Vacuum pumping condensate water recovery method for direct air cooling unit

Abstract

The invention discloses a direct air cooling unit vacuumizing condensate water recovery method. The method is achieved based on a direct air cooling unit vacuumizing condensate water recovery system. The method comprises the following steps: S1, counting parameters of a power plant, and determining the highest backpressure value of a unit at the highest temperature and full load stage in a summer environment; s2, performing statistics on parameters of the power plant, and determining a back pressure average value of the unit in high-temperature and full-load stages in spring and autumn environments and a steam side pressure average value of a vacuum pump interstage cooler; s3, the height of the pump set foundation support is determined; s4, determining the water return position of the steam exhaust device of the main engine; s5, adjusting operation modes in spring, autumn and winter; s6, adjusting the operation mode in the high-temperature and high-load period in summer; the problem that due to the fact that annual back pressure change in a direct air cooling unit is large, vacuumizing condensate water of an interstage cooler of an efficient roots vacuum pump unit cannot be recycled in the high-temperature and high-back-pressure period in summer, and the unit cannot operate normally is solved, and annual normal operation of the unit is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of condensate water recovery of generator set, and particularly relates to a method for recovering condensate water of a direct air-cooling generator set. BACKGROUND

[0002] The direct air-cooling generator set has many advantages such as small water consumption, small land occupation and high social economy, and is widely used in the northern region with rich coal and lack of water. However, the direct air-cooling generator set also has problems such as high back pressure, large range of back pressure change in a year and high coal consumption. Influenced by the environmental temperature, the back pressure of the exhaust steam of the direct air-cooling generator set can reach 40-60 kPa in the high temperature period in summer, and the back pressure is less than 10 kPa in winter. In order to improve the heat exchange efficiency, the air and other non-condensing gases leaked into the exhaust device, the pipeline and the air-cooling condenser need to be pumped out by the vacuum pump.

[0003] The condenser vacuum system of the direct air-cooling generator set is generally provided with 2-3 water ring vacuum pumps with large power. When the steam turbine generator set is started, the vacuum pumps are started at the same time, and are used for quickly pumping the condenser and the connected pipeline system. After the steam turbine generator set is put into stable operation, 1-2 running vacuum pumps are used for pumping out the non-condensing gases leaked into the vacuum system, and maintaining the vacuum of the condenser system, and the remaining water ring vacuum pumps are standby. However, the conventional water ring vacuum pump group needs liquid ring sealing, and the working efficiency is low. The limit vacuum and the pumping capacity of the water ring vacuum pump have great relationship with the working water temperature. In winter, the limit vacuum of the water ring vacuum pump is limited, and the pumping capacity is greatly reduced. Generally, 2 vacuum pumps need to be operated, so as to maintain the vacuum of the generator set, and the energy consumption of the equipment is increased.

[0004] In order to improve the vacuum of the generator set, reduce the back pressure of the generator set and reduce the power consumption of the water ring vacuum pump group, there is a part of the reform structure that a large amount of Roots vacuum pump and inter-stage cooler are connected in series in front of the water ring vacuum pump to form a Roots-water ring vacuum pump group, so as to improve the vacuum of the generator set in winter. However, in other seasons, due to the high environmental temperature, the back pressure of the generator set is increased, the pumping capacity of the water ring vacuum pump meets the demand, the Roots vacuum pump is not operated, and the high efficiency and energy saving advantage of the dry Roots vacuum pump is not played in the spring, autumn and summer period.

[0005] In addition, due to the great change of the back pressure of the direct air-cooling generator set in summer and winter, the recovery of the condensate water pumped out by the inter-stage cooler behind the Roots vacuum pump is a difficult problem. In summer, the back pressure of the direct air-cooling generator set can reach 40-60 kPa, and the inter-stage cooler behind the Roots vacuum pump adopts water cooling, and the pressure of the steam (shell) side is generally less than 10 kPa. The condensate water of the inter-stage cooler and the exhaust device of the main machine form a pressure difference of 30-50 kPa, that is, a height difference of 3-5 m of water column, so that the condensate water of the main machine is returned to the inter-stage cooler, and the Roots vacuum pump group cannot be normally operated. Or the foundation of the inter-stage cooler is 3 m-5 m high, and the construction demand cannot be met on site. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a method for recovering vacuum condensing water of a direct air-cooling unit, which can solve the problem that the vacuum condensing water of the inter-stage cooler of the Roots vacuum pump set cannot be normally recovered during the period of high temperature and high load in the environment due to the large change of the back pressure of the main unit exhaust device throughout the year, and effectively improve the economy and safety of the operation of the direct air-cooling unit.

