Condensation water system

Abstract

The invention discloses a condensation water system which comprises a condenser, a hot well, a condensation water pump, a heating device and a deaerator. The condenser is used for forming condensed water; a hot well is arranged below the condenser; the hot well is used for collecting and storing condensed water of the condenser; a hot well outlet is connected with a condensed water pump inlet; the condensate pump is used for pumping condensate water in the hot well and conveying the condensate water to the heating device; an outlet of the condensate pump is connected with an inlet of the heating device through a pipeline, a condensate bypass electric valve and a condensate adjusting valve are arranged on the pipeline, and the condensate adjusting valve is connected with the condensate bypass electric valve in parallel. The heating device is used for heating condensed water; an outlet of the heating device is connected with an inlet of the deaerator; the condensate pump comprises three stages of impellers, and the condensate pump with the three stages of impellers is obtained by removing the fourth-stage impeller in the condensate pump with the original four-stage impeller and additionally installing a fixing piece at the position where the impeller is removed.

Description

Technical Field

[0001] The invention belongs to the technical field of condensate water of a steam turbine for thermal power generation, and in particular relates to a condensate water system. Background Art

[0002] With the global push for new energy sources such as wind and solar energy, the large-scale grid-connected operation of new energy sources has significantly reduced the market share of thermal power generation, resulting in a decline in the utilization rate of traditional coal-fired power units, especially a significant reduction in the number of hours of power generation units. In the face of the large-scale consumption of new energy sources, thermal power generation units must have efficient deep peak-shaving capabilities to adapt to the needs of the power grid.

[0003] At present, with the load adjustment of thermal power generating units, especially the operation of condensate systems, severe technical and safety challenges are faced. The condensate pump is one of the main equipment of the condensate system. The condensate pump not only needs to meet the system head requirements and the water supply requirements of the deaerator when the unit is running under full load conditions; it also needs to ensure that the condensate pump frequency avoids the resonance range when the unit is running under low load conditions, otherwise the condensate pump will cause increased vibration due to low frequency operation. In order to maintain the safe operation of the condensate pump, the common solution is to artificially increase the speed of the condensate pump by adjusting the condensate main regulating valve. However, this approach not only increases the wear of the regulating valve, but also causes energy waste. At the same time, how to reduce the resistance in the condensate system and improve the economic benefits of the condensate system is also a problem. Summary of the invention

[0004] In response to the above problems, the present application provides a condensate water system. By modifying the condensate water pump in the system, not only when the unit is operating under low load conditions during deep peak regulation, the operating frequency of the condensate water pump avoids the resonance range, thereby eliminating the vibration of the condensate water pump, but also meets the system head requirements and deaerator water supply requirements when the unit is at full load. At the same time, by setting a condensate water bypass electric valve in the system, the resistance of the condensate water system is optimized and the economic benefits of the condensate water system are improved.

[0005] To achieve the purpose of this application, this application provides the following technical solutions:

[0006] A condensate system includes a condenser, a hot well, a condensate pump, a heating device, and a deaerator;

[0007] The condenser is used to form condensed water, and the bottom of the condenser is connected to the hot well;

[0008] The hot well is used to collect and store condensate from the condenser, and the outlet of the hot well is connected to the inlet of the condensate pump;

[0009] The condensate pump is used to extract condensate from the hot well and to transport the condensate to the heating device; the outlet of the condensate pump and the inlet of the heating device are connected by a pipeline, and a condensate bypass electric valve and a condensate regulating valve are provided on the pipeline, and the condensate regulating valve is connected in parallel with the condensate bypass electric valve;

[0010] The heating device is used to heat the condensate; the outlet of the heating device is connected to the inlet of the deaerator.

[0011] The condensate pump is a condensate pump including a three-stage impeller, and the three-stage impeller condensate pump is obtained by removing the fourth-stage impeller from the original four-stage impeller condensate pump and installing a fixing part at the position of the removed impeller.

[0012] In a possible implementation, the third-stage impeller in the condensate pump of the three-stage impeller is replaced, and the diameter of the replaced third-stage impeller is larger than that of the third-stage impeller before the replacement.

