CN111019714A - Process method for carrying out resource utilization and disposal on byproduct tar in gas station - Google Patents

Abstract

The invention relates to the field of waste disposal of gas furnaces, in particular to a process method for carrying out resource utilization disposal on byproduct tar in a gas station, 1) tar separation; 2) heavy tar conversion and coking disposal; 3) recovering the sensible heat of the coal gas; 4) gasifying and utilizing light oil; 5) reconverting light oil residual liquid; the process can effectively avoid the problem of spray system blockage caused by single tar conveying, and can also improve equivalent calorific value of coal gas, so that the resource treatment of tar is more thorough.

Description

Process method for carrying out resource utilization and disposal on byproduct tar in gas station

Technical Field

The invention relates to the field of waste disposal of gas furnaces, in particular to a process method for carrying out resource utilization disposal on tar byproduct in a gas station.

Background

The byproduct tar of the gas producer belongs to low-temperature pyrolysis tar, and generally, 40-70 kg of tar is generated from coal every 1000kg of gasification, and the tar contains about 20% of light tar. Coal tar has been used as fuel for melting glass in domestic glass melting furnaces, but because coal tar atomization difficulty is high, incomplete atomization can cause increase of smoke exhaust particles of the furnaces, blackness is high, and environmental pollution is high, so that the application of the coal tar as the fuel is greatly limited. At present, the separated and dehydrated tar is generally sold by domestic producer gas stations and entrusted to downstream tar deep processing enterprises for disposal. The low-temperature coal tar contains various organic components, can extract phenols, alkanes, aromatic hydrocarbons and the like, can be used for preparing engine fuel oil such as gasoline, diesel oil and the like which meet the specification of petroleum products by appropriate deep processing means such as catalytic hydrogenation, can also be used for preparing paraffin, lubricating oil, pyridyl, fatty amine and the like, and can be used for preparing light diesel oil and electrode coke by coking the contained asphalt.

At present, the national environmental protection-based control on coal tar byproduct of a gas station is becoming strict. In the national hazardous waste record carried out in 2016, 8, 1, the byproduct tar of the gas producer is listed as hazardous waste, wherein the list number of the tar is HW11, and the code number is 450-003-11. The gas station of the producer must carry out the normative management of collection, storage, transportation and transfer of the byproduct tar and the tar residues strictly according to the regulations of the pollution control Standard for Rich and No. storage (GB 18597-2001) and the management method of the Joint Listing of hazardous waste transfer (No. 5 of the State environmental protection agency) issued in 1999.

In view of the above, most enterprises desire that the tar byproduct of the gas station can be recycled and disposed in the gas station in a harmless and on-site manner, and the tar is not transported or transferred. In addition, for countries such as India, Africa and southeast Asia, the downstream tar deep processing industry is lacked, the byproduct tar of the gas station cannot be entrusted to be disposed, and only can be transported out and buried, the tar pollution problem is prominent, and the popularization and the application of the gas producer are severely restricted.

Disclosure of Invention

In order to solve the technical problems, the invention provides a process method for carrying out resource utilization and treatment on the byproduct tar in a gas station, which can realize in-situ, resource and harmless treatment of the byproduct tar of the gas producer.

The invention adopts the following technical scheme:

a process method for carrying out resource utilization and disposal on byproduct tar in a gas station comprises the following steps:

1) tar separation: condensing the coal gas generated by the coal gas producer in a coal gas cooling and purifying system to separate out crude tar, and collecting the crude tar into an oil-water circulating pool for storage;

pumping the oil-water mixture from the oil-water circulation pool to an oil-water separation system through a tar pump I, discharging heavy tar and phenolic water separated from the oil-water separation system from an oil-water drain valve and collecting the heavy tar and the phenolic water into a tar emulsification tank, adding an emulsifier into the tar emulsification tank, stirring and emulsifying the heavy tar, the phenolic water and the emulsifier in the emulsification tank to prepare tar emulsion, and discharging light oil separated from the oil-water separation system from a light oil drain valve and collecting the light oil into a light oil storage tank;

2) heavy tar conversion and coking disposal: pumping the tar emulsion to the top of the gas producer through a tar pump II, spraying the tar emulsion onto the coal material in the gas producer through a furnace top spraying system arranged on the top of the gas producer, vaporizing phenol water in the tar emulsion attached to the coal material into water vapor in a dry distillation section of the gas producer, mixing the water vapor into the gas, re-condensing the phenol water into liquid phenol water in the gas cooling and purifying process, returning the liquid phenol water to an oil-water circulation tank, and moving heavy tar attached to the coal material downwards along with the coal material in the dry distillation section of the gas producer;

the tar is heated and distilled by upstream gas in a counter-current manner when moving downwards to generate light fraction and solid residue, the light fraction is led out of the gas generator along with the gas in a gaseous form, the light fraction is cooled into liquid light oil in the gas cooling and purifying process and is led into an oil-water circulation pool, and the solid residue moves downwards along with the coal material and enters a gasification reaction section of the gas generator to participate in a gas making reaction together with the coal material to generate the gas;