[0007] To solve the above technical problem, the technical solution adopted by the present application is as follows.

[0008] The method for recovering vacuum condensing water of a direct air-cooling unit is realized based on a direct air-cooling unit vacuum condensing water recovery system, which comprises an air-cooling island condenser, a main unit exhaust device and a controller, wherein the air-cooling island condenser is communicated with the main unit exhaust device through a vacuum mother pipe; the vacuum mother pipe is communicated with a water ring vacuum pump set and a Roots vacuum pump set through branch pipes; the Roots vacuum pump set comprises Roots vacuum pumps and inter-stage coolers connected in sequence, and the condensing water drainage side of the inter-stage cooler is connected with the main unit exhaust device; the inter-stage cooler is also connected with a Roots vacuum pump pre-stage pump arranged on the pump set foundation support. The method comprises the following operation steps: S1, the parameters of the power plant are counted to determine the highest back pressure value P of the unit in the highest temperature and full load stage in the summer environment. 11 If the highest back pressure value P is in the high back pressure range, the next step of the method is run, if the highest back pressure value P is in the low back pressure range, the method of directly adding the cooler foundation of the high pump set is run. 11 11 S2, the parameters of the power plant are counted to determine the average back pressure value P of the unit in the high temperature and full load stage in the spring and autumn seasons. 12 21 The pressure difference value P1 is calculated. P1=P 12 -P 21 , and the pressure difference value is converted into m water column height H m1 , and the m water column reserved height H m11 is obtained after considering the coefficient. S3, the height H4 of the pump set foundation support is determined. S4, the backwater position of the inter-stage cooler steam side condensing drainage to the main unit exhaust device is determined. S5, when the Roots vacuum pump set is running in the spring, autumn and winter seasons, the inter-stage cooler is normally supplied with water to realize the real-time recovery of the vacuum condensing water. ​​​​S6, during the summer high temperature and high load period, real-time monitoring of the steam side pressure P1 of the main engine exhaust device and the steam side pressure P2 of the inter-stage cooler, calculating the pressure difference between the two P2 = P1 - P2, when the difference between the two P2 is higher than the set critical value, reducing the cooling water inlet flow of the inter-stage cooler, the set critical value is less than P1, by increasing the steam side pressure P2 of the inter-stage cooler, ensuring P2 is always less than P1, realizing the real-time recovery of vacuum extraction condensate water.

[0009] The above-mentioned direct air-cooled unit vacuum extraction condensate water recovery method, in step S3, according to the distance H2 from the condensate water highest water level h1 of the main engine exhaust device to the ground 0 meters of the turbine hall and the m water column reserved height H m11 calculated in step S2, the distance H3 from the bottom of the inter-stage cooler to the ground 0 meters of the turbine hall is determined, and finally the height H4 of the pump set foundation support from the ground 0 meters of the turbine hall is determined.

[0010] The above-mentioned direct air-cooled unit vacuum extraction condensate water recovery method, in step S3, the height H4 of the pump set foundation support from the ground 0 meters of the turbine hall is not higher than 800 mm.

[0011] The above-mentioned direct air-cooled unit vacuum extraction condensate water recovery method, in step S4, the return water position of the main engine exhaust device is determined according to the position of the condensate water lowest water level h2 of the main engine exhaust device, and the return water position of the main engine exhaust device is at least 300 mm below the condensate water lowest water level h2 of the main engine exhaust device.

[0012] The above-mentioned direct air-cooled unit vacuum extraction condensate water recovery method, in step S6, the adjustment of the cooling water inlet flow is realized by the cooling water inlet electric adjustment door arranged on the cooling water inlet pipe of the inter-stage cooler, and the controlled end of the cooling water inlet electric adjustment door is connected with the output end of the controller; the steam side pressure P1 of the main engine exhaust device is monitored by the main engine exhaust device pressure gauge arranged on the upper part of the main engine exhaust device, and the output end of the main engine exhaust device pressure gauge is connected with the input end of the controller; the steam side pressure P2 of the inter-stage cooler is monitored by the inter-stage cooler steam side pressure gauge arranged on the inter-stage cooler, and the output end of the inter-stage cooler steam side pressure gauge is connected with the input end of the controller.

