Coal gasification black water and heat combined system

Abstract

The utility model provides a coal gasification black water heat combination system which comprises a black water cooling unit and a heat recycling unit, the heat recycling unit comprises a first heat utilization part and a second heat utilization part, a bottom outlet of a high-pressure flash evaporator is connected with a black water inlet of a heat exchange unit, and a black water outlet of the heat exchange unit is connected with an inlet of a low-pressure flash evaporator. A bottom outlet of the low-pressure flash evaporator is connected with an inlet of the vacuum flash evaporator, a heating medium water outlet of the heat exchange unit is connected with an inlet of the heat using island, an outlet of the heat using island is connected with an inlet of the buffer tank, an outlet of the buffer tank is connected with an inlet of the circulating pump, and an outlet of the circulating pump is connected with a heating medium water inlet of the heat exchange unit. An inlet of the second heat utilization part is connected with a flash steam outlet of the high-pressure flash evaporator and a flash steam outlet of the low-pressure flash evaporator, black water heat at the bottom of the high-pressure flash evaporator is exchanged into heat medium water, the heat medium water obtained after heat exchange is used for a heat using island, and therefore the heat of the black water is comprehensively utilized.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal gasification preparation, and particularly relates to a coal gasification black water heat combined system. Background Technique

[0002] The coal chemical gasification process generally uses a water coal slurry gasifier or a pulverized coal gasifier. During the cooling and washing process of coal gasification, high-temperature gasification washing water at 230°C - 260°C is formed, namely gasification washing black water. The black water needs to be cooled to below 60°C for clarification treatment and then recycled.

[0003] In the prior art, the high-temperature gasification black water at 230°C - 260°C is cooled to below 60°C through a process flow of high-pressure, low-pressure, and vacuum three-stage flashing cooling and heat exchange cooling by a final heat exchanger. Among them, after high-pressure and low-pressure flashing, the temperature of the black water drops to about 130°C. The black water coming out of the high-pressure flash directly enters the low-pressure flash evaporator for flashing. The high temperature of the black water causes heat waste. Summary of the Invention

[0004] In view of this, the utility model provides a coal gasification black water heat combined system that reduces heat waste.

[0005] A coal gasification black water heat combined system includes a black water cooling unit and a heat recovery unit. The black water cooling unit includes a high-pressure flash evaporator, a low-pressure flash evaporator, and a vacuum flash evaporator. The heat recovery unit includes a first heat utilization part and a second heat utilization part. The first heat utilization part includes a heat exchange unit, a heat consumption island, a buffer tank, and a circulation pump. The bottom outlet of the high-pressure flash evaporator is connected to the black water inlet of the heat exchange unit. The black water outlet of the heat exchange unit is connected to the inlet of the low-pressure flash evaporator. The bottom outlet of the low-pressure flash evaporator is connected to the inlet of the vacuum flash evaporator. The hot medium water outlet of the heat exchange unit is connected to the inlet of the heat consumption island. The outlet of the heat consumption island is connected to the inlet of the buffer tank. The outlet of the buffer tank is connected to the inlet of the circulation pump. The outlet of the circulation pump is connected to the hot medium water inlet of the heat exchange unit. The inlets of the second heat utilization part are respectively connected to the flash steam outlets of the high-pressure flash evaporator and the low-pressure flash evaporator to comprehensively utilize the heat of the black water.

[0006] Preferably, the heat exchange unit includes at least one heat exchanger.

[0007] Preferably, the heat exchanger is a plate heat exchanger.

[0008] Preferably, the buffer tank is provided with a nitrogen inlet pipe, a vent pipe, and a makeup water pipe. The nitrogen inlet pipe is connected to the gas inlet of the buffer tank. The vent pipe is connected to the top of the buffer tank. The makeup water pipe is connected to the liquid inlet pipe of the buffer tank.

[0009] Preferably, the outlet of the high-pressure flash evaporator is also connected to the inlet of the low-pressure flash evaporator, and the outlet of the circulation pump is also connected to the circulation inlet of the buffer tank.