[0013] In one possible implementation, the heating device includes a first low-pressure heater group, which includes at least two low-pressure heaters connected in series; a pipeline is connected between the deaerator and the first low-pressure heater group, and a low-pressure bypass electric valve is provided on the pipeline, and the first low-pressure heater group is connected in parallel with the low-pressure bypass electric valve.

[0014] In one possible implementation, the heating device includes a second low-pressure heater group, which includes at least two low-pressure heaters connected in series; a low-pressure bypass electric valve is arranged between the inlet of the second low-pressure heater group and the pipeline of the condensate bypass electric valve; and the low-pressure bypass electric valve is connected in parallel with the second low-pressure heater group.

[0015] In a possible implementation, the system further includes a low-temperature economizer and a low-temperature economizer filter;

[0016] The low-temperature economizer inlet is connected to the outlet of the second low-pressure heater group, the low-temperature economizer outlet is connected to the low-pressure economizer filter inlet, the low-pressure economizer filter outlet is connected to the deaerator inlet, and the low-pressure economizer filter is used to prevent impurities from entering the system;

[0017] A pipeline is connected between the first outlet of the second low-pressure heater group and the deaerator inlet, and a low-temperature economizer bypass electric valve is arranged on the pipeline; the low-temperature economizer bypass electric valve is connected in parallel with the low-temperature economizer and the low-pressure filter.

[0018] In a possible implementation, a pipeline is connected between the second outlet of the second low-pressure heater group and the inlet of the low-temperature economizer, and an electric valve from the low-pressure heater outlet to the low-temperature economizer is provided on the pipeline; the electric valve from the low-pressure heater outlet to the low-temperature economizer is connected in series with the low-temperature economizer.

[0019] In a possible implementation, the system further includes: a shaft seal heater, wherein an inlet of the shaft seal heater is connected to an outlet of the condensate pump, a pipeline is connected between a first outlet of the shaft seal heater and a low-pressure heater module, and the shaft seal heater is used to heat the condensate.

[0020] In a possible implementation, the system also includes: a condensate recirculation regulating valve and a condensate recirculation manual valve; the second outlet of the shaft seal heater is connected to the inlet of the condenser through a condensate recirculation loop; the condensate recirculation regulating valve and the condensate recirculation manual valve are arranged on the condensate recirculation loop; the condensate recirculation regulating valve and the condensate recirculation manual valve are connected in series.

[0021] In one possible implementation, the system also includes a condensate polishing device; the inlet of the condensate polishing device is connected to the outlet of the condensate pump, and a pipeline is connected between the outlet of the condensate polishing device and the heating device, and the condensate polishing device is used to remove impurities, dissolved gases and dissolved salts in the condensate.

[0022] In a possible implementation, the system includes at least two condensate pumps connected in parallel;

[0023] A pipeline is connected between the hot well outlet and the two condensate pump inlets, and a condensate pump inlet electric valve and a condensate pump inlet filter are sequentially arranged on the two pipelines;

[0024] Pipelines are connected between the outlets of the two condensate pumps and the condensate bypass electric valve, and condensate pump outlet check valves and condensate pump outlet electric valves are sequentially arranged on the two pipelines.

[0025] The beneficial effect of the present invention is that, by modifying the condensate pump in the system, the resonance problem of the condensate pump when operating under low load conditions during deep peak regulation is solved, and the reliability of the equipment is guaranteed; it also meets the water supply demand of the deaerator when the unit is operating at full load, and significantly improves the operating efficiency of the condensate pump. At the same time, by opening the condensate bypass electric valve, the operating resistance of the condensate system is greatly reduced, the power consumption rate of the condensate system is greatly reduced, and the economic benefits of the condensate system are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation on the present application.

