Coal chemical industry gasified black water waste heat steam production system
By adding a heat exchange unit and a heat transfer water unit to the flash evaporation system, and introducing a second type of absorption heat pump, the problem of low waste heat utilization rate of coal chemical gasification black water was solved, achieving a high efficiency improvement in waste heat utilization rate, saving energy consumption, and increasing enterprise profits.
Patent Information
- Application Number
- CN202520449988.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-03-14
AI Technical Summary
In existing technologies, the waste heat utilization efficiency of coal chemical gasification black water is low, resulting in the waste of heat and water resources, and requiring additional electricity consumption.
A heat exchange unit and a heat transfer water unit are added to the flash evaporation system, and a second type of absorption heat pump is introduced. Through heat exchange between the heat transfer water and the black water, the waste heat of the black water is converted into high-grade steam, and the second type of absorption heat pump is used to produce high-temperature steam.
It improves the efficiency of waste heat recovery from black water, saves coal, water and electricity consumption, and has good economic and social benefits.
Smart Images
Figure CN223895955U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of waste heat recovery and utilization in the coal chemical industry, specifically to a steam generation system for waste heat from coal chemical gasification black water. Background Technology
[0002] In the coal chemical industry, high-temperature gasification washing water, also known as high-temperature gasification black water, is typically generated during the gasification process. The temperature of this black water can reach 230-260℃, and it usually needs to be cooled to below 80℃ before entering a clarification tank for further treatment.
[0003] In existing technologies, flash evaporation is commonly used to cool gasified black water. This involves three stages of flash evaporation: high pressure, low pressure, and vacuum, with the steam produced by high-pressure and low-pressure flash evaporation used to heat the process medium. However, the steam produced by vacuum flash evaporation often uses circulating cooling water, which not only wastes the high-quality heat energy of the black water but also requires a large amount of additional cooling energy, consuming electricity and water resources.
[0004] To reduce waste heat from blackwater treatment, lower water and electricity consumption, and reduce enterprise operating costs, the utility model proposes a treatment method that adds a heat exchange unit and a heat transfer medium system to the flash evaporation system. The heat exchange unit is connected in parallel with the vacuum flash tank via valves. By controlling the valves, blackwater output from the low-pressure flash tank enters the blackwater section of the heat exchange unit, where it exchanges heat with the heat transfer medium. The heated heat transfer medium is then pumped to the heat user. The cooled heat transfer medium at the heat user returns to the heat exchange unit to continue exchanging heat with the blackwater. After cooling, the blackwater is pumped to a clarification tank for clarification. This solution utilizes the heat from the gasification of blackwater to a certain extent. However, with the continuous development of heat exchange and heat pump technologies, maximizing the recovery and utilization of blackwater waste heat remains a continuous goal in this field. Utility Model Content
[0005] This utility model aims to address the problems existing in the prior art by providing a coal chemical gasification black water waste heat steam generation system. By setting up a heat exchange unit, a heat transfer medium water unit, and a second type of absorption heat pump, the black water waste heat is converted into high-grade steam required for production, reducing the waste of gasification black water waste heat, effectively improving the recovery efficiency and utilization quality of black water waste heat, improving the overall energy utilization efficiency, reducing enterprise energy costs, and increasing enterprise profits.
[0006] To achieve the above-mentioned objectives, the technical solution provided by this utility model is as follows:
[0007] A coal chemical gasification black water waste heat steam generation system includes a flash evaporation unit, characterized in that the system further includes a heat exchange unit, a heat transfer medium water unit, and a second type of absorption heat pump;
[0008] The heat exchange unit is connected to the flash evaporation unit via a bypass pipeline.
[0009] The heat transfer water unit is connected to the heat exchange unit;
[0010] The second type of absorption heat pump is connected to the heat transfer medium water unit;
[0011] The heat exchange unit is equipped with a water-to-water heat exchanger. The hot side of the water-to-water heat exchanger is connected to the high-temperature black water output from the flash evaporation unit, and the cold side is connected to the low-temperature heat medium water output from the heat medium water unit.
[0012] The high-temperature black water cools down after exchanging heat with the low-temperature heat transfer water in the water-to-water heat exchanger, while the low-temperature heat transfer water heats up after exchanging heat with the high-temperature black water in the water-to-water heat exchanger, becoming high-temperature heat transfer water.
[0013] High-temperature heat transfer medium water is transported to the second type of absorption heat pump as the driving heat source for producing high-temperature steam.