[0010] Preferably, the heat island is one or more of heating users, hot water refrigeration units, hot water power generation units, reboilers of heat regeneration towers, and deaerators.

[0011] Preferably, the first heat utilization part further includes a heat island central system, and the heat island central system is respectively connected to the heat exchange unit and the heat island for use.

[0012] Preferably, the second heat utilization part includes a stripping column and a deaeration water tank. The inlet of the stripping column is connected to the flash steam outlet of the high-pressure flash evaporator, and the inlet of the deaeration water tank is connected to the flash steam outlet of the low-pressure flash evaporator.

[0013] Preferably, the black water cooling unit further includes a transfer pump and an ash water tank. The bottom of the vacuum flash steam is connected to the inlet of the transfer pump, and the outlet of the transfer pump is connected to the inlet of the ash water tank.

[0014] Preferably, the black water cooling unit further includes a heater. The flash steam outlet of the high-pressure flash evaporator is connected to the inlet of the heater, and the outlet of the heater is connected to the inlet of the stripping column.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0016] In the coal gasification black water heat integration system of the present utility model, the bottom outlet of the high-pressure flash evaporator is connected to the black water inlet of the heat exchange unit, the black water outlet of the heat exchange unit is connected to the inlet of the low-pressure flash evaporator, the bottom outlet of the low-pressure flash evaporator is connected to the inlet of the vacuum flash evaporator, the hot medium water outlet of the heat exchange unit is connected to the inlet of the heat island for use, the outlet of the heat island for use is connected to the inlet of the buffer tank, the outlet of the buffer tank is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the hot medium water inlet of the heat exchange unit, and the inlets of the second heat utilization part are respectively connected to the flash steam outlets of the high-pressure flash evaporator and the low-pressure flash evaporator, so as to recover and utilize the heat of the steam of the high-pressure flash evaporator and the low-pressure flash evaporator. The black water flowing out from the bottom of the high-pressure flash evaporator takes heat through the heat exchange unit, the heat island for use, the buffer tank and the circulation pump, transfers the heat of the black water to the hot medium water, and the heat-exchanged hot medium water is used at the heat island for use, so that the heat of the black water is fully utilized, heat loss is reduced, and it is more energy-saving and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a process flow chart of the coal gasification black water heat integration system.

[0018] Figure 2 It is a schematic diagram of a heat exchange unit device.

[0019] In the figure: black water cooling unit 100, high-pressure flash evaporator 110, low-pressure flash evaporator 120, vacuum flash evaporator 130, transfer pump 140, ash water tank 150, heater 160, heat recovery unit 200, first heat utilization part 210, heat exchange unit 211, first electric valve 2111, second electric valve 2112, third electric valve 2113, fourth electric valve 2114, heat utilization island 212, buffer tank 213, nitrogen inlet pipe 2131, vent pipe 2132, make-up water pipe 2133, circulation pump 214, heat island center system 215, pressure reducing tank 216, second heat utilization part 220, stripping tower 221, deaeration water tank 222. Specific embodiments

[0020] The following further elaborates in detail on the technical solutions and technical effects of the embodiments of the present invention in conjunction with the drawings of the present invention.

