Heat network drain water reuse system and method applicable to thermal power plants

Abstract

The present invention discloses a system and method for recycling heat network drainage for thermal power plants, which comprises connecting an eighth low-pressure heater, a seventh low-pressure heater, a sixth low-pressure heater, and a fifth low-pressure heater in sequence through a main condensate pipe, wherein the fifth low-pressure heater is connected to a deaerator through the main condensate pipe; the fifth low-pressure heater is refluxed to the sixth low-pressure heater through the first drain pipe, the sixth low-pressure heater is refluxed to the seventh low-pressure heater through the second drain pipe, the seventh low-pressure heater is refluxed to the eighth low-pressure heater through the third drain pipe, and the eighth low-pressure heater is also refluxed to the hot well through the fourth drain pipe, and a condenser is also provided on the hot well; the sixth low-pressure heater is also connected to a detection unit. The present invention is applicable to a system and method for recycling heat network drainage for thermal power plants, which solves the waste of energy in heat network drainage recovery and the hidden danger of forced shutdown in the prior art, and has good practical value.

Description

Technical Field

[0001] The present invention belongs to the technical field of heating environmental protection equipment, and specifically relates to a heating network drain water recycling system applicable to a thermal power plant. The present invention also relates to a heating network drain water recycling method applicable to a thermal power plant. Background Art

[0002] At present, energy conservation and water conservation has become a very important research topic. According to the different parameters of the units, the thermal power plant has a design of direct recycling of the water drain of the heating network with lower parameters to the deaerator water tank, and a design of direct recycling of the water drain of the heating network with higher parameters to the condenser.

[0003] However, the water quality of the heat network drain fluctuates greatly. When the equipment is started up after maintenance or when there is a pipeline leak, the water quality parameters exceed the standard. If it is directly recycled to the deaerator water tank, the boiler water quality will deteriorate, and in severe cases, the unit will be shut down. If it is directly recycled to the condenser, it will be not conducive to energy saving. Even if the water quality parameters are qualified, if it is directly recycled to the deaerator water tank, the extraction volume of high-quality steam will increase, which is not conducive to energy saving. Summary of the invention

[0004] The first object of the present invention is to provide a heat network drain reuse system suitable for thermal power plants, which solves the problem that existing equipment cannot effectively utilize heat network drain, which easily leads to energy waste and equipment damage.

[0005] The second object of the present invention is to provide a method for recycling water from a heating network suitable for a thermal power plant.

[0006] The first technical solution adopted by the present invention is a heat network drain reuse system applicable to a thermal power plant, comprising an eighth low-pressure heater, a seventh low-pressure heater, a sixth low-pressure heater, and a fifth low-pressure heater connected in sequence through a main condensate pipe, and the fifth low-pressure heater is connected to a deaerator through the main condensate pipe;

[0007] The fifth low-pressure heater returns to the sixth low-pressure heater through the first drain pipe, the sixth low-pressure heater returns to the seventh low-pressure heater through the second drain pipe, the seventh low-pressure heater returns to the eighth low-pressure heater through the third drain pipe, and the eighth low-pressure heater also returns to the hot well through the fourth drain pipe, and a condenser is also provided on the hot well;

[0008] The sixth low-pressure heater is also connected to a detection unit.

[0009] The present invention is also characterized in that

[0010] The fifth low-pressure heater is specifically a JD-700-14 horizontal fully welded low-pressure heater;

[0011] The sixth low-pressure heater is specifically a JD-620-6 horizontal fully welded low-pressure heater;

[0012] The eighth low-pressure heater and the seventh low-pressure heater are both JD-700 / 800-8 horizontal combined low-pressure heaters.

[0013] The detection unit includes a heat network heater, a drain pump and a classification unit which are sequentially connected through a drain mother pipe, and the classification unit refluxes to the sixth low-pressure heater.

[0014] The drain pump is H40-315 2 / 37KW type drain pump.

[0015] The classification unit includes a drain branch a connected to the drain main pipe, the drain branch a is connected to the sensor unit and the PLC controller in sequence, the PLC controller flows back to the drain main pipe through the drain branch a and is provided with a drain electric valve a;

[0016] The seventh low-pressure heater is also connected to the drain electric valve b through the drain branch b, the drain branch b is connected to the drain main pipe, and the drain electric valve b is also connected to the PLC controller.

[0017] The PLC controller model is 10FXIS-20MR-D.