[0014] The high-temperature heat transfer medium water is cooled down by the second-type absorption heat pump and then returned to the water-to-water heat exchanger for recycling.
[0015] According to the technical solution of this utility model, the flash evaporation unit includes a high-pressure flash evaporator, a low-pressure flash evaporator, and a vacuum flash evaporator; the high-pressure flash evaporator, the low-pressure flash evaporator, and the vacuum flash evaporator are connected in sequence.
[0016] The heat exchange unit is connected in parallel or in series with the flash evaporation unit via a bypass pipeline and a valve group.
[0017] Preferably, the heat exchange unit is connected to the low-pressure flash tank via a valve group in the form of a bypass pipeline, and extracts black water from the high-pressure flash tank.
[0018] More preferably, the heat exchange unit is connected in parallel or in series with the vacuum flash tank of the flash evaporation unit via a valve group in the form of a bypass pipeline. Specifically, along the direction of black water flow, a first valve and a second valve are respectively installed on the black water input side and the black water output side of the vacuum flash tank; a third valve and a fourth valve are respectively installed on the black water input side and the black water output side of the heat exchange unit; the third valve is connected to the upstream pipeline of the first valve; the fourth valve is connected to the downstream pipeline of the second valve; and a fifth valve is installed between the downstream pipeline of the first valve and the upstream pipeline of the fourth valve.
[0019] The terms "upstream" and "downstream" in this invention are based on the direction of black water flow. For example, when black water flows from a high-pressure flash tank to a low-pressure flash tank via a pipeline, the high-pressure flash tank is upstream and the low-pressure flash tank is downstream.
[0020] Preferably, the heat exchange unit includes one or more water-to-water heat exchangers.
[0021] The high-temperature black water is cooled to about 75°C by a water-to-water heat exchanger using low-temperature heat transfer water, and then transported to the clarification tank. The low-temperature heat transfer water is heated to about 120°C by the high-temperature black water through the water-to-water heat exchanger to become high-temperature heat transfer water.
[0022] Preferably, the second type of absorption heat pump includes one or more stages of high-efficiency and stable second type of absorption heat pump, which can stably output steam of the required quality for production use.
[0023] More preferably, the second type of absorption heat pump is a second type of lithium bromide absorption heat pump, which uses circulating cooling water as refrigerant, lithium bromide solution as absorbent, and high-temperature heat transfer medium water as driving heat source to produce high-grade high-temperature steam under the condition of circulating cooling water.
[0024] Preferably, the circulating cooling water required by the second type of absorption heat pump can be the circulating water of the true flash steam cooled by a vacuum flash evaporation system.
[0025] Preferably, the water-to-water heat exchanger is a fully welded plate heat exchanger that is resistant to corrosion, wear, and blockage.
[0026] Preferably, the heat transfer water unit includes a heat transfer water pump, which enables the circulation of heat transfer water between the heat exchange unit and the second type of absorption heat pump.
[0027] Preferably, the coal chemical gasification black water waste heat steam generation system of this utility model adopts PLC automatic control, and can achieve smooth switching between the vacuum flash evaporation system and the black water waste heat steam generation system by switching valve groups.
[0028] The basic principle of the coal chemical gasification black water waste heat steam generation system provided by this utility model is as follows:
[0029] High-temperature black water is generated during the cooling and washing process of coal gasification. The high-temperature black water is sequentially fed into the high-pressure flash tank and the low-pressure flash tank. After the high-temperature black water is discharged from the bottom of the low-pressure flash tank, it is controlled and switched by the valve group so that the high-temperature black water no longer enters the vacuum flash tank, but enters the heat exchange unit.
[0030] A water-to-water heat exchanger is installed in the heat exchange unit. The hot side of the water-to-water heat exchanger is connected to the high-temperature black water output from the flash evaporation unit, and the cold side is connected to the low-temperature heat medium water output from the heat medium water unit. The high-temperature black water is cooled down by the low-temperature heat medium water in the water-to-water heat exchanger. The cooled black water is then transported to the clarification tank for treatment. In the water-to-water heat exchanger, the low-temperature heat medium water is heated up by the high-temperature black water and then becomes high-temperature heat medium water.
[0031] High-temperature heat transfer water is transported to the second-type absorption heat pump via the heat transfer water circulation pump of the heat transfer water unit; the second-type absorption heat pump uses high-temperature heat transfer water as the driving heat source to produce high-temperature steam; after the high-temperature heat transfer water is cooled down by the second-type absorption heat pump, it is returned to the water-to-water heat exchanger for recycling.
