High-efficiency coal water slurry gasification black water flash device

Abstract

The utility model belongs to a kind of high-efficiency coal water slurry gasification black water flash evaporation device;Including primary flash evaporation tower, and with primary flash evaporation tower connecting gasification furnace black water pipeline, scrubbing tower black water pipeline and grey water pipeline, the liquid phase outlet of primary flash evaporation tower bottom is connected with secondary flash evaporation tower by primary pressure recovery part, and the liquid phase outlet of secondary flash evaporation tower bottom is connected with grey water tank by secondary heat recovery unit and tertiary pressure temperature recovery unit;The above setting has energy recovery, also can reduce utility consumption, to reach the characteristics of energy saving, emission reduction.

Description

Technical Field

[0001] This utility model belongs to the field of coal gasification technology, specifically a high-efficiency water-coal slurry gasification black water flash evaporation device. Background Technology

[0002] In the coal chemical industry, the high-pressure coal-water slurry gasifier adopts a 6.5 MPa gasification pressurization process. After the raw coal is gasified, it is cooled by a quenching process. The gasifier discharges high-temperature and high-pressure gasified black water. The main treatment process of the black water in the slag water treatment system is: gasification and syngas washing system → evaporation hot water tower → low-pressure flash tank → vacuum flash tank → black water settling and clarification system → deoxygenation system → stripping tower → gasification and syngas washing system. The condensation of each stage of flash steam is completed by heat exchange with a large amount of circulating water. The defects of the existing process are: (1) High-pressure flash steam is generally around 0.8 MPa, low-pressure flash steam is generally around 0.25 MPa, and vacuum flash steam is generally around -75 kPa. Each stage of gasified black water needs to be depressurized by a black water pressure reducing valve. During the depressurization process, not only is the black water pressure reducing valve eroded, but there is also serious energy waste; (2) The temperature of the flash steam after each stage of flash steam is reduced by circulating water cooling, which not only increases the consumption of circulating water, but also wastes the heat of each stage of flash steam. Utility Model Content

[0003] To overcome the above deficiencies, this utility model provides a high-efficiency water-coal slurry gasification black water flash evaporation device to solve the technical problems existing in the prior art.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] A high-efficiency water-coal slurry gasification black water flash evaporation device is disclosed. The flash evaporation device includes a primary flash tower, and black water pipes for the gasifier, a black water pipe for the washing tower, and an ash water pipe connected to the primary flash tower. The liquid phase outlet at the bottom of the primary flash tower is connected to a secondary flash tower through a primary pressure recovery unit. The liquid phase outlet at the bottom of the secondary flash tower is connected to an ash water tank through a secondary heat recovery unit and a tertiary pressure and temperature recovery unit.

[0006] Preferably, the three-stage pressure and temperature recovery unit includes a primary flash heat exchanger, a secondary flash heat exchanger, a high-level heat exchanger, and a cryogenic expander;

[0007] The liquid phase of the secondary heat recovery unit is connected to the first heat exchange pipe of the secondary flash heat exchanger through the first heat exchange pipe of the primary flash heat exchanger. The outlet of the first heat exchange pipe of the secondary flash heat exchanger is connected to the cryogenic expander through the first heat exchange pipe of the high-level heat exchanger. The outlet of the cryogenic expander is connected to the ash water tank.

[0008] The liquid phase outlet at the bottom of the first-stage flash tower is connected to the first-stage pressure recovery unit through the second heat exchange pipe of the high-level heat exchanger.

[0009] The vapor outlet at the top of the first-stage flash tower is connected to the second heat exchange pipe of the second-stage flash heat exchanger;

[0010] The vapor outlet at the top of the secondary flash tower is connected to the second heat exchange pipe of the primary flash heat exchanger.

[0011] Preferably, the outlet of the second heat exchange pipe of the secondary flash heat exchanger and the outlet of the second heat exchange pipe of the primary flash heat exchanger are respectively connected to the flare combustion system.

[0012] Preferably, the primary pressure recovery unit is a high-temperature expander.

[0013] Preferably, the secondary heat recovery unit includes a heat energy utilization heat exchanger. The liquid phase outlet at the bottom of the secondary flash tower is connected to the first heat exchange pipe of the primary flash heat exchanger through the shell side of the heat energy utilization heat exchanger. The tube side of the heat energy utilization heat exchanger is connected to the inlet of the heat energy utilization section. The outlet of the heat energy utilization section is connected to the circulating water booster pump through a tee. The outlet of the circulating water booster pump is connected to the tube side inlet of the heat energy utilization heat exchanger. The third end of the tee is connected to the water supply pipe with a valve.