3) recovering sensible heat of the coal gas: the dry distillation section of the gas producer is provided with a water cooling jacket, circulating water in a circulating water tank is pumped into the water cooling jacket by using a water pump I, and the circulating water in the water cooling jacket is indirectly heated by using the sensible heat of gas at the dry distillation section, so that the cold circulating water becomes hot circulating water and flows back to the circulating water tank;

4) and (3) gasification and utilization of light oil: the method comprises the following steps that (1) saturated cold coal gas after desulfurization enters from the bottom of an indirect heat exchanger arranged behind a coal gas desulfurization system, light oil is pumped into the indirect heat exchanger from a light oil storage tank through a light oil pump, is sprayed into the indirect heat exchanger through an atomizing nozzle at the top of the indirect heat exchanger, hot circulating water is pumped into an indirect heat exchange unit of the indirect heat exchanger from a circulating water tank, the hot circulating water carries out indirect heat exchange with the coal gas and the light oil, the coal gas is separated from a saturated state after being heated, the light oil is gasified into gaseous light oil, the gaseous light oil is mixed into the;

5) and (3) reconversion of light oil residual liquid: substances which cannot be gasified in the indirect heat exchanger are enriched into light oil residual liquid in a light oil storage tank, the light oil residual liquid is pumped into a tar emulsifying tank at regular intervals, and the light oil residual liquid and the tar emulsifying liquid are sprayed into the surface of furnace burden of the gas producer through a furnace top spraying system together for reinjection coking treatment.

Compared with the prior art, the invention has the beneficial effects that:

the invention can lead the byproduct tar of the gas producer to be treated in situ, resource and harmless in the gas station without transporting and transferring the byproduct, thereby reducing the risk of pollution transfer caused by the outward transportation of the tar; the tar and the phenol water in the oil-water separation system are prepared into tar emulsion and then are sprayed into the coal gas generating furnace, so that the problem of blockage of a spraying system caused by independently spraying the tar is effectively avoided, and the tar is effectively utilized in the disposal process; after the tar is reinjected into the coking distillation treatment of the gas producer, the asphalt substances in the distillation product are converted in the furnace to generate gas, light oil in the distillation product is mixed into an oil-water circulation system, and the gas is heated and gasified in an indirect heat exchanger after oil-water separation and is mixed into the gas which is heated at the same time, so that the equivalent heat value of the gas discharged from the station is improved; the part of the light oil residual liquid which is not gasified and the tar emulsion are reinjected together for secondary coking treatment, so that the resource treatment of the byproduct tar is more thorough; the waste heat of the coal gas is used for indirectly heating the hot water, and then the hot water is used for indirectly heating the coal gas and heating the light oil to gasify the coal gas, so that the waste heat of the coal gas is effectively utilized, the energy utilization efficiency of a gas station system is improved, and the effect of saving coal resources is achieved.

Drawings

FIG. 1 is a schematic structural view of the present invention;

in the figure: a gas producer 1; a coal gas cooling and purifying system 2; an oil-water circulation tank 3; a gas desulfurization system 4; an indirect heat exchanger 5; a tar pump I6; a second water pump 7; a first water pump 8; a circulating water tank 9; a water cooling jacket 10; a second tar pump 11; a tar emulsification tank 12; a light oil pump 13; a light oil storage tank 14; a light oil drain valve 15; an oil-water drain valve 16; and an oil-water separation system 17.

Detailed Description

The invention is further described below with reference to the accompanying drawings and specific embodiments.

A process method for carrying out resource utilization and disposal on byproduct tar in a gas station comprises the following steps:

1) tar separation: the gas generated by the gas producer 1 is condensed in the gas cooling and purifying system 2 to separate out crude tar (the crude tar is a mixed solution of heavy tar, phenol water and light oil), and the crude tar is collected in the oil-water circulation pool 3 for storage.

The oil-water mixture is pumped from the oil-water circulation pool 3 to the oil-water separation system 17 through the tar pump I6, the heavy tar and the phenol water separated from the oil-water separation system 17 are discharged from an oil-water discharge valve (Q941F-16P) 16 and collected into the tar emulsification tank 12, the emulsifier is added into the tar emulsification tank 12, the heavy tar, the phenol water and the emulsifier in the tar emulsification tank 12 are stirred and emulsified to prepare tar emulsion, and the light oil separated from the oil-water separation system 17 is discharged from a light oil discharge valve (Q941F-16P) 15 and collected into the light oil storage tank 14.

