Treatment method for improving water-steam ratio of raw gas of gasification device in coal chemical industry

Abstract

The invention discloses a treatment method for improving the raw gas water-steam ratio of a coal chemical gasification device, and the coal chemical gasification device comprises a gasification furnace, a washing tower, an ash water system, a steam injection device and a circulating water system. The method is realized by installing a high-precision temperature sensor and a high-precision pressure sensor on an outlet pipeline of the gasification furnace, and the sensors transmit temperature and pressure data collected in real time to a control system. By monitoring the temperature and pressure of the raw gas at the outlet of the gasification furnace in real time and calculating the target water-steam ratio according to the preset water-steam ratio correlation model, parameters such as washing water flow, steam injection amount and circulating water temperature can be accurately adjusted according to actual working conditions, and accurate control of the water-steam ratio of the raw gas is realized. The stability of the subsequent process and the product quality are improved.

Description

Technical Field

[0001] The present invention relates to the field of coal chemical gasification, and in particular to a method for improving the water-steam ratio of crude coal gas in a coal chemical gasification device. Background Art

[0002] The hydrogen production and synthetic ammonia unit is a large-scale modern coal chemical project that uses coal as raw material to produce liquid ammonia and hydrogen. The coal gasification adopts the advanced HT-L pulverized coal pressurized gasification process developed by Aerospace Changzheng Chemical Engineering Co., Ltd. with independent intellectual property rights in my country; the conversion adopts a wide-temperature and sulfur-resistant isothermal conversion process; the desulfurization and decarbonization adopt a low-temperature methanol washing process; the synthesis gas refining adopts a liquid nitrogen washing process; the ammonia synthesis adopts low-pressure synthesis technology; the hydrogen production adopts the PSA pressure swing adsorption process; and the air separation adopts a new full low-pressure internal compression + molecular sieve purification energy-saving process, forming an annual production capacity of 500,000 tons of synthetic ammonia and 80,000 Nm3 / h of hydrogen.

[0003] At present, the temperature of the raw coal gas produced by the gasification device is low, resulting in a low water-vapor ratio of the raw coal gas. After being sent to the downstream isothermal conversion device, a large amount of superheated steam needs to be added from the public system to increase the water-vapor ratio and complete the CO reaction in the system. It is calculated that 200kg of superheated steam needs to be added from the public system to meet the production process requirements for 10,000Nm3 / h. Although the external addition of superheated steam can meet the production process requirements, it also causes an increase in the overall production cost. Therefore, it is very necessary and meaningful to design a treatment method for increasing the water-vapor ratio of the raw coal gas in the gasification device. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for improving the water-vapor ratio of crude coal gas in a coal chemical gasification device, so as to solve the problems of inaccurate control of the water-vapor ratio of crude coal gas, poor device synergy and low energy utilization efficiency in the prior art. Through real-time monitoring and precise regulation, stable control of the water-vapor ratio of crude coal gas can be achieved, thereby improving the stability and economy of the coal chemical production process.

[0005] The technical solution of the present invention is:

[0006] The treatment method of the present invention is applied to a coal chemical gasification device comprising a gasifier, a scrubber, an ash water system, a steam injection device, and a circulating water system. First, in step S1, the temperature and pressure of the raw coal gas at the outlet of the gasifier are monitored in real time. This step is achieved by installing high-precision temperature sensors and pressure sensors on the outlet pipe of the gasifier. The sensors transmit the real-time collected temperature and pressure data to the control system.

[0007] Next, in step S2, the target water-vapor ratio is calculated based on the monitored raw gas temperature and pressure and a pre-defined water-vapor ratio correlation model. This water-vapor ratio correlation model, established through extensive experimental data and theoretical analysis, considers the impact of various factors on the water-vapor ratio, such as gas composition, temperature, and pressure. The control system utilizes a built-in calculation module, combining the input temperature and pressure data with the model to calculate the target water-vapor ratio for the current operating conditions.

[0008] Then, in step S3, adjustable parameters are adjusted based on the target water-vapor ratio. The adjustable parameters include the wash water flow rate of the scrubber, the steam injection amount of the steam injection device, and / or the circulating water temperature of the circulating water system. When the target water-vapor ratio increases and the crude gas pressure at the gasifier outlet is within a preset pressure range, the wash water replenishment flow rate of the scrubber and / or the high-pressure steam injection flow rate of the steam injection device are increased. For example, the wash water replenishment flow rate is increased by controlling the opening of a regulating valve on the scrubber water inlet pipe, or the high-pressure steam injection flow rate is increased by controlling the opening of an electric valve on the steam pipe of the steam injection device. If the target water-vapor ratio increases and the crude gas pressure at the gasifier outlet exceeds the preset pressure range, the high-pressure steam injection flow rate of the steam injection device is reduced to avoid system instability due to excessive pressure.

