Coal gas-water separation system for underground coal gasification

Abstract

The utility model relates to the field of gas-water separation, in particular to a gas-water separation system for underground coal gasification. Comprising a product well, a synthesis gas washing assembly communicated with a gas outlet of the product well, a gas-water separation treatment assembly communicated with a liquid outlet of the synthesis gas washing assembly, a torch device communicated with a gas outlet of the gas-water separation treatment assembly, and a storage tank assembly communicated with a liquid outlet of the gas-water separation treatment assembly. According to the utility model, the combustible waste gas released in the gas-water separation process is safely combusted by using the torch device, so that atmospheric pollution caused by direct emission of the combustible waste gas is avoided; acid gas, phenols and ammonia nitrogen in the coal gas water are deeply removed through the phenol and ammonia recovery assembly, resource recovery of phenolic substances and liquid ammonia is achieved, meanwhile, purified wastewater can be reused for a chilling water circulating pump and conveyed to a product well or discharged after reaching the standard, the cyclic utilization rate of water resources is greatly increased, and the energy consumption is reduced. Therefore, the fresh water consumption and the wastewater treatment cost are obviously reduced.

Description

Technical Field

[0001] This utility model relates to the field of coal gas-water separation, and in particular to a coal underground gasification coal gas-water separation system. Background Technology

[0002] Crude syngas is transported from the product well to the surface and then via surface pipelines to downstream units for processing and application. A quench water system is installed at the product well end to effectively and actively control the temperature of the syngas during the underground coal gasification process, preventing malfunctions and damage to the product well. Before entering downstream applications, the product gas undergoes a series of treatment and impurity removal processes. An essential part of the product gas surface treatment process is the condensation, cleaning, and separation of liquid impurities and small amounts of solid particles entrained in the product gas stream. These separated impurities are collectively referred to as gas water. This gas water mainly consists of wastewater and coal tar.

[0003] In traditional coal gas water treatment processes, particulate matter (such as coal dust, ash, unreacted combustible components, etc.) is usually regarded as impurities and is discarded or landfilled as solid waste after simple separation. This not only wastes combustible resources, but also causes soil and water pollution due to direct discharge. Utility Model Content

[0004] In order to overcome the problem that the particulate matter in the existing coal gas water is not effectively separated and utilized as a resource, and that direct discharge or disposal leads to pollution, waste of resources, and may affect the stability of subsequent system operation.

[0005] The technical solution of this utility model is as follows: a coal underground gasification gas-water separation system, including a product well, a syngas scrubbing component connected to the gas outlet of the product well, a gas-water separation treatment component connected to the liquid outlet of the syngas scrubbing component, a flare device connected to the gas outlet of the gas-water separation treatment component, a storage tank component connected to the liquid outlet of the gas-water separation treatment component, a pump body component connected to the liquid outlet of the storage tank component, and a phenol-ammonia recovery component connected to the liquid outlet of the pump body component.

[0006] The gas-water separation and treatment assembly includes a cooler connected to the outlet of the syngas washing assembly, a coarse filter connected to the outlet of the cooler, a multi-stage vacuum flash tank connected to the outlet of the coarse filter, a tar separator connected to the outlet of the multi-stage vacuum flash tank, and a light oil separator connected to the outlet of the tar separator.

[0007] Preferably, the storage tank assembly includes a tar storage tank connected to the oil outlet of the tar separator, a tar residue storage tank connected to the slag outlet of the tar separator, a light oil storage tank connected to the oil outlet of the light oil separator, and a gas-water storage tank connected to the liquid outlet of the light oil separator.

[0008] Preferably, the pump assembly includes a gas-water pump, a quench water circulation pump, and a washing water circulation pump, which are respectively connected to the drain port of the gas-water storage tank. A multi-port is provided at the connection point between the drain port of the gas-water storage tank and the gas-water pump, the quench water circulation pump, and the washing water circulation pump.

[0009] Preferably, the outlet of the syngas scrubbing assembly is provided with a downstream syngas device, the slag discharge port of the coarse filter is provided with an injection well, the inlet of the downstream syngas device is connected to the outlet of the syngas scrubbing assembly, and the inlet of the injection well is connected to the slag discharge port of the coarse filter.

[0010] Preferably, the outlet of the quench water circulation pump is connected to the inlet of the product well, and the outlet of the washing water circulation pump is connected to the inlet of the syngas washing assembly.