[0021] Please refer to Figure 1 , a coal gasification black water heat integration system, including a black water cooling unit 100 and a heat recovery unit 200. The black water cooling unit 100 includes a high-pressure flash evaporator 110, a low-pressure flash evaporator 120, and a vacuum flash evaporator 130. The heat recovery unit 200 includes a first heat utilization part 210 and a second heat utilization part 220. The first heat utilization part 210 includes a heat exchange unit 211, a heat utilization island 212, a buffer tank 213, and a circulation pump 214. The bottom outlet of the high-pressure flash evaporator 110 is connected to the black water inlet of the heat exchange unit 211. The black water outlet of the heat exchange unit 211 is connected to the inlet of the low-pressure flash evaporator 120. The bottom outlet of the low-pressure flash evaporator 120 is connected to the inlet of the vacuum flash evaporator 130. The heat medium water outlet of the heat exchange unit 211 is connected to the inlet of the heat utilization island 212. The outlet of the heat utilization island 212 is connected to the inlet of the buffer tank 213. The outlet of the buffer tank 213 is connected to the inlet of the circulation pump 214. The outlet of the circulation pump 214 is connected to the heat medium water inlet of the heat exchange unit 211. The inlet of the second heat utilization part 220 is respectively connected to the flash steam outlets of the high-pressure flash evaporator 110 and the low-pressure flash evaporator 120 to comprehensively utilize the heat of the black water.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] The coal gasification black water heat combined system of the utility model is connected with the black water inlet of the heat exchange unit 211 through the bottom outlet of the high-pressure flash evaporator 110. The black water outlet of the heat exchange unit 211 is connected with the inlet of the low-pressure flash evaporator 120. The bottom outlet of the low-pressure flash evaporator 120 is connected with the inlet of the vacuum flash evaporator 130. The heat medium water outlet of the heat exchange unit 211 is connected with the inlet of the heat utilization island 212. The outlet of the heat utilization island 212 is connected with the inlet of the buffer tank 213. The outlet of the buffer tank 213 is connected with the inlet of the circulation pump 214. The outlet of the circulation pump 214 is connected with the heat medium water inlet of the heat exchange unit 211. The inlet of the second heat utilization part 220 is respectively connected with the flash steam outlets of the high-pressure flash evaporator 110 and the low-pressure flash evaporator 120 to recover and utilize the heat of the steam of the high-pressure flash evaporator 110 and the low-pressure flash evaporator 120. The black water flowing out from the bottom of the high-pressure flash evaporator 110 takes heat through the heat exchange unit 211, the heat utilization island 212, the buffer tank 213 and the circulation pump 214. The low-temperature black water at 170-182°C exchanges heat with the heat medium water in the heat exchange unit 211. The heat exchange medium water is used at the heat utilization island 212. The black water at 110°C after heat exchange continues to return to the low-temperature flash evaporator for flash evaporation, so that the heat of the black water is fully utilized, reducing heat loss and being more energy-saving and environmentally friendly.

[0024] Further, the heat exchange unit 211 includes at least one heat exchanger.

[0025] Please refer to Figure 2, Further, the heat exchange unit 211 includes: a first electric valve 2111, a second electric valve 2112, a third electric valve 2113, and a fourth electric valve 2114. The bottom outlet of the high-pressure flash evaporator 110 is respectively connected to the first electric valve 2111 and the fourth electric valve 2114. The outlets of the first electric valve 2111 and the fourth electric valve 2114 are connected to the heat exchange unit 211. The outlet of the heat exchange unit 211 is connected to the inlets of the second electric valve 2112 and the third electric valve 2113. The outlets of the second electric valve 2112 and the third electric valve 2113 are connected to the inlet of the low-pressure flash evaporator 120; at the beginning, control the first electric valve 2111 and the third electric valve 2113 to open, and the second valve and the fourth valve to close. The black water comes out from the bottom of the high-pressure flash evaporator 110 and enters the heat exchange unit 211 through the first electric valve 2111. After the black water exchanges heat with the heat medium water of the heat exchange unit 211, the heat-exchanged black water enters the low-pressure flash evaporator 120 through the third electric valve 2113. After running for 12 hours, control the fourth electric valve 2114 and the second electric valve 2112 to open, and the first valve and the third valve to close. The black water comes out from the bottom of the high-pressure flash evaporator 110 and enters the heat exchange unit 211 through the fourth electric valve 2114. After the black water exchanges heat with the heat medium water of the heat exchange unit 211, the heat-exchanged black water enters the low-pressure flash evaporator 120 through the second electric valve 2112 to perform positive and reverse flow interval flushing to reduce the deposition of impurities in the black water inside the heat exchanger.

[0026] Further, the heat exchanger is a vortex flow channel heat exchanger. The inside of the vortex flow channel heat exchanger is a plate. The plates can be increased or decreased arbitrarily according to the flow rate and heat exchange area. The pressure-bearing effect is good. It can withstand the pressure of the fluid in the high-pressure flash evaporator 110 and can bear the pressure of the liquid in the high-pressure flash evaporator 110. And once the plate frame heat exchanger is damaged, the plates are easy to replace.