[0009] In a further technical solution, when the target water-vapor ratio increases and the crude coal gas pressure at the gasifier outlet is within a preset pressure range, after increasing the washing water replenishment flow of the washing tower and / or increasing the high-pressure steam injection flow of the steam injection device, it is also necessary to obtain the real-time temperature of the circulating ash water in the ash water system. The real-time temperature data is collected by installing a temperature sensor on the circulating pipe of the ash water system. If the real-time circulating ash water temperature exceeds the preset temperature range, the circulating water flow of the circulating water system is adjusted to lower the ash water temperature. For example, the circulating water flow is changed by adjusting the frequency of the circulating water pump, thereby achieving control of the ash water temperature.

[0010] In addition, when the target water vapor ratio increases and the pressure of the raw coal gas at the gasifier outlet is within a preset pressure range, after increasing the washing water replenishment flow of the washing tower and / or increasing the high-pressure steam injection flow of the steam injection device, if the actual water vapor ratio of the raw coal gas does not reach the target water vapor ratio within the set time period, the circulating water temperature set value of the circulating water system is reduced. The control system compares the actual water vapor ratio of the raw coal gas monitored in real time with the target water vapor ratio. If the standard is not reached within the set time, the set value of the circulating water system temperature controller is adjusted to further optimize the water vapor ratio.

[0011] The coal chemical gasification device of the present invention also includes a waste heat recovery device, and the adjustable parameters also include the heat exchange efficiency of the waste heat recovery device. The target water vapor ratio is negatively correlated with the heat exchange efficiency of the waste heat recovery device. When the target water vapor ratio needs to be increased, the heat exchange efficiency of the waste heat recovery device is appropriately reduced, for example, by adjusting the flow rate of the heat exchange medium in the waste heat recovery device or adjusting the heat exchange area of ​​the heat exchanger.

[0012] The controller of the present invention includes at least one processor and a memory communicatively connected to the at least one processor. The memory stores instructions that can be executed by the at least one processor. The instructions are executed by the at least one processor so that the at least one processor can execute the above-mentioned processing method for improving the water-vapor ratio of crude coal gas. The controller obtains data from each sensor through the data acquisition module, and after calculation and logical judgment by the processor, sends control signals to the actuators of each device through the control output module to achieve precise control of parameters such as washing water flow, steam injection amount, circulating water temperature and heat exchange efficiency of the waste heat recovery device.

[0013] In a further technical solution, the coal chemical gasification system of the present invention includes a gasifier, a washing tower, an ash water system, a steam injection device, a circulating water system and the above-mentioned controller, the controller controls the washing water flow of the washing tower, the steam injection amount of the steam injection device and / or the circulating water temperature of the circulating water system, wherein the washing tower includes a tower body and a distributor, the distributor is arranged in the middle and upper part of the tower body, and is used to evenly distribute the washing water to ensure the consistency of the washing effect, a crude gas outlet and a washing water outlet are provided at the bottom of the tower body, and the washing water outlet is connected to the ash water system, the steam injection device includes an injector and a steam pipe, one end of the steam pipe is connected to an external steam source, and the other end is connected to the injector, and the injector is arranged on the crude gas pipe and is used to inject steam into the crude gas The controller controls the valve opening on the steam pipe according to the target water-vapor ratio to adjust the steam injection amount. The gray water system includes a gray water tank and a circulation pump. The gray water tank is used to store washing water and circulate gray water. The circulation pump transports the gray water in the gray water tank to the washing tower. The controller controls the washing water flow by adjusting the frequency of the circulation pump. The circulating water system includes a cooling tower and a heat exchanger. The cooling tower is used to cool the circulating water. The heat exchanger is arranged between the gray water system and the circulating water system and is used to cool the gray water through the circulating water. The controller adjusts the circulating water temperature by controlling the fan speed of the cooling tower and / or the valve opening of the heat exchanger. In addition, the coal chemical gasification system also includes a waste heat recovery device for recovering waste heat. The controller controls the heat exchange efficiency of the waste heat recovery device to achieve efficient utilization of energy.