[0011] Preferably, the light oil separator is equipped with a TPI plate and an activated carbon adsorption frame inside. The TPI plate has a continuous sawtooth shape with a corrugation of 60°±5°, a peak height of 3-5mm, and a wave pitch of 8-12mm. The surface of the TPI plate is coated with a 25-40μm thick polytetrafluoroethylene coating. A trapezoidal guide groove with a depth of 2mm is opened at the trough of the corrugation of the TPI plate, and the groove width gradually decreases from 4mm at the inlet end to 1.5mm at the outlet end.

[0012] Preferably, a scraper is provided at the bottom of the tar separator, and a steam coil is provided on the outer wall of the bottom of the tar separator.

[0013] The beneficial effects of this utility model are:

[0014] This invention safely combusts the combustible waste gas released during the gas-water separation process using a flare device to avoid direct emissions that could cause air pollution. It also deeply removes acidic gases, phenols, and ammonia nitrogen from the gas-water mixture through a phenol-ammonia recovery component, achieving the resource recovery of phenolic substances and liquid ammonia. Meanwhile, the purified wastewater can be reused in the quench water circulation pump and transported to the product well or discharged in compliance with standards, which greatly improves the water resource recycling rate and thus significantly reduces the consumption of fresh water and the cost of wastewater treatment.

[0015] This invention involves first cooling the crude syngas produced from underground coal gasification using a quench water device in the product well to prevent damage from high temperatures. Then, after passing through a syngas scrubbing device, it produces coal gas water. The syngas then enters a downstream syngas unit for further processing. The coal gas water is cooled by a cooler, with the cooler outlet temperature controlled at 50-60℃ to prevent premature tar condensation. The cooler outlet is connected to a coarse filter to remove particulate matter from the coal gas water. Finally, it is transported to the injection well to enter the combustion zone of the underground coal gasifier to participate in the underground gasification reaction. The outlet of the coarse filter's gas-water mixture is connected to the inlet of the multi-stage pressure-reducing flash tank. The gas-water mixture enters the multi-stage pressure-reducing flash tank and is depressurized to atmospheric pressure, where dissolved CO2, CO, NH3, and some water vapor are flash-separated. The gas-water mixture from the multi-stage pressure-reducing flash tank flows into the tar separator by gravity. The density difference between tar, tar residue, and water is used to separate the gas-water mixture from the tar and tar residue. When the liquid level in the tar separator reaches a certain height, the gas-water mixture overflows through the tar separator outlet pipe into the light oil separator. After passing through the TPI plate, the gas-water mixture enters the water chamber and is then led out through the overflow weir into the gas-water storage tank. Of the gas-water mixture entering the gas-water storage tank, a portion is pumped to the product well via a quench water pump for use in the product well quenching device, and another portion is pumped to the syngas scrubbing device via a washing water circulation pump for syngas scrubbing. The excess gas-water mixture is pumped to the phenol-ammonia recovery unit for further treatment via a gas-water pump. Attached Figure Description

[0016] Figure 1 The diagram shown is a structural schematic of the underground coal gasification gas-water separation system of this utility model.

[0017] Figure 2 The diagram shown is a structural schematic of the gas-water separation and treatment component of the underground coal gasification gas-water separation system of this utility model.

[0018] Explanation of reference numerals in the attached drawings: 1. Product well; 2. Syngas scrubbing assembly; 3. Downstream syngas unit; 4. Cooler; 5. Coarse filter; 6. Injection well; 7. Multistage pressure-reducing flash tank; 8. Flare device; 9. Tar separator; 10. Tar storage tank; 11. Tar residue storage tank; 12. Light oil separator; 13. Light oil storage tank; 14. Gas-water storage tank; 15. Gas-water pump; 16. Quenching water circulation pump; 17. Washing water circulation pump; 18. Phenol-ammonia recovery assembly. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] A coal underground gasification gas-water separation system, based on Figures 1-2As shown, it includes a product well 1, a syngas scrubbing assembly 2 connected to the gas outlet of the product well 1, a coal gas-water separation and treatment assembly connected to the liquid outlet of the syngas scrubbing assembly 2, a flare device 8 connected to the gas outlet of the coal gas-water separation and treatment assembly, a storage tank assembly connected to the liquid outlet of the coal gas-water separation and treatment assembly, a pump assembly connected to the liquid outlet of the storage tank assembly, and a phenol-ammonia recovery assembly 18 connected to the liquid outlet of the pump assembly.

[0021] The gas-water separation treatment assembly includes a cooler 4 connected to the outlet of the syngas washing assembly 2, a coarse filter 5 connected to the outlet of the cooler 4, a multi-stage vacuum flash tank 7 connected to the outlet of the coarse filter 5, a tar separator 9 connected to the outlet of the multi-stage vacuum flash tank 7, and a light oil separator 12 connected to the outlet of the tar separator 9.

