solved, which improves the operation safety of the steam turbine. Therefore, the present invention solves the defects that the transformation of the existing boiler equipment reduces the temperature of the hot reheated steam, thereby reducing the overall efficiency of the thermal power unit, and in order to meet the deep peak shaving capacity of the unit, the current operating unit adopts a relatively economical sliding parameter operation mode, when the deviation between the main steam temperature and the reheated steam temperature is large, the large shaft and cylinder body of the steam turbine in the over-bridge steam seal area will be in an extremely complex thermal stress state, and there are certain safety risks.

[0065] It should be noted that not all steps and modules in the above-mentioned processes and system structure diagrams are necessary, and some steps or modules can be ignored according to actual needs. The execution order of each step is not fixed and can be adjusted as needed. The system structures described in the above-mentioned embodiments can be physical structures or logical structures, that is, some modules may be implemented by the same physical entity, or some modules may be implemented by multiple physical entities, or some components in multiple independent devices may be jointly implemented.

[0066] In the above-mentioned embodiments, the hardware modules can be implemented mechanically or electrically. For example, a hardware module can include a permanently dedicated circuit or logic (such as a dedicated processor, FPGA or ASIC) to complete the corresponding operations. The hardware module can also include programmable logic or circuits (such as a general-purpose processor or other programmable processors), which can be temporarily set by software to complete the corresponding operations. The specific implementation method (mechanical method, or dedicated permanent circuit, or temporarily set circuit) can be determined based on cost and time considerations.

[0067] The present invention has been described in detail through the accompanying drawings and preferred embodiments above. However, the present invention is not limited to these disclosed embodiments. Based on the above-mentioned multiple embodiments, those skilled in the art can know that more embodiments of the present invention can be obtained by combining the code review means in the above different embodiments, and these embodiments are also within the protection scope of the present invention.

Claims

1. A device for improving the temperature of reheated steam in a reheating and regenerative hybrid mode in a thermal power plant, characterized in that, Including: A boiler (10), a steam turbine (20), a pressure matcher (30) and a mixing heater (40). The boiler (10) is communicated with the steam turbine (20) through a main pipeline (50). The steam turbine (20) is provided with a first extraction steam pipeline of the first stage (21) and a first extraction steam pipeline of the third stage (22). A second extraction steam pipeline of the first stage (23) is provided on the first extraction steam pipeline of the first stage (21). A third electric stop valve (230), a second check valve (231) and a first electric regulating valve (232) are provided on the second extraction steam pipeline of the first stage (23). A second extraction steam pipeline of the third stage (24) is provided on the first extraction steam pipeline of the third stage (22). A sixth electric stop valve (240), a fourth check valve (241) and a second electric regulating valve (242) are provided on the second extraction steam pipeline of the third stage (24). The second extraction steam pipeline of the first stage (23) and the second extraction steam pipeline of the third stage (24) are both connected to the pressure matcher (30). The mixing heater (40) is provided on the high-pressure extraction steam pipeline (60) between the boiler (10) and the steam turbine (20). The pressure matcher (30) and the mixing heater (40) are connected through a first pipeline (70); The first electric regulating valve (232) regulates the injection steam flow of the high-pressure steam in the second extraction steam pipeline of the first stage (23) entering the pressure matcher (30), and the second electric regulating valve (242) regulates the temperature-adjusting steam flow of the low-pressure steam in the second extraction steam pipeline of the third stage (24) entering the pressure matcher (30).

2. The device for increasing the temperature of reheated steam in the reheating and regenerative hybrid mode of a thermal power plant according to claim 1, characterized in that, A first electric stop valve (210), a first check valve (211) and a second electric stop valve (212) are provided on the first extraction steam pipeline of the first stage (21). The first check valve (211) is located between the first electric stop valve (210) and the second electric stop valve (212), and a first three-way pipe is provided between the first check valve (211) and the second electric stop valve (212).