[0027] Further, the first heat utilization part 210 further includes a pressure reducing tank 216. The inlet of the pressure reducing tank 216 is connected to the bottom outlet of the high-pressure flash evaporator 110. The bottom outlet of the pressure reducing tank 216 is connected to the inlet of the heat exchange unit 211. The top outlet of the pressure reducing tank 216 is connected to the inlet of the deaeration water tank 222; due to the high flash evaporation pressure in the high-pressure flash evaporator 110 and the high layout position of the high-pressure flash evaporator 110, the pressure reducing tank 216 reduces the pressure of the incoming black water to prevent the inlet pressure of the black water entering the heat exchange unit 211 from being too high, so that the heat exchange unit 211 can operate in a long cycle. On the other hand, the flash steam at the top of the pressure reducing tank 216 can also heat the deaeration water tank 222.

[0028] Further, the buffer tank 213 is provided with a nitrogen inlet pipe 2131, a vent pipe 2132, and a makeup water pipe 2133. The nitrogen inlet pipe 2131 is connected to the gas inlet of the buffer tank 213. The vent pipe 2132 is connected to the top of the buffer tank 213. The makeup water pipe 2133 is connected to the liquid inlet pipe of the buffer tank 213. The nitrogen inlet supplements gas to the pressure stabilizing buffer tank to prevent the formation of negative pressure.

[0029] Specifically, the heat transfer medium water is demineralized water.

[0030] Further, the outlet of the high-pressure flash evaporator 110 is also connected to the inlet of the low-pressure flash evaporator 120. The outlet of the circulation pump 214 is also connected to the circulation inlet of the buffer tank 213.

[0031] Further, the heat utilization island 212 is one or more of a heating user, a hot water refrigeration unit, a hot water power generation unit, a reboiler of a heat regeneration tower, and a deaerator.

[0032] Further, the first heat utilization unit 210 further includes a heat island central system 215. The heat island central system 215 is respectively connected to the heat exchange unit 211 and the heat utilization island 212.

[0033] Specifically, the heat island central system 215 is a system with an authorization announcement number of 102360181B in the prior art. The heat exchange unit 211 is equipped with on-line monitoring instruments for the temperature and pressure of the inlet and outlet pipelines. The data is uploaded to the heat island central system 215 to monitor and judge the heat exchange effect and whether the heat exchanger is blocked or leaked. The heat transfer medium water coming out of the heat utilization island 212 enters the buffer tank 213 through the main heat transfer medium water pipe, is pressurized by the circulation pump 214 and then returns to the heat exchange unit 211 to extract heat. Control valves, temperature, pressure, flow rate, water quality analysis and other instruments are provided on the pipeline of the whole heat extraction process, including the flow rate, flow velocity, temperature, pressure, surface temperature, heat dissipation amount of each section of the pipeline. The collected real-time data uniformly enters the heat island central system 215, and neural network algorithms and big data modeling are used for heat calculation, prediction analysis and intelligent optimization control of the low-temperature heat system to improve the operation efficiency of the low-temperature heat system.

[0034] Further, the second heat utilization unit 220 includes a stripping column 221 and a deaeration water tank 222. The inlet of the stripping column 221 is connected to the flash steam outlet of the high-pressure flash evaporator 110, and the inlet of the deaeration water tank 222 is connected to the flash steam outlet of the low-pressure flash evaporator 120. A grey water inlet pipe is provided at the inlet of the stripping column 221. The flash steam from the high-pressure flash evaporator 110 is sent into the stripping column 221 to conduct countercurrent contact heat exchange with the grey water from the deaeration water pump, stripping and secondarily preheating the grey water while recovering heat; the bottom liquid of the high-pressure flash evaporator 110 is sent into the low-pressure flash evaporator 120 for flashing, and the flash steam from the low-pressure flash evaporator 120 is sent into the deaeration water tank 222 to replace part of the 0.5 MPa low-pressure steam to deaerate and primarily preheat the grey water from the grey water tank and the desalted water (or recycled water) replenished into the system, recovering the low-grade heat energy in the system.