[0014] Preferably, the heat energy utilization unit includes a working fluid evaporator, the tube-side inlet of the working fluid evaporator is connected to the tube-side outlet of the heat energy utilization heat exchanger, and the tube-side outlet of the working fluid evaporator is connected to a tee; the shell-side outlet of the working fluid evaporator is connected to a chiller unit, and the outlet of the chiller unit is connected to the working fluid buffer tank and the working fluid pump, which are connected to the shell-side inlet of the working fluid evaporator.

[0015] A high-efficiency water-coal slurry gasification black water flash evaporation device prepared according to the above technical solution, by systematically coupling the gasification flash evaporation demand with energy recovery, not only realizes the potential energy recovery during the black water flash evaporation process, but also effectively recovers the heat of the flash steam at each stage, while greatly reducing the consumption of circulating water. Specifically, this utility model sets up a first-stage pressure recovery unit between the first-stage and second-stage flash evaporation towers to recover the interstage potential energy. Furthermore, a second-stage heat recovery unit recovers the heat energy from the liquid phase in the second-stage flash evaporation tower. Further still, the heat of the flash steam from each stage is used to progressively increase the inlet liquid temperature of the third-stage pressure and temperature recovery unit, thereby improving energy recovery. The above process not only recovers energy but also reduces utility consumption, thus achieving energy saving and emission reduction. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the process of this utility model.

[0018] In the diagram: 1. First-stage flash evaporator; 2. High-temperature expander; 3. Second-stage flash evaporator; 4. Heat exchanger for energy utilization; 5. Working fluid evaporator; 6. First-stage flash steam heat exchanger; 7. Second-stage flash steam heat exchanger; 8. High-level heat exchanger; 9. Low-temperature expander; 10. Ash water pipeline; 11. Chiller unit; 12. Working fluid pump; 13. Ash water tank; 14. Circulating water booster pump; 15. Working fluid buffer tank; 16. Makeup water pipeline; 17. Flare combustion system; 18. Gasifier black water pipeline; 19. Scrubber black water pipeline. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0020] The following is in conjunction with the appendix Figure 1 This application provides a further detailed description of a high-efficiency flash evaporation device for coal-water slurry gasification. The flash evaporation device includes a primary flash tower 1, and a gasifier black water pipe 18, a washing tower black water pipe 19, and an ash water pipe 10 connected to the primary flash tower 1. The liquid phase outlet at the bottom of the primary flash tower 1 is connected to a secondary flash tower 3 via a primary pressure recovery unit. The liquid phase outlet at the bottom of the secondary flash tower 3 is connected to an ash water tank 13 via a secondary heat recovery unit and a tertiary pressure and temperature recovery unit. Based on the characteristics of the coal-water slurry gasification system, this invention incorporates a primary pressure recovery unit, a secondary heat recovery unit, and a tertiary pressure and temperature recovery unit to achieve energy recovery and reuse, while simultaneously reducing the amount of circulating water used.

[0021] Furthermore, the three-stage pressure and temperature recovery unit includes a primary flash heat exchanger 6, a secondary flash heat exchanger 7, a high-level heat exchanger 8, and a low-temperature expander 9; the liquid phase of the secondary heat recovery unit is connected to the first heat exchange pipe of the secondary flash heat exchanger 7 through the first heat exchange pipe of the primary flash heat exchanger 6, the outlet of the first heat exchange pipe of the secondary flash heat exchanger 7 is connected to the low-temperature expander 9 through the first heat exchange pipe of the high-level heat exchanger 8, and the outlet of the low-temperature expander 9 is connected to the ash water tank 13; the liquid phase outlet at the bottom of the primary flash tower 1 is connected to the primary pressure recovery unit through the second heat exchange pipe of the high-level heat exchanger 8; the gas phase outlet at the top of the primary flash tower 1 is connected to the second heat exchange pipe of the secondary flash heat exchanger 7; and the gas phase outlet at the top of the secondary flash tower 3 is connected to the second heat exchange pipe of the primary flash heat exchanger 6. In traditional technologies, the gas phase from the first-stage flash tower 1 and the second-stage flash tower 3 is typically recovered and utilized by driving a cryogenic steam turbine. However, in actual use, it has been found that this gas phase is corrosive and contains a large number of impurities, which seriously affects the use and lifespan of the cryogenic steam turbine and requires frequent maintenance. To solve the above technical problems, this utility model sets up a three-stage pressure and temperature recovery unit. It utilizes the gas and liquid phases of the first-stage flash tower 1 and the gas phase of the second-stage flash tower 3 to perform stepped heating of the liquid phase in the second-stage heat recovery unit. This overcomes the defects of the existing technology while recovering and utilizing energy, and avoids the use of circulating water.