[0018] Both steam trap electric valve a and steam trap electric valve b are Q11F-16P steam traps.

[0019] The sensor unit includes an online sodium meter, an online silicon meter, an online hydrogen conductivity meter and a total iron analyzer which are connected in parallel.

[0020] The model of the online sodium meter is HGY-2068; the model of the online silicon meter is Polymetron Silkostat 9210; the model of the online hydrogen conductivity meter is METTLER TOLEDO200CR.

[0021] The second technical solution adopted by the present invention is a method for recycling water from a heat network in a thermal power plant, using a system for recycling water from a heat network in a thermal power plant, comprising the following steps:

[0022] Step 1, respectively setting reference values ​​of the online sodium meter, the online silicon meter, the online hydrogen conductivity meter and the total iron analyzer;

[0023] Step 2, the main condensate pipe passes through the eighth low-pressure heater, the seventh low-pressure heater, the sixth low-pressure heater and the fifth low-pressure heater in sequence according to the water flow direction. At this time, the drain pump is started, and water samples are collected on the drain main pipe and enter the detection unit;

[0024] Step 3: The water sample enters the online sodium meter, online silicon meter, online hydrogen conductivity meter and total iron analyzer through the drain branch a for detection, and four sets of detection data are obtained and transmitted to the PLC controller. After the PLC controller compares it with the reference value in step 1:

[0025] If all four sets of data are qualified, open the drain electric valve b, close the drain electric valve a, and drain water enters the sixth low-pressure heater pipe, enters the fifth low-pressure heater after heating, and is finally recovered to the deaerator through the main condensate pipe;

[0026] If at least one parameter of the four sets of data is unqualified, the drain electric valve a is opened and the drain electric valve b is closed. The drain enters the shell side of the sixth low-pressure heater and flows back to the seventh low-pressure heater through the second drain pipe. The seventh low-pressure heater flows back to the eighth low-pressure heater through the third drain pipe, and the eighth low-pressure heater flows back to the hot well through the fourth drain pipe.

[0027] The beneficial effects of the present invention are:

[0028] (1) The present invention is applicable to a heat network drain recycling system of a thermal power plant, wherein the heat network drain is detected by an online sensor unit, and the drain is recycled more scientifically. When the drain is qualified, it is recycled to a deaerator, and when the drain is unqualified, it is recycled to a condenser, thereby eliminating the need for high-temperature iron removers, heat network deaerators and other processing equipment;

[0029] (2) The present invention is applicable to the heat network drain reuse system of a thermal power plant. The hot water drain is recovered to the deaerator water tank through the low-pressure heater pipe, which increases the drain temperature and effectively reduces the amount of high-quality steam extraction used by the deaerator;

[0030] (3) The present invention is applicable to the heat network drain reuse system of a thermal power plant. The heat network drain is recovered to the condenser hot well through the shell side of the low-pressure heater. A large amount of heat from the heat network drain can be utilized step by step through the low-pressure heater.

[0031] (4) The present invention is applicable to a method for recycling drain water from a heat network of a thermal power plant, and the method can scientifically carry out the recycling of drain water with simple operation steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a schematic structural diagram of a heat network drain reuse system applicable to a thermal power plant.

[0033] In the figure, 1. deaerator, 2. heat network heater, 3. drain pump, 4. drain main pipe, 5. fifth low-pressure heater, 6. sixth low-pressure heater, 7. seventh low-pressure heater, 8. eighth low-pressure heater, 9. drain electric valve b, 10. drain electric valve a, 11. online sodium meter, 12. online silicon meter, 13. online hydrogen conductivity meter, 14. full iron analyzer, 15. PLC controller, 16. condenser, 17. hot well, 18. main condensate pipe, 19. first drain pipe, 20. second drain pipe, 21. third drain pipe, 22. drain branch a, 23. drain branch b, 24. fourth drain pipe. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] The present invention is applicable to the heat network drainage reuse system of thermal power plants, such as Figure 1 As shown, the eighth low-pressure heater 8, the seventh low-pressure heater 7, the sixth low-pressure heater 6, and the fifth low-pressure heater 5 are sequentially connected through the main condensate pipe 18, and the fifth low-pressure heater 5 is connected to the deaerator 1 through the main condensate pipe 18;

[0036] The fifth low-pressure heater 5 flows back to the sixth low-pressure heater 6 through the first drain pipe 19, the sixth low-pressure heater 6 flows back to the seventh low-pressure heater 7 through the second drain pipe 20, the seventh low-pressure heater 7 flows back to the eighth low-pressure heater 8 through the third drain pipe 21, and the eighth low-pressure heater 8 also flows back to the hot well 17 through the fourth drain pipe 24. The hot well 17 is also provided with a condenser 16. The steam in the hot well 17 is condensed by the condenser 16 and falls into the hot well 17;

[0037] The sixth low-pressure heater 6 is also connected to a detection unit.