[0027] Figure 1 It is a schematic diagram of the condensate water system of the present invention;

[0028] Figure 2 It is a simple structural schematic diagram of the condensate pump with the original four-stage impeller in the condensate system of the present invention;

[0029] Figure 3 It is a simple structural schematic diagram of a condensate pump with three-stage impellers in the condensate system of the present invention;

[0030] In the figure,

[0031] 1. Condenser; 2. Hot well; 3. Condensate pump; 3-1. Condensate pump inlet electric valve; 3-2 Condensate pump inlet filter; 3-3. Condensate pump outlet check valve; 3-4. Condensate pump outlet electric valve; 4. Heating device; 4-1 First low-pressure heater group; 4-2 Second low-pressure heater group; 4-3a First low-pressure heater group low-pressure bypass electric valve, 4-3b First low-pressure heater group low-pressure bypass electric valve; 5. Deaerator; 6. Condensate regulating valve; 7. Condensate bypass electric valve; 8. Low temperature Economizer; 8-1 low-temperature economizer bypass electric valve; 8-2 low-temperature heater outlet to low-temperature economizer electric valve; 9, low-temperature economizer filter; 10, shaft seal heater; 11, condensate polishing device; 12-1, condensate recirculation regulating valve; 12-2 and condensate recirculation manual valve; 301-1, first-stage impeller; 301-2, second-stage impeller; 301-3a, third-stage impeller; 301-3b replaced third-stage impeller; 301-4, fourth-stage impeller; 301-5, pump shaft; 301-6, fixings. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of this application, unless otherwise specified, "plurality" means two or more.

[0034] With the global push for new energy sources such as wind and solar energy, the large-scale grid-connected operation of new energy sources has significantly reduced the market share of thermal power generation, resulting in a decline in the utilization rate of traditional coal-fired power units, especially a significant reduction in the number of hours of power generation units. In the face of the large-scale consumption of new energy sources, thermal power generation units must have efficient deep peak-shaving capabilities to adapt to the needs of the power grid.

[0035] At present, with the load adjustment of thermal power generating units, especially the operation of condensate systems, severe technical and safety challenges are faced. The present invention provides a condensate system, which aims to solve the problems of large resistance of the condensate system and large vibration of the condensate pump in the prior art. Through the technical solution of the present invention, the resonance problem of the condensate pump when operating under low-load conditions during deep peak regulation is solved, and the reliability of the equipment is guaranteed; it also meets the water supply demand of the deaerator when the unit is running at full load, and significantly improves the operating efficiency of the condensate pump. At the same time, by opening the condensate bypass electric valve, the operating resistance of the condensate system is greatly reduced, the power consumption rate of the condensate system is greatly reduced, and the economic benefits of the condensate system are improved.

[0036] The condensate system of the embodiment of the present application is described below with reference to the accompanying drawings. Figure 1 As shown, the present invention provides a condensate system, including a condenser 1, a hot well 2, a condensate pump 3, a heating device 4, and a deaerator 5;

[0037] The condenser 1 is used to form condensate, and the bottom of the condenser 1 is connected to the hot well 2; the hot well 2 is used to collect and store the condensate of the condenser 1, and the outlet of the hot well 2 is connected to the inlet of the condensate pump 3; the condensate pump 3 is used to extract the condensate in the hot well 2 and to transport the condensate to the heating device 4; the outlet of the condensate pump 3 and the inlet of the heating device 4 are connected by a pipeline, and the pipeline is provided with a condensate bypass electric valve 6 and a condensate regulating valve 7, and the condensate regulating valve 6 is connected in parallel with the condensate bypass electric valve 7; the heating device 4 is used to heat the condensate; the outlet of the heating device 4 is connected to the inlet of the deaerator 5. Among them, the condensate pump 3 is a condensate pump including a three-stage impeller, and the three-stage impeller condensate pump is obtained by removing the fourth-stage impeller of the original four-stage impeller condensate pump and installing a fixing at the position of the removed impeller.

