阅读说明：本技术 一种轻烃回收技术改进工艺 (Improved process of light hydrocarbon recovery technology ) 是由 陶春风 滕明才 于 2019-08-14 设计创作，主要内容包括：本发明涉及一种轻烃回收技术改进工艺,包括裂解工段加工工艺、急冷工段加工工艺、压缩碱洗工段加工工艺、气分工段加工工艺、碳四加氢加工工艺,该工艺的轻烃回收效率高,操作方便,实现了资源的有效回收利用。(The invention relates to an improved process for a light hydrocarbon recovery technology, which comprises a cracking section processing process, a quenching section processing process, a compressed alkali washing section processing process, a gas separation section processing process and a carbon four-hydrogenation processing process.)

1. An improved process for light hydrocarbon recovery technology comprises a cracking section processing process, a quenching section processing process, a compressed alkali washing section processing process, a gas separation section processing process and a carbon four-hydrogenation processing process, and is characterized in that the cracking section processing process comprises the following steps: the light hydrocarbon raw material enters a raw material vaporizer for vaporization, the light hydrocarbon raw material enters a cracking furnace and is preheated at an upper raw material preheating section of a convection section of the cracking furnace at first to 130 ℃, the preheated raw material enters a lower raw material preheating I section and a lower raw material preheating II section, is preheated to 318 ℃, is mixed with dilution steam, has the temperature of 304 ℃ after being mixed, enters a lower mixing superheating section for heating to 642 ℃, a hydrocarbon/steam mixture discharged from the convection section enters a U-shaped radiation furnace tube of the radiation section after being distributed by a Venturi tube distributor, the hydrocarbon/steam mixture carries out thermal cracking reaction in the U-shaped radiation furnace tube, the outlet temperature of the cracking furnace is 870 ℃, the generated high-temperature pyrolysis gas enters a quenching heat exchanger for quenching, the pyrolysis gas of each hearth is converged at the outlet of the quenching heat exchanger and then enters a pyrolysis gas header pipe of the hearth, the ethane raw material enters a raw material heater, then the raw material is preheated in a preheating section similar to the light hydrocarbon raw material, mixed with the dilution steam, heated to the temperature of 650 ℃ across, enters a radiation furnace tube of the cracking furnace, the temperature of an outlet of the cracking furnace is 880 ℃, the generated high-temperature pyrolysis gas enters a quenching heat exchanger, and finally the pyrolysis gas is combined and enters a quenching section.

2. An improved process for light hydrocarbon recovery technology as claimed in claim 1, wherein said quench section process comprises the steps of: the temperature of pyrolysis gas from a quenching heat exchanger is higher, about 345 ℃, in order to rapidly reduce the temperature of the pyrolysis gas, the pyrolysis gas and circulating quenching oil in a quenching oil tower kettle are directly quenched for cooling, the temperature of the pyrolysis gas and the circulating quenching oil is rapidly reduced to about 210 ℃ after heat exchange in a quenching device, then the pyrolysis gas and the circulating quenching oil enter the quenching oil tower kettle, heavy components are condensed and converged in the quenching oil tower kettle, the pyrolysis gas continuously rises and exchanges heat with the quenching oil circulating to the lower end of the tower, the heavy components are washed away, the pyrolysis gas continuously rises and conducts mass transfer and heat transfer with the tray oil reflowing in the tower, and the pyrolysis gasoline coming out of the quenching water system at the top of the quenching oil tower is used as reflux;

circulating quenching oil at the bottom of a quenching oil tower is high in temperature, the quenching oil is used as a heat source for diluting steam, most of the circulating quenching oil is used as quenching oil to be continuously mixed with pyrolysis gas for cooling after the heat of the quenching oil is recovered, a small part of the circulating quenching oil is extracted, light components are extracted through medium-pressure steam at the bottom of a heavy oil stripping tower, heavy oil components are discharged to be used as products, pyrolysis fuel oil is extracted from the side line of the quenching oil tower, the pyrolysis fuel oil passes through a negative pressure tower, the light components are separated out, the pyrolysis fuel oil is extracted to be used as a byproduct, coil oil is extracted from the side line of the quenching oil, the coil oil after the heat is recovered by heating and diluting steam boiler, the coil oil enters the quenching oil tower and is further subjected to mass transfer with the pyrolysis gas, heavy components in the pyrolysis gas are condensed as much as possible, and;

pyrolysis gas from the top of a quenching oil tower enters a quenching water tower kettle, is in countercurrent contact with quenching oil from the upper part for heat exchange, is cooled to 40 ℃ and then enters a section of suction tank of a pyrolysis gas compressor, pyrolysis gasoline and dilution steam are condensed in a quenching water tower, the pyrolysis gasoline and water are subjected to sedimentation separation in the quenching water tower kettle, the quenching water tower kettle is divided into three chambers, the first chamber is an oil-water mixing zone and enters a second oil-water sedimentation separation chamber through a baffle with holes, an oil phase overflows through a second five-hole partition plate and enters a third oil chamber, most of the pyrolysis gasoline separated from the oil chamber enters the top of the quenching oil tower to be used as the reflux of the quenching oil tower, the small part of the pyrolysis gasoline enters a pyrolysis gasoline stripping tower for steam stripping, and the pyrolysis gasoline tower kettle collects a;

the temperature of the water extracted from the bottom of the second chamber is about 80 ℃, after the water is extracted, the water is respectively sent to a feed heater of a heating alkaline washing tower, a reboiler of a propylene tower kettle and a reboiler of a section, the water is cooled to 40 ℃ through water cooling, the water is respectively used as the top of a quenching water tower and the reflux of the section, a small part of the water is coalesced through a coalescer to remove medium and small oil drops in water, the water enters a water stripping tower for stripping, hydrocarbons in the water are removed, the water is stripped from a water stripping tower kettle, and the water is heated through coil oil and then enters a dilution steam generator to be.