[0014] The beneficial effects of the present invention are:

[0015] By real-time monitoring of the temperature and pressure of the raw gas at the gasifier outlet and calculating the target water vapor ratio based on a pre-set water vapor ratio correlation model, parameters such as the washing water flow rate, steam injection volume, and circulating water temperature can be accurately adjusted according to actual operating conditions, thereby achieving precise control of the raw gas water vapor ratio and improving the stability of subsequent processes and product quality.

[0016] In addition, an effective linkage mechanism has been established between the various devices. When the target water-vapor ratio changes and the crude gas pressure is different, the work of the washing tower, steam injection device and circulating water system can be reasonably coordinated to give full play to the adjustment capabilities of each device and improve the overall operating efficiency of the system. The relationship between the waste heat recovery device and the water-vapor ratio control is taken into consideration. The heat exchange efficiency of the waste heat recovery device is adjusted according to the target water-vapor ratio to achieve reasonable allocation and efficient utilization of energy and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall process of an embodiment of the present invention.

[0018] Description of reference numerals:

[0019] 1. Gasifier; 2. High-pressure black water valve; 3. High-pressure black water pipeline; 4. High-pressure flash tank; 5. High-pressure flash gas outlet valve; 6. High-pressure ash water pipeline; 7. Chiller water pump; 8. Chiller water pump outlet valve; 9. Crude synthesis gas inlet valve to scrubber; 10. Scrubber; 11. Chiller water pump inlet valve; 12. Crude gas outlet valve; 13. Crude gas outlet pipeline; 14. Scrubber feed pump outlet valve I; 15. Scrubber feed pump outlet valve II; 16. Scrubber feed pump; 17. Low-pressure flash gas outlet valve; 18. Low-pressure flash tank; 19. Medium-pressure black water valve; 20. Medium-pressure ash water pipeline; 21. Low-pressure black water pipeline; 22. Low-pressure black water valve; 23. Vacuum flash tank; 24. High-pressure flash gas pipeline ; 25. Washing tower feed pump inlet valve; 26. High-pressure stripping tower; 27. High-pressure stripping tower flash gas outlet valve; 28. High-pressure stripping tower flash gas outlet pipeline; 29. ​​High-pressure ash water pump outlet valve; 30. High-pressure ash water pump; 31. High-pressure ash water pump inlet valve; 32. Black water inlet settling tank valve; 33. Black water inlet settling tank pipeline; 34. Settling tank; 35. Ash water pipeline; 36. Low-pressure flash gas outlet pipeline; 37. Low-pressure stripping tower; 38. Acidic analysis gas outlet valve; 39. Acidic analysis gas outlet pipeline; 40. Low-pressure ash water pipeline; 41. Low-pressure ash water pump outlet valve; 42. Low-pressure ash water pump; 43. Low-pressure ash water pump inlet valve; 44. Ash water tank; 45. Vacuum valve; 46. Vacuum pipeline. DETAILED DESCRIPTION

[0020] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0021] Example:

[0022] like Figure 1 As shown, a method for improving the water-steam ratio of raw coal gas in a coal chemical gasification device has been effectively applied in actual production scenarios. The coal chemical gasification device includes a gasifier 1, a washing tower 10, an ash water system, a steam injection device and a circulating water system.

[0023] In a specific operation cycle, the circulation process of the gray water system is first started. When the liquid level of the gray water tank 44 reaches 80%, the operator opens the low-pressure gray water pump outlet valve 43 and starts the low-pressure gray water pump 42. After the low-pressure gray water pump 42 is running normally, the low-pressure gray water pump outlet valve 41 is opened. At this time, the gray water is sent to the low-pressure stripping tower 37 through the low-pressure gray water pipeline 40. After a period of operation, when the liquid level of the low-pressure stripping tower 37 reaches 80%, the high-pressure gray water is opened. The pump inlet valve 31 starts the high-pressure ash water pump 30. After the high-pressure ash water pump 30 is running normally, the high-pressure ash water pump outlet valve 29 is opened, and the ash water is sent to the high-pressure stripping tower 26 through the high-pressure ash water pipeline. When the liquid level of the high-pressure stripping tower 26 reaches 80%, the washing tower feed pump inlet valve 25 is opened, and the washing tower feed pump 16 is started. After the washing tower feed pump 16 is running normally, the washing tower feed pump outlet valve I14 is opened to send the ash water to the washing tower 10. As the system Continuous operation, after the liquid level of the washing tower 10 reaches 80%, open the quenching water pump inlet valve 11, start the quenching water pump 7, after the quenching water pump 7 is running normally, open the quenching water pump outlet valve 8, and send black water into the quenching chamber of the gasifier 1. When the liquid level of the quenching chamber of the gasifier 1 reaches 70%, open the high-pressure black water valve 2 and discharge the black water into the high-pressure flash tank 4. After the liquid level of the high-pressure flash tank 4 reaches 70%, open the medium-pressure black water valve 19, and the black water passes through the medium-pressure gray water pipeline 20 is discharged into the low-pressure flash tower tank 18. After the liquid level of the low-pressure flash tower tank 18 reaches 70%, the low-pressure black water valve 22 is opened, and the black water is discharged into the vacuum flash tank 23 through the low-pressure black water pipeline 21. After the liquid level of the vacuum flash tank 23 reaches 70%, the black water inlet settling tank valve 32 is opened, and the black water is discharged into the settling tank through the black water inlet settling tank pipeline 33. After the black water is solid-liquid separated in the settling tank 33, the gray water is discharged into the gray water tank 44 through the gray water pipeline to achieve recycling.