[0013] The above-mentioned direct air-cooled unit vacuum extraction condensate water recovery method, in step S6, the set critical value is 0.9 P1; when the pressure difference between the steam side pressure P1 of the main engine exhaust device and the steam side pressure P2 of the inter-stage cooler P2 ≥ 0.9 When P1, the cooling water inlet electric adjustment door of the inter-stage cooler is automatically closed; when P2 < 0.9 When P1, the cooling water inlet electric adjustment door of the inter-stage cooler is in full open state.

[0014] The direct air-cooled unit vacuum condensate recovery method, the condensate drainage side of the inter-stage cooler is connected with the main engine exhaust device through the steam condensate water return pipe, the steam condensate water return pipe is provided with a steam condensate water return pipe pneumatic door, and the controlled end of the steam condensate water return pipe pneumatic door is connected with the output end of the controller.

[0015] The direct air-cooled unit vacuum condensate recovery method, the steam condensate water return pipe is also provided with a U-shaped bend pipe, the height H5 of the U-shaped bend pipe is greater than or equal to 2 m, and the bottom center of the U-shaped bend pipe is connected with the steam condensate water return pipe U-shaped bend drain door.

[0016] The direct air-cooled unit vacuum condensate recovery method, the cooling water inlet pipe of the inter-stage cooler is also provided with a cooling water inlet manual door, and the condenser water return pipe of the inter-stage cooler is provided with a cooling water return manual door.

[0017] The direct air-cooled unit vacuum condensate recovery method, the inlet end of the Roots vacuum pump is respectively provided with a Roots vacuum pump inlet manual valve and a Roots vacuum pump inlet pneumatic valve, and the controlled end of the Roots vacuum pump inlet pneumatic valve is connected with the output end of the controller.

[0018] Thanks to the above technical solutions, the technical progress achieved by the present application is as follows.

[0019] The direct air-cooled unit vacuum condensate recovery method provided by the present application can use the Roots vacuum pump pump group to complete vacuumizing when the unit is normally running, and use the water ring vacuum pump pump group to complete vacuumizing when the unit is started or stopped, thereby reducing the power consumption in the vacuumizing process. The steam side pressure of the inter-stage cooler in the Roots vacuum pump pump group and the steam side pressure of the main engine exhaust device are monitored, and the cooling water amount of the cooling water inlet pipe and the steam side pressure of the inter-stage cooler are timely adjusted according to the pressure difference between the steam side pressure of the main engine exhaust device and the steam side pressure of the inter-stage cooler, so that the condensate backflow caused by the excessively high pressure difference between the main engine exhaust device and the inter-stage cooler is avoided, and efficient recovery of the condensate is realized. The problem that the Roots vacuum pump group vacuumizing system in the direct air-cooled unit cannot normally run in summer high temperature and high load due to the large annual back pressure variation of the main engine exhaust device is solved, and the basic height of the Roots vacuum pump group is significantly reduced. Attached Figure Description

[0020] Fig. 1 This is a flowchart of the present invention; Fig. 2 This is a schematic diagram of the specific structure of the system described in this invention.

[0021] The components are as follows: 1. Air-cooled island condenser; 2. Vacuum main pipe; 3. Branch pipes; 4. Main engine exhaust system; 5. Main engine exhaust system vacuum valve; 6. Roots vacuum pump inlet manual valve; 7. Roots vacuum pump inlet pneumatic valve; 8. Main engine exhaust system pressure gauge; 9. Roots vacuum pump; 10. Cooling water return manual valve; 11. Interstage cooler; 12. Cooling water inlet manual valve; 13. Cooling water inlet electric adjusting valve; 14. Extraction steam condensate return pneumatic valve; 15. Interstage cooler steam side pressure gauge; 16. Roots vacuum pump backing pump inlet pneumatic valve; 17. Roots vacuum pump backing pump; 18. Pump set foundation support; 19. Turbine room 0-meter ground level; 20. Extraction steam condensate return pipe; 21. Extraction steam condensate return pipe to main engine exhaust system manual valve; 22. Extraction steam condensate return pipe U-bend drain valve. Detailed Implementation