[0022] Furthermore, the outlet of the second heat exchange pipe of the secondary flash heat exchanger 7 and the outlet of the second heat exchange pipe of the primary flash heat exchanger 6 are connected to the flare combustion system 17. This invention aims to achieve environmental friendliness by sending the heat-exchanged gas phase into the flare combustion system 17 for combustion treatment.

[0023] Furthermore, the primary pressure recovery unit is a high-temperature expander 2.

[0024] Furthermore, the secondary heat recovery unit includes a heat energy utilization heat exchanger 4. The liquid phase outlet at the bottom of the secondary flash tower 3 is connected to the first heat exchange pipe of the primary flash heat exchanger 6 through the shell side of the heat energy utilization heat exchanger 4. The tube side of the heat energy utilization heat exchanger 4 is connected to the inlet of the heat energy utilization section. The outlet of the heat energy utilization section is connected to the circulating water booster pump 14 through a tee. The outlet of the circulating water booster pump 14 is connected to the tube side inlet of the heat energy utilization heat exchanger 4. The third end of the tee is connected to the water supply pipe 16 with a valve.

[0025] Furthermore, the heat energy utilization unit includes a working fluid evaporator 5, the tube-side inlet of the working fluid evaporator 5 is connected to the tube-side outlet of the heat energy utilization heat exchanger 4, and the tube-side outlet of the working fluid evaporator 5 is connected to a tee; the shell-side outlet of the working fluid evaporator 5 is connected to a chiller unit 11, and the outlet of the chiller unit 11 is connected to the working fluid buffer tank 15 and the working fluid pump 12 and the shell-side inlet of the working fluid evaporator 5.

[0026] The specific working process of this utility model is as follows: Step 1: The black water from the gasifier quench chamber enters the first-stage flash tower 1 through the gasifier black water pipe 18. The black water from the crude gas scrubbing tower enters the first-stage flash tower 1 through the scrubbing tower black water pipe 19. The ash water in the ash water pipe 20 also enters the first-stage flash tower 1. The first-stage flash tower 1 is subjected to depressurized flash evaporation. The flashed gas phase is sent to the second heat exchange pipe of the second-stage flash heat exchanger 7, and the flashed liquid phase enters the second heat exchange pipe of the high-level heat exchanger 8. The pressure of the first-stage flash tower 1 is 0.6-0.8 MPa, the liquid phase outlet temperature is 161-181℃, and the gas phase outlet temperature is 156-173℃. Step 2: The liquid phase of the first-stage flash tower 1 exchanges heat in the second heat exchange pipe of the high-level heat exchanger 8, and after releasing the heat, it enters the high-temperature expander 2 for expansion and power generation. After power generation, it is sent to the second-stage flash tower 3. The liquid black water of the first-stage flash tower 1 exchanges heat with the second heat exchange pipe of the high-level heat exchanger 8. The temperature after heat exchange is 141-161℃ and the pressure is 0.58-0.78 MPa. The liquid temperature after expansion in the high-temperature expander 2 is 127-143℃ and the pressure is 0.15-0.3 MPa. Step 3: Second-stage flash tower 3 The black water undergoes flash evaporation. The vapor phase after flash evaporation is sent to the second heat exchange pipe of the primary flash steam heat exchanger 6 for heat exchange, while the liquid phase after flash evaporation is sent to heat exchanger 4. After heat extraction by heater 4, the outlet temperature of the black water is 62-72℃. Step four: In the primary flash steam heat exchanger 6, the black water exchanges heat with the vapor phase of the secondary flash evaporation tower 3. After heat exchange, the black water in the first heat exchange pipe of the primary flash steam heat exchanger 6 is heated, while the vapor phase in the second heat exchange pipe of the primary flash steam heat exchanger 6 is cooled. The temperature of the heated black water is 72-82℃; the temperature of the cooled vapor phase is 56-62℃. Step 5: The black water passes sequentially through the secondary flash heat exchanger 7 and the high-level heat exchanger 8, with its temperature gradually increasing. After passing through the high-level heat exchanger 8, the temperature of the black water rises to 123-130℃, and the temperature of the black water at the bottom of the primary flash tower 1 after passing through the high-level heat exchanger 8 is 141-161℃. Step 6: The black water heated by the high-level heat exchanger 8 is sent to the low-temperature expander 9 to further recover potential energy. The pressure of the black water after expansion by the low-temperature expander 9 is 8 kPa, and the temperature is 55-58℃. Step 7: The circulating water heated in the heat energy utilization heat exchanger 4 is sent to the working fluid evaporator 5 to react with the... The working fluid undergoes heat exchange, and the circulating water after heat extraction is pressurized by the circulating water pressurization pump 14 and returned to the heat energy utilization heat exchanger 4 for circulation; the temperature of the circulating water after passing through the heat energy utilization heat exchanger 4 is 120-128℃ and the pressure is 0.56-0.76MPa; Step 8: The circulating water exchanges heat with the organic working fluid in the working fluid evaporator 5, and after heat exchange, it is sent to the chiller unit 11 for heat energy utilization. After utilization, it is sent back to the working fluid evaporator 5 for repeated circulation through the working fluid buffer tank 15 and the working fluid pump 12; the organic working fluid can be pentafluoropropane.