3. The improved process for light hydrocarbon recovery technology of claim 2, wherein the process of the compressed caustic washing section comprises the following steps: the pyrolysis gas from the top of the quenching water tower enters a first-section suction tank of a pyrolysis gas compressor, water carried by the pyrolysis gas is separated, a liquid phase is sent to a quenching water tower by a condensate circulating pump, a gas phase enters a first-section compressor for compression, the compressed gas phase enters a second-section compressor suction tank after being cooled by a first-section compressor water cooler, partial water and heavy hydrocarbon are separated, the gas phase enters a second-section compressor for compression, the gas phase is cooled by a second-section water cooler and enters a third-section compressor suction tank, partial water and heavy hydrocarbon are separated, the gas phase is cooled by a third-section water cooler and enters a fourth-section compressor suction tank, partial water and heavy hydrocarbon are separated, the gas phase is cooled by a fourth-section cooler and enters a fourth-section compressor for compression, the gas phase is compressed to the pressure of 1.73MPa, the pyrolysis gas enters an outlet tank of the fourth-section compressor after being cooled by the fourth-section water, the rich solvent is removed from an analytical tower for analysis, the analytical gas is removed from an original sulfur device in a plant area, the poor solvent after poor solution analysis is continuously returned to an absorption tower after analysis, the absorbed cracked gas is heated to 50 ℃ through quenching water and then enters an alkaline tower, the poor solvent is respectively countercurrent to a weak alkali section and a strong alkali section of the alkaline tower, the residual acid gas is removed, the cracked gas is washed through the alkaline tower, the cracked gas enters a precooler for precooling and is cooled to 15 ℃, saturated water in the cracked gas is condensed as much as possible, the liquid after the precooler is condensed is subjected to oil-water separation, the oil phase is subjected to coalescer to remove water drops as much as possible and then enters an oil phase dryer, the water content in the oil phase is controlled to be less than 1ppm, and the water phase; and (3) the gas after the precooler enters a gas phase dryer, so that the moisture in the gas phase is less than 1ppm, the cracked gas and the condensed oil phase both enter corresponding feeding positions of a high-pressure depropanizing tower to carry out gas-component separation, and the gas phase at the top of the high-pressure depropanizing tower enters an inlet of a five-section compressor after heat exchange to carry out five-section compression to 3.88MPa, so as to provide pressure for subsequent separation.

4. An improved process for light hydrocarbon recovery technology as claimed in claim 3, wherein said gas separation section process comprises the steps of: the materials from the liquid phase dryer and the gas phase dryer enter a high-pressure depropanizing tower, the reflux of the top of the high-pressure depropanizing tower is the material after the subsequent hydrogenation and precooling, the carbon content is controlled by the tower kettle of the tower, and the carbon content is controlled by the tower top;

the method comprises the following steps that materials at the top of a tower and gas-phase feeding materials of a depropanizing tower exchange heat, enter a five-section inlet of a cracking gas compressor, are cooled to the inlet temperature required by a dearsenization reactor after being compressed, enter the dearsenization reactor, are heated to the inlet temperature required by a carbon dioxide hydrogenation reactor, are hydrogenated through three sections of carbon dioxide hydrogenation reactors with inter-section coolers, ensure that acetylene is hydrogenated to be below 1ppm, are cooled step by step, are condensed, and enter a precooling liquid-separating tank of a deethanizing tower to carry out gas-liquid separation;

the separated gas phase enters a deethanizer, most of the liquid phase returns to the top of the high-pressure depropanizer as reflux, and a small part of the liquid phase enters the deethanizer;

feeding the tower kettle material of the high-pressure depropanizing tower into a low-pressure depropanizing tower;

separating the carbon three components in a low-pressure depropanizing tower, feeding the carbon three components at the tower top and the tower bottom materials of a deethanizing tower into a carbon three hydrogenation reactor, and feeding the tower bottom materials into a decarburization four tower;

the four decarbonizing towers separate the four components of mixed carbon, the four components of mixed carbon at the tower top are taken as reflux, and part of mixed carbon is extracted and enters a four carbon hydrogenation working section;

the kettle of the four decarbonization towers is a gasoline component, and is mixed with gasoline stripping tower materials and cooled to be taken as a byproduct to be discharged out of a boundary area;

the carbon three components in the tower bottom and the components in the tower top of the low-pressure depropanizing tower are cooled and enter a dearsenization reactor, then enter a carbon three hydrogenation reactor after being heated, and the hydrogenated materials are partially circulated.

5. An improved process for light hydrocarbon recovery technology as claimed in claim 4, wherein the ethylbenzene plant includes an ethylbenzene separation section, the ethylbenzene separation section includes a benzene recovery and treatment system and an ethylbenzene, propylbenzene and polyethylbenzene recovery system.

6. The improved light hydrocarbon recovery technology of claim 5, wherein the benzene recovery and treatment system comprises a benzene column, a benzene column reboiler, a benzene column reflux drum, a benzene recovery column condenser, a hydrocarbonized liquid heater, a benzene column top steam generator, a benzene column-2 reflux pump, a recycle benzene booster pump, a benzene pre-treater, a fresh benzene heat exchanger, a benzene column reflux pump, a benzene column bottom pump, a rough separation column condenser, a rough separation column top aftercooler, an absorption column feed cooler, a rough separation column reflux drum, a benzene column feed pump, a clay treater, a rough separation column reflux pump, a reaction product-benzene column feed heat exchanger, an absorption column, a reverse hydrocarbonized material-absorbent heat exchanger;

the benzene tower is provided with 50 floating valve trays;

the heat required by the operation of the tower is provided by high-pressure steam, the reboiler of the benzene recovery tower is a horizontal thermosyphon reboiler, and the crude ethylbenzene of the tower bottom product is extracted from the tower bottom and is conveyed to an ethylbenzene recovery system.