[0038] The fifth low-pressure heater 5 is specifically a JD-700-14 horizontal fully welded low-pressure heater; the sixth low-pressure heater 6 is specifically a JD-620-6 horizontal fully welded low-pressure heater; the eighth low-pressure heater 8 and the seventh low-pressure heater 7 are both JD-700 / 800-8 horizontal combination low-pressure heaters.

[0039] The detection unit includes a heat network heater 2, a drain pump 3 with a model of H40-3152 / 37KW and a classification unit which are connected in sequence through a drain main pipe 4, and the classification unit refluxes to the sixth low-pressure heater 6.

[0040] The classification unit includes a drain branch a22 connected to the drain main pipe 4, the drain branch a22 is connected to the sensor unit and the PLC controller 15 of model 10FXIS-20MR-D in turn, the PLC controller 15 flows back to the drain main pipe 4 through the drain branch a22 and is provided with a drain electric valve a10;

[0041] The seventh low-pressure heater 7 is also connected to the drain electric valve b9 via the drain branch b23 . The drain branch b23 is connected to the drain main pipe 4 . The drain electric valve b9 is also connected to the PLC controller 15 .

[0042] The steam trap electric valve a10 and the steam trap electric valve b9 are both Q11F-16P steam traps.

[0043] The sensor unit includes an online sodium meter 11, an online silicon meter 12, an online hydrogen conductivity meter 13 and a total iron analyzer 14 which are connected in parallel.

[0044] The sensor unit includes an online sodium meter 11 model HGY-2068;

[0045] The online silicon meter 12 model is Polymetron Silkostat 9210;

[0046] The model of the online hydrogen conductivity meter 13 is METTLER TOLEDO200CR.

[0047] The present invention is applicable to a method for recycling water from a heat network in a thermal power plant, using a system for recycling water from a heat network in a thermal power plant, and comprises the following steps:

[0048] Step 1, respectively setting reference values ​​of the online sodium meter 11, the online silicon meter 12, the online hydrogen conductivity meter 13 and the total iron analyzer 14;

[0049] Step 2: The water in the main condensate pipe 18 passes through the eighth low-pressure heater 8, the seventh low-pressure heater 7, the sixth low-pressure heater 6, and the fifth low-pressure heater 5 in sequence according to the water flow direction. At this time, the drain pump 3 is started, and the water sample is collected on the drain main pipe 4 and enters the detection unit;

[0050] Step 3: The water sample enters the online sodium meter 11, the online silicon meter 12, the online hydrogen conductivity meter 13 and the total iron analyzer 14 through the drain branch a22 for detection, and four sets of detection data are obtained and transmitted to the PLC controller 15. After the PLC controller 15 determines:

[0051] If all four sets of data are qualified, open the drain electric valve b9, close the drain electric valve a10, and drain water enters the sixth low-pressure heater 6 pipe, enters the fifth low-pressure heater 5 after heating, and finally is recovered to the deaerator 1 through the main condensate pipe 18;

[0052] If at least one parameter of the four sets of data is unqualified, the drain electric valve a10 is opened and the drain electric valve b9 is closed. The drain enters the shell side of the sixth low-pressure heater 6 and flows back to the seventh low-pressure heater 7 through the second drain pipe 20. The seventh low-pressure heater 7 flows back to the eighth low-pressure heater 8 through the third drain pipe 21. The eighth low-pressure heater 8 flows back to the hot well 17 through the fourth drain pipe 24.

