CN112408709A - Crushed coal pressurized gasification gas water separation and recycling system and method capable of recycling sewage - Google Patents
Crushed coal pressurized gasification gas water separation and recycling system and method capable of recycling sewage Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
- C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
- C02F11/122—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using filter presses
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/06—Flash evaporation
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/40—Devices for separating or removing fatty or oily substances or similar floating material
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2301/00—General aspects of water treatment
- C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
Abstract
The invention provides a system and a method for separating and recycling crushed coal pressure gasification gas water capable of recycling sewage, and belongs to the field of gas separation and recycling. The invention separates and recycles the gas water with different classifications, which not only makes the whole system have small floor area, low investment and operation cost, but also has short treatment process, less equipment, less pollutant discharge point and difficult environmental pollution. By arranging equipment such as a medium-pressure flash evaporator, a vacuum flash separator and an ammonia still and arranging a settling tank and the top of a gas water tank to be hermetically connected with an inert gas pipeline, the whole system and the separation and recycling process are kept in micro-positive pressure operation of more than 0.2kPa, and the concentrated treatment of the VOCs and the odor discharged from the system can be ensured. The water outlet of the second vacuum flash evaporator is connected with the water inlet of the heat exchanger connected with the waste heat boiler through the pipeline and the water pump, so that the recycling of waste water is realized, the waste water amount going to biochemical treatment equipment can be reduced, and the heat in the waste water can be fully utilized.
Description
Technical Field
The invention relates to the technical field of coal gas separation and recycling, in particular to a system and a method for separating and recycling crushed coal pressure gasification coal gas water capable of recycling sewage.
Background
The raw gas produced by the pressure gasification of crushed coal contains a large amount of water vapor, dust, and by-products of carbonization, such as tar, light oil, naphthalene, phenol, fatty acids, dissolved gases, and inorganic salts, and the temperature is also high. Therefore, it needs to be cooled and washed to lower the temperature and remove harmful substances from the raw gas. During the washing and cooling process of the crude gas, the impurity components enter water to form gas water with various components existing in gas, liquid and solid states, the components of the gas water are complex, and the contents of the various components are different along with the difference of coal types. The gas water can not be directly treated by conventional biochemical, filtering, reverse osmosis and other methods, and oil, dust, phenol, ammonia and the like in the gas water must be separated and recovered, so that on one hand, valuable substances in the wastewater are recovered, and certain economic benefit can be generated; on the other hand, the wastewater can meet the water inlet requirement of a common wastewater treatment method and is discharged after the wastewater is biochemically treated to reach the national discharge standard.
The most classical gas-water separation and recovery process is briefly described in the modern technical handbook of coal chemical industry, which is also a process commonly used in the conventional crushed coal pressure gasification technology, and specifically, after gasified gas water with the pressure of 3.0-6.0MPa and conversion cooling gas water are respectively sent into a gas-water separation system, the gasified gas water is firstly cooled to 90 ℃, and then enters a gas-water expander to be subjected to flash evaporation expansion to normal pressure, and CO dissolved in the gas water is subjected to flash evaporation expansion to be normal pressure2、NH3And flash separation of gas such as part of water vapor. The coal gas water after flash evaporation enters a tar separator at the lower part to separate the coal gas water from tar by using density difference, and dust-containing tar with the density higher than that of the water is discharged from the bottom and can be used as a product and also can return to a gasification furnace for gasification again; light oil with density less than that of water and coal gas water overflow from the upper part of the tar separator and enter a coal gas water buffer tank, part of the coal gas water is pumped back to gasification for recycling by a high-pressure pump, and the redundant coal gas water enters the light oil separator. The light oil separator is provided with a coke and TPI plate assembly for filtering impuritiesOil drops are condensed on the surface of the water and then float on the water surface to form an oil layer, light oil is led out through an overflow weir at the upper part and is sent into an oil storage tank, water at the lower part enters a water chamber through a TPI plate and is led out through the overflow weir, the water passes through a buffer tank and is sent into a double-medium filter by a pump to be further dedusted and then sent to a phenol and ammonia recovery device, the purpose is to separate dust, oil and dissolved gas in coal gas water, most of the water is recycled, and a small part of the water is subjected to water quality biochemical treatment which meets biochemical requirements after further deoiling, ammonia evaporation and dephenolization.
However, with the development of the coal gas technology, the development gradually proceeds to the direction of large-scale, energy-saving, environmental protection, high efficiency and stability, and the coal gas water separation and recovery process of the conventional crushed coal pressure gasification technology cannot meet the modern requirements, and mainly appears as follows:
1. the existing gas water treatment system collects different types of gas water from different devices together for gas water separation and recovery, so that the whole gas water separation and recovery system has large floor area, high investment and high operation cost;
2. the current gas-water separation and recovery processes are long, and the number of devices is large, so that the pollutant discharge points are large, and serious environmental pollution is easily caused;
3. the existing gas-water separation and recovery system can use a plurality of gas-water storage tanks, oil separators and the like, and the devices are operated under normal pressure, so that the discharged VOCs (Volatile Organic Compounds), odor and the like can not be collected and then intensively treated, and the field environment is severe.
4. The condensed water obtained by the heat exchange of the existing gas-water separation and recovery system is often directly discharged as wastewater, so that the wastewater amount to the biochemical treatment equipment is large, and the heat in the condensate cannot be fully utilized.
Disclosure of Invention
In order to solve the technical problems, the invention provides a system and a method for separating and recycling crushed coal pressure gasification gas water capable of recycling sewage.
In order to solve the technical problems, the invention adopts the technical scheme that:
the utility model provides a but garrulous coal of sewage retrieval and utilization pressurization gasification gas water separation and recycling system, its includes middling pressure flash vessel, first vacuum flash vessel, subsider, gas water jar, deacidification tower, first vacuum flash separator, ammonia still, second vacuum flash vessel, second vacuum flash separator, third vacuum flash separator, flocculating agent jar, pressure filter, filtrate jar, a plurality of water pump and pipeline, wherein: the first water inlet of the medium-pressure flash evaporator is connected with a pipeline for transforming high-temperature condensate, the second water inlet of the medium-pressure flash evaporator is connected with a pipeline for gasifying dust-containing gasified water, the water outlet of the medium-pressure flash evaporator is connected with the first water inlet of the first vacuum flash evaporator through a pipeline, the second water inlet of the first vacuum flash evaporator is connected with a pipeline for low-pressure gasified gas water, the third water inlet of the first vacuum flash evaporator is connected with a pipeline for low-pressure start-up gas water, the water outlet of the first vacuum flash evaporator is connected with the water inlet of the settling tank through a pipeline and a water pump, the water outlet of the settling tank is connected with the water inlet of a filter press through a pipeline and a water pump, the water outlet of the filter press is connected with the water inlet of a filtrate tank through a pipeline and a water pump, the water inlet of the settling tank is also connected with the, a gas water outlet of the settling tank is connected with a gas water inlet of a gas water tank through a pipeline, the gas water outlet of the gas water tank is connected with a gas water biochemical treatment device and a gas water recycling device through a pipeline and a water pump, and the settling tank and the top of the gas water tank are hermetically connected with an inert gas pipeline; the gas outlet of the medium-pressure flash evaporator is connected with the gas inlet of the deacidification tower through a pipeline, the water inlet of the second vacuum flash evaporator is connected with a pipeline for transforming low-temperature condensate, the water outlet of the second vacuum flash evaporator is connected with the water inlet of the heat exchanger connected with the waste heat boiler through a pipeline and a water pump, the water outlet of the deacidification tower is connected with the water inlet of the ammonia still through a pipeline and a water pump, and the water outlet of the ammonia still is connected with crude gas washing equipment; the gas outlet of the first vacuum flash evaporator is connected with the gas inlet of the first vacuum flash evaporator separator through a pipeline, the gas outlet of the first vacuum flash evaporator separator is connected with the gas inlet of the third vacuum flash evaporator separator through a pipeline, and the water outlet of the first vacuum flash evaporator separator is connected with the water inlet of the deacidification tower through a pipeline and a water pump; the gas outlet of the second vacuum flash evaporator is connected with the gas inlet of the second vacuum flash evaporator separator through a pipeline, the gas outlet of the second vacuum flash evaporator separator is connected with the gas inlet of the third vacuum flash evaporator separator through a pipeline, the water outlet of the second vacuum flash evaporator separator is connected with the water inlet of the deacidification tower through a pipeline, and the water outlet of the third vacuum flash evaporator separator is connected with the water inlet of the deacidification tower through a pipeline.