[0024] During the operation of the system, the temperature and pressure of the raw coal gas at the outlet of the gasifier are monitored in real time. When the temperature of the raw coal gas at the outlet of the gasifier is monitored to be 202°C and the pressure is 3.2MPa, the target water vapor ratio is calculated to be 1.2 based on the preset water vapor ratio correlation model. At this time, the pressure is within the preset pressure range of 3-3.5MPa, and the target water vapor ratio is greater than the current actual water vapor ratio. In order to achieve the target water vapor ratio, the parameters are adjusted according to the method in the claim.

[0025] By adjusting the outlet valve Ⅰ14 of the washing tower feed pump, the ash water flow entering the washing tower 10 is reduced, thereby adjusting the temperature of the raw synthesis gas. Since the ash water flow entering the washing tower 10 is reduced, the quenching water flow delivered by the quenching water pump 7 is reduced, which may easily cause a reduction in the overall quenching water volume and there is a risk of interlocking shutdown. At the same time, the operator opens the outlet valve Ⅱ15 of the washing tower feed pump and sends the ash water into the quenching water pipeline through the high-pressure ash water pipeline 6 to adjust and increase the quenching water volume to ensure that the liquid level in the quenching chamber is stable within the normal range of 30-35%.

[0026] During the adjustment process, the precautions were strictly followed to control the crude synthesis gas temperature at the outlet of the gasification unit at 204-208°C, the amount of ash water entering the washing tower 10 at 80-130t / h, and the amount of ash water entering the quenching water pipeline at 60-100t / h.

[0027] In addition, during operation, the flash gas and desorption gas in each device are rationally recovered and processed for heat. The high-pressure flash gas flashed in the high-pressure flash tank 4 is discharged through the high-pressure flash gas outlet valve 5 and the high-pressure flash gas pipeline 24 to the high-pressure stripping tower 26 for heat recovery. The low-pressure flash gas flashed in the low-pressure flash tank 18 is discharged through the low-pressure flash gas outlet valve 17 and the low-pressure flash gas pipeline 36 to the low-pressure stripping tower 37 for heat recovery. The high-pressure desorption gas in the high-pressure stripping tower 26 is discharged through the high-pressure stripping tower flash gas outlet valve 27 and the high-pressure stripping tower flash gas outlet pipeline 28 to the low-pressure stripping tower 37 for heat recovery. The low-pressure desorption gas in the low-pressure stripping tower 37 is sent to the sulfur recovery acid plant through the acid desorption gas outlet valve 38 and the acid desorption gas outlet pipeline 39. The non-condensable gas in the vacuum flash tank 23 is discharged through the vacuum valve 45 and the vacuum pipeline 46 to the vacuum pumping system.

[0028] After adjustment and stable operation, the actual water-vapor ratio of the crude gas gradually approached the target water-vapor ratio, effectively improving the water-vapor ratio of the crude gas, while ensuring the stable operation of the entire gasification unit and achieving good economic and environmental benefits.

