CN111558230B - Combined distillation and separation process of pseudocumene and durene - Google Patents

Combined distillation and separation process of pseudocumene and durene Download PDF

Info

Publication number
CN111558230B
CN111558230B CN202010486240.2A CN202010486240A CN111558230B CN 111558230 B CN111558230 B CN 111558230B CN 202010486240 A CN202010486240 A CN 202010486240A CN 111558230 B CN111558230 B CN 111558230B
Authority
CN
China
Prior art keywords
tower
pseudocumene
durene
liquid
pipeline
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010486240.2A
Other languages
Chinese (zh)
Other versions
CN111558230A (en
Inventor
李裕超
韩刚
王雪妮
赵承群
刘晓清
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shandong Minghua New Material Co ltd
Original Assignee
Shandong Minghua New Material Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shandong Minghua New Material Co ltd filed Critical Shandong Minghua New Material Co ltd
Priority to CN202010486240.2A priority Critical patent/CN111558230B/en
Publication of CN111558230A publication Critical patent/CN111558230A/en
Application granted granted Critical
Publication of CN111558230B publication Critical patent/CN111558230B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/14—Fractional distillation or use of a fractionation or rectification column
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/10—Vacuum distillation
    • B01D3/101—Recirculation of the fluid used as fluid working medium in a vacuum creating device
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/14—Fractional distillation or use of a fractionation or rectification column
    • B01D3/32—Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
    • B01D3/322—Reboiler specifications
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/42—Regulation; Control
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention provides a combined distillation and separation process of pseudocumene and durene, which belongs to the technical field of chemical industry. The method changes the normal pressure distillation of the pseudocumene rectifying tower into the pressurized distillation, changes the normal pressure distillation of the durene rectifying tower into the reduced pressure distillation, uses the gas phase of the pseudocumene rectifying tower as a heat source to heat the durene tower kettle liquid, realizes the comprehensive utilization of the heat source of the two towers, and saves the steam consumption. In order to realize the durene reduced pressure distillation operation, the gas phase at the top of the tower needs to be vacuumized. By changing the operating pressure of the two rectifying towers, the heat coupling is realized, the heating steam of the durene tower is saved, and the consumption of cooling water on the top of the pseudocumene tower is reduced.

Description

Combined distillation and separation process of pseudocumene and durene
Technical Field
The invention relates to the technical field of chemical industry, in particular to a combined distillation and separation process of pseudocumene and durene.
Background
Durene, 1,2,4, 5-tetramethylbenzene, white crystal, the most main use is to produce pyromellitic dianhydride, pyromellitic dianhydride can produce polyimide, with the continuous expansion of polyimide market usage, the demand of durene is increasing day by day, no matter at present is C10 separation method or chemical synthesis method, need all adopt rectification technology to realize the concentration of durene finally, durene rectifying column needs to adopt the heat source of higher quality to realize the rectification separation, traditional chemical industry is subject to heat source restriction and energy consumption balance, can't guarantee long period steady operation.
Disclosure of Invention
The technical task of the invention is to solve the defects of the prior art and provide a combined distillation and separation process of pseudocumene and durene.
At present, xylene and pseudocumene are used for isomerization, alkylation and conversion alkylation, and pseudocumene is disproportionated and isomerized to prepare tetramethylbenzene. Because the chemical structures of the pseudocumene and the durene are similar, the chemical industry can simultaneously have the production lines of the pseudocumene and the durene during the design process.
The technical scheme of the invention is realized by the following modes:
the invention relates to a separation process of durene rectification gas, which is characterized in that the gas phase at the top of a durene rectification tower is vacuumized to realize the reduced pressure distillation of the durene rectification tower, an organic solvent is used as a liquid ring working solution to construct a vacuum liquid ring system, the liquid ring working solution is utilized to circularly absorb durene materials, the liquid ring working solution is separated, and the durene is finally collected.
The organic solvent of the liquid ring working solution adopts pseudocumene.