Optionally, the system for separating and recycling crushed coal pressure gasification gas water capable of recycling sewage further comprises an oil collecting floater and an oil tank, wherein the oil collecting floater is arranged inside the gas water tank, and the bottom of the oil collecting floater is connected with the oil tank through a hose.
Optionally, a cooling water sleeve is arranged outside the breathing gas discharge pipeline at the top of the gas water tank and the settling tank.
A method for separating and recycling crushed coal pressure gasification gas water capable of recycling sewage comprises the following steps:
s1, degassing the transformed high-temperature condensate and the gasified dust-containing gasified water through a medium-pressure flash evaporator, entering the first vacuum flash evaporator together with the gasified low-pressure coal gas water and the gasified starting coal gas water, and deeply removing dissolved gas in the first vacuum flash evaporator;
s2, mixing the gas water after the gas is dissolved and a flocculating agent from a flocculating agent tank, and then sending the mixture into a settling tank;
s3, performing filter pressing and dehydration on the solid material settled at the bottom of the settling tank by a filter press to prepare mud cakes, feeding the filtrate generated by filter pressing and dehydration into a filtrate tank and returning the filtrate to the settling tank, feeding the gas water at the upper part of the settling tank into a gas water tank, recycling a part of the gas water in the gas water tank as washing water for gasifying low-pressure gas water by using gas water recycling equipment, and removing the rest of the gas water by using gas water biochemical treatment equipment;
s4, spraying the flash steam flashed by the medium-pressure flash evaporator from the bottom of the deacidification tower into the deacidification tower as a heat source of the deacidification tower, and simultaneously removing acid gas in the flash steam by the deacidification tower;
s5, transforming the low-temperature condensate to remove dissolved gas in a second vacuum flash evaporator, pressurizing and exchanging heat after removing the dissolved gas, and sending the solution into a waste heat boiler to be used as make-up water so as to reduce the water amount of the biochemical treatment equipment for removing the coal gas water;
s6, feeding the condensate formed by flash evaporation of the first vacuum flash evaporator and the second vacuum flash evaporator into a first vacuum flash evaporation separator, a second vacuum flash evaporation separator and a third vacuum flash evaporation separator respectively for vacuum flash evaporation separation, and feeding the condensate condensed by the first vacuum flash evaporation separator, the second vacuum flash evaporation separator and the third vacuum flash evaporation separator into a deacidification tower from the tower top of the deacidification tower for deacidification;
s7, desulfurizing and recovering the deacidified gas obtained by deacidification in the deacidification tower, feeding the deacidified gas water into an ammonia still, using the gas water obtained after ammonia still in the ammonia still as washing water for washing crude gas for recycling, and recycling ammonia water/liquid ammonia generated in the ammonia still.
Optionally, the conversion high-temperature condensate is coal gas water with dust content not more than 2000mg/L, temperature of 150-190 ℃ and pressure of 3.0-7.0 MPa; the gasified dust-containing gasified water is coal gas water with dust content not more than 3000mg/L, temperature of 180-200 ℃ and pressure of 3.0-7.0 MPa; the conversion low-temperature condensate is gas water with dust content less than 50mg/L, temperature of 40-80 ℃ and pressure of 3.0-5.0 MPa; the low-pressure gasified gas water is gas water with the dust content of less than 100mg/L, the temperature of 60-80 ℃ and the pressure of 0.5-0.7 MPa; the low-pressure starting gas water is gas water with the dust content of less than 200mg/L, the temperature of 60-80 ℃ and the pressure of 0.5-0.7 MPa.
Optionally, the flash evaporation temperature of the medium-pressure flash evaporator is 140-160 ℃, and the pressure is 0.4-0.5 MPa.
Optionally, the flash evaporation temperature of the first vacuum flash evaporator is 80-86 ℃ and the vacuum degree is 50-60 kPa.
Optionally, the addition amount of the flocculant is 3-5g of flocculant added into 1 ton of coal gas water.
Optionally, the inert gas is continuously introduced into the settling tank and the top of the gas water tank.
The invention has the beneficial effects that:
1. through separating and recycling the gas water of different classification respectively, not only make entire system area little, the investment is low, the running cost is low, and the processing procedure is short moreover, equipment is few for the pollutant emission point is few, is difficult for causing environmental pollution, has energy-concerving and environment-protective, high-efficient stable advantage.
2. Through setting up equipment such as middling pressure flash vessel, vacuum flash separator and ammonia still to set up subsider and gas water tank top and inert gas pipeline sealing connection, make entire system and separation retrieval and utilization process keep being greater than 0.2kPa pressure-fired operation, thereby can guarantee that exhaust VOCs and foul smell can the centralized processing in the system, make site environment friendly.
3. The whole system has simple equipment and safe and stable operation, and can effectively reduce the cost of gas water treatment.
4. The water outlet through setting up second vacuum flash vessel passes through the pipeline and the water pump is connected with the water inlet of the heat exchanger that waste heat boiler is connected, makes the coal gas water portion after dirty reposition of redundant personnel as waste heat boiler's make-up water, and the production dirty steam uses as the gasification agent, has realized the recycle of waste water, not only can reduce the waste water volume to biochemical treatment equipment, can make full use of the heat in the waste water moreover.
Practice proves that compared with the prior gas-water separation and recycling system, the system and the method have the advantages that the investment is reduced by 50 percent, the operating cost is saved by 50 percent, and the amount of wastewater to biochemical treatment equipment is reduced by 25 percent.
Drawings
FIG. 1 is a schematic diagram of the system components of the present invention.