7. A light hydrocarbon recovery technology improvement process as claimed in claim 6, wherein the ethylbenzene recovery system is composed of an ethylbenzene column, an ethylbenzene column-2 reboiler, an ethylbenzene column-2 condenser, an ethylbenzene column top steam generator, a fresh benzene heat exchanger, an ethylbenzene cooler, an ethylbenzene column-2 reflux tank, an ethylbenzene column-2 kettle pump, an ethylbenzene column-2 reflux pump, an ethylbenzene column reflux pump, and an ethylbenzene column bottom pump;

the propyl benzene recovery system consists of a propyl benzene tower, a propyl benzene tower reboiler, a propyl benzene tower top steam generator, a propyl benzene high-boiling residue cooler, a propyl benzene tower reflux tank, a propyl benzene tower bottom pump and a propyl benzene tower reflux pump;

the Polyethylbenzene (PEB) recovery system consists of a diethylbenzene tower, a diethylbenzene tower reboiler, a diethylbenzene tower top steam generator, a vacuum pump inlet cooler, a high-boiling-point substance cooler, a diethylbenzene reflux tank, a diethylbenzene tower reflux pump, a diethylbenzene tower bottom pump and a diethylbenzene tower vacuum pump.

Technical Field

The invention relates to the field of chemical industry, in particular to an improved process for a light hydrocarbon recovery technology.

Background

Light hydrocarbon is also called natural gas condensate (NGL), and is covered with C2-C6+ and contains condensate oil component (C3-C5). Light hydrocarbon recovery refers to the process of recovering components heavier than methane or ethane in natural gas in liquid form. On one hand, the aim is to control the hydrocarbon dew point of the natural gas to achieve the quality index of the commodity gas and avoid the gas-liquid two-phase flow; on the other hand, the recovered liquid hydrocarbons have a great economic value, and can be used as fuels directly or further separated into ethane, propane, butane or propane-butane mixtures (liquefied gases), light oils, and the like, and can also be used as chemical raw materials. If gas is injected back into the formation to maintain reservoir pressure, oil and gas recovery is enhanced.

Chinese patent publication No. CN105567288A discloses a light hydrocarbon recovery system, comprising: a light hydrocarbon recovery tower; the inlet of the air cooler is connected with the top outlet of the light hydrocarbon recovery tower, and the upper part of the air cooler is provided with a temperature control execution device; the inlet of the water cooler is connected with the outlet of the air cooler; a light hydrocarbon separator with an inlet connected with an outlet of the water cooler, wherein a temperature control device is arranged on the light hydrocarbon separator; the inlet is connected with the light hydrocarbon recovery device of the gas outlet of the light hydrocarbon separator, the temperature control device on the light hydrocarbon separator is a three-way adjusting device arranged between the outlet of the water cooler and the inlet of the light hydrocarbon separator, and the three-way adjusting device is respectively connected with the water cooler, the air cooler and the light hydrocarbon separator. The whole additional product of retrieving of this light dydrocarbon recovery system is single relatively, and this patent is to light dydrocarbon recovery technology further improvement.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide an improved process for light hydrocarbon recovery technology.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an improved process for light hydrocarbon recovery technology comprises a cracking section processing process, a quenching section processing process, a compressed alkali washing section processing process, a gas separation section processing process and a carbon four-hydrogenation processing process, wherein the cracking section processing process comprises the following steps: the light hydrocarbon raw material enters a raw material vaporizer for vaporization, the light hydrocarbon raw material enters a cracking furnace and is preheated at an upper raw material preheating section of a convection section of the cracking furnace at first to 130 ℃, the preheated raw material enters a lower raw material preheating I section and a lower raw material preheating II section, is preheated to 318 ℃, is mixed with dilution steam, has the temperature of 304 ℃ after being mixed, enters a lower mixing superheating section for heating to 642 ℃, a hydrocarbon/steam mixture discharged from the convection section enters a U-shaped radiation furnace tube of the radiation section after being distributed by a Venturi tube distributor, the hydrocarbon/steam mixture carries out thermal cracking reaction in the U-shaped radiation furnace tube, the outlet temperature of the cracking furnace is 870 ℃, the generated high-temperature pyrolysis gas enters a quenching heat exchanger for quenching, the pyrolysis gas of each hearth is converged at the outlet of the quenching heat exchanger and then enters a pyrolysis gas header pipe of the hearth, the ethane raw material enters a raw material heater, then the raw material is preheated in a preheating section similar to the light hydrocarbon raw material, mixed with the dilution steam, heated to the temperature of 650 ℃ across, enters a radiation furnace tube of the cracking furnace, the temperature of an outlet of the cracking furnace is 880 ℃, the generated high-temperature pyrolysis gas enters a quenching heat exchanger, and finally the pyrolysis gas is combined and enters a quenching section.

Further, the processing technology of the quenching section comprises the following steps: the temperature of pyrolysis gas from a quenching heat exchanger is higher, about 345 ℃, in order to rapidly reduce the temperature of the pyrolysis gas, the pyrolysis gas and circulating quenching oil in a quenching oil tower kettle are directly quenched for cooling, the temperature of the pyrolysis gas and the circulating quenching oil is rapidly reduced to about 210 ℃ after heat exchange in a quenching device, then the pyrolysis gas and the circulating quenching oil enter the quenching oil tower kettle, heavy components are condensed and converged in the quenching oil tower kettle, the pyrolysis gas continuously rises and exchanges heat with the quenching oil circulating to the lower end of the tower, the heavy components are washed away, the pyrolysis gas continuously rises and conducts mass transfer and heat transfer with the tray oil reflowing in the tower, and the pyrolysis gasoline coming out of the quenching water system at the top of the quenching oil tower is used as reflux;