[0032] The switching operation of the valve group is as follows:
[0033] If the black water outlet temperature of the heat exchange unit is lower than the outlet temperature of the original vacuum flash tank, open the third and fourth valves and close the first, second and fifth valves. After the black water is output from the low-pressure flash tank, it enters the heat exchange unit through the pipeline via the third valve. In this case, the black water no longer enters the vacuum flash tank, the vacuum flash tank is shut down, and the high-temperature black water flows out through the fourth valve into the clarification tank after being cooled by heat exchange in the heat exchange unit.
[0034] If the black water outlet temperature of the heat exchange unit is higher than the outlet temperature of the original vacuum flash tank, open the third and fifth valves and close the first and fourth valves. After the black water is output from the low-pressure flash tank, it enters the heat exchange unit through the pipeline via the third valve. After the high-temperature black water is cooled down by heat exchange in the heat exchange unit, it is output from the heat exchange unit and enters the vacuum flash tank through the fifth valve. The vacuum flash tank works normally. After the black water is further cooled down by the vacuum flash tank, it enters the clarification tank through the second valve.
[0035] Technical effects of this utility model:
[0036] This invention achieves effective utilization of waste heat from gasification black water. By adding a heat exchange unit and a heat transfer water unit, the temperature of the black water discharged from the low-pressure flash tank after flash evaporation can be reduced to about 75°C. The waste heat recovery utilization rate reaches 32%–40%, accounting for 10%–20% of the total heat of the high-temperature black water.
[0037] This invention combines a heat exchange unit, a heat transfer medium water unit, and a second-type absorption heat pump to produce high-quality steam from waste heat of black water for production use, saving coal consumption and water and electricity consumption, thus achieving good economic and social benefits. Attached Figure Description
[0038] Figure 1 The schematic diagram of the coal chemical gasification black water waste heat steam generation system shown in Embodiment 1 of this utility model.
[0039] Figure 2 The schematic diagram of the coal chemical gasification black water waste heat steam generation system shown in Embodiment 2 of this utility model.
[0040] Figure 3 The schematic diagram of the coal chemical gasification black water waste heat steam generation system shown in Embodiment 3 of this utility model.
[0041] Figure 4The schematic diagram of the coal chemical gasification black water waste heat steam generation system shown in Embodiment 4 of this utility model.
[0042] Explanation of reference numerals in the attached figures:
[0043] High-pressure flash evaporator 1; Low-pressure flash evaporator 2; Vacuum flash evaporator 3;
[0044] Heat exchange unit 4; water-to-water heat exchanger 41;
[0045] Heat transfer water unit 5; heat transfer water pump 51
[0046] Type II absorption heat pump 6;
[0047] First valve 7, second valve 8, third valve 9, fourth valve 10, fifth valve 11;
[0048] Steam compressor 12. Detailed Implementation
[0049] The present invention will now be further described with reference to the accompanying drawings, but the following embodiments do not constitute a limitation on the present invention.
[0050] Example 1
[0051] Figure 1 This invention provides a schematic diagram of the structure of a coal chemical gasification black water waste heat steam generation system. Figure 1 As shown, the system includes: a flash evaporation unit, a heat exchange unit, a heat transfer medium water unit, and a second type of absorption heat pump;
[0052] The flash unit includes a high-pressure flash tank 1, a low-pressure flash tank 2, and a vacuum flash tank 3, which are connected in sequence.
[0053] The heat exchange unit 4 is connected to the vacuum flash tank 3 of the flash unit in the form of a bypass pipeline;
[0054] The heat transfer water unit 5 is connected to the heat exchange unit 4;
[0055] The second type of absorption heat pump 6 is connected to the heat transfer water unit 5;
[0056] A water-to-water heat exchanger 41 is installed in the heat exchange unit 4. The hot side of the water-to-water heat exchanger 41 is connected to the high-temperature black water output from the flash evaporation unit, and the cold side is connected to the low-temperature heat medium water output from the heat medium water unit 5. The high-temperature black water cools down after exchanging heat with the low-temperature heat medium water in the water-to-water heat exchanger, and the low-temperature heat medium water heats up after exchanging heat with the high-temperature black water in the water-to-water heat exchanger to become high-temperature heat medium water.