[0022] A method for recovering condensate from a direct air-cooled unit under vacuum, such as... Figs. 1-2 As shown, this method is based on a vacuum condensate recovery system for a direct air-cooled unit. This system includes an air-cooled island condenser 1, a main unit exhaust system 4, and a controller. The controller uses a DCS distributed control system for regulation. The air-cooled island condenser 1 is connected to the main unit exhaust system 4 via a vacuum header 2. A vacuum valve 5 for the main unit exhaust system is installed on the vacuum header 2 near the outlet of the main unit exhaust system 4. The vacuum header 2 is connected to a water ring vacuum pump group and a high-efficiency Roots vacuum pump group via branch pipes 3, meaning the water ring vacuum pump group and the high-efficiency Roots vacuum pump group are connected in parallel.

[0023] The water ring vacuum pump set is used to operate during the generator set startup or shutdown phase to evacuate the vacuum header 2 between the air-cooled island condenser 1 and the main unit exhaust device 4; the high-efficiency Roots vacuum pump set is used during the normal operation phase of the unit to achieve effective recovery of condensate while evacuating the vacuum.

[0024] The structure of the water ring vacuum pump set is conventional and has not been modified. It is generally connected to the interstage cooler through the water ring vacuum pump, and its structure will not be described in detail here.

[0025] The high-efficiency Roots vacuum pump set comprises Roots vacuum pumps 9 and an inter-stage cooler 11 connected in sequence, the inlet end of the Roots vacuum pump 9 is connected with the vacuumizing main pipe 2 through a branch pipe 3, the outlet end of the Roots vacuum pump 9 is connected with the steam-side inlet end of the inter-stage cooler 11 for condensing the steam extracted, the condensate water drainage side of the inter-stage cooler 11 is connected with the main steam exhaust device 4 through a steam condensate water return pipe 20, and the inter-stage cooler 11 is also communicated with a cooling water inlet pipe and a cooling water return pipe for providing the circulating cooling capacity required for steam condensation.

[0026] The method comprises the following operation steps: S1, counting power plant parameters to determine the highest back pressure value P of the unit in the summer environment under the highest temperature and full load stage 11 , if the highest back pressure value P 11 is in the high back pressure range, then the next step of the method is run, if the highest back pressure value P 11 is in the low back pressure range, then the method of directly adding the high pump set cooler base is run 。

[0027] Step S1 is mainly used to determine whether the running method of the application needs to be implemented by determining the highest back pressure value, and the division of the "low back pressure range" and the "high back pressure range" is determined according to the back pressure economic running range and the limit running range of the unit of this type known in the art.

[0028] The "low back pressure range" refers to the highest back pressure value P 11 not higher than the design back pressure value or the rated back pressure value of the unit under the summer design cooling water temperature and full load working condition; and the "high back pressure range" refers to the highest back pressure value P 11 higher than the design back pressure value or the rated back pressure value.

[0029] When the highest back pressure value is in the high back pressure range, the problem of the condensate water backflow to the inter-stage cooler to cause the high-efficiency Roots vacuum pump set to be unable to run mentioned in the background technology will occur, therefore, the running method provided by the application is needed to solve the problem.

[0030] S2, counting power plant parameters to determine the average back pressure value P 12 of the unit in the spring and autumn season environment under the high temperature and full load stage, and the average steam-side pressure value P 21 of the vacuum pump inter-stage cooler; calculating the pressure difference value P1, P1=P 12 -P 21 , and converting the pressure difference value into m water column height H m1 , and obtaining the m water column reserved height H m11 after considering the coefficient.

[0031] The coefficient considered in step S2 is 1.1-1.3 times. The purpose of setting the consideration coefficient is to reserve the amount of adjustment to avoid backwater.

[0032] S3, determine the height H4 of the pump group foundation support 18.

[0033] Specifically, in step S3, the distance H2 from the condensate water highest water level h1 of the main engine exhaust device to the 0-meter ground 19 of the turbine room and the m water column reserved height H m11 calculated in step S2 are used to determine the distance H3 from the bottom of the inter-stage cooler 11 to the 0-meter ground 19 of the turbine room, and finally determine the height H4 of the pump group foundation support 18 from the 0-meter ground 19 of the turbine room.