circulating quenching oil at the bottom of a quenching oil tower is high in temperature, the quenching oil is used as a heat source for diluting steam, most of the circulating quenching oil is used as quenching oil to be continuously mixed with pyrolysis gas for cooling after the heat of the quenching oil is recovered, a small part of the circulating quenching oil is extracted, light components are extracted through medium-pressure steam at the bottom of a heavy oil stripping tower, heavy oil components are discharged to be used as products, pyrolysis fuel oil is extracted from the side line of the quenching oil tower, the pyrolysis fuel oil passes through a negative pressure tower, the light components are separated out, the pyrolysis fuel oil is extracted to be used as a byproduct, coil oil is extracted from the side line of the quenching oil, the coil oil after the heat is recovered by heating and diluting steam boiler, the coil oil enters the quenching oil tower and is further subjected to mass transfer with the pyrolysis gas, heavy components in the pyrolysis gas are condensed as much as possible, and;

pyrolysis gas from the top of the quenching oil tower enters a quenching water tower kettle, is in countercurrent contact heat exchange with quenching oil from the upper part, is cooled to 40 ℃ and then enters a section of suction tank of a pyrolysis gas compressor, pyrolysis gasoline and dilution steam are condensed in a quenching water tower, the pyrolysis gasoline and water are subjected to sedimentation separation in the quenching water tower kettle, the quenching water tower kettle is divided into three chambers, the first chamber is an oil-water mixing zone and enters a second oil-water sedimentation separation chamber through a baffle with a hole, an oil phase overflows through a second five-hole partition plate and enters a third oil chamber, most of the pyrolysis gasoline separated from the oil chamber enters the top of the quenching oil tower and flows back as the quenching oil tower, and the small part of the pyrolysis gasoline enters a pyrolysis gasoline stripping tower for stripping, and the pyrolysis gasoline tower kettle collects product pyrolysis gasoline. The temperature of the water extracted from the bottom of the second chamber is about 80 ℃, after the water is extracted, the water is respectively sent to a feed heater of a heating alkaline washing tower, a reboiler of a propylene tower kettle and a reboiler of a section, the water is cooled to 40 ℃ through water cooling, the water is respectively used as the top of a quenching water tower and the reflux of the section, a small part of the water is coalesced through a coalescer to remove medium and small oil drops in water, the water enters a water stripping tower for stripping, hydrocarbons in the water are removed, the water is stripped from a water stripping tower kettle, and the water is heated through coil oil and then enters a dilution steam generator to be.

Further, the processing technology of the compressed alkali washing section comprises the following steps: the pyrolysis gas from the top of the quenching water tower enters a first-section suction tank of a pyrolysis gas compressor, water carried by the pyrolysis gas is separated, a liquid phase is sent to a quenching water tower by a condensate circulating pump, a gas phase enters a first-section compressor for compression, the compressed gas phase enters a second-section compressor suction tank after being cooled by a first-section compressor water cooler, partial water and heavy hydrocarbon are separated, the gas phase enters a second-section compressor for compression, the gas phase is cooled by a second-section water cooler and enters a third-section compressor suction tank, partial water and heavy hydrocarbon are separated, the gas phase is cooled by a third-section water cooler and enters a fourth-section compressor suction tank, partial water and heavy hydrocarbon are separated, the gas phase is cooled by a fourth-section cooler and enters a fourth-section compressor for compression, the gas phase is compressed to the pressure of 1.73MPa, the pyrolysis gas enters an outlet tank of the fourth-section compressor after being cooled by the fourth-section water, the rich solvent is removed from an analytical tower for analysis, the analytical gas is removed from an original sulfur device in a plant area, the poor solvent after poor solution analysis is continuously returned to an absorption tower after analysis, the absorbed cracked gas is heated to 50 ℃ through quenching water and then enters an alkaline tower, the poor solvent is respectively countercurrent to a weak alkali section and a strong alkali section of the alkaline tower, the residual acid gas is removed, the cracked gas is washed through the alkaline tower, the cracked gas enters a precooler for precooling and is cooled to 15 ℃, saturated water in the cracked gas is condensed as much as possible, the liquid after the precooler is condensed is subjected to oil-water separation, the oil phase is subjected to coalescer to remove water drops as much as possible and then enters an oil phase dryer, the water content in the oil phase is controlled to be less than 1ppm, and the water phase; and (3) the gas after the precooler enters a gas phase dryer, so that the moisture in the gas phase is less than 1ppm, the cracked gas and the condensed oil phase both enter corresponding feeding positions of a high-pressure depropanizing tower to carry out gas-component separation, and the gas phase at the top of the high-pressure depropanizing tower enters an inlet of a five-section compressor after heat exchange to carry out five-section compression to 3.88MPa, so as to provide pressure for subsequent separation.

Further, the gas separation section processing technology comprises the following steps: the materials from the liquid phase dryer and the gas phase dryer enter a high-pressure depropanizing tower, the reflux of the top of the high-pressure depropanizing tower is the material after subsequent hydrogenation and precooling, the carbon content is controlled by the tower kettle of the tower, and the carbon content is controlled by the tower top. The method comprises the following steps of enabling materials at the top of a tower to exchange heat with gas-phase feeding materials of a depropanizing tower, enabling the materials to enter a five-section inlet of a cracking gas compressor, cooling the materials to an inlet temperature required by a dearsenization reactor after compression, enabling the materials to enter the dearsenization reactor, heating the materials to an inlet temperature required by a carbon dioxide hydrogenation reactor, carrying out hydrogenation through three sections of carbon dioxide hydrogenation reactors with inter-section coolers to ensure that acetylene is hydrogenated to be below 1ppm, cooling the materials step by step, condensing the materials, and enabling the materials to enter a precooling liquid-separating tank. The separated gas phase enters a deethanizer, most of the liquid phase returns to the top of the high-pressure depropanizer as reflux, and a small part of the liquid phase enters the deethanizer. Feeding the tower kettle material of the high-pressure depropanizing tower into a low-pressure depropanizing tower;

separating the carbon three components in a low-pressure depropanizing tower, feeding the carbon three components at the tower top and the tower bottom materials of a deethanizing tower into a carbon three hydrogenation reactor, and feeding the tower bottom materials into a decarburization four tower;

and (4) separating the mixed carbon four component in the decarburization four tower, taking the mixed carbon four component at the tower top as reflux, and partially extracting to enter a carbon four hydrogenation working section. The kettle of the four decarbonization towers is a gasoline component, and is mixed with gasoline stripping tower materials and cooled to be taken as a byproduct to be discharged out of a boundary area;

the carbon three components in the tower bottom and the components in the tower top of the low-pressure depropanizing tower are cooled and enter a dearsenization reactor, then enter a carbon three hydrogenation reactor after being heated, and the hydrogenated materials are partially circulated.