[0057] The heat transfer water unit 5 includes a heat transfer water pump 51, which enables the circulation of heat transfer water between the heat exchange unit 4 and the second-type absorption heat pump 6. The high-temperature heat transfer water in the heat exchange unit 4 is transported to the second-type absorption heat pump 6 as the driving heat source for producing high-temperature steam. After being cooled by the second-type absorption heat pump 6, the high-temperature heat transfer water is returned to the water-to-water heat exchanger of the heat exchange unit 4 for reuse.
[0058] Heat exchange unit 4 is connected in parallel or in series with the vacuum flash tank of the flash unit via a bypass pipeline and a valve group. Specifically, the valve group is configured as follows along the direction of black water flow:
[0059] A first valve 7 and a second valve 8 are respectively installed on the black water input side and black water output side of the vacuum flash tank 3; a third valve 9 and a fourth valve 10 are respectively installed on the black water input side and black water output side of the heat exchange unit; the third valve 9 is connected to the upstream pipeline of the first valve 7; the fourth valve 10 is connected to the downstream pipeline of the second valve 8; at the same time, a fifth valve 11 is installed between the downstream pipeline of the first valve 7 and the upstream pipeline of the fourth valve 10.
[0060] The terms "upstream" and "downstream" in this invention are based on the direction of black water flow.
[0061] Preferably, the heat exchange unit 4 includes one or more water-to-water heat exchangers 41, and the water-to-water heat exchangers are preferably all-welded plate heat exchangers that are resistant to corrosion, wear, and blockage.
[0062] The high-temperature black water is cooled to about 75°C by the low-temperature heat transfer water through the water-to-water heat exchanger 41, and then transported to the clarification tank. The low-temperature heat transfer water is heated to about 120°C by the high-temperature black water through the water-to-water heat exchanger 41 to become high-temperature heat transfer water. The high-temperature heat transfer water is transported to the second type of absorption heat pump 6 as the driving heat source of the second type of absorption heat pump 6 to produce high-temperature steam.
[0063] The second type of absorption heat pump 6 comprises one or more stages of high-efficiency and stable second-type absorption heat pumps, capable of stably outputting steam of the required quality for production use. More preferably, the second type of absorption heat pump 6 is a second-type lithium bromide absorption heat pump, using circulating water as the refrigerant and lithium bromide solution as the absorbent, utilizing high-temperature heat transfer medium water as the driving heat source, and producing high-grade, high-temperature steam under the condition of circulating cooling water.
[0064] Further preferably, the circulating cooling water required by the second type of absorption heat pump can be the circulating water from the original vacuum flash evaporation system used to cool the true flash steam.
[0065] The coal chemical gasification black water waste heat steam generation system described in this utility model adopts PLC automatic control. By switching valve groups, it can achieve smooth switching between the vacuum flash evaporation system and the black water waste heat steam generation system.
[0066] The valve group switching operation is as follows:
[0067] The valve group includes a first valve 7, a second valve 8, a third valve 9, a fourth valve 10, and a fifth valve 11. If the black water outlet temperature of the heat exchange unit 4 is lower than the outlet temperature of the original vacuum flash tank 3, the third valve 9 and the fourth valve 10 are opened, and the first valve 7, the second valve 8, and the fifth valve 11 are closed. After the black water is output from the low-pressure flash tank 2, it enters the heat exchange unit 4 through the pipeline via the third valve 9. At this time, the black water does not enter the vacuum flash tank 3, and the vacuum flash tank 3 is shut down. After the high-temperature black water is cooled down by heat exchange in the heat exchange unit 4, it flows out through the fourth valve 10 and enters the clarification tank.
[0068] If the black water outlet temperature of heat exchange unit 4 is higher than the outlet temperature of the original vacuum flash tank 3, open the third valve 9 and the fifth valve 11, and close the first valve 7 and the fourth valve 10. After the black water is output from the low-pressure flash tank 2, it enters the heat exchange unit 4 through the pipeline via the third valve 9. After the high-temperature black water is cooled down by heat exchange in the heat exchange unit 4, it is output from the heat exchange unit 4 and enters the vacuum flash tank 3 through the fifth valve 11. The vacuum flash tank 3 works normally. After the black water is further cooled down by the vacuum flash tank 3, it enters the clarification tank through the second valve 8.
[0069] Technical effects of this utility model:
[0070] This invention achieves effective utilization of waste heat from gasification black water. By adding a heat exchange unit and a heat transfer water unit, the temperature of the black water discharged from the low-pressure flash tank after flashing can be reduced to about 75°C, and the waste heat recovery utilization rate reaches 32% to 40%, accounting for 10% to 20% of the total heat of the high-temperature black water.