[0034] In step S3, the height H4 of the pump group foundation support 18 from the 0-meter ground 19 of the turbine room is not higher than 800 mm.

[0035] S4, determine the backwater position of the condensate water from the inter-stage cooler steam side to the main engine exhaust device 4.

[0036] Specifically, in step S4, the backwater position of the main engine exhaust device 4 is determined according to the position of the condensate water lowest water level h2 of the main engine exhaust device 4. The backwater position of the main engine exhaust device 4 is at least 300 mm below the condensate water lowest water level h2 of the main engine exhaust device 4.

[0037] S5, in spring, autumn and winter seasons, when the Roots vacuum pump group is running, the inter-stage cooler 11 is normally supplied with water to realize real-time recovery of vacuum condensate water.

[0038] S6, in summer high temperature and high load period, the steam side pressure P1 of the main engine exhaust device 4 and the steam side pressure P2 of the inter-stage cooler 11 are monitored in real time, and the pressure difference P2 = P1 - P2, when the difference between the two is P2 is higher than the set critical value, the cooling water inflow of the inter-stage cooler is reduced, the set critical value is less than P1, by increasing the steam side pressure P2 of the inter-stage cooler 11, it is ensured that P2 is always less than P1, realizing real-time recovery of vacuum steam condensate water.

[0039] In step S6, the adjustment of the cooling water inflow is realized by the cooling water inflow electric adjustment door 13 arranged on the cooling water inflow pipe of the inter-stage cooler 11. The controlled end of the cooling water inflow electric adjustment door 13 is connected with the output end of the controller.

[0040] When the difference between the steam side pressure of the main engine exhaust device and the steam side pressure of the inter-stage cooler is When P2 is higher than the set critical value, the cooling water inlet electric adjustment door of the inter-stage cooler is automatically closed to reduce the water inlet amount of the cooling water, and then the steam side pressure P2 of the inter-stage cooler is increased to ensure P2 is always less than P1, and the real-time recovery of the vacuum extraction condensate water is realized.

[0041] When When P2 is lower than the set critical value, the cooling water inlet electric adjustment door of the inter-stage cooler is in the fully open state.

[0042] The steam side pressure P1 of the main engine exhaust device 4 is monitored by the main engine exhaust device pressure gauge 8 arranged on the upper part of the main engine exhaust device 4, and the output end of the main engine exhaust device pressure gauge 8 is connected with the input end of the controller.

[0043] The steam side pressure P2 of the inter-stage cooler 11 is monitored by the inter-stage cooler steam side pressure gauge 15 arranged on the inter-stage cooler 11, and the output end of the inter-stage cooler steam side pressure gauge 15 is connected with the input end of the controller.

[0044] The extraction condensate water return pipe 20 is provided with an extraction condensate water return pneumatic door 14, and the extraction condensate water return pipe 20 close to the main engine exhaust device 4 is provided with an extraction condensate water return pipe to main engine exhaust device manual door 21, and the controlled end of the extraction condensate water return pneumatic door 14 is connected with the output end of the controller.

[0045] The extraction condensate water return pipe 20 is also provided with a U-shaped bend pipe, the height H5 of the U-shaped bend pipe is greater than or equal to 2m, and the bottom center of the U-shaped bend pipe is connected with the extraction condensate water return pipe U-shaped bend drain door 22.

[0046] The cooling water inlet pipe of the inter-stage cooler 11 is provided with a cooling water inlet manual door 12 for controlling the opening and closing of the cooling water inlet pipe.

[0047] The cooler return pipe of the inter-stage cooler 11 is provided with a cooling water return manual door 10.

[0048] The inlet end of the Roots vacuum pump 9 is respectively provided with a Roots vacuum pump inlet manual valve 6 and a Roots vacuum pump inlet pneumatic valve 7, the controlled end of the Roots vacuum pump inlet pneumatic valve 7 is connected with the output end of the controller, and is used for controlling the opening and closing of the Roots vacuum pump.