[0038] In the embodiment of the present application, the gas discharged from the low-pressure cylinder of the steam turbine is first cooled by the condenser 1; condensed water is formed after cooling; the hot well 2 located below the condenser 1 collects the condensed water from the condenser and stores it; the condensed water pump 3 extracts the condensed water from the hot well 2 and provides sufficient pressure to transport the condensed water to the heating device 4; the heating device 4 preheats the condensed water to increase its temperature and reduce the energy consumption when the boiler is heated; the condensed water from the heating device 4 flows to the deaerator 5 through the pipeline, and the deaerator 5 is used to remove dissolved gases in the condensed water, especially oxygen and carbon dioxide, to prevent them from corroding the boiler and pipeline at high temperature. The main function of the condensed water system is to send the condensed water from the condenser hot well to the deaerator. In order to ensure the safe and reliable operation of the system and improve the thermal efficiency of the cycle, the condensed water system is controlled, heated, deoxidized and other necessary links during the transportation process.

[0039] First, in the embodiment of the present application, a condensate regulating valve 6 and a condensate bypass electric valve 7 connected in parallel are arranged on the pipeline between the outlet of the condensate pump 3 and the inlet of the heating device 4. Due to the structure of the condensate regulating valve 6 itself, the system resistance is large when the system is running. Specifically, the condensate regulating valve 6 mainly includes a valve body, a valve core, and a valve seat; wherein, the gap between the valve core and the valve seat will produce a certain resistance to the water flow. As the valve opening decreases, the flow area becomes smaller and the flow rate will further increase, which leads to a significant increase in the flow resistance; the design form of the valve core and the valve seat, the flow channel curve, and the flow channel design inside the valve body will affect the resistance. Therefore, the use of the condensate regulating valve 6 in the condensate system will lead to a large system resistance. The condensate bypass electric valve 7 is a butterfly valve, and the structure of the butterfly valve is relatively simple, mainly including a valve body, a valve plate, a valve stem, and a sealing ring. When the butterfly valve is in a fully open state, the valve plate is parallel to the flow direction of the fluid, and the fluid can pass through the valve body smoothly with very little resistance. Therefore, when the system is running, the condensate regulating valve 6 can be closed and the condensate bypass electric valve 7 can be opened to reduce the flushing of the condensate regulating valve 6, reduce the system resistance, and improve the economic benefits of the system.

[0040] Secondly, the condensate pump 3 in this embodiment is a condensate pump including a three-stage impeller, which is obtained by removing the fourth-stage impeller from the original four-stage impeller condensate pump and installing a fixing member at the position where the impeller was removed. Figure 2 As shown, it includes a first-stage impeller 301-1, a second-stage impeller 301-2, a third-stage impeller 301-3a, a fourth-stage impeller 301-4, and a pump shaft 301-5. The structure of the condensate pump with three impellers is obtained by removing the fourth-stage impeller 301-4 and installing a fixing member 301-6 at the position where the fourth-stage impeller is removed. Figure 3As shown, it includes a first-stage impeller 301 - 1 , a second-stage impeller 301 - 2 , a third-stage impeller 301 - 3 a , a pump shaft 301 - 5 , and a fixing member 301 - 6 .

[0041] It should be noted that the pump shaft 301-5 of the original four-stage impeller condensate pump and any impeller are mechanically connected through a keyway and a key. The keyway is a groove on the pump shaft 301-5 and any impeller, which is used to accommodate the key to ensure the mechanical connection between the pump shaft 301-5 and any impeller. The key is a metal part that is inserted into the keyway of the pump shaft 301-5 and any impeller to play a locking role, ensuring that the rotational force of the pump shaft 5 can be directly transmitted to the impeller to prevent relative sliding between any impeller and the pump shaft 5. However, after removing the fourth-stage impeller in the original four-stage impeller condensate pump, the key will not be fixed in the keyway, so it is necessary to add a fixing to fix the key in the keyway. The fixing 301-6 is a manually made and processed shaft sleeve, which covers the key and fixes the key on the pump shaft 301-5. The shaft sleeve is connected to the keyway and the pump shaft 5. The inner diameter of the shaft sleeve is the same as the inner diameter of the removed impeller. After the fixing parts are installed, the key can be fixed on the pump shaft 5, thereby preventing the dynamic balance of the condensate pump rotor from being affected after the fourth-stage impeller is removed.