[0071] This invention combines a heat exchange unit, a heat transfer medium water unit, and a second-type absorption heat pump to produce high-quality steam from waste heat of black water for production use, saving coal consumption and water and electricity consumption, thus achieving good economic and social benefits.
[0072] Example 2
[0073] Figure 2 This invention provides a schematic diagram of the structure of a coal chemical gasification black water waste heat steam generation system. Figure 2 As shown, the system includes: a flash evaporation unit, a heat exchange unit, a heat transfer medium water unit, and a second type of absorption heat pump;
[0074] The flash unit includes a high-pressure flash tank 1, a low-pressure flash tank 2, and a vacuum flash tank 3, which are connected in sequence.
[0075] The heat exchange unit 4 is connected to the vacuum flash tank 3 of the flash unit in the form of a bypass pipeline;
[0076] The heat transfer water unit 5 is connected to the heat exchange unit 4;
[0077] The second type of absorption heat pump 6 is connected to the heat transfer water unit 5;
[0078] A water-to-water heat exchanger 41 is installed in the heat exchange unit 4. The hot side of the water-to-water heat exchanger 41 is connected to the high-temperature black water output from the flash evaporation unit, and the cold side is connected to the low-temperature heat medium water output from the heat medium water unit 5. The high-temperature black water cools down after exchanging heat with the low-temperature heat medium water in the water-to-water heat exchanger, and the low-temperature heat medium water heats up after exchanging heat with the high-temperature black water in the water-to-water heat exchanger to become high-temperature heat medium water.
[0079] The heat transfer water unit 5 includes a heat transfer water pump 51, which enables the circulation of heat transfer water between the heat exchange unit 4 and the second-type absorption heat pump 6. The high-temperature heat transfer water in the heat exchange unit 4 is transported to the second-type absorption heat pump 6 as the driving heat source for producing high-temperature steam. After being cooled by the second-type absorption heat pump 6, the high-temperature heat transfer water is returned to the water-to-water heat exchanger of the heat exchange unit 4 for reuse.
[0080] Heat exchange unit 4 is connected in parallel with the low-pressure flash tank of the flash unit, or in parallel with the vacuum flash tank, or in series via a valve group through a bypass pipeline. Specifically, the valve group is configured as follows along the direction of black water flow:
[0081] A first valve 7 and a second valve 8 are respectively installed on the black water input side of the low-pressure flash tank 2 and the black water output side of the vacuum flash tank 3; a third valve 9 and a fourth valve 10 are respectively installed on the black water input side and the black water output side of the heat exchange unit; the third valve 9 is connected to the upstream pipeline of the first valve 7; the fourth valve 10 is connected to the downstream pipeline of the second valve 8; at the same time, a fifth valve 11 is installed between the downstream pipeline of the first valve 7 and the upstream pipeline of the fourth valve 10.
[0082] The terms "upstream" and "downstream" in this invention are based on the direction of black water flow.
[0083] Preferably, the heat exchange unit 4 includes one or more water-to-water heat exchangers 41, and the water-to-water heat exchangers are preferably all-welded plate heat exchangers that are resistant to corrosion, wear, and blockage.
[0084] The high-temperature black water is cooled to about 75°C by the low-temperature heat transfer water through the water-to-water heat exchanger 41, and then transported to the clarification tank. The low-temperature heat transfer water is heated to about 120°C by the high-temperature black water through the water-to-water heat exchanger 41 to become high-temperature heat transfer water. The high-temperature heat transfer water is transported to the second type of absorption heat pump 6 as the driving heat source of the second type of absorption heat pump 6 to produce high-temperature steam.
[0085] The second type of absorption heat pump 6 comprises one or more stages of high-efficiency and stable second-type absorption heat pumps, capable of stably outputting steam of the required quality for production use. More preferably, the second type of absorption heat pump 6 is a second-type lithium bromide absorption heat pump, using circulating water as the refrigerant and lithium bromide solution as the absorbent, utilizing high-temperature heat transfer medium water as the driving heat source, and producing high-grade, high-temperature steam under the condition of circulating cooling water.
[0086] Further preferably, the circulating cooling water required by the second type of absorption heat pump can be the circulating water from the original vacuum flash evaporation system used to cool the true flash steam.
[0087] The coal chemical gasification black water waste heat steam generation system described in this utility model adopts PLC automatic control. By switching valve groups, it can achieve smooth switching between the vacuum flash evaporation system and the black water waste heat steam generation system.