[0049] The inter-stage cooler 11 is also connected with the Roots vacuum pump front stage pump 17 through a pipeline, the inlet end of the Roots vacuum pump front stage pump 17 is provided with a Roots vacuum pump front stage pump inlet pneumatic door 16, the controlled end of the Roots vacuum pump front stage pump inlet pneumatic door 16 is connected with the output end of the controller, the Roots vacuum pump front stage pump 17 is arranged on the pump group foundation support 18, and the pump group foundation support 18 is arranged on the 0m ground 19 of the steam turbine house.

[0050] When in use, the water ring vacuum pump set is used to pump vacuum during the start-up or shut-down stage of the generator set, at this time, the high-efficiency Roots vacuum pump set arranged in parallel with the water ring vacuum pump set is in standby state or maintenance state, the Roots vacuum pump inlet pneumatic valve, the Roots vacuum pump pre-stage pump inlet pneumatic valve and the condensate water return pneumatic valve are automatically closed, so as to realize the automatic isolation of the high-efficiency Roots vacuum pump set condensate water pipeline and the main system; during the operation stage of the generator set, the high-efficiency Roots vacuum pump set is operated, and the water ring vacuum pump set is in standby state, at this time, the Roots vacuum pump inlet pneumatic valve, the Roots vacuum pump pre-stage pump inlet pneumatic valve and the condensate water return pneumatic valve are opened, the cooling water inlet electric adjustment door is put into self-adjustment according to the steam side pressure difference value of the main steam exhaust device and the inter-stage cooler, so as to realize the real-time recovery of the pumped vacuum condensate water.

[0051] The application will be further described in detail below with reference to the specific embodiments.

[0052] A direct air-cooled unit vacuum pumping condensate water recovery method, comprising the following steps: S11, statistics of power plant parameters, determine the highest temperature of the unit in summer environment, the highest value P of back pressure in full load stage 11 When the back pressure value does not exceed 25kPa, it is low back pressure range, otherwise, it is high back pressure range.

[0053] In this embodiment, P 11 =45kPa, in high back pressure range, continue to run the next step 。

[0054] S21, statistics of power plant parameters, determine the average value P of back pressure in spring, autumn season environment temperature 25℃ and above, 350MW full load stage 12 And the steam side pressure average P of vacuum pump inter-stage cooler 21 , P 12 =22kPa, P 21 =6kPa, the pressure difference value P1 is calculated as P1=P 12 -P 21 =16 kPa, converted into m water column height H m1 =1.6m, in this embodiment, the coefficient is 1.1 times, finally the m water column reserved height H m11 is 1.8m.

[0055] S31, determine the height H4 of the pump set foundation support 18.

[0056] In this embodiment, the distance H2 from the condensate water highest water level h1 of the main steam exhaust device to the 0m ground 19 of the turbine house is 1.1m, and the m water column reserved height H m11, determine the distance H3=H between the bottom of the inter-stage cooler 11 and the 0-meter ground 19 of the steam turbine building m11 -H2=0.7m, and finally determine the height H4 of the pump group foundation support 18 from the 0-meter ground 19 of the steam turbine building as 0.5m.

[0057] S41, determine the backwater position of the inter-stage cooler steam side condensate drainage to the main engine exhaust device 4.

[0058] In this embodiment, the backwater position of the inter-stage cooler steam side condensate drainage to the main engine exhaust device 4 is located 300mm below the lowest water level h2 of the condensate of the main engine exhaust device 4, and the height of the U-shaped bend pipe is 2m.

[0059] S51, in spring, autumn and winter seasons, when the Roots vacuum pump group is running, the inter-stage cooler 11 is normally supplied with water to realize real-time recovery of vacuum condensate.

[0060] S61, in summer high temperature and high load period, the steam side pressure P1 of the main engine exhaust device 4 and the steam side pressure P2 of the inter-stage cooler 11 are monitored in real time, and the cooling water inflow of the inter-stage cooler 11 is adjusted according to the difference P1-P2 between the two to realize real-time recovery of vacuum steam condensate.

[0061] In this embodiment, the set critical value is 0.9 P1, 0.9 P1=14.4kPa, that is, when the difference P1-P2 between the steam side pressure of the main engine exhaust device and the steam side pressure of the inter-stage cooler is ≥14.4kPa (0.9 P1), the cooling water inflow electric adjustment door of the inter-stage cooler is automatically closed to reduce the inflow of cooling water, thereby increasing the steam side pressure P2 of the inter-stage cooler, and ensuring P2 is always less than P 1， that is, 16 kPa, to realize real-time recovery of vacuum steam condensate.