Further, the ethylbenzene plant comprises an ethylbenzene separation section, and the ethylbenzene separation section comprises a benzene recovery and treatment system and an ethylbenzene, propylbenzene and polyethylbenzene recovery system.

Further, the benzene recovery and treatment system comprises a benzene tower, a benzene tower reboiler, a benzene tower reflux tank, a benzene recovery tower condenser, a alkylation liquid heater, a benzene tower top steam generator, a benzene tower-2 reflux pump, a circulating benzene booster pump, a benzene pre-treater, a fresh benzene heat exchanger, a benzene tower reflux pump, a benzene tower bottom pump, a rough separation tower condenser, a rough separation tower top after-cooler, an absorption tower feeding cooler, a rough separation tower reflux tank, a benzene tower feeding pump, a clay treater, a rough separation tower reflux pump, a reaction product-benzene tower feeding heat exchanger, an absorption tower and an anti-alkylation material-absorbent heat exchanger;

the benzene column had 50 valve trays. The heat required by the operation of the tower is provided by high-pressure steam, the reboiler of the benzene recovery tower is a horizontal thermosyphon reboiler, and the crude ethylbenzene of the tower bottom product is extracted from the tower bottom and is conveyed to an ethylbenzene recovery system.

Further, the ethylbenzene recovery system consists of an ethylbenzene tower, an ethylbenzene tower-2 reboiler, an ethylbenzene tower-2 condenser, an ethylbenzene tower top steam generator, a fresh benzene heat exchanger, an ethylbenzene cooler, an ethylbenzene tower-2 reflux tank, an ethylbenzene tower-2 tower kettle pump, an ethylbenzene tower-2 reflux pump, an ethylbenzene tower reflux pump and an ethylbenzene tower bottom pump;

the propyl benzene recovery system consists of a propyl benzene tower, a propyl benzene tower reboiler, a propyl benzene tower top steam generator, a propyl benzene high-boiling residue cooler, a propyl benzene tower reflux tank, a propyl benzene tower bottom pump and a propyl benzene tower reflux pump;

the Polyethylbenzene (PEB) recovery system consists of a diethylbenzene tower, a diethylbenzene tower reboiler, a diethylbenzene tower top steam generator, a vacuum pump inlet cooler, a high-boiling-point substance cooler, a diethylbenzene reflux tank, a diethylbenzene tower reflux pump, a diethylbenzene tower bottom pump and a diethylbenzene tower vacuum pump.

The invention has the beneficial effects that: the process has high light hydrocarbon recovery efficiency and convenient operation, and realizes effective recycling of resources.

Drawings

FIG. 1 is a schematic system diagram of the process of the present invention;

FIG. 2 is a detailed flow chart of the present invention.

Detailed Description

As shown in fig. 1 and 2, an improved process for light hydrocarbon recovery technology comprises a cracking section processing process, a quenching section processing process, a compressed alkaline washing section processing process, a gas separation section processing process and a carbon four-hydrogenation processing process, wherein the cracking section processing process comprises the following steps: the light hydrocarbon raw material enters a raw material vaporizer for vaporization, the light hydrocarbon raw material enters a cracking furnace and is preheated at an upper raw material preheating section of a convection section of the cracking furnace at first to 130 ℃, the preheated raw material enters a lower raw material preheating I section and a lower raw material preheating II section, is preheated to 318 ℃, is mixed with dilution steam, has the temperature of 304 ℃ after being mixed, enters a lower mixing superheating section for heating to 642 ℃, a hydrocarbon/steam mixture discharged from the convection section enters a U-shaped radiation furnace tube of the radiation section after being distributed by a Venturi tube distributor, the hydrocarbon/steam mixture carries out thermal cracking reaction in the U-shaped radiation furnace tube, the outlet temperature of the cracking furnace is 870 ℃, the generated high-temperature pyrolysis gas enters a quenching heat exchanger for quenching, the pyrolysis gas of each hearth is converged at the outlet of the quenching heat exchanger and then enters a pyrolysis gas header pipe of the hearth, the ethane raw material enters a raw material heater, then the raw material is preheated in a preheating section similar to the light hydrocarbon raw material, mixed with the dilution steam, heated to the temperature of 650 ℃ across, enters a radiation furnace tube of the cracking furnace, the temperature of an outlet of the cracking furnace is 880 ℃, the generated high-temperature pyrolysis gas enters a quenching heat exchanger, and finally the pyrolysis gas is combined and enters a quenching section.