[0088] The valve group switching operation is as follows:
[0089] The valve group includes a first valve 7, a second valve 8, a third valve 9, a fourth valve 10, and a fifth valve 11. If the black water outlet temperature of the heat exchange unit 4 is lower than the outlet temperature of the original vacuum flash tank 3, the third valve 9 and the fourth valve 10 are opened, and the first valve 7, the second valve 8, and the fifth valve 11 are closed. After the black water is output from the high-pressure flash tank 1, it enters the heat exchange unit 4 through the pipeline via the third valve 9. At this time, the black water does not enter the low-pressure flash tank 2 and the vacuum flash tank 3. The low-pressure flash tank 2 and the vacuum flash tank 3 are shut down. After the high-temperature black water is cooled down by heat exchange in the heat exchange unit 4, it flows out through the fourth valve 10 and enters the clarification tank.
[0090] If the black water outlet temperature of heat exchange unit 4 is higher than the outlet temperature of the original vacuum flash tank 3, open the third valve 9 and the fifth valve 11, and close the first valve 7 and the fourth valve 10. After the black water is output from the high-pressure flash tank 1, it enters the heat exchange unit 4 through the pipeline via the third valve 9. After the high-temperature black water is cooled down by heat exchange in the heat exchange unit 4, it is output from the heat exchange unit 4 and enters the vacuum flash tank 3 through the fifth valve 11. The low-pressure flash tank 2 is shut down and the vacuum flash tank 3 is working normally. After the black water is further cooled down by the vacuum flash tank 3, it enters the clarification tank through the second valve 8.
[0091] Compared with Example 1, the difference between the two is that the heat exchange unit is connected to the low-pressure flash tank through a valve group in the form of a bypass pipeline, and extracts black water from the high-pressure flash tank.
[0092] Example 3
[0093] Figure 3 This invention provides a schematic diagram of the structure of a coal chemical gasification black water waste heat steam generation system. Figure 3As shown, the system includes: a flash evaporation unit, a heat exchange unit, a heat transfer medium water unit, a second type of absorption heat pump, and a steam compressor;
[0094] The flash unit includes a high-pressure flash tank 1, a low-pressure flash tank 2, and a vacuum flash tank 3, which are connected in sequence.
[0095] The heat exchange unit 4 is connected to the vacuum flash tank 3 of the flash unit in the form of a bypass pipeline;
[0096] The heat transfer water unit 5 is connected to the heat exchange unit 4;
[0097] The second type of absorption heat pump 6 is connected to the heat transfer water unit 5;
[0098] A water-to-water heat exchanger 41 is installed in the heat exchange unit 4. The hot side of the water-to-water heat exchanger 41 is connected to the high-temperature black water output from the flash evaporation unit, and the cold side is connected to the low-temperature heat medium water output from the heat medium water unit 5. The high-temperature black water cools down after exchanging heat with the low-temperature heat medium water in the water-to-water heat exchanger, and the low-temperature heat medium water heats up after exchanging heat with the high-temperature black water in the water-to-water heat exchanger to become high-temperature heat medium water.
[0099] The heat transfer water unit 5 includes a heat transfer water pump 51, which enables the circulation of heat transfer water between the heat exchange unit 4 and the second-type absorption heat pump 6. The high-temperature heat transfer water in the heat exchange unit 4 is transported to the second-type absorption heat pump 6 as the driving heat source for producing high-temperature steam. After being cooled by the second-type absorption heat pump 6, the high-temperature heat transfer water is returned to the water-to-water heat exchanger of the heat exchange unit 4 for reuse.
[0100] Heat exchange unit 4 is connected in parallel or in series with the vacuum flash tank of the flash unit via a bypass pipeline and a valve group. Specifically, the valve group is configured as follows along the direction of black water flow:
[0101] A first valve 7 and a second valve 8 are respectively installed on the black water input side and black water output side of the vacuum flash tank 3; a third valve 9 and a fourth valve 10 are respectively installed on the black water input side and black water output side of the heat exchange unit; the third valve 9 is connected to the upstream pipeline of the first valve 7; the fourth valve 10 is connected to the downstream pipeline of the second valve 8; at the same time, a fifth valve 11 is installed between the downstream pipeline of the first valve 7 and the upstream pipeline of the fourth valve 10.
[0102] The terms "upstream" and "downstream" in this invention are based on the direction of black water flow.