3. The device for improving the temperature of reheated steam in a reheating and regenerative hybrid mode of a thermal power plant according to claim 2, characterized in that The first extraction steam pipeline of the first stage (21) is communicated with the second extraction steam pipeline of the first stage (23) through the first three-way pipe. The second check valve (231) is located between the third electric stop valve (230) and the first electric regulating valve (232), and the first electric regulating valve (232) is arranged close to the pressure matcher (30).

4. The device for improving the temperature of reheated steam in a reheating and regenerative hybrid mode of a thermal power plant according to claim 1, characterized in that A fourth electric stop valve (220), a third check valve (221) and a fifth electric stop valve (222) are provided on the first extraction steam pipeline of the third stage (22). The third check valve (221) is located between the fourth electric stop valve (220) and the fifth electric stop valve (222), and a second three-way pipe is provided between the third check valve (221) and the fifth electric stop valve (222).

5. The device for increasing the reheat steam temperature in a thermal power plant reheat recovery mixed mode according to claim 4 is characterized in that: The first three-section steam extraction pipeline (22) is connected to the second three-section steam extraction pipeline (24) through the second three-way pipe, the fourth check valve (241) is located between the sixth electric stop valve (240) and the second electric regulating valve (242), and the second electric regulating valve (242) is arranged close to the pressure matcher (30).

6. A method for increasing the temperature of reheated steam in a thermal power plant by using a reheating and regenerative hybrid mode, which is a method for increasing the temperature of reheated steam by using the device for increasing the temperature of reheated steam in a thermal power plant in the reheating and regenerative hybrid mode according to any one of claims 1 to 5, characterized in that, include: Step 1: Using the first electric regulating valve (232) to regulate the injection steam flow of the high-pressure steam in the second-stage steam extraction pipeline (23) entering the pressure matcher (30), and using the second electric regulating valve (242) to regulate the temperature-regulating steam flow of the low-pressure steam in the second-third-stage steam extraction pipeline (24) entering the pressure matcher (30); Step 2: After the high-pressure steam and the low-pressure steam enter the pressure matching device (30), the ratio between the high-pressure steam and the low-pressure steam is adjusted by the pressure automatic control system of the pressure matching device (30) so that the pressure of the mixed steam in the pressure matching device (30) is higher than the steam pressure in the mixing heater (40), and then the mixed steam is sprayed into the mixing heater (40); Step three, using the outlet temperature automatic adjustment system of the mixing heater (40) to adjust the outlet flow of the pressure matcher (30), and then adjust the temperature of the mixed steam so that the temperature of the mixed steam plus the high exhaust steam temperature is equal to the cold reheat steam temperature.

7. The method for increasing the temperature of reheated steam in a reheating and regenerative hybrid mode in a thermal power plant according to claim 6, wherein The step 1 also includes: The mixed heating steam flow rate, mixed heating steam enthalpy value and mixed heating steam temperature are calculated based on the known high exhaust steam flow rate, high exhaust steam enthalpy value and cold reheat steam enthalpy value.

8. The method for increasing the temperature of reheated steam in a reheating and regenerative hybrid mode of a thermal power plant according to claim 7, wherein The formulas for calculating the mixed heating steam flow rate and the mixed heating steam enthalpy are as follows: （1）； （2）； Combine (1) and (2); Among them, is the high-pressure exhaust steam flow rate, is the enthalpy value of the high-pressure exhaust steam, is the enthalpy value of the cold reheat steam, is the flow rate of the mixed heating steam, is the enthalpy value of the mixed heating steam.

9. The method for increasing the temperature of reheated steam in a reheating and regenerative hybrid mode in a thermal power plant according to claim 8, wherein Calculate the injection steam flow rate based on the known enthalpy value of the mixed heating steam, the flow rate of the mixed heating steam, the enthalpy value of the injection steam, and the enthalpy value of the temperature control steam , and the temperature control steam flow rate ; The formula is as follows: （3）； （4）； Combine (3) and (4); Among them, is the enthalpy value of the mixed heating steam, is the flow rate of the mixed heating steam, is the enthalpy value of the injection steam, is the enthalpy value of the temperature-regulating steam, is the flow rate of the injection steam, is the flow rate of the temperature-regulating steam.

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