Further, the processing technology of the quenching section comprises the following steps: the temperature of pyrolysis gas from a quenching heat exchanger is higher, about 345 ℃, in order to rapidly reduce the temperature of the pyrolysis gas, the pyrolysis gas and circulating quenching oil in a quenching oil tower kettle are directly quenched for cooling, the temperature of the pyrolysis gas and the circulating quenching oil is rapidly reduced to about 210 ℃ after heat exchange in a quenching device, then the pyrolysis gas and the circulating quenching oil enter the quenching oil tower kettle, heavy components are condensed and converged in the quenching oil tower kettle, the pyrolysis gas continuously rises and exchanges heat with the quenching oil circulating to the lower end of the tower, the heavy components are washed away, the pyrolysis gas continuously rises and conducts mass transfer and heat transfer with the tray oil reflowing in the tower, and the pyrolysis gasoline coming out of the quenching water system at the top of the quenching oil tower is used as reflux;

circulating quenching oil at the bottom of a quenching oil tower is high in temperature, the quenching oil is used as a heat source for diluting steam, most of the circulating quenching oil is used as quenching oil to be continuously mixed with pyrolysis gas for cooling after the heat of the quenching oil is recovered, a small part of the circulating quenching oil is extracted, light components are extracted through medium-pressure steam at the bottom of a heavy oil stripping tower, heavy oil components are discharged to be used as products, pyrolysis fuel oil is extracted from the side line of the quenching oil tower, the pyrolysis fuel oil passes through a negative pressure tower, the light components are separated out, the pyrolysis fuel oil is extracted to be used as a byproduct, coil oil is extracted from the side line of the quenching oil, the coil oil after the heat is recovered by heating and diluting steam boiler, the coil oil enters the quenching oil tower and is further subjected to mass transfer with the pyrolysis gas, heavy components in the pyrolysis gas are condensed as much as possible, and;

pyrolysis gas from the top of the quenching oil tower enters a quenching water tower kettle, is in countercurrent contact heat exchange with quenching oil from the upper part, is cooled to 40 ℃ and then enters a section of suction tank of a pyrolysis gas compressor, pyrolysis gasoline and dilution steam are condensed in a quenching water tower, the pyrolysis gasoline and water are subjected to sedimentation separation in the quenching water tower kettle, the quenching water tower kettle is divided into three chambers, the first chamber is an oil-water mixing zone and enters a second oil-water sedimentation separation chamber through a baffle with a hole, an oil phase overflows through a second five-hole partition plate and enters a third oil chamber, most of the pyrolysis gasoline separated from the oil chamber enters the top of the quenching oil tower and flows back as the quenching oil tower, and the small part of the pyrolysis gasoline enters a pyrolysis gasoline stripping tower for stripping, and the pyrolysis gasoline tower kettle collects product pyrolysis gasoline. The temperature of the water extracted from the bottom of the second chamber is about 80 ℃, after the water is extracted, the water is respectively sent to a feed heater of a heating alkaline washing tower, a reboiler of a propylene tower kettle and a reboiler of a section, the water is cooled to 40 ℃ through water cooling, the water is respectively used as the top of a quenching water tower and the reflux of the section, a small part of the water is coalesced through a coalescer to remove medium and small oil drops in water, the water enters a water stripping tower for stripping, hydrocarbons in the water are removed, the water is stripped from a water stripping tower kettle, and the water is heated through coil oil and then enters a dilution steam generator to be.

Further, the processing technology of the compressed alkali washing section comprises the following steps: the pyrolysis gas from the top of the quenching water tower enters a first-section suction tank of a pyrolysis gas compressor, water carried by the pyrolysis gas is separated, a liquid phase is sent to a quenching water tower by a condensate circulating pump, a gas phase enters a first-section compressor for compression, the compressed gas phase enters a second-section compressor suction tank after being cooled by a first-section compressor water cooler, partial water and heavy hydrocarbon are separated, the gas phase enters a second-section compressor for compression, the gas phase is cooled by a second-section water cooler and enters a third-section compressor suction tank, partial water and heavy hydrocarbon are separated, the gas phase is cooled by a third-section water cooler and enters a fourth-section compressor suction tank, partial water and heavy hydrocarbon are separated, the gas phase is cooled by a fourth-section cooler and enters a fourth-section compressor for compression, the gas phase is compressed to the pressure of 1.73MPa, the pyrolysis gas enters an outlet tank of the fourth-section compressor after being cooled by the fourth-section water, the rich solvent is removed from an analytical tower for analysis, the analytical gas is removed from an original sulfur device in a plant area, the poor solvent after poor solution analysis is continuously returned to an absorption tower after analysis, the absorbed cracked gas is heated to 50 ℃ through quenching water and then enters an alkaline tower, the poor solvent is respectively countercurrent to a weak alkali section and a strong alkali section of the alkaline tower, the residual acid gas is removed, the cracked gas is washed through the alkaline tower, the cracked gas enters a precooler for precooling and is cooled to 15 ℃, saturated water in the cracked gas is condensed as much as possible, the liquid after the precooler is condensed is subjected to oil-water separation, the oil phase is subjected to coalescer to remove water drops as much as possible and then enters an oil phase dryer, the water content in the oil phase is controlled to be less than 1ppm, and the water phase; and (3) the gas after the precooler enters a gas phase dryer, so that the moisture in the gas phase is less than 1ppm, the cracked gas and the condensed oil phase both enter corresponding feeding positions of a high-pressure depropanizing tower to carry out gas-component separation, and the gas phase at the top of the high-pressure depropanizing tower enters an inlet of a five-section compressor after heat exchange to carry out five-section compression to 3.88MPa, so as to provide pressure for subsequent separation.

Further, the gas separation section processing technology comprises the following steps: the materials from the liquid phase dryer and the gas phase dryer enter a high-pressure depropanizing tower, the reflux of the top of the high-pressure depropanizing tower is the material after subsequent hydrogenation and precooling, the carbon content is controlled by the tower kettle of the tower, and the carbon content is controlled by the tower top. The method comprises the following steps of enabling materials at the top of a tower to exchange heat with gas-phase feeding materials of a depropanizing tower, enabling the materials to enter a five-section inlet of a cracking gas compressor, cooling the materials to an inlet temperature required by a dearsenization reactor after compression, enabling the materials to enter the dearsenization reactor, heating the materials to an inlet temperature required by a carbon dioxide hydrogenation reactor, carrying out hydrogenation through three sections of carbon dioxide hydrogenation reactors with inter-section coolers to ensure that acetylene is hydrogenated to be below 1ppm, cooling the materials step by step, condensing the materials, and enabling the materials to enter a precooling liquid-separating tank. The separated gas phase enters a deethanizer, most of the liquid phase returns to the top of the high-pressure depropanizer as reflux, and a small part of the liquid phase enters the deethanizer. Feeding the tower kettle material of the high-pressure depropanizing tower into a low-pressure depropanizing tower;