[0103] Preferably, the heat exchange unit 4 includes one or more water-to-water heat exchangers 41, and the water-to-water heat exchangers are preferably all-welded plate heat exchangers that are resistant to corrosion, wear, and blockage.
[0104] The high-temperature black water is cooled to about 75°C by the low-temperature heat transfer water through the water-to-water heat exchanger 41, and then transported to the clarification tank. The low-temperature heat transfer water is heated to about 120°C by the high-temperature black water through the water-to-water heat exchanger 41 to become high-temperature heat transfer water. The high-temperature heat transfer water is transported to the second type of absorption heat pump 6 as the driving heat source of the second type of absorption heat pump 6 to produce high-temperature steam.
[0105] The second type of absorption heat pump 6 comprises one or more stages of high-efficiency and stable second-type absorption heat pumps, capable of stably outputting steam of the required quality for production use. More preferably, the second type of absorption heat pump 6 is a second-type lithium bromide absorption heat pump, using circulating water as the refrigerant and lithium bromide solution as the absorbent, utilizing high-temperature heat transfer medium water as the driving heat source, and producing high-grade, high-temperature steam under the condition of circulating cooling water.
[0106] In a further preferred embodiment, the saturated steam produced by the second type of absorption heat pump is compressed into superheated steam at a higher pressure by the steam compressor 12.
[0107] Further preferably, the circulating cooling water required by the second type of absorption heat pump can be the circulating water from the original vacuum flash evaporation system used to cool the true flash steam.
[0108] The coal chemical gasification black water waste heat steam generation system described in this utility model adopts PLC automatic control. By switching valve groups, it can achieve smooth switching between the vacuum flash evaporation system and the black water waste heat steam generation system.
[0109] The valve group switching operation is as follows:
[0110] The valve group includes a first valve 7, a second valve 8, a third valve 9, a fourth valve 10, and a fifth valve 11. If the black water outlet temperature of the heat exchange unit 4 is lower than the outlet temperature of the original vacuum flash tank 3, the third valve 9 and the fourth valve 10 are opened, and the first valve 7, the second valve 8, and the fifth valve 11 are closed. After the black water is output from the low-pressure flash tank 2, it enters the heat exchange unit 4 through the pipeline via the third valve 9. At this time, the black water does not enter the vacuum flash tank 3, and the vacuum flash tank 3 is shut down. After the high-temperature black water is cooled down by heat exchange in the heat exchange unit 4, it flows out through the fourth valve 10 and enters the clarification tank.
[0111] If the black water outlet temperature of heat exchange unit 4 is higher than the outlet temperature of the original vacuum flash tank 3, open the third valve 9 and the fifth valve 11, and close the first valve 7 and the fourth valve 10. After the black water is output from the low-pressure flash tank 2, it enters the heat exchange unit 4 through the pipeline via the third valve 9. After the high-temperature black water is cooled down by heat exchange in the heat exchange unit 4, it is output from the heat exchange unit 4 and enters the vacuum flash tank 3 through the fifth valve 11. The vacuum flash tank 3 works normally. After the black water is further cooled down by the vacuum flash tank 3, it enters the clarification tank through the second valve 8.
[0112] Compared with Example 1, the difference between the two is that the saturated steam produced by the second type of absorption heat pump 6 is compressed into superheated steam with higher pressure by the steam compressor 12, which is convenient for pipeline transportation and meets user needs.
[0113] Example 4
[0114] Figure 4 A schematic diagram of a coal chemical gasification black water waste heat steam generation system according to another embodiment of the present invention is shown. Combining Embodiments 2 and 3, Embodiment 4 adds a steam compressor 12 to Embodiment 2. The saturated steam generated by the second type of absorption heat pump is compressed into superheated steam at a higher pressure by the steam compressor 12, facilitating pipeline transportation and meeting user needs.
[0115] The technical solution of this utility model has been described in detail above, and the principle and implementation method of this utility model have been explained through specific embodiments. However, the embodiments are only used to help understand this utility model and should not be construed as limiting this utility model.