The equipment for realizing the separation process of the durene rectification gas has the structure that: a vacuum pump is connected with the downstream of the durene rectification gas pipeline, a working fluid intervention nozzle is arranged between the durene rectification gas pipeline and the vacuum pump,
the vacuum pump outputs a pump-out gas path of the vacuum pump, the downstream of the pump-out gas path of the vacuum pump is connected to a first gas-liquid cavity of the gas-liquid separator, the bottom of the first gas-liquid cavity is communicated with a working liquid-liquid loop pipeline, an intercooler is arranged on the working liquid-liquid loop pipeline, and the downstream end of the working liquid-liquid loop pipeline at the downstream of the intercooler is connected with a working liquid inlet of the vacuum pump in a backflow mode;
the working liquid spraying pipeline is communicated to a first gas-liquid cavity of the gas-liquid separator;
the gas-liquid separator is provided with a second gas-liquid cavity, a filler clapboard is arranged between the first gas-liquid cavity and the second gas-liquid cavity of the gas-liquid separator,
the top of the second gas-liquid cavity is communicated with an exhaust pipe, and the exhaust pipe is communicated to the outside;
the bottom of the second gas-liquid cavity is communicated with a separation pipeline, the downstream of the separation pipeline is communicated to a separation tower, the bottom of the separation tower is communicated with a durene recovery pipeline, the top of the separation tower is communicated with a working liquid return pipeline, and the downstream of the working liquid return pipeline converges to a working liquid spraying pipeline;
the working fluid spraying pipeline is communicated with the working fluid intervention nozzle;
the upstream of the working solution spraying pipeline is introduced into a working solution supplementing pipeline.
The intercooler is provided with a cooling liquid inlet pipeline and a cooling liquid return pipeline, the cooling liquid inlet pipeline and the cooling liquid return pipeline are communicated with a heat exchange shell pass of the intercooler, and a working liquid loop pipeline is arranged on a heat exchange tube pass of the intercooler;
a first gas-liquid cavity and a second gas-liquid cavity of the gas-liquid separator are horizontally arranged side by side, and a filler partition plate is longitudinally arranged between the first gas-liquid cavity and the second gas-liquid cavity in a partitioned manner;
and a second gas-liquid cavity return pipeline is arranged in a second gas-liquid cavity of the gas-liquid separator, a return valve is arranged on the second gas-liquid cavity return pipeline, and the return valve is in signal linkage control connection with a separation flow regulating valve on the separation pipeline.
A combined distillation and separation process for pseudocumene and durene comprises a pseudocumene rectification section and a durene rectification section,
introducing heavy components of reaction liquid of the methanol-alkylated pseudocumene, after three-phase separation, of the oil phase subjected to lightness removal into a pseudocumene rectifying tower for pseudocumene rectifying section treatment;
the pressure distillation is adopted in the pseudocumene rectifying section,
the gas phase at the top of the pseudocumene rectifying tower is used as a heat source to heat the bottom liquid of the durene rectifying tower so as to realize the utilization of the heat source,
cooling the gas phase at the top of the pseudocumene rectifying tower by a durene rectifying tower kettle, returning to the top of the pseudocumene condensing reflux section for condensing reflux and collecting pseudocumene;
the durene rectification working section adopts reduced pressure distillation,
part of the bottom liquid of the pseudocumene rectifying tower is boiled and refluxed to the bottom of the pseudocumene rectifying tower, the other part is introduced into the durene rectifying tower,
durene rectifying column sets up the top of the tower condensation reflux and collects durene, wherein:
condensing the product at the top of the durene rectifying tower by a condenser, then feeding the product into a durene tower top reflux tank, connecting the top of the durene tower top reflux tank with a vacuum pump, connecting the downstream of the air flow of the vacuum pump with a washing tower, outputting the top of the washing tower by the vacuum pump for exhausting, shunting the bottom liquid of the washing tower, refluxing one part of the liquid to the vacuum pump, pumping out the other part of the liquid by a washing tower bottom washing liquid pump, refluxing and introducing the other part of the liquid to the pseudocumene rectifying tower,
introducing the pseudocumene liquid collected in the pseudocumene working section into a washing tower as a washing liquid working solution to enter the washing tower to wash the gas phase in the washing tower;
the bottom of the durene tower top reflux tank is partially pumped by a reflux pump to reflux the durene rectifying tower top, and the other part is pumped to collect durene.