separating the carbon three components in a low-pressure depropanizing tower, feeding the carbon three components at the tower top and the tower bottom materials of a deethanizing tower into a carbon three hydrogenation reactor, and feeding the tower bottom materials into a decarburization four tower;

and (4) separating the mixed carbon four component in the decarburization four tower, taking the mixed carbon four component at the tower top as reflux, and partially extracting to enter a carbon four hydrogenation working section. The kettle of the four decarbonization towers is a gasoline component, and is mixed with gasoline stripping tower materials and cooled to be taken as a byproduct to be discharged out of a boundary area;

the carbon three components in the tower bottom and the components in the tower top of the low-pressure depropanizing tower are cooled and enter a dearsenization reactor, then enter a carbon three hydrogenation reactor after being heated, and the hydrogenated materials are partially circulated.

Further, the ethylbenzene plant comprises an ethylbenzene separation section, and the ethylbenzene separation section comprises a benzene recovery and treatment system and an ethylbenzene, propylbenzene and polyethylbenzene recovery system.

Further, the benzene recovery and treatment system comprises a benzene tower T-35201/T-26203, a benzene tower reboiler E-35201, a benzene tower reflux tank V-35201/V-26202, a benzene recovery tower condenser E-35202, a hydrocarbon liquid heater E-26214, a benzene tower top steam generator ER-26201, a benzene tower-2 reflux pump P-35201/S, a recycle benzene booster pump P-35202/S, a benzene pre-processor V-35203A/B, a fresh benzene heat exchanger E-35205A/B, a benzene tower reflux pump P-26204NA/B, a benzene tower bottom pump P-26205A/B/C, a crude separation tower T-26201, a crude separation tower condenser EC-26201A/B, a crude separation tower top rear E-26201, an absorption tower feed cooler E-26202, a crude separation tower reflux tank V-01 262262262262262262262262262262262262262, Benzene tower feed pump P-26202A/B/C, clay treater V-31103A/B, crude separation tower reflux pump P-26201NA/B, reaction product-benzene tower feed heat exchanger E-26104, absorption tower T-26202, anti-hydrocarbonization material-absorbent heat exchanger E-26203A/B/C/D.

Benzene column T-35201 had 50 valve trays. The heat required for the operation of the column is provided by high pressure steam and the benzene recovery column reboiler E-35201 is a horizontal thermosiphon reboiler. Crude ethylbenzene as a bottom product is extracted from the bottom of the T-35201 tower and is conveyed to an ethylbenzene recovery system.

The overhead from T-35201 was partially condensed in the benzene recovery column condenser E-35202 against boiler feed water (BW), which was heated to vaporize, producing 0.32MPaG low pressure steam. The obtained low-pressure steam is conveyed to a steam pipe network system outside the battery limits. The condensed benzene condensate from E-35202 is fed to the overhead reflux drum V-35201 of the benzene recovery column where vapor/liquid separation is effected. The obtained liquid benzene is combined with fresh benzene which comes from a tank area and is deprived of basic nitrogen through a benzene preprocessor V35203A/B, and is heated to 145 ℃ through a fresh benzene heat exchanger E-35205A/B, one part of the liquid benzene is pressurized by P-35201/S and enters the top of the T-35201 as a reflux liquid of the T-35201, and the other part of the liquid benzene is pressurized by P-35202/S and enters the top of a first ethylene-rich absorption tower as an absorption liquid.

Benzene column T-26203 had 100 trays. The heat required by the operation of the tower is provided by benzene tower bottom oil, and the benzene tower bottom oil is heated by a heating furnace F-26201 and then returns to the tower kettle after passing through each heater. Crude ethylbenzene which is a bottom product is extracted from the bottom of the T-26203 tower and is conveyed to an ethylbenzene recovery system.

The overhead product of T-26203 is partially condensed by heat exchange with boiler feed water (BW) after heating the gas phase alkylation feed benzene by E-26105, BW is heated and vaporized to produce 0.32MPaG low pressure steam. The obtained low-pressure steam is conveyed to a steam pipe network system outside the battery limits. The condensed benzene condensate from ER-26201 enters benzene column reflux drum V-26202 where vapor/liquid separation is effected. The obtained liquid benzene enters the top of the T-26203 tower through the total reflux of P-26204 NA/B. Part of benzene liquid is taken out from a T-26203 side line and enters V-26101/V-26102 to supplement the raw material benzene for alkylation and anti-alkylation.

The uncondensed gases obtained in V-35201 and E-26204, the main component of which is benzene, were sent as the obtained vapor phase to the crude separation column T-26201 together with the liquid phase hydrocarbonized flash gas and the vapor phase hydrocarbonized product. T-26201 overhead vapor enters the after-cooler (E-26201) of the rough separation column after passing through the air cooler (EC-26201A/B) of the rough separation column and is partially condensed and cooled by circulating water, the gaseous phase enters E-26202 after the material is condensed and is cooled to 10 ℃ by using chilled water, the condensate is converged into V-26201, the residual gaseous phase is sent to the absorption column T-26202, and the condensate of the gaseous phase of the stabilization column which is condensed for three times is totally entered into the reflux tank V-26201 of the stabilization column. Because of the small amount of free water, the liquid in the V-26201 tank is separated into an oil phase and a water phase, and the water collected in the water separating tank is discharged into a sewage treatment system under the control of the liquid level. Part of materials in the oil phase are sent back to the tower as reflux under the flow control of a reflux tank of the stabilizing tower through a reflux pump (P-26201 NA/B) of the rough fractionating tower; part of the materials are heated under the liquid level control of the flow reflux tank and then are subjected to gas-phase alkylation, and are intermittently extracted to the outside to prevent the accumulation of non-aromatic hydrocarbons in the system. Under the control of liquid level, the tower bottom material is sent to V-31103A/B for treatment by a crude tower kettle pump (P-26202A/B/C), enters E-26104 for heat exchange with a gas-phase alkylation product, and enters a benzene recovery tower T-26203.