[0042] The transformation principle and reasons of the original four-stage condensate pump are as follows:

[0043] The original four-stage condensate pump has a lift of 60m for the first-stage impeller 1, 160m for the second-stage impeller 2, 260m for the third-stage impeller, and 360m for the fourth-stage impeller. However, the motor frequency of the condensate pump is 44HZ and the outlet pressure is 2.58MPa under the actual full-load condition of the unit. At this time, the lift is 265m. It can be seen that the actual lift of the condensate pump is 360m, which is higher than the actual lift requirement, resulting in high energy consumption during use. Therefore, the original four-stage impeller condensate pump needs to be modified. The theoretical minimum lift of the modified three-stage impeller condensate pump is about 260m, and the outlet pressure is about 2.52MPa. According to the basic theory of the pump, it is possible to improve the performance within 5%. Therefore, it is expected that the lift can reach 260m-273m after removing the fourth-stage impeller, which can basically meet the lift requirements of the unit's full-load condensate pump.

[0044] The condensate pump operates at a power frequency of 50HZ, and its resonance range is between 24-28HZ. When the unit is deeply peak-shifted, when the unit's operating load is reduced from full load to low load, the frequency of the original four-stage condensate pump gradually decreases, and the operating frequency is reduced to near the resonance range of 28HZ. The speed of the original four-stage condensate pump will drop below the critical level, and the vibration of the original four-stage condensate pump will increase significantly. In order to maintain the safe operation of the condensate pump, a common solution is to artificially increase the speed of the condensate pump by adjusting the condensate main regulating valve. However, this approach not only increases the wear of the regulating valve, but also causes energy waste. Therefore, the original four-stage condensate pump needs to be modified. After the modification, when the unit is running at full load, the head of the condensate pump is reduced, which reduces the energy consumption of the motor; when the unit is deeply peak-shifted, the operating frequency of the condensate pump is guaranteed to avoid the resonance range of 24-28HZ, eliminate the vibration of the condensate pump caused by resonance, and ensure the safe operation of the condensate pump.

[0045] Specifically, Table 1 shows the variable frequency operation parameters of the original four-stage impeller condensate pump, and Table 2 shows the variable frequency operation parameters of the three-stage impeller condensate pump after the transformation. It can be seen from Tables 1 and 2 that during deep peak regulation, as the unit load decreases from 1000MW to 350MW, under the same unit load, outlet pressure, and flow rate, the operating frequency of the condensate pump in Table 2 is significantly higher than that in Table 2; before the transformation, as the unit load decreases in Table 1, the operating frequency of the condensate pump decreases to below 30HZ, close to the resonance frequency of 24-28HZ. After the transformation, as the unit load decreases in Table 2, the operating frequency of the condensate pump decreases slower than that in Table 1, stabilizes above 33HZ, and avoids the resonance range. Therefore, after the transformation, the frequency of the condensate pump is guaranteed, the resonance of the condensate pump is eliminated, and the safe operation of the condensate pump is guaranteed.

[0046] Serial number Unit load Outlet pressure flow Current frequency 1 1000MW 2.58MPa 1920t / h 100A 44HZ 2 800MW 2.1MPa 1564t / h 66A 35HZ 3 600MW 1.52MPa 1336t / h 43A 32HZ 4 500MW 1.47MPa 935t / h 31A 30HZ 5 400MW 1.43MPa 778t / h 24A 28HZ 6 350MW 1.29MPa 661t / h 23A 28HZ

[0047] Table 1

[0048]

[0049]

[0050] Table 2

[0051] In a possible implementation manner, the third-stage impeller 301 - 3a in the condensate pump of the three-stage impeller is replaced, and the diameter of the replaced third-stage impeller 301 - 3b is larger than that of the third-stage impeller 301 - 3a before the replacement.

[0052] The condensate pump with three-stage impeller in the above embodiment can reach a head of 260m-273m when the unit is actually running at full load, while the outlet pressure of the unit is 2.58MPa under the actual full load condition, and the head requirement is 265m. Therefore, in order to ensure that the head fully meets the requirements, it can be further modified to increase the output of the condensate pump by 0.1MPa and the head by 10.3m, that is, to increase the outlet pressure of the condensate pump to 2.67MPa and the head to 275m, that is, to increase the head by about 6%.