FIG. 2 is a schematic diagram of the connection of the present invention to a gasification unit, a scrubbing unit and a shift unit.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
As shown in fig. 1, the system for separating and recycling crushed coal pressure gasification gas water capable of recycling sewage in this embodiment includes a medium-pressure flash evaporator 1, a first vacuum flash evaporator 2, a settling tank 3, a gas water tank 4, a deacidification tower 5, a first vacuum flash evaporator separator 6, an ammonia still 7, a second vacuum flash evaporator 8, a second vacuum flash evaporator separator 9, a third vacuum flash evaporator 10, a flocculant tank 11, a filter press 12, a filtrate tank 13, a plurality of water pumps and pipelines, wherein: the first water inlet of the medium-pressure flash evaporator 1 is connected with a pipeline for transforming high-temperature condensate, the second water inlet of the medium-pressure flash evaporator 1 is connected with a pipeline for gasifying dust-containing gasified water, the water outlet of the medium-pressure flash evaporator 1 is connected with the first water inlet of the first vacuum flash evaporator 2 through a pipeline, the second water inlet of the first vacuum flash evaporator 2 is connected with a pipeline for gasifying gas at low pressure, the third water inlet of the first vacuum flash evaporator 2 is connected with a pipeline for driving gas at low pressure, the water outlet of the first vacuum flash evaporator 2 is connected with the water inlet of the settling tank 3 through a pipeline and a water pump, the water outlet of the settling tank 3 is connected with the water inlet of a filter press 12 through a pipeline and a water pump, the water outlet of the filter press 12 is connected with the water inlet of a filtrate tank 13 through a pipeline, the water outlet of the filtrate tank 13 is connected with the water inlet of the settling tank 3 through a pipeline and a water pump, a gas water outlet of the settling tank 3 is connected with a gas water inlet of a gas water tank 4 through a pipeline, a gas water outlet of the gas water tank 4 is connected with a gas water biochemical treatment device and a gas water recycling device (a coal gas lock gas washing device and a start gas washing device) through a pipeline and a water pump, and the tops of the settling tank 3 and the gas water tank 4 are hermetically connected with an inert gas pipeline so that micro positive pressure greater than 0.2kPa is kept in the settling tank 3 and the gas water tank 4; the gas outlet of the medium-pressure flash evaporator 1 is connected with the gas inlet of the deacidification tower 5 through a pipeline, the water inlet of the second vacuum flash evaporator 8 is connected with a pipeline for converting low-temperature condensate, the water outlet of the second vacuum flash evaporator 8 is connected with the water inlet of a heat exchanger connected with a waste heat boiler through a pipeline and a water pump, the water outlet of the deacidification tower 5 is connected with the water inlet of an ammonia still 7 through a pipeline and a water pump, and the water outlet of the ammonia still 7 is connected with a crude gas washing device; the gas outlet of the first vacuum flash evaporator 2 is connected with the gas inlet of the first vacuum flash separator 6 through a pipeline, the gas outlet of the first vacuum flash separator 6 is connected with the gas inlet of the third vacuum flash separator 10 through a pipeline, and the water outlet of the first vacuum flash separator 6 is connected with the water inlet of the deacidification tower 5 through a pipeline and a water pump; the gas outlet of the second vacuum flash evaporator 8 is connected with the gas inlet of the second vacuum flash evaporator separator 9 through a pipeline, the gas outlet of the second vacuum flash evaporator separator 9 is connected with the gas inlet of the third vacuum flash evaporator separator 10 through a pipeline, the water outlet of the second vacuum flash evaporator separator 9 is connected with the water inlet of the deacidification tower 5 through a pipeline, and the water outlet of the third vacuum flash evaporator separator 10 is connected with the water inlet of the deacidification tower 5 through a pipeline.
As shown in fig. 2, a gasification unit, a washing unit and a conversion unit are connected in front of the crushed coal pressure gasification gas-water separation and recycling system capable of recycling sewage according to the embodiment of the invention. Specifically, crushed coal raw materials are added into a crushed coal pressure gasification furnace through a coal adding lock hopper to be subjected to pressure gasification to generate gasified raw gas, the gasified raw gas is dedusted through a cyclone separator and then reaches a waste heat boiler, after heat in the gas is recovered by the waste heat boiler, the gas is continuously subjected to three-stage dedusting through a Venturi washing device and a raw gas washing device and then is sent into a conversion device, a precooler, an intermediate and final cooling device and an ammonia washing tower in a conversion unit. And one part of coal gas in the crushed coal pressure gasification furnace enters coal gas locking washing equipment, and the other part of the coal gas also enters start-up coal gas washing equipment. The crushed coal is any one of anthracite, coke or semicoke. Wherein the precooler produces shift high temperature condensate. The intermediate, final cooling equipment and ammonia scrubber produce shift low temperature condensate. The venturi scrubbing apparatus produces gasified dusty gasified water. The coal lock gas washing equipment generates low-pressure gasified gas water. The start-up gas washing equipment generates low-pressure start-up gas water.
Optionally, the system for separating and recycling crushed coal pressure gasification gas and water capable of recycling sewage further comprises an oil collecting float 14 and an oil tank 15, the oil collecting float 14 is arranged inside the gas water tank 4, the bottom of the oil collecting float 14 is connected with the oil tank 15 through a hose, the height of the oil collecting float 14 can change along with the liquid level inside the gas water tank 4, and light oil floating on the upper portion of the gas water tank 4 can enter the oil collecting float 14 and be collected into the oil tank 15 through the hose, so that the collection of the light oil is realized.
Optionally, a cooling water sleeve 16 is arranged outside the breathing gas discharge pipeline at the top of the gas water tank 4 and the settling tank 3. The cooling water jacket 16 can cool the respiratory air discharged from the respiratory air discharge pipeline at the top of the gas water tank 4 and the settling tank 3, so that the condensed easily condensed odor flows back to the equipment, thereby avoiding the discharge of VOCs or odor from the gas water tank 4 and the settling tank 3.
The embodiment of the invention also provides a method for separating and recycling crushed coal pressure gasification gas-water capable of recycling sewage, which can be realized by adopting the system for separating and recycling the crushed coal pressure gasification gas-water capable of recycling sewage shown in figure 1, and specifically comprises the following steps:
and S1, degassing the transformed high-temperature condensate and the gasified dust-containing gasified water through the medium-pressure flash evaporator 1, feeding the degassed high-temperature condensate and the gasified dust-containing gasified water, together with the gasified low-pressure coal gas water and the gasified starting coal gas water into the first vacuum flash evaporator 2, and deeply removing dissolved gas in the first vacuum flash evaporator 2.
Optionally, the flash evaporation temperature of the medium-pressure flash evaporator 1 is 140-160 ℃, and the pressure is 0.4-0.5 MPa. The flash evaporation temperature of the first vacuum flash evaporator 2 is 80-86 ℃, and the vacuum degree is 50-60 kPa.
And S2, mixing the gas water after gas stripping with a flocculating agent from a flocculating agent tank 11, and then sending the mixture into a settling tank 3.
Optionally, the addition amount of the flocculant is 3-5g of flocculant added into 1 ton of coal gas water.
S3, performing filter pressing and dehydration on the solid material settled at the bottom of the settling tank 3 by a filter press 12 to prepare mud cakes, feeding the filtrate generated by filter pressing and dehydration into a filtrate tank 13 and then returning the filtrate to the settling tank 3, feeding the gas water at the upper part of the settling tank 3 into a gas water tank 4, recycling a part of the gas water in the gas water tank 4 as washing water for gasifying low-pressure gas water for gas water recycling equipment (coal lock gas washing equipment and start gas washing equipment), and removing the rest of the gas water for gas water biochemical treatment equipment.
S4, spraying the flash steam flashed by the medium-pressure flash evaporator 1 from the bottom of the deacidification tower 5 into the deacidification tower 5 to be used as a heat source of the deacidification tower 5, and simultaneously removing the acid gas in the flash steam by the deacidification tower 5.
And S5, transforming the low-temperature condensate to remove dissolved gas in the second vacuum flash evaporator 8, pressurizing and exchanging heat after removing the dissolved gas, and sending the solution into a waste heat boiler to be used as make-up water so as to reduce the water amount of the biochemical treatment equipment for removing the coal gas water.
S6, feeding the condensate formed by flash evaporation in the first vacuum flash evaporator 2 and the second vacuum flash evaporator 8 into the first vacuum flash separator 6, the second vacuum flash separator 9 and the third vacuum flash separator 10 respectively for vacuum flash evaporation separation, and feeding the condensate condensed in the first vacuum flash separator 6, the second vacuum flash separator 9 and the third vacuum flash separator 10 from the top of the deacidification tower 5 to deacidify.
S7, desulfurizing and recovering the deacidified gas obtained by deacidification in the deacidification tower 5, feeding the deacidified gas water into an ammonia still 7, taking the gas water after ammonia still in the ammonia still 7 as washing water for washing crude gas for recycling, and recycling ammonia water/liquid ammonia generated in the ammonia still 7.
Wherein the conversion high-temperature condensate is coal gas water with dust content not more than 2000mg/L, temperature of 150-190 ℃ and pressure of 3.0-7.0 MPa; the gasified dust-containing gasified water is coal gas water with dust content not more than 3000mg/L, temperature of 180-200 ℃ and pressure of 3.0-7.0 MPa; the conversion low-temperature condensate is gas water with dust content less than 50mg/L, temperature of 40-80 ℃ and pressure of 3.0-5.0 MPa; the low-pressure gasified gas water is gas water with the dust content of less than 100mg/L, the temperature of 60-80 ℃ and the pressure of 0.5-0.7 MPa; the low-pressure starting gas water is gas water with the dust content of less than 200mg/L, the temperature of 60-80 ℃ and the pressure of 0.5-0.7 MPa.