The gas phase from the top of the T-26201 tower enters an absorption tower T-26202, after being absorbed by an absorbent of diethylbenzene extracted from the diethylbenzene tower, the tail gas at the top of the tower is sent to V-26603, and the rich solvent at the bottom of the tower exchanges heat with the absorbent and then enters a reverse alkylation feed tank V-26102.

Ethylbenzene, propyl benzene and polyethyl benzene recovery system

The ethylbenzene recovery system comprises an ethylbenzene column-2T-35202, an ethylbenzene column T-26204, an ethylbenzene column-2 reboiler E-35203, an ethylbenzene column reboiler E-26206, an ethylbenzene column-2 condenser E-35204, an ethylbenzene column top steam generator ER-26202, a fresh benzene heat exchanger-2E-35205A/B, a fresh benzene heat exchanger E-35206A/B, ethylbenzene cooler-2E-35207, ethylbenzene cooler E-26205N, ethylbenzene column-2 reflux tank V-35202, ethylbenzene column reflux tank V-26203, ethylbenzene column-2 kettle pump P-35204/S, ethylbenzene column-2 reflux pump P-35203/S, ethylbenzene column reflux pump P-26206 NA/B, ethylbenzene column bottom pump P-26207NA/B and the like.

The propyl benzene recovery system comprises propyl benzene tower T-35203, a propyl benzene tower reboiler E-35208, a propyl benzene tower top steam generator E-35209, a propyl benzene high-boiling-point substance cooler E-26207A, a propyl benzene tower reflux tank V-26204, a propyl benzene tower bottom pump P-35205/S, a propyl benzene tower reflux pump P-35206/S and other equipment.

The Polyethylbenzene (PEB) recovery system comprises a diethylbenzene tower T-26206N, a diethylbenzene tower reboiler E-26211, a diethylbenzene tower top steam generator ER-26204N, a vacuum pump inlet cooler E-26210, a high-boiling-point substance cooler E-26207B, a diethylbenzene reflux tank V-26205, a diethylbenzene tower reflux pump P-35207A/B, a diethylbenzene tower bottom pump P-26211A/B, a diethylbenzene tower vacuum pump P-26212NA/B and other equipment.

The ethylbenzene column-2T-35202 is a plate column with 100 plates, from which 60 plates of T-35201 bottoms enter. The column reboiler was heated using high pressure steam and the overhead passed through E-35204, which generated low pressure steam on the shell side, which condensed itself into V-35202. Noncondensable gas is sent to a styrene unit, the condensate partially flows back through P-35203/S, the other part of the condensate is preheated to fresh benzene, one part of the condensate is sent to the styrene unit, and the other part of the condensate is sent to a tank field through cooling under the control of liquid level. The bottom oil of the T-35202 tower is sent to a propylbenzene tower T-35203 for treatment.

The ethylbenzene recovery column T-26204 consists of four stages of packing and tray columns. The hot crude ethylbenzene from the bottom of the benzene recovery tower enters an ethylbenzene tower T-26204 from the top to the bottom between the 3 rd section packing and the 4 th section packing. The reboiler E-26206 of this column was heated with benzene bottoms. The overhead flows through an ethylbenzene overhead steam generator ER-26202 tube pass to exchange heat with boiler feed water (BW) in the shell pass, which is condensed, and the boiler feed water is vaporized to produce low pressure steam. The liquid phase condensed by ER-26202 enters an ethylbenzene column reflux tank V-26203, and the non-condensable gas enters an emptying header pipe. The tank was provided with a pressure split regulating system by which the operating pressure of the ethylbenzene recovery column T-26204 was controlled. One part of condensate of the T-26204 overhead collected in the V-26203 is returned to the top of the T-26204 as reflux, and the other part is preheated and then sent to a downstream styrene unit as a dehydrogenation reactor, or further cooled to about 40 ℃ by an ethylbenzene product cooler E-26205N, and then sent to a tank area for storage.

The product at the bottom of the ethyl benzene recovery tower T-26204 contains a trace amount of ethyl benzene and C₉Aromatic hydrocarbons (e.g., propylbenzene, isopropylbenzene, etc.), diethylbenzene, and other heavy components, togetherIs sent to a propyl benzene recovery tower T-35203 for treatment.

The bottom oil of the ethylbenzene tower enters from the third section and the fourth section of the packing from top to bottom of the propylbenzene tower T-35203, the gas phase at the top of the T-35203 is cooled by a tube pass of a propylbenzene tower condenser E-35209, the condensate enters a propylbenzene tower reflux tank V-26204 to partially reflux, and part of the condensate is extracted and cooled by a propylbenzene high-boiling substance cooler E-26207A and then enters a tank area. The shell side of E-35209 produces low pressure steam that is sent to the piping network. The bottom of the T-35203 column is mainly polyethylbenzene and other heavy components, and then is sent to a diethylbenzene recovery column T-26206N for treatment. It should be noted that the above devices are indicated by the model, but the actual manufacturing process is not limited to the model of the above devices.

In order to improve the conversion rate of the polyethylbenzene in the anti-alkylation reactor, the ethylbenzene content in the bottom discharge of the T-26204 and T-35202 towers should be as low as possible, because the ethylbenzene concentration in the feed of the anti-alkylation reactor is reduced, so that the conversion rate of the polyethylbenzene into ethylbenzene can be improved, and the circulation rate of the Polyethylbenzene (PEB) in the system can be reduced, thereby reducing the energy consumption. The control index of the ethylbenzene content in the discharged material at the bottom of the ethylbenzene tower is less than or equal to 0.5 percent (wt.).

The process has high light hydrocarbon recovery efficiency and convenient operation, and realizes effective recycling of resources.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.