[0053] Specifically, the transformation method to increase the head by about 6% is to replace the third-stage impeller 301-3a in the condensate pump. The diameter of the third-stage impeller 301-3a before replacement is 619mm, and the diameter of the third-stage impeller 301-3b after replacement is 625mm. After increasing the diameter of the third-stage impeller, the head increases to 290m, which fully meets the head requirement of the unit under full load conditions.

[0054] The modified condensate pump 3 meets the head requirement of the unit at full load operation and can ensure that the outlet pressure and head of the condensate pump quickly rise to full load capacity.

[0055] In a possible embodiment, the heating device 4 includes a first low-pressure heater group 4-1, and the first low-pressure heater group 4-1 includes at least two low-pressure heaters connected in series; a pipeline is connected between the deaerator 5 and the first low-pressure heater group 4-1, and a first low-pressure heater group low-pressure bypass electric valve 4-3a is provided on the pipeline, and the first low-pressure heater group 4-1 is connected in parallel with the first low-pressure heater group low-pressure bypass electric valve 4-3a.

[0056] In the embodiment of the present application, the low-pressure heater preheats the condensate to increase its temperature and reduce the energy consumption when the boiler is heated; the condensate passes through multiple low-pressure heaters to gradually increase the water temperature and reduce the heating burden when entering the boiler. The first low-pressure heater group 4-1 is connected in parallel with the first low-pressure heater group low-pressure bypass electric valve 4-3a, which can bypass the first low-pressure heater group 4-1 when any low-pressure heater in the first low-pressure heater group 4-1 is under maintenance or fails, to ensure the normal operation of the system.

[0057] In a possible embodiment, the heating device 4 includes a second low-pressure heater group 4-2, which includes at least two low-pressure heaters connected in series; a second low-pressure heater group low-pressure bypass electric valve 4-3b is arranged between the inlet of the second low-pressure heater group 4-2 and the pipeline of the condensate bypass electric valve 7; the first low-pressure heater group low-pressure bypass electric valve 4-3b is connected in parallel with the second low-pressure heater group 4-2.

[0058] In a possible embodiment, the system also includes a low-temperature economizer 8 and a low-pressure economizer filter 9; the inlet of the low-temperature economizer 8 is connected to the outlet of the second low-pressure heater group 4-2, the outlet of the low-temperature economizer 8 is connected to the inlet of the low-pressure economizer filter 9, the outlet of the low-pressure economizer filter 9 is connected to the inlet of the deaerator 5, and the low-pressure economizer filter 9 is used to prevent impurities from entering the system; a pipeline is connected between the first outlet of the second low-pressure heater group 4-2 and the inlet of the deaerator 5, and a low-temperature economizer bypass electric valve 8-1 is arranged on the pipeline; the low-temperature economizer bypass electric valve 8-1 is connected in parallel with the low-temperature economizer 8 and the low-pressure economizer filter 9.

[0059] In an embodiment of the present application, the low-temperature economizer 8 heats the condensate by utilizing the waste heat in the flue gas. The heated condensate enters the low-temperature economizer filter 9, which filters the condensate to prevent impurities, particles or foreign matter from entering the system. However, the low-temperature economizer 8 has a large resistance during the use of the system. One of the reasons is that when the condensate flows through the heat exchange tubes of the low-temperature economizer 8, it will produce friction with the tube wall, resulting in flow resistance. This friction resistance is related to the water flow rate, the smoothness of the pipe surface and the length of the pipe. Since the low-temperature economizer 8 has a large resistance to the system, it is necessary to set a low-temperature economizer bypass electric valve 8-1 next to the low-temperature economizer 8. In an emergency, the low-temperature economizer bypass electric valve 8-1 can be partially opened to ensure the water supply demand of the deaerator 5, and the resistance of the low-temperature economizer 8 in the system can be reduced to improve the economic benefits of the condensate system.