Optionally, the inert gas is continuously introduced into the top of the settling tank 3 and the top of the gas water tank 4, so that the micro-positive pressure (0.2-0.5kPa) greater than 0.2kPa is always maintained inside the settling tank 3 and the gas water tank 4.
The method provided by the embodiments of the present invention is illustrated below by several examples.
Example 1
The crushed coal in the embodiment is anthracite with water content of 5%, the coal sample is crushed and screened to obtain a coal sample with particle size of 5-50mm, the coal sample is put into a crushed coal pressure gasification furnace for crushed coal pressure gasification, the gasification pressure is 4.0MPa, the gasification temperature is 1250 ℃, crude coal gas generated by gasification is divided into high-temperature coal gas water and low-temperature coal gas water according to the dust content, temperature and pressure in water during washing, the high-temperature coal gas water is divided into high-temperature condensate and gasified dust-containing gasified water according to the dust content, temperature and pressure, and the low-temperature coal gas water is divided into low-temperature condensate, low-pressure gasified coal gas water and low-pressure start coal gas water according to the dust content, temperature and pressure. The gas water of different classifications is separated and recycled respectively, the whole separation and recycling process of the gas water keeps micro-positive pressure operation larger than 0.2kPa and adopts inert gas protection to ensure that VOCs and odor in the system can be treated in a centralized way.
The dust content of the converted high-temperature condensate obtained by processing the coal sample by the gasification unit, the washing unit and the conversion unit is 1900mg/L, the temperature is 150 ℃, the pressure is 4MPa, the dust content of the gasified dust-containing gasified water is 2800mg/L, the temperature is 189 ℃, and the pressure is 4.0 MPa. The dust content of the conversion low-temperature condensate is 45mg/L, the temperature is 67.5 ℃, the pressure is 3.75MPa, the dust content of the low-pressure gasification gas water is 90mg/L, the temperature is 70 ℃, the pressure is 0.5MPa, the dust content of the low-pressure start gas water is 180mg/L, the temperature is 65 ℃, and the pressure is 0.65 MPa.
Wherein, the main pollutant characteristic data of the high-temperature gas water and the low-temperature gas water are respectively shown in the table 1 and the table 2.
TABLE 1
| Item | Unit of | Gasified dust-containing gasified water | Conversion of high temperature condensate |
| Dust content | mg/L | ＜3000 | ＜2000 |
| Oil content | mg/L | ＜5 | ＜0.06 |
| COD | mg/L | ＜800 | ＜2500 |
| Total salt | mg/L | ＜2000 | ＜300 |
TABLE 2
| Item | Unit of | Shift low temperature condensate | Low-pressure gasified gas water | Low pressure gas water for starting |
| Dust content | mg/L | ＜50 | ＜50 | ＜200 |
| Oil content | mg/L | ＜65 | ＜80 | ＜100 |
| COD | mg/L | ＜800 | ＜600 | ＜2500 |
| Total salt | mg/L | ＜10 | ＜500 | ＜700 |
The conversion high-temperature condensate and the gasified dust-containing gasified water are degassed by a medium-pressure flash evaporator 1, enter a first vacuum flash evaporator 2 together with gasified low-pressure coal gas water and gasified starting coal gas water to deeply remove dissolved gas, wherein the flash evaporation temperature of the medium-pressure flash evaporator 1 is 144 ℃, the pressure is 0.4MPa, the flash evaporation temperature of the first vacuum flash evaporator 2 is 84.8 ℃, and the vacuum degree is 50 kPa; adding 3g of flocculating agent into 1 ton of gas water after gas desolventizing, mixing the gas water with the flocculating agent, feeding the mixture into a settling tank 3, performing filter pressing and dehydration on solid materials settled at the bottom of the settling tank 3 by a filter press 12 to prepare mud cakes with the water content of 22%, feeding filtrate into a filtrate tank 13, returning the filtrate to the settling tank 3, feeding the gas water at the upper part of the settling tank 3 into a gas water tank 4 as washing water for gasifying low-pressure gas water, recycling the washing water for gas lock gas washing equipment and starting gas washing equipment, and using the remaining biochemical treatment equipment for removing the gas water. And (3) spraying the flash steam flashed by the medium-pressure flash evaporator 1 from the bottom of the deacidification tower 5 to be used as a heat source of the deacidification tower 5, and simultaneously removing the acid gas in the flash steam. The low-temperature converted condensate is firstly subjected to solution gas removal by the second vacuum flash evaporator 8, then is subjected to pressurization and heat exchange, and then is sent to a waste heat boiler to be used as make-up water, the condensate condensed by the first vacuum flash separator 6, the second vacuum flash separator 9 and the third vacuum flash separator 10 is sent to the deacidification tower 5 from the top of the deacidification tower 5 to be deacidified, the deacidified gas is subjected to desulfurization recovery equipment, the deacidified gas water enters the ammonia still 7 to be distilled into ammonia and then is used as washing water to be recycled as crude gas washing equipment, and the generated ammonia water/liquid ammonia is recycled.
The operating pressure of the whole gas-water separation and recycling process is micro-positive pressure operation larger than 0.2kPa, inert gas serving as protective gas is continuously introduced into the top of the settling tank 3 and the top of the gas water tank 4, the pressure of the system is ensured to be micro-positive pressure larger than 0.2kPa, and VOCs, odor and the like in the system can be intensively collected to burn or RTO byproduct steam. The effect of continuously introducing inert gas into the settling tank 3 and the gas water tank 4 to seal the tops of the settling tank 3 and the gas water tank 4 is mainly to prevent the settling tank 3 and the gas water tank 4 from generating negative pressure and sucking air from breathing valves of the settling tank 3 and the gas water tank 4 so as to keep micro-positive pressure in the tanks, the normal pressure set value of the sealing valve is preferably 0.2kPa, and the intersection with the set pressure of the breathing valve, a single-breathing valve or a control valve and the like is avoided so as to generate unnecessary inert gas circulation and have high operation cost.
The embodiment of the invention adopts the crushed anthracite coal for pressurized gasification, and utilizes the characteristics of low oil content, low COD content and low dust content in the coal gas water. In the embodiment, the anthracite is used for pressure gasification, and because the anthracite has low moisture content, the total moisture content is generally below 10%, the volatile matter is less than 10%, the carbon content is high, the melting point of the coal ash is high, and the ash content is high. The true density is generally 1.4-1.8g/cm3The mineral content in the anthracite is high, and the true density reaches 1.8-1.9g/cm3In addition, the anthracite has high thermal stability, is not easy to pulverize when entering the gasification furnace, has small coal dust amount brought out of the gasification furnace and large density difference between coal dust particles and coal gas water, so the coal dust is easier to separate, and the retention time of the dust-containing coal gas water separator can be shortened.
At present, the water quality requirements of biochemical treatment equipment are that COD is less than or equal to 3500mg/L, pH is between 8.0 and 9.0, oil content is less than or equal to 50mg/L, and BOD is not more than 1100 mg/L. The current effluent and reuse indexes of the gas water are shown in a table 3, the oil content of the gas water which is treated by biochemical treatment equipment is high, oxidation treatment is required before the gas water enters the biochemical treatment equipment, and the COD content is reduced.
TABLE 3
After the coal gas water treated by the method provided by the embodiment of the invention is sent to biochemical treatment equipment and reused by the coal gas water, the ammonia content, COD content and the like are far less than those of the coal gas water treated by the existing coal gas water separation and recovery system and method.