[0022] It should be noted that the syngas scrubbing assembly 2 includes a scrubbing tower, a spraying device, a quench water device, a demister, and a scrubbing water circulation device.

[0023] according to Figure 1 As shown, the storage tank assembly includes a tar storage tank 10 connected to the oil outlet of the tar separator 9, a tar residue storage tank 11 connected to the slag outlet of the tar separator 9, a light oil storage tank 13 connected to the oil outlet of the light oil separator 12, and a gas-water storage tank 14 connected to the liquid outlet of the light oil separator 12.

[0024] It should be noted that a tar separator 9 is installed at the bottom of the multi-stage vacuum flash tank 7. The outlet pipeline of the multi-stage vacuum flash tank 7 is connected to the upper inlet of the tar separator 9. The gas and water flowing through the multi-stage vacuum flash tank 7 flow into the tar separator 9 by gravity. The gas and water are separated from the tar and tar residue by utilizing the density difference between tar, tar residue, and water. The tar residue, which has a density greater than water, is collected at the bottom of the tar separator 9. A scraper is installed at the bottom and periodically starts to discharge the tar residue from the bottom of the tar separator 9. The bottom of the tar separator 9 is connected to the inlet of the tar residue storage tank 11. The discharged tar residue is stored in the tar residue storage tank 11. The tar separator 9 is equipped with a level gauge. The outer wall of the tar separator 9 is covered with steam coils and insulation material to maintain a suitable temperature, prevent tar condensation and adhesion to the inner wall of the equipment, and improve operational stability.

[0025] according to Figure 1 As shown, the pump assembly includes a gas water pump 15, a quench water circulation pump 16, and a washing water circulation pump 17, which are respectively connected to the drain port of the gas water storage tank 14. A multi-port is provided at the connection between the drain port of the gas water storage tank 14 and the gas water pump 15, the quench water circulation pump 16, and the washing water circulation pump 17.

[0026] according to Figure 1As shown, the outlet of the syngas scrubbing assembly 2 is equipped with a downstream syngas device 3, the slag discharge port of the coarse filter 5 is equipped with an injection well 6, the inlet of the downstream syngas device 3 is connected to the outlet of the syngas scrubbing assembly 2, and the inlet of the injection well 6 is connected to the slag discharge port of the coarse filter 5.

[0027] It should be noted that the crude syngas produced from underground coal gasification is first cooled by a quench water device in product well 1 to prevent damage to product well 1 due to high temperature. Then, it passes through syngas scrubbing device 2 to produce coal gas water. The syngas enters downstream syngas device 3 for further processing. The coal gas water is cooled by cooler 4. The outlet temperature of the cooler is controlled at 50-60℃ to prevent premature condensation of tar. The outlet of cooler 4 is connected to coarse filter 5 to filter out particulate matter in the coal gas water. Then, it is transported to injection well 6 to enter the combustion zone of the underground coal gasifier to participate in the underground gasification reaction.

[0028] according to Figure 1 As shown, the outlet of the quench water circulation pump 16 is connected to the inlet of the product well 1, and the outlet of the washing water circulation pump 17 is connected to the inlet of the syngas washing assembly 2.

[0029] It should be noted that, of the gas water in the gas water storage tank 14, a portion is transported to the product well via the quench water pump 16 for use in the quenching device of the product well 1, and a portion is transported to the syngas washing device 2 via the washing water circulation pump 17 for syngas washing. The excess gas water is transported to the phenol-ammonia recovery component 18 via the gas water pump 15 for further processing.

[0030] according to Figures 1-2 As shown, the interior of the light oil separator 12 is equipped with a TPI plate and an activated carbon adsorption frame. The TPI plate has a continuous sawtooth shape with a corrugation of 60°±5°, a peak height of 3-5mm, and a wave pitch of 8-12mm. The surface of the TPI plate is coated with a 25-40μm thick polytetrafluoroethylene coating. A trapezoidal guide groove with a depth of 2mm is opened at the trough of the corrugation of the TPI plate. The width of the groove gradually decreases from 4mm at the inlet end to 1.5mm at the outlet end.

[0031] It should be noted that the light oil separator 12 is equipped with coke and TPI plate assembly. The coke can be used to filter impurities and intercept larger impurity particles. The TPI plate accelerates the rise of light oil through the oil droplet coalescence effect and can further finely filter the gas-water after coke filtration, intercepting smaller impurity particles and improving water quality. The separated light oil is introduced into the light oil storage tank 12 through the overflow weir. The water at the bottom enters the water chamber after passing through the TPI plate and is then led out through the overflow weir and sent to the gas-water storage tank 14.