Claims

1. Applicable to the heat network drainage reuse system of thermal power plants, characterized by: The method comprises connecting an eighth low-pressure heater (8), a seventh low-pressure heater (7), a sixth low-pressure heater (6), and a fifth low-pressure heater (5) in sequence through a main condensate pipe (18), wherein the fifth low-pressure heater (5) is connected to the deaerator (1) through the main condensate pipe (18); The fifth low-pressure heater (5) flows back to the sixth low-pressure heater (6) through the first drain pipe (19), the sixth low-pressure heater (6) flows back to the seventh low-pressure heater (7) through the second drain pipe (20), the seventh low-pressure heater (7) flows back to the eighth low-pressure heater (8) through the third drain pipe (21), the eighth low-pressure heater (8) also flows back to the hot well (17) through the fourth drain pipe (24), and the hot well (17) is also provided with a condenser (16); The sixth low-pressure heater (6) is also connected to a detection unit; The detection unit comprises a heat network heater (2), a drain pump (3) and a classification unit which are sequentially connected via a drain main pipe (4), and the classification unit is connected to the shell side of the sixth low-pressure heater (6); The classification unit comprises a drain branch a (22) connected to the drain main pipe (4), the drain branch a (22) being connected to the sensor unit and the PLC controller (15) in sequence, the PLC controller (15) returning water to the drain main pipe (4) through the drain branch a (22) and being provided with a drain electric valve a (10); The pipe side of the seventh low-pressure heater (7) is also connected to a drain electric valve b (9) via a drain branch b (23), the drain branch b (23) is connected to the drain main pipe (4), and the drain electric valve b (9) is also connected to a PLC controller (15); The sensor unit comprises an online sodium meter (11), an online silicon meter (12), an online hydrogen conductivity meter (13) and a total iron analyzer (14) which are connected in parallel.

2. The heat network drain water reuse system suitable for thermal power plants according to claim 1, characterized in that: The fifth low-pressure heater (5) is specifically a JD-700-14 horizontal fully welded low-pressure heater; The sixth low-pressure heater (6) is specifically a JD-620-6 horizontal fully welded low-pressure heater; The eighth low-pressure heater (8) and the seventh low-pressure heater (7) are both JD-700 / 800-8 horizontal combined low-pressure heaters.

3. The heat network drain water reuse system suitable for thermal power plants according to claim 1, characterized in that: The drain pump (3) is a H40-315 2 / 37KW drain pump.

4. The heat network drain water reuse system suitable for thermal power plants according to claim 1, characterized in that: The model of the PLC controller (15) is 10FXIS-20MR-D.

5. The heat network drain water reuse system suitable for thermal power plants according to claim 1, characterized in that: The steam trap electric valve a (10) and the steam trap electric valve b (9) are both Q11F-16P steam trap valves.

6. The heat network drain water reuse system suitable for thermal power plants according to claim 1, characterized in that: The model of the online sodium meter (11) is HGY-2068; the model of the online silicon meter (12) is Polymetron Silkostat 9210; and the model of the online hydrogen conductivity meter (13) is METTLER TOLEDO200CR.

7. A method for recycling water from a heating network of a thermal power plant, characterized in that: The use of the heat network drain water reuse system applicable to a thermal power plant as described in any one of claims 1 to 6 specifically comprises the following steps: Step 1, respectively setting reference values ​​of an online sodium meter (11), an online silicon meter (12), an online hydrogen conductivity meter (13) and a total iron analyzer (14); Step 2, the water in the main condensate pipe (18) passes through the eighth low-pressure heater (8), the seventh low-pressure heater (7), the sixth low-pressure heater (6) and the fifth low-pressure heater (5) in sequence according to the water flow direction. At this time, the drain pump (3) is started, and a water sample is collected on the drain main pipe (4) and enters the detection unit; In step 3, the water sample enters the online sodium meter (11), the online silicon meter (12), the online hydrogen conductivity meter (13) and the total iron analyzer (14) through the drain branch a (22) for detection, and four sets of detection data are obtained and transmitted to the PLC controller (15). After the PLC controller (15) compares the data with the reference value in step 1: If all four sets of data are qualified, the drain electric valve b (9) is opened, the drain electric valve a (10) is closed, and the drain enters the sixth low-pressure heater (6) pipe line, and after the temperature is increased, enters the fifth low-pressure heater (5), and is finally recovered to the deaerator (1) through the main condensate pipe (18); If at least one parameter of the four sets of data is unqualified, the drain electric valve a (10) is opened, the drain electric valve b (9) is closed, and the drain enters the shell side of the sixth low-pressure heater (6), and flows back to the seventh low-pressure heater (7) through the second drain pipe (20). The seventh low-pressure heater (7) flows back to the eighth low-pressure heater (8) through the third drain pipe (21), and the eighth low-pressure heater (8) flows back to the hot well (17) through the fourth drain pipe (24).

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