Example 2
The crushed coal in the embodiment is anthracite with 6% of water content, the coal sample is crushed and screened to obtain a coal sample with the particle size of 5-50mm, the coal sample is put into a crushed coal pressure gasification furnace to perform crushed coal pressure gasification, the gasification pressure is 5.0MPa, the gasification temperature is 1250 ℃, crude coal gas generated by gasification is divided into high-temperature coal gas water and low-temperature coal gas water according to the dust content, temperature and pressure in water during washing, the high-temperature coal gas water is divided into high-temperature condensate and gasified dust-containing gasified water according to the dust content, temperature and pressure, and the low-temperature coal gas water is divided into low-temperature condensate, low-pressure gasified coal gas water and low-pressure start coal gas water according to the dust content, temperature and pressure. The gas water of different classifications is separated respectively and is retrieved, and the pressure-fired operation that the separation retrieval and utilization process of whole gas water keeps being greater than 0.2kPa adopts inert gas protection, guarantees that VOCs and foul smell can centralized processing in the system.
The dust content of the transformed high-temperature condensate obtained by processing the coal sample through the gasification unit, the washing unit and the transformation unit is 1800mg/L, the temperature is 158 ℃ and the pressure is 5MPa, and the dust content of the gasified dust-containing gasified water is 1985mg/L, the temperature is 196 ℃ and the pressure is 5.0 MPa. The dust content of the conversion low-temperature condensate is 48mg/L, the temperature is 70.5 ℃, the pressure is 4.75MPa, the dust content of the low-pressure gasification gas water is 98mg/L, the temperature is 72 ℃, the pressure is 0.6MPa, the dust content of the low-pressure start gas water is 160mg/L, the temperature is 75 ℃, and the pressure is 0.55 MPa.
The conversion high-temperature condensate and the gasified dust-containing gasified water are degassed by a medium-pressure flash evaporator 1, and enter a first vacuum flash evaporator 2 together with gasified low-pressure coal gas water and gasified starting coal gas water to deeply remove dissolved gas, wherein the flash evaporation temperature of the medium-pressure flash evaporator 1 is 148 ℃, the pressure is 0.5MPa, the flash evaporation temperature of the first vacuum flash evaporator 2 is 86 ℃, and the vacuum degree is 60 kPa; adding a flocculating agent into the gas water after desolventizing according to the proportion of adding 4.5g of the flocculating agent into 1 ton of the gas water, mixing, then sending the mixture into a settling tank 3, carrying out filter pressing and dehydration on solid materials settled at the bottom of the settling tank 3 by a filter press 12 to prepare mud cakes with the water content of 28%, sending filtrate into a filtrate tank 13, then returning the filtrate into the settling tank 3, sending the gas water at the upper part of the settling tank 3 into a gas water tank 4 as washing water of gasified low-pressure gas water for recycling the gas lock gas washing equipment and the start gas washing equipment, and removing the remaining gas water for biochemical treatment equipment. And (3) spraying the flash steam flashed by the medium-pressure flash evaporator 1 from the bottom of the deacidification tower 5 to be used as a heat source of the deacidification tower 5, and simultaneously removing the acid gas in the flash steam. The low-temperature converted condensate is subjected to solution gas removal by the second vacuum flash evaporator 8, then is subjected to pressurization and heat exchange, and then is sent to a waste heat boiler to be used as make-up water, the condensate condensed by the first vacuum flash separator 6, the second vacuum flash separator 9 and the third vacuum flash separator 10 is sent to deacidification from the top of the deacidification tower 5, the deacidification gas is subjected to desulphurization recovery equipment, the deacidified gas water enters the ammonia still 7 to be used as washing water to be recycled as crude gas washing equipment after ammonia distillation, and the generated ammonia water/liquid ammonia is recycled.
The operating pressure of whole gas-water separation retrieval and utilization process is greater than the pressure-fired operation of 0.2kPa, and setting up inert gas as the protective gas is lastingly let in at settling tank 3 and 4 tops of gas water tank, guarantees that system's pressure is greater than the pressure-fired operation of 0.2kPa, and VOCs and foul smell etc. can concentrate in the system and collect and burn or RTO byproduct steam. The effect of continuously introducing inert gas into the settling tank 3 and the gas water tank 4 to seal the tops of the settling tank 3 and the gas water tank 4 is mainly to prevent the settling tank 3 and the gas water tank 4 from generating negative pressure and sucking air from breathing valves of the settling tank 3 and the gas water tank 4 so as to keep micro-positive pressure in the tanks, the normal pressure set value of the sealing valve is preferably 0.2kPa, and the unnecessary inert gas circulation and high operation cost are generated due to the fact that the normal pressure set value is intersected with the set pressure of the breathing valve, a single-breathing valve or a.
Example 3
The crushed coal in the embodiment is Yangquan anthracite with water content of 8%, the coal sample is crushed and screened to obtain a coal sample with particle size of 5-50mm, the coal sample is placed in a crushed coal pressure gasification furnace to be subjected to crushed coal pressure gasification, the gasification pressure is 7.0MPa, the gasification temperature is 1350 ℃, crude gas generated by gasification is divided into high-temperature gas water and low-temperature gas water according to the dust content, temperature and pressure in water during washing, the high-temperature gas water is divided into conversion high-temperature condensate and gasification dust-containing gasification water according to the dust content, temperature and pressure, and the low-temperature gas water is divided into conversion low-temperature condensate, low-pressure gasification gas water and low-pressure start gas water according to the dust content, temperature and pressure. The gas water of different classifications is separated respectively and is retrieved, and the pressure-fired operation that the separation retrieval and utilization process of whole gas water keeps being greater than 0.2kPa adopts inert gas protection, guarantees that VOCs and foul smell can centralized processing in the system.
The dust content of the converted high-temperature condensate obtained by processing the coal sample through the gasification unit, the washing unit and the conversion unit is 1785mg/L, the temperature is 170 ℃, the pressure is 7MPa, the dust content of the gasified dust-containing gasified water is 1650mg/L, the temperature is 197 ℃, and the pressure is 7.0 MPa. The dust content of the conversion low-temperature condensate is 35mg/L, the temperature is 67.5 ℃, the pressure is 3.75MP, the dust content of the low-pressure gasification gas water is 65mg/L, the temperature is 70 ℃, the pressure is 0.5MPa, the dust content of the low-pressure start gas water is 150mg/L, the temperature is 60 ℃, and the pressure is 0.5 MPa.
The conversion high-temperature condensate and the gasified dust-containing gasified water are degassed by a medium-pressure flash evaporator 1, and enter a first vacuum flash evaporator 2 together with gasified low-pressure coal gas water and gasified starting coal gas water to deeply remove dissolved gas, wherein the flash evaporation temperature of the medium-pressure flash evaporator 1 is 144 ℃, the pressure is 0.4MPa, the flash evaporation temperature of the first vacuum flash evaporator 2 is 84.8 ℃, and the vacuum degree is 50 kPa; adding a flocculating agent into the gas water after desolventizing according to the proportion of adding 4.8g of the flocculating agent into 1 ton of the gas water, mixing, then sending the mixture into a settling tank 3, carrying out filter pressing and dehydration on solid materials settled at the bottom of the settling tank 3 by a filter press 12 to prepare mud cakes with the water content of 28%, sending filtrate into a filtrate tank 13, then returning the filtrate into the settling tank 3, sending the gas water at the upper part of the settling tank 3 into a gas water tank 4 as washing water of gasified low-pressure gas water for recycling the gas lock gas washing equipment and the start gas washing equipment, and removing the remaining gas water for biochemical treatment equipment. And (3) spraying the flash steam flashed by the medium-pressure flash evaporator 1 from the bottom of the deacidification tower 5 to be used as a heat source of the deacidification tower 5, and simultaneously removing the acid gas in the flash steam. The low-temperature converted condensate is subjected to solution gas removal by the second vacuum flash evaporator 8, then is subjected to pressurization and heat exchange, and then is sent to a waste heat boiler to be used as make-up water, the condensate condensed by the first vacuum flash separator 6, the second vacuum flash separator 9 and the third vacuum flash separator 10 is sent to deacidification from the top of the deacidification tower 5, the deacidification gas is subjected to desulphurization recovery equipment, the deacidified gas water enters the ammonia still 7 to be used as washing water to be recycled as crude gas washing equipment after ammonia distillation, and the generated ammonia water/liquid ammonia is recycled.