2) Heavy tar conversion and coking disposal: the tar emulsion is pumped to the top of the coal gas producer 1 through a tar pump II 11, the tar emulsion is sprayed into the coal material in the coal gas producer 1 in a timing and quantitative mode through a furnace top spraying system arranged on the top of the coal gas producer 1, wherein the spraying frequency is consistent with the coal adding frequency of the coal gas producer 1, the tar emulsion is sprayed once every time the coal is added by the coal feeder of the coal gas producer 1, the spraying amount of each time is related to the coal adding amount of each time of the coal feeder, and the spraying amount of each time is generally 8-10% of the coal adding amount of each time of the coal feeder.

The phenol water in the tar emulsion attached to the coal material is gasified into water vapor in the dry distillation section of the coal gas producer 1 and mixed into the coal gas, the water vapor is condensed into liquid phenol water again in the coal gas cooling and purifying system 2 and returned to the oil-water circulation tank 3, and the heavy tar attached to the coal material moves downwards along with the coal material at the dry distillation section of the coal gas producer 1 at the speed of about 0.01 m/min.

High-temperature coal moving upward when heavy tar moves downwardThe gas (the gas temperature is 500-600 ℃) is heated and distilled in a counter-current way, light fractions such as light tar and solid residue asphalt are generated in the heavy tar distillation process, wherein the light fractions such as the light tar are led out of the gas producer 1 along with the gas in a gaseous form, are cooled to be liquid light oil in a gas cooling and purifying system 2 and are led into an oil-water circulation pool 3, the solid residue asphalt continuously moves downwards along with the coal material, and the liquid light oil and the solid residue asphalt enter into a gas making reaction with the coal material together at a gasification reaction section of the gas producer 1 to generate CO and H₂Coal gas which is the main combustible component.

3) Recovering sensible heat of the coal gas: the dry distillation section of the gas producer 1 is provided with a water cooling jacket 10, circulating water in a circulating water tank 9 is pumped into the water cooling jacket 10 by a water pump I8, and the circulating water in the water cooling jacket 10 is indirectly heated by sensible heat of gas at the dry distillation section, so that cold circulating water becomes hot circulating water and flows back to the circulating water tank 9, wherein the temperature of the hot circulating water is about 80 ℃.

4) And (3) gasification and utilization of light oil: the desulfurized saturated cold coal gas (the temperature of the saturated cold coal gas is 35-45 ℃) enters from the bottom of an indirect heat exchanger 5 arranged behind a coal gas desulfurization system 4, light oil is pumped into the indirect heat exchanger 5 from a light oil storage tank 14 through a light oil pump 13 and is sprayed into the indirect heat exchanger 5 through an atomizing nozzle at the top of the indirect heat exchanger 5, hot circulating water is pumped into an indirect heat exchange unit of the indirect heat exchanger 5 from a circulating water tank 9, the hot circulating water performs indirect heat exchange with the coal gas and the light oil, the coal gas is heated and then is separated from a saturated state, most of the light oil is gasified into gaseous light oil, the gaseous light oil is mixed into the heated coal gas, and; the hot circulating water after heat exchange returns to the circulating water pool 9 from the indirect heat exchange unit of the indirect heat exchanger 5.

5) And (3) reconversion of light oil residual liquid: the light oil contains partial substances with relatively high boiling points, which can not be gasified in the indirect heat exchanger 5, the partial substances can be enriched into light oil residual liquid in the light oil storage tank 14, the light oil residual liquid is periodically pumped into the tar emulsifying tank 12, the light oil residual liquid and the tar emulsifying liquid are sprayed into the charging surface of the gas producer 1 through the top spraying system together for reinjection coking treatment, in the secondary coking treatment process of the reinjection gas producer 1, the substances with relatively high boiling points in the light oil residual liquid are converted into light oil with lower boiling points, and the light oil with lower boiling points is gasified in the indirect heat exchanger 5 to become gaseous light oil which is mixed into the heated gas for utilization.