[0062] When P1-P2 is lower than 14.4kPa (0.9 P1), the cooling water inflow electric adjustment door of the inter-stage cooler is in full open state.

[0063] The application provides a kind of direct air cooling unit vacuum condensate water recovery method, by setting parallel water ring vacuum pump set and efficient Roots vacuum pump set and respectively with vacuum mother pipe connection, can use efficient Roots vacuum pump set to complete vacuumizing when unit normal operation, use water ring vacuum pump set to complete vacuumizing when unit starts or stops, reduce the power consumption in the process of vacuumizing in unit operation;Through monitoring the steam side pressure of interstage cooler in efficient Roots vacuum pump set and the steam side pressure of main engine exhaust device, according to the pressure difference between the steam side pressure of main engine exhaust device and the steam side pressure of interstage cooler, the cold water quantity of cooling water inlet pipe and the steam side pressure of interstage cooler are adjusted in time, to ensure that there is no condensate backflow due to the high pressure difference between interstage cooler and main engine exhaust device, efficient recovery of condensate is realized, the problem that efficient Roots vacuum pump set vacuumizing system of direct air cooling unit cannot operate normally in summer high temperature and high load period is solved, and the base height of efficient Roots vacuum pump set is significantly reduced, which effectively improves the economy and safety of generator set operation.

Claims

1. A method for recovering condensate water by vacuumizing a direct air-cooling unit, characterized in that: The method is realized based on a direct air cooling unit vacuum condensing water recovery system, the direct air cooling unit vacuum condensing water recovery system comprising an air cooling island condenser (1), a main engine exhaust device (4) and a controller, the air cooling island condenser (1) being communicated with the main engine exhaust device (4) through a vacuum main pipe (2); the vacuum main pipe (2) is communicated with a water ring vacuum pump group and a Roots vacuum pump group through branch pipes (3) respectively; the Roots vacuum pump group comprises Roots vacuum pumps (9) and inter-stage coolers (11) connected in sequence, and a condensing water drainage side of the inter-stage cooler (11) is connected with the main engine exhaust device (4); the inter-stage cooler (11) is also connected with a Roots vacuum pump pre-stage pump (17) arranged on a pump group foundation support (18); The method comprises the following operation steps: S1, count the parameters of power plant, determine the highest value P of back pressure in the highest temperature and full load stage of unit in summer environment 11 , if the highest value P of back pressure is in high back pressure range, then run according to the next step of the method, if the highest value P of back pressure is in low back pressure range, then run by the method of directly adding high pump group cooler foundation 11 11 , if the highest value P of back pressure is in high back pressure range, then run according to the next step of the method, if the highest value P of back pressure is in low back pressure range, then run by the method of directly adding high pump group cooler foundation​ S2, statistics of power plant parameters, determine the average value of back pressure P of the unit in the high temperature and full load stage in spring and autumn season environment 12 And the average value of vacuum pump inter-stage cooler vapor side pressure P 21 ; Calculate the pressure difference value P1, P1=P 12 -P 21 , and convert the pressure difference value into m water column height H m1 , and the m water column reserved height H m11 is obtained after considering the coefficient; S3, determining the height H4 of the pump group foundation support (18); S4, determining the backwater position of the inter-stage cooler steam side condensing drainage to the main engine exhaust device (4); S5, in spring, autumn and winter seasons, when the Roots vacuum pump group is running, the inter-stage cooler (11) is normally supplied with water, so that the real-time recovery of the vacuum condensing water is realized; S6, in the summer high temperature, high load period, real-time monitoring of the host exhaust device (4) steam side pressure P1 and inter-cooler (11) steam side pressure P2, the pressure difference between the two is calculated P2=P1-P2, when the difference between the two P2 is higher than the set threshold value, reduce the inter-cooler cooling water inlet, the set threshold value is less than P1, by increasing the inter-cooler (11) steam side pressure P2, ensure P2 is always less than P1, the real-time recovery of vacuum extraction condensate.