[0032] according to Figures 1-2 As shown, a scraper is installed at the bottom of the tar separator 9, and a steam coil and insulation material are arranged on the outer wall of the bottom of the tar separator 9.

[0033] It should be noted that the gas-water mixture from the multi-stage pressure-reducing flash tank 7 flows into the tar separator 9 by gravity. The gas-water mixture is separated from the tar and tar residue by utilizing the density difference between tar, tar residue, and water. The tar residue, which has a density greater than water, is collected at the bottom of the tar separator 9. A scraper is installed at the bottom and periodically starts to discharge the tar residue from the bottom of the tar separator 9. The bottom of the tar separator 9 is connected to the inlet of the tar residue storage tank 11. The discharged tar residue is stored in the tar residue storage tank 11. The tar separator 9 is equipped with a level gauge. The outer wall of the tar separator 9 is covered with steam coils and insulation material to maintain a suitable temperature, prevent tar from condensing and adhering to the inner wall of the equipment, and improve operational stability.

[0034] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A coal gasification gas-water separation system for underground coal gasification, characterized in that: The system includes a product well (1), a syngas scrubbing assembly (2) connected to the outlet of the product well (1), a coal gas-water separation treatment assembly connected to the liquid outlet of the syngas scrubbing assembly (2), a flare device (8) connected to the outlet of the coal gas-water separation treatment assembly, a storage tank assembly connected to the liquid outlet of the coal gas-water separation treatment assembly, a pump assembly connected to the liquid outlet of the storage tank assembly, and a phenol-ammonia recovery assembly (18) connected to the liquid outlet of the pump assembly; the coal gas-water separation treatment assembly includes a cooler (4) connected to the liquid outlet of the syngas scrubbing assembly (2), a coarse filter (5) connected to the liquid outlet of the cooler (4), a multi-stage vacuum flash tank (7) connected to the liquid outlet of the coarse filter (5), a tar separator (9) connected to the liquid outlet of the multi-stage vacuum flash tank (7), and a light oil separator (12) connected to the liquid outlet of the tar separator (9).

2. The underground coal gasification gas-water separation system according to claim 1, characterized in that: The tank assembly includes a tar tank (10) connected to the oil outlet of the tar separator (9), a tar residue tank (11) connected to the slag outlet of the tar separator (9), a light oil tank (13) connected to the oil outlet of the light oil separator (12), and a gas-water tank (14) connected to the liquid outlet of the light oil separator (12).

3. The underground coal gasification gas-water separation system according to claim 2, characterized in that: The pump assembly includes a gas water pump (15), a chill water circulation pump (16), and a washing water circulation pump (17) that are respectively connected to the drain port of the gas water storage tank (14). A multi-port is provided at the connection between the drain port of the gas water storage tank (14) and the gas water pump (15), the chill water circulation pump (16), and the washing water circulation pump (17).

4. A coal gasification underground gasification gas-water separation system according to claim 1, characterized in that: The outlet of the syngas scrubbing assembly (2) is provided with a downstream syngas device (3), the slag discharge port of the coarse filter (5) is provided with an injection well (6), the inlet of the downstream syngas device (3) is connected to the outlet of the syngas scrubbing assembly (2), and the inlet of the injection well (6) is connected to the slag discharge port of the coarse filter (5).

5. A coal gasification underground gasification gas-water separation system according to claim 3, characterized in that: The outlet of the quench water circulation pump (16) is connected to the inlet of the product well (1), and the outlet of the washing water circulation pump (17) is connected to the inlet of the syngas washing assembly (2).

6. A coal gasification underground gasification gas-water separation system according to claim 1, characterized in that: The light oil separator (12) is equipped with a TPI plate and an activated carbon adsorption frame. The TPI plate has a continuous sawtooth shape with a corrugation of 60°±5°, a peak height of 3-5mm, and a wave pitch of 8-12mm. The surface of the TPI plate is coated with a 25-40μm thick polytetrafluoroethylene coating. A trapezoidal guide groove with a depth of 2mm is opened at the trough of the corrugation of the TPI plate. The groove width gradually decreases from 4mm at the inlet end to 1.5mm at the outlet end.

7. A coal gasification underground gasification gas-water separation system according to claim 1, characterized in that: The bottom of the tar separator (9) is equipped with a scraper, and a steam coil is arranged on the outer wall of the bottom of the tar separator (9).

Images