Claims
1. A coal chemical gasification black water waste heat steam generation system, comprising a flash evaporation unit, characterized in that, The system also includes: a heat exchange unit, a heat transfer water unit, and a second type of absorption heat pump; The heat exchange unit is connected to the flash evaporation unit via a bypass pipeline. The heat transfer water unit is connected to the heat exchange unit; The second type of absorption heat pump is connected to the heat transfer medium water unit; The heat exchange unit is equipped with a water-to-water heat exchanger. The hot side of the water-to-water heat exchanger is connected to the high-temperature black water output from the flash evaporation unit, and the cold side of the water-to-water heat exchanger is connected to the low-temperature heat medium water output from the heat medium water unit. The high-temperature black water cools down after exchanging heat with the low-temperature heat medium water in the water-to-water heat exchanger. The low-temperature heat medium water heats up after exchanging heat with the high-temperature black water in the water-to-water heat exchanger and becomes high-temperature heat medium water. High-temperature heat transfer medium water is transported to a type II absorption heat pump to produce high-grade steam; The high-temperature heat transfer medium water is cooled down by the second-type absorption heat pump and then returned to the water-to-water heat exchanger for recycling.
2. The coal chemical gasification black water waste heat steam generation system as described in claim 1, characterized in that: The flash evaporation unit includes a high-pressure flash evaporator, a low-pressure flash evaporator, and a vacuum flash evaporator. The heat exchange unit is connected to the vacuum flash evaporator via a bypass pipeline.
3. The coal chemical gasification black water waste heat steam generation system as described in claim 2, characterized in that: The heat exchange unit is connected to the vacuum flash tank via a valve group, which includes a first valve, a second valve, a third valve, a fourth valve, and a fifth valve. Along the direction of black water flow, the first valve is installed on the black water input side of the vacuum flash tank, and the second valve is installed on the black water output side; the third valve is installed on the black water input side of the heat exchange unit, and the fourth valve is installed on the black water output side; the third valve is connected to the upstream pipeline of the first valve; the fourth valve is connected to the downstream pipeline of the second valve; and the fifth valve is installed between the downstream pipeline of the first valve and the upstream pipeline of the fourth valve.
4. The coal chemical gasification black water waste heat steam generation system as described in claim 1, characterized in that: The heat exchange unit is equipped with one or more water-to-water heat exchangers, which are all-welded plate heat exchangers.
5. The coal chemical gasification black water waste heat steam generation system as described in claim 1, characterized in that: The second type of absorption heat pump includes one or more stages of the second type of absorption heat pump, which stably outputs steam of the required quality.
6. The coal chemical gasification black water waste heat steam generation system as described in claim 5, characterized in that: The second type of absorption heat pump is the lithium bromide absorption heat pump.
7. The coal chemical gasification black water waste heat steam generation system as described in claim 3, characterized in that: The valve group switching operation is as follows: When the black water outlet temperature of the heat exchange unit is lower than the outlet temperature of the vacuum flash tank, the third valve and the fourth valve are opened, and the first valve, the second valve and the fifth valve are closed. After the black water is output from the low-pressure flash tank, it enters the heat exchange unit through the pipeline via the third valve. The vacuum flash tank is stopped. After the high-temperature black water is cooled down by heat exchange in the heat exchange unit, it flows out through the fourth valve and enters the clarification tank.
8. The coal chemical gasification black water waste heat steam generation system as described in claim 3, characterized in that: The valve group switching operation is as follows: When the black water outlet temperature of the heat exchange unit is higher than the outlet temperature of the vacuum flash tank, the third valve and the fifth valve are opened, and the first valve and the fourth valve are closed. After the black water is output from the low-pressure flash tank, it enters the heat exchange unit through the pipeline via the third valve. After the high-temperature black water is cooled down by heat exchange in the heat exchange unit, it is output from the heat exchange unit and enters the vacuum flash tank through the fifth valve. The vacuum flash tank works normally. After the black water is further cooled down by the vacuum flash tank, it enters the clarification tank through the second valve.
9. The coal chemical gasification black water waste heat steam generation system as described in claim 2, characterized in that: The second type of absorption heat pump requires circulating cooling water from a vacuum flash tank to cool the true flash steam.
10. The coal chemical gasification black water waste heat steam generation system as described in claim 1, characterized in that: The heat transfer water unit includes a heat transfer water pump, which enables the circulation of heat transfer water between the heat exchange unit and the second type of absorption heat pump.
11. The coal chemical gasification black water waste heat steam generation system as described in claim 1, characterized in that: The flash evaporation unit includes a high-pressure flash tank, a low-pressure flash tank, and a vacuum flash tank. The heat exchange unit is connected to the low-pressure flash tank via a bypass pipeline and extracts black water from the high-pressure flash tank.
12. The coal chemical gasification black water waste heat steam generation system as described in claim 1, characterized in that: The high-grade steam produced by the second type of absorption heat pump is compressed into superheated steam with higher pressure by a steam compressor.