[0029] In another embodiment, when the temperature of the crude coal gas at the gasifier outlet is monitored to be 210°C and the pressure is 3.6 MPa, which exceeds the preset pressure range of 3-3.5 MPa, the target water vapor ratio is calculated to be 1.3 based on the water vapor ratio correlation model, and is greater than the current actual water vapor ratio. At this time, according to claim 2, the high-pressure steam injection flow rate of the steam injection device is reduced. At the same time, due to the high temperature of the crude coal gas, when adjusting the outlet valve I14 of the washing tower feed pump to reduce the ash water flow entering the washing tower 10, more close attention is paid to the change in the quenching water volume, and the outlet valve II15 of the washing tower feed pump is opened to appropriately increase the amount of ash water entering the quenching water pipeline to ensure the stability of the liquid level in the quenching chamber. In the subsequent operation process, the actual water vapor ratio of the crude coal gas is continuously monitored. If the actual water vapor ratio does not reach the target water vapor ratio within the set time period, the circulating water temperature set value of the circulating water system is further reduced to promote the improvement of the water vapor ratio.

[0030] In another embodiment, the initial temperature of the raw coal gas at the gasifier outlet is 206°C and the pressure is 3.3 MPa, which are within the preset pressure range. The target water vapor ratio is calculated to be 1.15, which is greater than the current actual value. First, the washing water replenishment flow of the washing tower is increased, and the gray water flow entering the washing tower 10 is increased by adjusting the outlet valve Ⅰ14 of the washing tower feed pump. At the same time, the high-pressure steam injection flow of the steam injection device is increased. After running for a period of time, the real-time temperature of the circulating gray water in the gray water system is obtained. If the real-time circulating gray water temperature exceeds the preset temperature range, the circulating water flow of the circulating water system is adjusted to lower the gray water temperature. Within the set time period, if the actual water vapor ratio of the raw coal gas does not reach the target water vapor ratio, the circulating water temperature setting value of the circulating water system is reduced to further optimize the water vapor ratio.

[0031] In another embodiment, the temperature of the crude coal gas at the gasifier outlet is 205°C and the pressure is 3.4 MPa, which are within the preset pressure range. The target water-vapor ratio is 1.2, which is greater than the current value. This time, the steam injection amount of the steam injection device is increased, and the outlet valve I14 of the washing tower feed pump is appropriately adjusted to increase the ash water flow entering the washing tower 10. During operation, the liquid level in the quenching chamber and the operating parameters of each equipment are closely monitored. When it is found that the amount of quenching water has a decreasing trend, the outlet valve II15 of the washing tower feed pump is opened in time to replenish the quenching water. If the actual water-vapor ratio does not meet the standard within the set time, not only the circulating water temperature set value of the circulating water system is reduced, but also the opening of the outlet valve I14 and outlet valve II15 of the washing tower feed pump is further fine-tuned to make the actual water-vapor ratio of the crude coal gas close to the target value.

[0032] In another embodiment, the initial temperature of the raw coal gas is 203°C and the pressure is 3.1 MPa, which are within the preset pressure range. The target water vapor ratio is 1.1, which is greater than the current actual water vapor ratio. The washing water flow rate of the washing tower is first increased, while the steam injection amount of the steam injection device is maintained unchanged. During the adjustment process, the amount of gray water entering the washing tower 10 is strictly controlled within the range of 80-130 t / h. If the actual water vapor ratio does not reach the target water vapor ratio within the set time, the liquid level in the quenching chamber and the operating status of each equipment are first checked to ensure system stability. Then, the circulating water temperature setting value of the circulating water system is reduced, and the steam injection amount of the steam injection device is appropriately increased to gradually increase the water vapor ratio of the raw coal gas so that it approaches the target value.

[0033] The above-described embodiments merely represent specific implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A method for increasing the water-steam ratio of crude coal gas in a coal chemical gasification device, the coal chemical gasification device comprising a gasifier (1), a washing tower (10), an ash water system, a steam injection device and a circulating water system, characterized in that: The processing method comprises: S1, real-time monitoring of the temperature and pressure of the crude coal gas at the outlet of the gasifier (1); S2. Calculate the target water vapor ratio based on the monitored raw gas temperature and pressure and a pre-set water vapor ratio correlation model; S3. Adjust the adjustable parameters according to the target water vapor ratio, wherein the adjustable parameters include: The washing water flow rate is regulated by the washing tower feed pump (16) and the washing tower feed pump outlet valve I (14), the washing tower feed pump outlet valve II (15), and the washing tower feed pump inlet valve (25); the steam injection amount is controlled by the high-pressure flash steam pipeline (24) connected to the high-pressure stripping tower (26), the high-pressure stripping tower flash steam export valve (27), and the high-pressure stripping tower flash steam export pipeline (28); and / or the circulating water temperature is controlled by the gray water tank (44) and the gray water pipeline (35) and the low-pressure gray water pipeline (40).