Part of the bottom product of the pseudocumene rectifying tower in the pseudocumene rectifying section is introduced into a durene rectifying tower to be used as working liquid of a vacuum liquid ring system,
part of the pseudocumene of the product collected in the pseudocumene rectification section is introduced into a washing tower of the durene rectification section to be used as a liquid supplement of a working liquid of a vacuum liquid ring system,
in the durene reduced pressure distillation link, the pseudocumene and the durene are produced at the top of the durene rectifying tower, the pseudocumene and the durene are condensed and then sent to a top reflux tank of the durene rectifying tower,
pumping the gas at the top of the durene tower from the reflux tank to a washing tower by a vacuum pump, outputting the gas at the top of the washing tower by the vacuum pump for exhaust, shunting the liquid at the bottom of the washing tower, pumping one part of the gas back to a vacuum pump for circulating and pumping into the washing tower, pumping the other part of the gas out of the washing tower by a washing liquid pump at the bottom of the washing tower for refluxing and introducing into a pseudocumene rectifying tower as the circulating working liquid of a vacuum liquid ring system,
the washing tower is simultaneously introduced with the liquid supplement of the pseudocumene working solution,
part of the bottom of the durene tower top reflux tank is pumped by a reflux pump to reflux the durene rectifying tower top, and the other part of the bottom of the durene tower top reflux tank is pumped by a reflux pump to collect durene;
the pseudocumene working solution and the working solution supplement liquid are circulated to assist in separating and collecting the durene in the durene vacuum reduced pressure distillation process, and the flow of the pseudocumene working solution forms a vacuum liquid ring system.
The reaction liquid of the pseudocumene after methanol alkylation comes from an upstream process, and the upstream process comprises the following steps:
(1) reaction section
After carrying out dehydration pretreatment on the pseudocumene from the tank area, mixing the pseudocumene with the collected pseudocumene produced in the pseudocumene rectification working section, entering a pseudocumene feeding buffer tank, boosting the pressure to 2.0MPaA through a pseudocumene feeding pump, entering a pseudocumene heater, and carrying out heat exchange with a reaction product to heat the pseudocumene to 340 ℃;
after the mixed methanol in the methanol feeding buffer tank is boosted to 2.0MPaA by a methanol feeding pump, the mixed methanol enters a methanol feeding heater to be heated to 160 ℃ and is divided into two parts: one part of the mixed solution enters the inlets of a second bed layer and a third bed layer of the alkylation reactor, and the reaction temperature of the catalyst bed layer is controlled; the other part of the mixed raw material and the mixed pseudocumene are mixed and enter a reaction feeding vaporizer, the vaporized mixed raw material enters a reaction feeding and discharging heat exchanger to be overheated to 370 ℃, and then enters an alkylation reactor to react methanol and pseudocumene under the action of a catalyst to generate durene; in order to ensure the control of reaction heat, the pseudocumene in the material of the alkylation reactor adopts an excess circulation process, and the reaction product contains part of the circulating pseudocumene which does not participate in the reaction;
the reaction product from the alkylation reactor is heat-exchanged to 170 ℃ by a steam generator and a low-pressure steam generator, then enters a thermal high-pressure separation gas-liquid separation tank, the pressure of the reaction system is maintained at 2.0MPaA by adjusting the discharge amount of purge gas, the discharged purge gas is sent to a torch, the gas phase and the liquid phase are cooled to 70 ℃ by a thermal high-pressure separation gas cooler and a reaction product air cooler respectively, the gas phase and the liquid phase enter a three-phase separation tank for gas-liquid-oil three-phase separation, and the separated water phase enters a methanol recovery tower; the oil phase enters a feed preheater of the debutanizer to exchange heat with the rich durene solution and then enters the debutanizer;
(2) rectification section
The water phase from the three-phase separator enters a methanol recovery tower, the gas-phase methanol at the top of the tower is condensed by a condenser at the top of the tower, enters a reflux tank at the top of the methanol recovery tower, and is divided into two parts after being boosted by a reflux pump at the top of the methanol recovery tower: one part is taken as overhead reflux; the other part is mixed with a methanol raw material to be used as reaction feed; the tower bottom water is pressurized by a tower bottom pump of the methanol recovery tower, cooled to 40 ℃ by a tower bottom cooler of the methanol recovery tower and then sent out of a boundary area;
the oil phase from the three-phase separator enters a light component removal tower, the gas phase at the top of the tower is condensed by an air cooler at the top of the tower, then enters a reflux tank at the top of the light component removal tower, and is divided into two parts after being boosted by a reflux pump at the top of the light component removal tower: one part is taken as overhead reflux; the other part is taken as a product by a light hydrocarbon cooler and is cooled to 40 ℃ and then is sent out of the boundary area, and the main components in the tower bottom liquid are pseudocumene, durene and a small amount of heavy components;
the reaction liquid of the pseudocumene produced by the upstream process after methanol alkylation is obtained and used as a heavy component, the heavy component respectively passes through a pseudocumene rectification section and a durene rectification section, the pseudocumene and the durene are respectively recovered, and finally the residual heavy component is pumped out of a battery limit.