The operating pressure of whole gas-water separation retrieval and utilization process is greater than the pressure-fired operation of 0.2kPa, and setting up inert gas as the protective gas is lastingly let in at settling tank 3 and 4 tops of gas water tank, guarantees that system's pressure is greater than the pressure-fired operation of 0.2kPa, and VOCs and foul smell etc. can concentrate in the system and collect and burn or RTO byproduct steam. The function of continuously introducing inert gas into the settling tank 3 and the gas water tank 4 to seal the tops of the settling tank 3 and the gas water tank 4 is to prevent the settling tank 3 and the gas water tank 4 from generating negative pressure and sucking air from breathing valves of the settling tank 3 and the gas water tank 4 so as to keep micro-positive pressure in the tanks, the normal pressure set value of the sealing valve is preferably 0.2kPa, and the intersection with the set pressure of the breathing valve, a single breathing valve or a control valve and the like is avoided, so that unnecessary inert gas circulation is generated, and the operation cost is.
Example 4
The crushed coal in the embodiment is semicoke containing 8% of water, the coal sample is crushed and screened to obtain a coal sample with the particle size of 5-50mm, the coal sample is put into a crushed coal pressure gasification furnace for crushed coal pressure gasification, the gasification pressure is 3MPa, the gasification temperature is 1250 ℃, crude gas generated by gasification is divided into high-temperature coal gas water and low-temperature coal gas water according to the dust content, temperature and pressure in water during washing, the high-temperature coal gas water is divided into conversion high-temperature condensate and gasification dust-containing gasification water according to the dust content, temperature and pressure, and the low-temperature coal gas water is divided into conversion low-temperature condensate, low-pressure gasification coal gas water and low-pressure start coal gas water according to the dust content, temperature and pressure. The gas water of different classifications is separated respectively and is retrieved, and the pressure-fired operation that the separation retrieval and utilization process of whole gas water keeps being greater than 0.2kPa adopts inert gas protection, guarantees that VOCs and foul smell can centralized processing in the system.
The dust content of the converted high-temperature condensate obtained by processing the coal sample through the gasification unit, the washing unit and the conversion unit is 980mg/L, the temperature is 155 ℃, the pressure is 3MPa, the dust content of the gasified dust-containing gasified water is 1250mg/L, the temperature is 185 ℃, and the pressure is 3.0 MPa. The dust content of the conversion low-temperature condensate is 30mg/L, the temperature is 66 ℃, the pressure is 3MPa, the dust content of the low-pressure gasification gas water is 65mg/L, the temperature is 75 ℃, the pressure is 0.5MPa, the dust content of the low-pressure start gas water is 120mg/L, the temperature is 60 ℃, and the pressure is 0.5 MPa.
The conversion high-temperature condensate and the gasified dust-containing gasified water are degassed by a medium-pressure flash evaporator 1, and enter a first vacuum flash evaporator 2 together with gasified low-pressure coal gas water and gasified starting coal gas water to deeply remove dissolved gas, wherein the flash evaporation temperature of the medium-pressure flash evaporator 1 is 142 ℃, the pressure is 0.4MPa, the flash evaporation temperature of the first vacuum flash evaporator 2 is 82 ℃, and the vacuum degree is 50 kPa; adding 3g of flocculating agent into 1 ton of gas water after gas desolventizing, mixing the gas water with the flocculating agent, feeding the mixture into a settling tank 3, performing filter pressing and dehydration on solid materials settled at the bottom of the settling tank 3 by a filter press 12 to prepare mud cakes with the water content of 23%, feeding filtrate into a filtrate tank 13, returning the filtrate to the settling tank 3, feeding the gas water at the upper part of the settling tank 3 into a gas water tank 4, and feeding the gas water serving as washing water of gasified low-pressure gas water into a gas lock gas washing device and a start gas washing device for recycling, and using the rest gas water to remove biochemical treatment equipment. And (3) spraying the flash steam flashed by the medium-pressure flash evaporator 1 from the bottom of the deacidification tower 5 to be used as a heat source of the deacidification tower 5, and simultaneously removing the acid gas in the flash steam. The low-temperature converted condensate is subjected to solution gas removal by the second vacuum flash evaporator 8, then is subjected to pressurization and heat exchange, and then is sent to a waste heat boiler to be used as make-up water, the condensate condensed by the first vacuum flash separator 6, the second vacuum flash separator 9 and the third vacuum flash separator 10 is sent to deacidification from the top of the deacidification tower 5, the deacidification gas is subjected to desulphurization recovery equipment, the deacidified gas water enters the ammonia still 7 to be used as washing water to be recycled as crude gas washing equipment after ammonia distillation, and the generated ammonia water/liquid ammonia is recycled.
The operating pressure of whole gas-water separation retrieval and utilization process is greater than the pressure-fired operation of 0.2kPa, and setting up inert gas as the protective gas is lastingly let in at settling tank 3 and 4 tops of gas water tank, guarantees that system's pressure is greater than the pressure-fired operation of 0.2kPa, and VOCs and foul smell etc. can concentrate in the system and collect and burn or RTO byproduct steam. The function of continuously introducing inert gas into the settling tank 3 and the gas water tank 4 to seal the tops of the settling tank 3 and the gas water tank 4 is to prevent the settling tank 3 and the gas water tank 4 from generating negative pressure and sucking air from breathing valves of the settling tank 3 and the gas water tank 4 so as to keep micro-positive pressure in the tanks, and the normal pressure of the sealing valve is set to be 0.4kPa, and the intersection with the set pressure of the breathing valve, a single-breathing valve or a control valve and the like is avoided, so that unnecessary inert gas circulation is generated, and.
Example 5
The crushed coal in the embodiment is coke with 5% of water content, the coal sample is crushed and screened to obtain a coal sample with the particle size of 5-50mm, the coal sample is put into a crushed coal pressure gasification furnace for crushed coal pressure gasification, the gasification pressure is 3MPa, the gasification temperature is 1250 ℃, crude gas generated by gasification is divided into high-temperature coal gas water and low-temperature coal gas water according to the dust content, temperature and pressure in water during washing, the high-temperature coal gas water is divided into conversion high-temperature condensate and gasification dust-containing gasification water according to the dust content, temperature and pressure, and the low-temperature coal gas water is divided into conversion low-temperature condensate, low-pressure gasification coal gas water and low-pressure start coal gas water according to the dust content, temperature and pressure. The gas water of different classifications is separated respectively and is retrieved, and the pressure-fired operation that the separation retrieval and utilization process of whole gas water keeps being greater than 0.2kPa adopts inert gas protection, guarantees that VOCs and foul smell can centralized processing in the system.
The dust content of the converted high-temperature condensate obtained by processing the coal sample through the gasification unit, the washing unit and the conversion unit is 1200mg/L, the temperature is 164 ℃, the pressure is 3MPa, the dust content of the gasified dust-containing gasified water is 1800mg/L, the temperature is 185 ℃, and the pressure is 3.0 MPa. The dust content of the conversion low-temperature condensate is 46mg/L, the temperature is 66 ℃, the pressure is 3.0MPa, the dust content of the low-pressure gasification gas water is 84mg/L, the temperature is 75 ℃, the pressure is 0.5MPa, the dust content of the low-pressure start gas water is 170mg/L, the temperature is 78 ℃, and the pressure is 0.7 MPa.