[0035] Further, the black water cooling unit 100 further includes a transfer pump 140 and a grey water tank 150. The bottom of the vacuum flash steam is connected to the inlet of the transfer pump 140, and the outlet of the transfer pump 140 is connected to the inlet of the grey water tank 150.

[0036] Further, the black water cooling unit 100 further includes a heater 160. The flash steam outlet of the high-pressure flash evaporator 110 is connected to the inlet of the heater 160, and the outlet of the heater 160 is connected to the inlet of the stripping column 221.

[0037] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of rights of the present invention cannot be limited thereby. Those of ordinary skill in the art can understand the entire or partial processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A coal gasification black water heat combined system, characterized in that: It includes a black water cooling unit and a heat recycling unit. The black water cooling unit includes a high-pressure flash evaporator, a low-pressure flash evaporator, and a vacuum flash evaporator. The heat recycling unit includes a first heat utilization part and a second heat utilization part. The first heat utilization part includes a heat exchanger unit, a heat island, a buffer tank, and a circulation pump. The bottom outlet of the high-pressure flash evaporator is connected to the black water inlet of the heat exchanger unit, the black water outlet of the heat exchanger unit is connected to the inlet of the low-pressure flash evaporator, the bottom outlet of the low-pressure flash evaporator is connected to the inlet of the vacuum flash evaporator, the heat medium water outlet of the heat exchanger unit is connected to the inlet of the heat island, the outlet of the heat island is connected to the inlet of the buffer tank, the outlet of the buffer tank is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the heat medium water inlet of the heat exchanger unit, and the inlet of the second heat utilization part is respectively connected to the flash gas outlets of the high-pressure flash evaporator and the low-pressure flash evaporator to fully utilize the heat of the black water.

2. The coal gasification black water heat combined system according to claim 1, characterized in that: The heat exchange unit includes at least one heat exchanger.

3. The coal gasification black water heat combined system according to claim 2, characterized in that: The heat exchanger is a plate heat exchanger.

4. The coal gasification black water heat combined system according to claim 1, characterized in that: The buffer tank is provided with a nitrogen inlet pipe, a vent pipe, and a water supply pipe, wherein the nitrogen inlet pipe is connected to the gas inlet of the buffer tank, the vent pipe is connected to the top of the buffer tank, and the water supply pipe is connected to the liquid inlet pipe of the buffer tank.

5. The coal gasification black water heat combined system according to claim 4, characterized in that: The outlet of the high-pressure flash evaporator is also connected to the inlet of the low-pressure flash evaporator, and the outlet of the circulation pump is also connected to the circulation inlet of the buffer tank.

6. The coal gasification black water heat combined system according to claim 5, characterized in that: The heat island is one or more of a heating user, a hot water refrigeration unit, a hot water generator unit, a heat regeneration tower reboiler, and a deaerator.

7. The coal gasification black water heat combined system according to claim 6, characterized in that: The first heat utilization unit also includes a heat island center system, and the heat island center system is connected to the heat exchange unit and the heat island respectively.

8. The coal gasification black water heat combined system according to claim 7, characterized in that: The second heat utilization part includes a stripping tower and a deoxygenation water tank. The inlet of the stripping tower is connected to the flash gas outlet of the high-pressure flash evaporator, and the inlet of the deoxygenation water tank is connected to the flash gas outlet of the low-pressure flash evaporator.

9. The coal gasification black water heat combined system according to claim 8, characterized in that: The black water cooling unit further comprises a delivery pump and a grey water tank. The bottom of the vacuum flash evaporator is connected to the inlet of the delivery pump, and the outlet of the delivery pump is connected to the inlet of the grey water tank.

10. The coal gasification black water heat integrated system according to claim 9, characterized in that: The black water cooling unit further comprises a heater, the flash gas outlet of the high-pressure flash evaporator is connected to the inlet of the heater, and the outlet of the heater is connected to the inlet of the stripping tower.

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