[0060] In a possible embodiment, a pipeline is connected between the second outlet of the second low-pressure heater group 4-2 and the inlet of the low-temperature economizer 8, and an electric valve 8-2 from the low-pressure heater outlet to the low-temperature economizer is provided on the pipeline; the electric valve 8-2 from the low-pressure heater outlet to the low-temperature economizer is connected in series with the low-temperature economizer 8.

[0061] In a possible embodiment, the system further includes: a shaft seal heater 10, the inlet of the shaft seal heater 10 is connected to the outlet of the condensate pump 3, a pipeline is connected between the first outlet of the shaft seal heater 10 and the heating device 4, and the shaft seal heater 10 is used to heat the condensate.

[0062] In a possible embodiment, the system also includes: a condensate recirculation regulating valve 12-1 and a condensate recirculation manual valve 12-2; the second outlet of the shaft seal heater 10 is connected to the inlet of the condenser 1 through a condensate recirculation loop; a condensate recirculation regulating valve 12-1 and a condensate recirculation manual valve 12-2 are arranged on the condensate recirculation loop; the condensate recirculation regulating valve 12-1 and the condensate recirculation manual valve 12-2 are connected in series.

[0063] In the embodiment of the present application, a condensate recirculation pipe with a rated flow rate of 25% is introduced from the second outlet of the shaft seal heater 10 to the condenser 1, and the condensate is recirculated in the system. The recirculation process can maintain system stability, optimize the operation of the condensate pump, and reduce the demand for boiler water.

[0064] In a possible embodiment, the system also includes a condensate polishing device 11; the inlet of the condensate polishing device 11 is connected to the outlet of the condensate pump 3, and a pipeline is connected between the outlet of the condensate polishing device 11 and the heating device 4, and the condensate polishing device 11 is used to remove impurities, dissolved gases and dissolved salts in the condensate.

[0065] In a possible embodiment, the system includes at least two condensate pumps 3 connected in parallel; a pipeline is connected between the outlet of the hot well 2 and the inlets of the two condensate pumps 3, and the condensate pump inlet electric valve 3-1 and the condensate pump inlet filter 3-2 are arranged in sequence on the two pipelines; a pipeline is connected between the outlet of the two condensate pumps 3 and the condensate bypass electric valve 7, and the condensate pump outlet check valve 3-3 and the condensate pump outlet electric valve 3-4 are arranged in sequence on the two pipelines.

[0066] In the embodiment of the present application, by providing at least two condensate pumps 3 connected in parallel, not only can the water supply demand of the deaerator 5 be met, but also the failure of any condensate pump 3 can be dealt with in time, thereby improving the system availability.

[0067] The electric valve 3-1 at the inlet of the condensate pump controls the water inlet of the condensate pump, prevents cavitation of the condensate pump 3, and isolates the water source during maintenance. The electric valve 3-4 at the outlet of the condensate pump is used to adjust the water flow of the condensate pump, maintain the system pressure, prevent the condensate from flowing back into the condensate pump, and isolate the system during maintenance. The filter screen 3-2 at the inlet of the condensate pump protects the condensate pump by filtering impurities in the condensate, preventing damage and blockage, and maintaining stable water flow; the check valve 3-3 at the outlet of the condensate pump ensures that the condensate passes through the system in one direction, prevents the condensate from flowing back into the condensate pump, avoids damage to the condensate pump, and ensures the safe operation of the condensate pump.

[0068] The condensate water system of the present invention has the following beneficial effects:

[0069] 1. When the unit is running at full load, it can reduce motor energy consumption and improve the efficiency of condensate pump. It can solve the resonance problem of condensate pump during deep peak regulation and ensure equipment reliability.

[0070] 2. Optimize the resistance of the condensate system, reduce the operating resistance of the condensate system, and significantly improve the operating economy.