The conversion high-temperature condensate and the gasified dust-containing gasified water are degassed by a medium-pressure flash evaporator 1, and enter a first vacuum flash evaporator 2 together with gasified low-pressure coal gas water and gasified starting coal gas water to deeply remove dissolved gas, wherein the flash evaporation temperature of the medium-pressure flash evaporator 1 is 142 ℃, the pressure is 0.4MPa, the flash evaporation temperature of the first vacuum flash evaporator 2 is 82 ℃, and the vacuum degree is 50 kPa; adding 3g of flocculating agent into 1 ton of gas water after gas desolventizing, mixing the gas water with the flocculating agent, feeding the mixture into a settling tank 3, performing filter pressing and dehydration on solid materials settled at the bottom of the settling tank 3 by a filter press 12 to prepare mud cakes with the water content of 22%, feeding filtrate into a filtrate tank 13, returning the filtrate to the settling tank 3, feeding the gas water at the upper part of the settling tank 3 into a gas water tank 4, and feeding the gas water serving as washing water of gasified low-pressure gas water into a gas lock gas washing device and a start gas washing device for recycling, and using the rest gas water to remove biochemical treatment equipment. And (3) spraying the flash steam flashed by the medium-pressure flash evaporator 1 from the bottom of the deacidification tower 5 to be used as a heat source of the deacidification tower 5, and simultaneously removing the acid gas in the flash steam. The low-temperature converted condensate is subjected to solution gas removal by the second vacuum flash evaporator 8, then is subjected to pressurization and heat exchange, and then is sent to a waste heat boiler to be used as make-up water, the condensate condensed by the first vacuum flash separator 6, the second vacuum flash separator 9 and the third vacuum flash separator 10 is sent to deacidification from the top of the deacidification tower 5, the deacidification gas is subjected to desulphurization recovery equipment, the deacidified gas water enters the ammonia still 7 to be used as washing water to be recycled as crude gas washing equipment after ammonia distillation, and the generated ammonia water/liquid ammonia is recycled.
The operating pressure of whole gas-water separation retrieval and utilization process is greater than the pressure-fired operation of 0.2kPa, and setting up inert gas as the protective gas is lastingly let in at settling tank 3 and 4 tops of gas water tank, guarantees that system's pressure is greater than the pressure-fired operation of 0.2kPa, and VOCs and foul smell etc. can concentrate in the system and collect and burn or RTO byproduct steam. The function of continuously introducing inert gas into the settling tank 3 and the gas water tank 4 to seal the tops of the settling tank 3 and the gas water tank 4 is to prevent the settling tank 3 and the gas water tank 4 from generating negative pressure and sucking air from breathing valves of the settling tank 3 and the gas water tank 4 so as to keep micro-positive pressure in the tanks, the normal pressure of the sealing valve is set to be 0.5kPa, and the intersection with the set pressure of the breathing valve, a single breathing valve or a control valve and the like is avoided, so that unnecessary inert gas circulation is generated, and the
It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.
Claims (9)
1. The utility model provides a but separation of crushed coal pressurization gasification gas water and recycling system of sewage retrieval and utilization which characterized in that, including middling pressure flash vessel (1), first vacuum flash vessel (2), settling tank (3), gas water tank (4), deacidification tower (5), first vacuum flash vessel separator (6), ammonia still (7), second vacuum flash vessel separator (8), second vacuum flash vessel separator (9), third vacuum flash vessel separator (10), flocculating agent jar (11), pressure filter (12), filtrating jar (13), a plurality of water pumps and pipeline, wherein:
a first water inlet of the medium-pressure flash evaporator (1) is connected with a pipeline for transforming high-temperature condensate, a second water inlet of the medium-pressure flash evaporator (1) is connected with a pipeline for gasifying dust-containing gasified water, a water outlet of the medium-pressure flash evaporator (1) is connected with a first water inlet of the first vacuum flash evaporator (2) through a pipeline, a second water inlet of the first vacuum flash evaporator (2) is connected with a pipeline for low-pressure gasified gas water, a third water inlet of the first vacuum flash evaporator (2) is connected with a pipeline for low-pressure started gas water, a water outlet of the first vacuum flash evaporator (2) is connected with a water inlet of the settling tank (3) through a pipeline and a water pump, a water outlet of the settling tank (3) is connected with a water inlet of a filter press (12) through a pipeline and a water pump, a water outlet of the filter press (12) is connected with a water inlet of the filtrate tank (13) through a pipeline, a water outlet of the filtrate tank (13) is, the water inlet of the settling tank (3) is also connected with the discharge hole of the flocculating agent tank (11) through a pipeline, the gas water outlet of the settling tank (3) is connected with the gas water inlet of the gas water tank (4) through a pipeline, the gas water outlet of the gas water tank (4) is connected with gas water biochemical treatment equipment and gas water recycling equipment through a pipeline and a water pump, and the tops of the settling tank (3) and the gas water tank (4) are hermetically connected with an inert gas pipeline; the gas outlet of the medium-pressure flash evaporator (1) is connected with the gas inlet of the deacidification tower (5) through a pipeline, the water inlet of the second vacuum flash evaporator (8) is connected with a transformation low-temperature condensate pipeline, the water outlet of the second vacuum flash evaporator (8) is connected with the water inlet of a heat exchanger connected with a waste heat boiler through a pipeline and a water pump, the water outlet of the deacidification tower (5) is connected with the water inlet of an ammonia still (7) through a pipeline and a water pump, and the water outlet of the ammonia still (7) is connected with a crude gas washing device; the gas outlet of the first vacuum flash evaporator (2) is connected with the gas inlet of the first vacuum flash separator (6) through a pipeline, the gas outlet of the first vacuum flash separator (6) is connected with the gas inlet of the third vacuum flash separator (10) through a pipeline, and the water outlet of the first vacuum flash separator (6) is connected with the water inlet of the deacidification tower (5) through a pipeline and a water pump; the gas outlet of the second vacuum flash evaporator (8) is connected with the gas inlet of the second vacuum flash evaporator separator (9) through a pipeline, the gas outlet of the second vacuum flash evaporator separator (9) is connected with the gas inlet of the third vacuum flash evaporator separator (10) through a pipeline, the water outlet of the second vacuum flash evaporator separator (9) is connected with the water inlet of the deacidification tower (5) through a pipeline, and the water outlet of the third vacuum flash evaporator separator (10) is connected with the water inlet of the deacidification tower (5) through a pipeline.
2. The system for separating and recycling crushed coal pressure gasification gas and water capable of recycling sewage according to claim 1, further comprising an oil collecting float (14) and an oil tank (15), wherein the oil collecting float (14) is arranged inside the gas water tank (4), and the bottom of the oil collecting float (14) is connected with the oil tank (15) through a hose.
3. The system for separating and recycling crushed coal pressure gasification gas and water capable of recycling sewage according to claim 1 or 2, wherein a cooling water jacket (16) is arranged outside the breathing gas discharge pipelines at the top of the gas water tank (4) and the settling tank (3).
