A heat recovery system for coal gasification black water

Abstract

The utility model embodiment provides a kind of heat recovery system of coal gasification black water, comprising: soft water heat exchanger, first soft water water supply pipe, first flash tank and first circulating water pump;Soft water heat exchanger is arranged on the output pipeline of coal gasification black water, and soft water heat exchanger, first soft water water supply pipe, first flash tank and first circulating water pump form soft water circulation closed loop.Wherein, the soft water in soft water heat exchanger exchanges heat with the coal gasification black water flowing, enters first flash tank and is flashed, and the saturated steam that meets the requirement of industrial production obtained by flashing is transported to steam pipe network, and the soft water that is not gasified by flashing is transported to first circulating water pump after soft water replenishment, and is transported back to soft water heat exchanger to continue heat exchange.By using soft water to absorb part of the high efficiency heat in the coal gasification black water flowing, and by forming soft water circulation closed loop, the heat energy of coal gasification black water is continuously recycled, so that high-value industrial production steam is continuously produced.

Claims

1. A heat recovery system of coal gasification black water, characterized by, include: The system includes a soft water heat exchanger (110), a first flash tank (130) with a first soft water supply pipe (120), and a first circulating water pump (140). The soft water heat exchanger (110) is installed on the output pipeline of the coal gasification black water. The output end of the soft water heat exchanger (110) is connected to the input end (130-i) of the first flash tank (130). The first output end (130-o1) of the first flash tank (130) is connected to the input end of the steam pipeline network of the coal chemical plant. The second output end (130-o2) of the first flash tank (130) is connected to the input end of the first circulating water pump (140). The output end of the first circulating water pump (140) is connected to the input end of the soft water heat exchanger (110). The soft water heat exchanger (110), the first soft water makeup pipe (120), the first flash tank (130), and the first circulating water pump (140) form a first closed loop of soft water circulation. In this process, the soft water in the soft water heat exchanger (110) exchanges heat with the coal gasification black water flowing through it. The soft water after heat exchange enters the first flash tank (130) for flash evaporation. The saturated steam obtained after flash evaporation that meets the requirements of industrial production is transported to the input end of the steam pipeline network. The soft water that has not been vaporized after flash evaporation is transported to the first circulating water pump (140) after soft water replenishment and is then transported back to the soft water heat exchanger (110) to continue heat exchange.

2. The heat recovery system of claim 1, wherein, The heat recovery system further includes a second flash tank (160) equipped with a second soft water supply pipe (150) and a steam compressor (170). The first flash tank (130) is also equipped with a third output terminal (130-o3). The input terminal (160-i) of the second flash tank (160) is connected to the third output terminal (130-o3) of the first flash tank (130). The first output terminal (160-o1) of the second flash tank (160) is connected to the input terminal of the first circulating water pump (140). The second output terminal (160-o2) of the second flash tank (160) is connected to the input terminal of the steam compressor (170). The output terminal of the steam compressor (170) is connected to the input terminal of the steam pipeline network. The soft water that has not been vaporized after flash evaporation in the first flash tank (130) is transported to the second flash tank (160) for secondary flash evaporation. The saturated steam obtained after secondary flash evaporation is transported to the steam compressor (170) for compression to obtain saturated steam that meets the requirements of industrial production. The compressed steam is transported to the input end of the steam pipeline network. The soft water that has not been vaporized after secondary flash evaporation is transported to the first circulating water pump (140) after soft water replenishment and is transported back to the soft water heat exchanger (110) for continued heat exchange.

3. The heat recovery system of claim 1 or 2, wherein, The heat recovery system also includes an Organic Rankine Cycle (ORC) waste heat power generation system (200) located downstream of the black water outlet of the soft water heat exchanger (110). The Organic Rankine Cycle (ORC) waste heat power generation system (200) includes an ORC preheater (210), an ORC evaporator (220), an expander (230), a first generator (240), an ORC working fluid condenser (250), a first working fluid circulation pump (260), a circulating cooling tower (270), and a second circulating water pump (280). The ORC preheater (210), ORC evaporator (220), expander (230), ORC working fluid condenser (250), and the first working fluid circulation pump (260) are sequentially connected to form a closed loop of ORC working fluid circulation. The ORC working fluid condenser (250), circulating cooling tower (270), and second circulating water pump (280) are sequentially connected to form a closed loop of water circulation. The coal gasification black water, after being heated by the soft water heat exchanger (110), flows sequentially through the ORC evaporator (220) and the ORC preheater (210) before flowing out.

4. The heat recovery system as described in claim 3, characterized in that, The heat recovery system further includes a heat pump waste heat recovery subsystem (300) located downstream of the black water outlet of the soft water heat exchanger (110) or the ORC preheater (210). The heat pump waste heat recovery subsystem (300) includes a heat pump evaporator (310), a heat pump working fluid compressor (320), a heat pump working fluid condenser (330), a throttle valve (340), and a second working fluid circulation pump (350). The heat pump evaporator (310), the heat pump working fluid compressor (320), the heat pump working fluid condenser (330), the throttle valve (340), and the second working fluid circulation pump (350) are sequentially connected to form a closed loop of heat pump working fluid circulation. In this process, the heat pump working fluid in the heat pump evaporator (310) exchanges heat with the coal gasification black water that has been heated by the soft water heat exchanger (110) or the ORC preheater (210) and changes phase to gas. The gaseous heat pump working fluid is compressed by the heat pump working fluid compressor (320) and enters the heat pump working fluid condenser (330) and exchanges heat with the water flowing into the heat pump working fluid condenser (330). After heat exchange, the heat pump working fluid is depressurized by the throttle valve (340) and changes phase to liquid. The liquid heat pump working fluid is then sent to the heat pump evaporator (310) by the second working fluid circulation pump (350) to continue heat exchange.

5. The heat recovery system as described in claim 4, characterized in that, The heat recovery system further includes a water turbine power generation system (400) located downstream of the black water outlet of the soft water heat exchanger (110), the organic Rankine cycle (ORC) waste heat power generation system (200), or the heat pump waste heat recovery subsystem (300). The water turbine power generation system (400) includes a water turbine (410) and a second generator (420) connected to the water turbine (410). The inlet of the water turbine (410) is connected to the black water outlet pipe of the soft water heat exchanger (110), the ORC preheater (210), or the heat pump evaporator (310). The second generator (420) is connected to the water turbine (410).

6. The heat recovery system as described in any one of claims 1 to 5, characterized in that, The saturated steam that meets the requirements of industrial production is low-pressure steam, and the steam pipeline network is the low-pressure steam pipeline network of the coal chemical plant.

7. The heat recovery system as described in any one of claims 1 to 5, characterized in that, The soft water heat exchanger (110) is installed on the bypass of the output pipeline of coal gasification black water.

8. The heat recovery system as described in claim 1, characterized in that, The amount of water supplied through the first soft water supply pipe (120) corresponds to the amount of water used to generate saturated steam obtained by flash evaporation in the first flash tank (130).

9. The heat recovery system as described in claim 2, characterized in that, The amount of water supplied through the second soft water supply pipe (150) corresponds to the amount of water used to generate saturated steam obtained by flash evaporation in the second flash tank (160).

10. The heat recovery system as described in claim 2, characterized in that, A valve is provided between the first flash tank (130) and the second flash tank (160).

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