[0027] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A high-efficiency coal-water slurry gasification black water flasher, the flasher comprising a primary flasher tower (1), and a gasifier black water pipeline (18), a scrubber black water pipeline (19) and a grey water pipeline (20) connected to the primary flasher tower (1), characterized in that: The liquid phase outlet at the bottom of the first-stage flash tower (1) is connected to the second-stage flash tower (3) through the first-stage pressure recovery unit. The liquid phase outlet at the bottom of the second-stage flash tower (3) is connected to the ash water tank (13) through the second-stage heat recovery unit and the third-stage pressure and temperature recovery unit.

2. The high-efficiency coal-water slurry gasification black water flash evaporation device according to claim 1, characterized in that: The three-stage pressure and temperature recovery unit includes a primary flash heat exchanger (6), a secondary flash heat exchanger (7), a high-level heat exchanger (8), and a low-temperature expander (9); The liquid phase of the secondary heat recovery unit is connected to the first heat exchange pipe of the secondary flash heat exchanger (7) through the first heat exchange pipe of the primary flash heat exchanger (6). The outlet of the first heat exchange pipe of the secondary flash heat exchanger (7) is connected to the low temperature expander (9) through the first heat exchange pipe of the high-level heat exchanger (8). The outlet of the low temperature expander (9) is connected to the ash water tank (13). The liquid phase outlet at the bottom of the first-stage flash tower (1) is connected to the first-stage pressure recovery unit through the second heat exchange pipe of the high-level heat exchanger (8); The vapor outlet at the top of the primary flash tower (1) is connected to the second heat exchange pipe of the secondary flash heat exchanger (7); The gas phase outlet at the top of the secondary flash tower (3) is connected to the second heat exchange pipe of the primary flash heat exchanger (6).

3. The high-efficiency coal-water slurry gasification black water flash evaporation device according to claim 2, characterized in that: The outlet of the second heat exchange pipe of the secondary flash heat exchanger (7) and the outlet of the second heat exchange pipe of the primary flash heat exchanger (6) are respectively connected to the flare combustion system (17).

4. A high-efficiency coal-water slurry gasification black water flash evaporation device according to claim 1 or 2, characterized in that: The primary pressure recovery unit is a high-temperature expander (2).

5. The high-efficiency coal-water slurry gasification black water flash evaporation device according to claim 2, characterized in that: The secondary heat recovery unit includes a heat energy utilization heat exchanger (4). The liquid phase outlet at the bottom of the secondary flash tower (3) is connected to the first heat exchange pipe of the primary flash heat exchanger (6) through the shell side of the heat energy utilization heat exchanger (4). The tube side of the heat energy utilization heat exchanger (4) is connected to the inlet of the heat energy utilization section. The outlet of the heat energy utilization section is connected to the circulating water booster pump (14) through a tee. The outlet of the circulating water booster pump (14) is connected to the tube side inlet of the heat energy utilization heat exchanger (4). The third end of the tee is connected to the water supply pipe (16) with a valve.

6. The high-efficiency coal-water slurry gasification black water flash evaporation device according to claim 5, characterized in that: The heat energy utilization unit includes a working fluid evaporator (5), the tube side inlet of the working fluid evaporator (5) is connected to the tube side outlet of the heat energy utilization heat exchanger (4), and the tube side outlet of the working fluid evaporator (5) is connected to a tee. The shell-side outlet of the working fluid evaporator (5) is connected to the chiller unit (11), and the outlet of the chiller unit (11) is connected to the working fluid buffer tank (15) and the working fluid pump (12) is connected to the shell-side inlet of the working fluid evaporator (5).

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