Claims

1. A condensate water system, characterized in that: Including condenser, hot well, condensate pump, heating device, deaerator; The condenser is used to form condensed water, and the bottom of the condenser is connected to the hot well; The hot well is used to collect and store condensate from the condenser, and the outlet of the hot well is connected to the inlet of the condensate pump; The condensate pump is used to extract condensate from the hot well and to transport the condensate to the heating device; the outlet of the condensate pump and the inlet of the heating device are connected by a pipeline, and a condensate bypass electric valve and a condensate regulating valve are provided on the pipeline, and the condensate regulating valve is connected in parallel with the condensate bypass electric valve; The heating device is used to heat the condensed water; the outlet of the heating device is connected to the inlet of the deaerator; The condensate pump is a condensate pump including a three-stage impeller, and the three-stage impeller condensate pump is obtained by removing the fourth impeller from the original four-stage impeller condensate pump and installing a fixing part at the position of the removed impeller.

2. The condensate water system according to claim 1, characterized in that: The third-stage impeller in the condensate pump that replaces the three-stage impeller is larger in diameter than the third-stage impeller before the replacement.

3. The condensate water system according to claim 1, characterized in that: The heating device includes a first low-pressure heater group, which includes at least two low-pressure heaters connected in series; a pipeline is connected between the deaerator and the first low-pressure heater group, and a low-pressure bypass electric valve is provided on the pipeline, and the first low-pressure heater group is connected in parallel with the low-pressure bypass electric valve.

4. The condensate water system according to claim 1, characterized in that: The heating device includes a second low-pressure heater group, which includes at least two low-pressure heaters connected in series; a low-pressure bypass electric valve is arranged between the inlet of the second low-pressure heater group and the pipeline of the condensate bypass electric valve; the low-pressure bypass electric valve is connected in parallel with the second low-pressure heater group.

5. The condensate water system according to claim 4, characterized in that: The system also includes a low-temperature economizer and a low-temperature economizer filter; The low-temperature economizer inlet is connected to the outlet of the second low-pressure heater group, the low-temperature economizer outlet is connected to the low-pressure economizer filter inlet, the low-pressure economizer filter outlet is connected to the deaerator inlet, and the low-pressure economizer filter is used to prevent impurities from entering the system; A pipeline is connected between the first outlet of the second low-pressure heater group and the deaerator inlet, and a low-temperature economizer bypass electric valve is arranged on the pipeline; the low-temperature economizer bypass electric valve is connected in parallel with the low-temperature economizer and the low-pressure filter.

6. The condensate system according to claim 4, characterized in that: A pipeline is connected between the second outlet of the second low-pressure heater group and the inlet of the low-temperature economizer, and an electric valve from the low-pressure heater outlet to the low-temperature economizer is arranged on the pipeline; the electric valve from the low-pressure heater outlet to the low-temperature economizer is connected in series with the low-temperature economizer.

7. The condensate water system according to claim 1, characterized in that: The system further comprises: a shaft seal heater, wherein an inlet of the shaft seal heater is connected to an outlet of the condensate pump, a pipeline is connected between a first outlet of the shaft seal heater and a low-pressure heater module, and the shaft seal heater is used to heat the condensate.

8. The condensate water system according to claim 7, characterized in that: The system further comprises: a condensate recirculation regulating valve and a condensate recirculation manual valve; The second outlet of the shaft seal heater is connected to the inlet of the condenser through a condensate recirculation loop; the condensate recirculation regulating valve and the condensate recirculation manual valve are arranged on the condensate recirculation loop; the condensate recirculation regulating valve and the condensate recirculation manual valve are connected in series.

9. The condensate water system according to claim 1, characterized in that: The system also includes a condensate polishing device; the inlet of the condensate polishing device is connected to the outlet of the condensate pump, and a pipeline is connected between the outlet of the condensate polishing device and the heating device. The condensate polishing device is used to remove impurities, dissolved gases and dissolved salts in the condensate.

10. The condensate water system according to claim 1, characterized in that: The system includes at least two condensate pumps connected in parallel; A pipeline is connected between the hot well outlet and the two condensate pump inlets, and a condensate pump inlet electric valve and a condensate pump inlet filter are sequentially arranged on the two pipelines; Pipelines are connected between the outlets of the two condensate pumps and the condensate bypass electric valve, and condensate pump outlet check valves and condensate pump outlet electric valves are sequentially arranged on the two pipelines.

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