2. The method for recovering condensate water by vacuumizing a direct air-cooling unit according to claim 1, characterized in that: In step S3, the distance H2 from the highest water level h1 of the condensate of the main exhaust device to the ground (19) of the turbine hall and the m water column reserve height H calculated in step S2 are used to determine the distance H3 from the bottom of the inter-stage cooler (11) to the ground (19) of the turbine hall, and finally determine the height H4 of the pump group foundation support (18) from the ground (19) of the turbine hall. m11 , determine the distance H3 from the bottom of the inter-stage cooler (11) to the ground (19) of the turbine hall, and finally determine the height H4 of the pump group foundation support (18) from the ground (19) of the turbine hall.

3. The method for recovering condensate water by vacuumizing a direct air-cooling unit according to claim 1, characterized in that: In the step S3, the height H4 of the pump group foundation support (18) from the 0-meter ground (19) of the steam engine house is not higher than 800 mm.

4. The method for recovering condensate water by vacuumizing a direct air-cooling unit according to claim 1, characterized in that: In the step S4, the backwater position of the main engine exhaust device (4) is determined according to the position of the condensing water lowest water level h2 of the main engine exhaust device (4), and the backwater position of the main engine exhaust device (4) is located at least 300 mm below the condensing water lowest water level h2 of the main engine exhaust device (4).

5. The method for recovering condensate water by vacuumizing a direct air-cooling unit according to claim 1, characterized in that: In the step S6, the adjustment of the cooling water inflow is realized by a cooling water inflow electric adjustment door (13) arranged on a cooling water inflow pipe of the inter-stage cooler (11), a controlled end of the cooling water inflow electric adjustment door (13) is connected with an output end of the controller; the steam side pressure P1 of the main engine exhaust device (4) is monitored by a main engine exhaust device pressure gauge (8) arranged on the upper part of the main engine exhaust device (4), an output end of the main engine exhaust device pressure gauge (8) is connected with an input end of the controller; the steam side pressure P2 of the inter-stage cooler (11) is monitored by an inter-stage cooler steam side pressure gauge (15) on the inter-stage cooler (11), an output end of the inter-stage cooler steam side pressure gauge (15) is connected with an input end of the controller.

6. The method for recovering condensate water by vacuumizing a direct air-cooling unit according to claim 1, characterized in that: The threshold value set in the step S6 is 0.9 P1; When the pressure difference between the steam side pressure P1 of the host steam exhaust device (4) and the steam side pressure P2 of the inter-stage cooler (11) is P2 ≥ 0.9 P1, the cooling water inlet electric adjustment door (13) of the inter-stage cooler is automatically closed; when P2 < 0.9 P1, the cooling water inlet electric adjustment door (13) of the inter-stage cooler is in a fully open state.

7. The method for recovering condensate water by vacuum extraction of a direct air-cooling unit according to claim 1, characterized in that: The condensing water drainage side of the inter-stage cooler (11) is connected with the main engine exhaust device (4) through a steam condensing water backwater pipe (20), a steam condensing water backwater pneumatic door (14) is arranged on the steam condensing water backwater pipe (20), a controlled end of the steam condensing water backwater pneumatic door (14) is connected with an output end of the controller; a steam condensing water backwater pipe to main engine exhaust manual door (21) is arranged on the steam condensing water backwater pipe (20) close to the main engine exhaust device (4).

8. The method for recovering condensate water by vacuum extraction of a direct air-cooling unit according to claim 1, characterized in that: A U-shaped bend pipe is further arranged on the steam condensing water backwater pipe (20), the height H5 of the U-shaped bend pipe is greater than or equal to 2 m, and a center of a bottom of the U-shaped bend pipe is connected with a steam condensing water backwater pipe U-shaped bend drain door (22).

9. The method for recovering condensate water by vacuum extraction of a direct air-cooling unit according to claim 1, characterized in that: The inter-stage cooler (11) is further provided with a cooling water inlet manual door (12) on the cooling water inlet pipe, and a cooling water return manual door (10) on the cooler return water pipe.

10. The method for recovering condensate water by vacuum extraction of a direct air-cooling unit according to claim 1, characterized in that: The inlet end of the Roots vacuum pump (9) is respectively provided with a Roots vacuum pump inlet manual valve (6) and a Roots vacuum pump inlet pneumatic valve (7), and the controlled end of the Roots vacuum pump inlet pneumatic valve (7) is connected with the output end of the controller.

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