2. The method for increasing the water-gas ratio of crude coal gas in a coal chemical gasification device according to claim 1, characterized in that: The adjustment of the adjustable parameters includes: if the target water vapor ratio increases and the outlet pressure of the gasifier (1) is within a preset range, increasing the flow rate through the washing tower feed pump outlet valve I (14) and the washing tower feed pump outlet valve II, and / or increasing the steam injection amount of the high-pressure flash steam pipeline (24); if the target water vapor ratio increases and the pressure exceeds the limit: reducing the opening of the high-pressure stripping tower flash steam outlet valve (27).

3. The method for increasing the water-gas ratio of crude coal gas in a coal chemical gasification device according to claim 2, characterized in that: The adjustment also includes: obtaining the real-time temperature of the gray water system, monitoring the gray water pipeline (35) / low-pressure gray water pipeline (40), and if the temperature exceeds the limit: adjusting the circulating water flow of the low-pressure gray water pump (42) or the high-pressure gray water pump (30).

4. The method for increasing the water-gas ratio of crude coal gas in a coal chemical gasification device according to claim 2, characterized in that: If the actual water vapor ratio does not reach the standard within the set period: the temperature setting value of the low-pressure gray water pipeline (40) is adjusted through the cooling tower.

5. The method for increasing the water-gas ratio of crude coal gas according to any one of claims 1 to 4, characterized in that: The waste heat recovery device is connected to a low-pressure flash tank (18), a vacuum flash tank (23), and a low-pressure stripping tower (37), and its heat exchange efficiency is negatively correlated with the target water vapor ratio.

6. The method for increasing the water-steam ratio of crude coal gas in a coal chemical gasification device according to claim 1, characterized in that: The invention comprises a controller, wherein the controller is configured to: receive real-time data of a gasifier (1) and a washing tower (10); control the openings of a high-pressure flash steam delivery valve (5), a crude synthesis gas inlet washing tower valve (9), a quenching water pump inlet valve (11), a crude coal gas delivery valve (12), a low-pressure flash steam delivery valve (17), a low-pressure black water valve (22), a high-pressure ash water pump outlet valve (29), an acidic analytical gas delivery valve (38), and a vacuum valve (45); and regulate the operating parameters of a quenching water pump (7), a washing tower feed pump (16), a high-pressure ash water pump (30), and a low-pressure ash water pump (42).

7. The method for increasing the water-steam ratio of crude coal gas in a coal chemical gasification device according to claim 6, characterized in that: The invention also includes a coal chemical gasification system, wherein the coal chemical gasification system includes: a raw gas inlet valve (9) of a gasifier (1) connected to a washing tower (10); an ash water system including a high-pressure flash tank (4), a settling tank (34) and an ash water tank (44) connected in series; a steam injection device including a high-pressure stripping tower (26) and a supporting pipeline high-pressure flash steam pipeline (24), a high-pressure stripping tower flash steam outlet pipeline (28); and a controller as described in claim 6, which controls the washing water flow of the washing tower (10), the steam injection amount of the steam injection device and / or the circulating water temperature of the circulating water system.

8. The coal chemical gasification system according to claim 7, characterized in that: It also includes a waste heat recovery device, wherein the controller controls the heat exchange efficiency of the waste heat recovery device and is connected to the low-pressure flash tank (18) and the vacuum flash tank (23).

9. The coal chemical gasification system according to claim 7 or 8, characterized in that: The washing tower (10) is provided with a distributor connected to the outlet valves of the feed pump (16), the washing tower feed pump outlet valve I (14) and the washing tower feed pump outlet valve II (15); the bottom outlet is connected to the high-pressure black water pipeline (3) and the gray water pipeline (35); the gray water system is provided with a gray water tank (44) connected to the high-pressure gray water pump (30) / low-pressure gray water pump (40) through the gray water pipeline (35) / low-pressure gray water pipeline (40); the frequency of the washing tower feed pump (16) / high-pressure gray water pump (30) is adjusted by a controller.

10. The coal chemical gasification system according to claim 9, characterized in that: The steam injection device comprises an ejector, which is arranged on the crude coal gas delivery pipeline (13); a steam pipeline (24) connecting the high-pressure flash tank (4) and the stripping tower (26); and a circulating water system, which comprises a heat exchanger connecting the low-pressure ash water pipeline (40) and the cooling tower; and temperature control via a low-pressure ash water pump outlet valve (41) / a low-pressure ash water pump inlet valve (43) and a fan.

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