The invention carries out on-site disposal on the byproduct tar in the gas producer 1 in the gas station without transporting and transferring the byproduct tar; the tar and the phenol water separated by the oil-water separation system 17 are made into a tar emulsifying agent and are conveyed to the gas producer 1, so that the problem of blockage of a spraying system when the tar is conveyed and sprayed independently can be effectively solved; after the tar is reinjected into the coal gas producer 1 for coking treatment, the distillation product asphalt is gasified in the furnace to generate coal gas, the distillation product light oil is mixed into the oil-water circulation tank 3, the light oil is subjected to oil-water separation, is heated and gasified in the indirect heat exchanger 5 and is mixed into the coal gas which is simultaneously heated, the equivalent heat value of the coal gas is improved, and the byproduct tar of a coal gas station is effectively subjected to harmless treatment and resource utilization; the heat required by heating and gasifying the light oil and heating the coal gas comes from the sensible heat of the coal gas at the dry distillation section of the coal gas producer 1, belongs to the utilization of the waste heat of the coal gas, and improves the energy utilization rate of a coal gas station system to a limited extent; the light oil residual liquid and the tar emulsion which are not gasified are returned to the gas producer 1 for secondary coking treatment, the light oil residual liquid is converted into light oil with lower boiling point, and the light oil is gasified into gaseous light oil in the indirect heat exchanger 5 and is mixed into heated gas for utilization, which is more thorough resource treatment of byproduct tar.

The above description is only for the specific embodiment of the present invention, but the protection of the present invention is not limited thereto, and all equivalent changes or substitutions proposed by the technical features of the present invention which can be conceived by those skilled in the art are included in the protection scope of the present invention.

Claims (1)

1. A process method for carrying out resource utilization and disposal on byproduct tar in a gas station is characterized by comprising the following steps:

1) tar separation: condensing the coal gas generated by the coal gas producer in a coal gas cooling and purifying system to separate out crude tar, and collecting the crude tar into an oil-water circulating pool for storage;

pumping the oil-water mixture from the oil-water circulation pool to an oil-water separation system through a tar pump I, discharging heavy tar and phenolic water separated from the oil-water separation system from an oil-water drain valve and collecting the heavy tar and the phenolic water into a tar emulsification tank, adding an emulsifier into the tar emulsification tank, stirring and emulsifying the heavy tar, the phenolic water and the emulsifier in the emulsification tank to prepare tar emulsion, and discharging light oil separated from the oil-water separation system from a light oil drain valve and collecting the light oil into a light oil storage tank;

2) heavy tar conversion and coking disposal: pumping the tar emulsion to the top of the gas producer through a tar pump II, spraying the tar emulsion onto the coal material in the gas producer through a furnace top spraying system arranged on the top of the gas producer, vaporizing phenol water in the tar emulsion attached to the coal material into water vapor in a dry distillation section of the gas producer, mixing the water vapor into the gas, re-condensing the phenol water into liquid phenol water in the gas cooling and purifying process, returning the liquid phenol water to an oil-water circulation tank, and moving heavy tar attached to the coal material downwards along with the coal material in the dry distillation section of the gas producer;

the tar is heated and distilled by upstream gas in a counter-current manner when moving downwards to generate light fraction and solid residue, the light fraction is led out of the gas generator along with the gas in a gaseous form, the light fraction is cooled into liquid light oil in the gas cooling and purifying process and is led into an oil-water circulation pool, and the solid residue moves downwards along with the coal material and enters a gasification reaction section of the gas generator to participate in a gas making reaction together with the coal material to generate the gas;

3) recovering sensible heat of the coal gas: the dry distillation section of the gas producer is provided with a water cooling jacket, circulating water in a circulating water tank is pumped into the water cooling jacket by using a water pump I, and the circulating water in the water cooling jacket is indirectly heated by using the sensible heat of gas at the dry distillation section, so that the cold circulating water becomes hot circulating water and flows back to the circulating water tank;

4) and (3) gasification and utilization of light oil: the method comprises the following steps that (1) saturated cold coal gas after desulfurization enters from the bottom of an indirect heat exchanger arranged behind a coal gas desulfurization system, light oil is pumped into the indirect heat exchanger from a light oil storage tank through a light oil pump, is sprayed into the indirect heat exchanger through an atomizing nozzle at the top of the indirect heat exchanger, hot circulating water is pumped into an indirect heat exchange unit of the indirect heat exchanger from a circulating water tank, the hot circulating water carries out indirect heat exchange with the coal gas and the light oil, the coal gas is separated from a saturated state after being heated, the light oil is gasified into gaseous light oil, the gaseous light oil is mixed into the;

5) and (3) reconversion of light oil residual liquid: substances which cannot be gasified in the indirect heat exchanger are enriched into light oil residual liquid in a light oil storage tank, the light oil residual liquid is pumped into a tar emulsifying tank at regular intervals, and the light oil residual liquid and the tar emulsifying liquid are sprayed into the surface of furnace burden of the gas producer through a furnace top spraying system together for reinjection coking treatment.

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