4. A method for separating and recycling crushed coal pressure gasification gas water capable of recycling sewage is characterized by comprising the following steps:
s1, after the high-temperature condensate and the gasified dust-containing gasified water are subjected to degassing by the medium-pressure flash evaporator (1), the high-temperature condensate and the gasified dust-containing gasified water enter the first vacuum flash evaporator (2) together with the gasified low-pressure coal gas water and the gasified starting coal gas water, and the dissolved gas is deeply removed from the first vacuum flash evaporator (2);
s2, mixing the gas water after gas stripping with a flocculating agent from a flocculating agent tank (11) and then sending the mixture into a settling tank (3);
s3, performing filter pressing and dehydration on the solid material settled at the bottom of the settling tank (3) through a filter press (12) to prepare mud cakes, feeding the filtrate generated by filter pressing and dehydration into a filtrate tank (13) and returning the filtrate to the settling tank (3), feeding the gas water at the upper part of the settling tank (3) into a gas water tank (4), reusing a part of the gas water in the gas water tank (4) as washing water for gasifying low-pressure gas water as gas water reuse equipment, and removing the rest of the gas water to gas water biochemical treatment equipment;
s4, spraying the flash steam flashed by the medium-pressure flash evaporator (1) into the deacidification tower (5) from the bottom of the deacidification tower (5) to be used as a heat source of the deacidification tower (5), and simultaneously removing acid gas in the flash steam by the deacidification tower (5);
s5, transforming the low-temperature condensate to remove dissolved gas in a second vacuum flash evaporator (8), pressurizing and exchanging heat after removing the dissolved gas, and sending the solution into a waste heat boiler to be used as make-up water so as to reduce the water amount of the biochemical treatment equipment for removing gas water;
s6, feeding condensate which is formed by flash evaporation of the first vacuum flash evaporator (2) and the second vacuum flash evaporator (8) into the first vacuum flash evaporation separator (6), the second vacuum flash evaporation separator (9) and the third vacuum flash evaporation separator (10) respectively for vacuum flash evaporation separation, and feeding the condensate which is condensed by the first vacuum flash evaporation separator (6), the second vacuum flash evaporation separator (9) and the third vacuum flash evaporation separator (10) into the deacidification tower (5) from the top of the deacidification tower (5) for deacidification;
s7, desulfurizing and recovering the deacidified gas obtained by deacidification in the deacidification tower (5), feeding the deacidified gas water into an ammonia still (7), recycling the gas water obtained after ammonia distillation in the ammonia still (7) as washing water for a crude gas washing device, and recycling the ammonia water/liquid ammonia generated in the ammonia still (7).
5. The method for separating and recycling crushed coal pressure gasification gas water capable of recycling sewage as claimed in claim 4, wherein the shift high temperature condensate is gas water with dust content not greater than 2000mg/L, temperature of 150-; the gasified dust-containing gasified water is coal gas water with dust content not more than 3000mg/L, temperature of 180-200 ℃ and pressure of 3.0-7.0 MPa; the conversion low-temperature condensate is gas water with dust content less than 50mg/L, temperature of 40-80 ℃ and pressure of 3.0-5.0 MPa; the low-pressure gasified gas water is gas water with the dust content of less than 100mg/L, the temperature of 60-80 ℃ and the pressure of 0.5-0.7 MPa; the low-pressure starting gas water is gas water with the dust content of less than 200mg/L, the temperature of 60-80 ℃ and the pressure of 0.5-0.7 MPa.
6. The method for separating and recycling crushed coal pressurized gasification gas water capable of recycling sewage as claimed in claim 4, wherein the flash evaporation temperature of the medium pressure flash evaporator (1) is 140 ℃ and 160 ℃, and the pressure is 0.4-0.5 MPa.
7. The method for separating and recycling crushed coal pressure gasification gas water capable of recycling sewage according to claim 4, wherein the flash evaporation temperature of the first vacuum flash evaporator (2) is 80-86 ℃ and the vacuum degree is 50-60 kPa.
8. The method for separating and recycling crushed coal pressure gasification gas-water capable of recycling sewage according to claim 4, wherein the addition amount of the flocculant is 3-5g of flocculant added into 1 ton of gas-water.
9. The method for separating and recycling crushed coal pressure gasification gas water capable of recycling sewage according to claim 4, wherein inert gas is continuously introduced into the top of the settling tank (3) and the top of the gas water tank (4).
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011302307.9A CN112408709A (en) | 2020-11-19 | 2020-11-19 | Crushed coal pressurized gasification gas water separation and recycling system and method capable of recycling sewage |
| PCT/CN2021/113369 WO2022105330A1 (en) | 2020-11-19 | 2021-08-18 | Crushed coal pressurized gasification coal gas-water separation and recycling system and method capable of recycling sewage |
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| CN202011302307.9A CN112408709A (en) | 2020-11-19 | 2020-11-19 | Crushed coal pressurized gasification gas water separation and recycling system and method capable of recycling sewage |
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| CN112408709A true CN112408709A (en) | 2021-02-26 |
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| WO (1) | WO2022105330A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113060785A (en) * | 2021-03-17 | 2021-07-02 | 宁夏神耀科技有限责任公司 | Coal gasification flash distillation device and coal gasification flash distillation process |
| WO2022105330A1 (en) * | 2020-11-19 | 2022-05-27 | 赛鼎工程有限公司 | Crushed coal pressurized gasification coal gas-water separation and recycling system and method capable of recycling sewage |
| WO2022105328A1 (en) * | 2020-11-19 | 2022-05-27 | 赛鼎工程有限公司 | Crushed coal pressurized gasification coal gas water separation and recovery system, and method |
| WO2022105329A1 (en) * | 2020-11-19 | 2022-05-27 | 赛鼎工程有限公司 | Simple pulverized coal pressurized gasification coal gas water separation and reuse system and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116969638A (en) * | 2023-08-30 | 2023-10-31 | 江苏沃德凯环保科技有限公司 | Deamination treatment method of semi-coke wastewater |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0967584A (en) * | 1995-09-05 | 1997-03-11 | Nkk Corp | Lng vaporization apparatus |
| CN105293804A (en) * | 2015-11-01 | 2016-02-03 | 张晓峰 | Coal gasification ash water treatment method |
| CN105967425A (en) * | 2016-07-04 | 2016-09-28 | 天津晟远环境有限公司 | Coal chemical industry grey water flashing treatment system capable of reducing ammonia accumulation and coal chemical industry grey water flashing treatment process capable of reducing ammonia accumulation |
| CN108128965A (en) * | 2016-11-30 | 2018-06-08 | 内蒙古大唐国际克什克腾煤制天然气有限责任公司 | A kind of coal chemical industry wastewater zero emission treatment method |
| CN109574323A (en) * | 2019-01-22 | 2019-04-05 | 苏州永峰联环保科技有限公司 | A kind of the coal gas water treatment technology and its processing unit of phenol ammonia recovery system |
| CN112299666A (en) * | 2020-11-19 | 2021-02-02 | 赛鼎工程有限公司 | Simple crushed coal pressurized gasification gas water separation and recycling system and method |
| CN112299665B (en) * | 2020-11-19 | 2024-03-26 | 赛鼎工程有限公司 | System and method for separating and recycling crushed coal pressurized gasification gas water |
| CN112299664B (en) * | 2020-11-19 | 2024-04-05 | 赛鼎工程有限公司 | System and method for separating and recycling crushed coal pressurized gasification gas water |
| CN112408709A (en) * | 2020-11-19 | 2021-02-26 | 赛鼎工程有限公司 | Crushed coal pressurized gasification gas water separation and recycling system and method capable of recycling sewage |
| CN112299667A (en) * | 2020-11-19 | 2021-02-02 | 赛鼎工程有限公司 | System and method for separating and recycling crushed coal pressure gasification gas water |
-
2020
- 2020-11-19 CN CN202011302307.9A patent/CN112408709A/en not_active Withdrawn
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2021
- 2021-08-18 WO PCT/CN2021/113369 patent/WO2022105330A1/en active Application Filing
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022105330A1 (en) * | 2020-11-19 | 2022-05-27 | 赛鼎工程有限公司 | Crushed coal pressurized gasification coal gas-water separation and recycling system and method capable of recycling sewage |
| WO2022105328A1 (en) * | 2020-11-19 | 2022-05-27 | 赛鼎工程有限公司 | Crushed coal pressurized gasification coal gas water separation and recovery system, and method |
| WO2022105329A1 (en) * | 2020-11-19 | 2022-05-27 | 赛鼎工程有限公司 | Simple pulverized coal pressurized gasification coal gas water separation and reuse system and method |
| CN113060785A (en) * | 2021-03-17 | 2021-07-02 | 宁夏神耀科技有限责任公司 | Coal gasification flash distillation device and coal gasification flash distillation process |
| CN113060785B (en) * | 2021-03-17 | 2022-11-15 | 宁夏神耀科技有限责任公司 | Coal gasification flash distillation device and coal gasification flash distillation process |
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| WO2022105330A1 (en) | 2022-05-27 |
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