A device for realizing the combined distillation and separation process of pseudocumene and durene has the structure that:
the heavy component pipeline end of the reaction liquid after the methanol alkylation of the pseudocumene is communicated with the tower body of the pseudocumene rectifying tower,
the gas phase output pipeline at the top of the pseudocumene rectifying tower is communicated with the shell pass of the durene tower kettle reboiler, the heat exchange tail end of the shell pass outputs a pseudocumene overhead condensation product pipeline,
the tail end of a condensation product pipeline at the top of the pseudocumene tower is communicated with the top of a reflux tank at the top of the pseudocumene tower,
the bottom of the tower top reflux tank of the pseudocumene column is communicated with a tower top reflux pipeline of the pseudocumene column through a pseudocumene column tower top reflux pump, and the tower top reflux pipeline of the pseudocumene column is communicated with the tower top of the pseudocumene rectifying tower in a reflux manner;
a flow-dividing output circulation pseudocumene output pipeline is arranged on the tower top reflux pipeline of the pseudocumene tower;
the bottom of the pseudocumene rectifying tower is communicated with a pseudocumene rectifying tower reboiler to reflux the bottom section of the pseudocumene rectifying tower;
the bottom of the pseudocumene rectifying tower is communicated with a third inlet pipeline and a fourth inlet pipeline through the output of a pseudocumene tower bottom pump,
the tail ends of the three-four inlet pipelines are communicated with a durene rectifying tower body,
the bottom of the durene rectifying tower is communicated with a durene tower kettle reboiler tube side through a durene tower bottom pump, the reboiling end of the durene tower kettle reboiler tube side is communicated with the bottom section of the durene rectifying tower in a backflow mode,
a durene tower bottom pump shunts and outputs a durene tower kettle liquid pipe;
the output pipeline at the top of the durene rectifying tower is communicated with the shell pass of a condenser at the top of the de-heavy tower, the tail end of the output pipeline at the top of the condensed durene rectifying tower is communicated with the top of a reflux tank at the top of the durene rectifying tower,
the bottom of the durene tower top reflux tank is pumped into two paths by a durene tower top reflux pump, one path is communicated with a durene rectifying tower top reflux pipeline and is communicated with the durene rectifying tower top section in a reflux way, and the other path is output and communicated with a durene collecting pipeline;
the tank top output of the durene top reflux tank is communicated with a vacuum decompression pipeline,
the tail end of the vacuum decompression pipeline is communicated with a vacuum pump, the downstream of the vacuum pump is communicated with an output pipeline of the vacuum pump,
the tail end of the output pipeline of the vacuum pump is communicated with the body of the washing tower,
the circulating pseudocumene output pipeline divides the flow and outputs a washing liquid pipeline, the downstream end of the washing liquid pipeline is communicated with the top section of the washing tower,
an exhaust pipeline of a vacuum pump is output from the top of the washing tower;
the bottom of the washing tower is divided into two paths, wherein one path of vacuum pump return pipeline is communicated to a vacuum decompression pipeline and flows back to a vacuum pump; the other path is pumped out by a washing liquid pump and communicated with the pseudocumene rectifying tower body in a reflux way through a pseudocumene return pipeline.
Compared with the prior art, the invention has the following beneficial effects:
according to the combined distillation and separation process of the pseudocumene and the durene, atmospheric distillation of a pseudocumene rectifying tower is changed into pressurized distillation, atmospheric distillation of a durene rectifying tower is changed into reduced pressure distillation, the gas phase of the pseudocumene rectifying tower is used as a heat source to heat the durene tower kettle liquid, the comprehensive utilization of the heat source of the two towers is realized, and the steam consumption is saved.
Because durene is easy to crystallize at the temperature lower than 80 ℃, in order to avoid crystallization blockage of vacuum-pumping equipment, pseudocumene can be selected as a working solution, durene is recovered during vacuum-pumping operation, a washing tower is arranged at an exhaust port for secondary washing, all gases in the vacuum-pumping material are recovered, and the absorbed solution returns to a pseudocumene rectifying tower for repeated separation and utilization.
The process is characterized in that:
1. by changing the operating pressure of the two rectifying towers, the heat coupling is realized, the heating steam of the durene tower is saved, and the consumption of cooling water on the top of the pseudocumene tower is reduced.
2. The gas phase at the top of the durene tower is vacuumized, pseudocumene is selected as the working solution of the vacuum equipment, the durene can be absorbed while vacuumizing is realized, and the durene crystallization is prevented from blocking pipeline equipment.
3. The pseudocumene solution after absorbing durene can return to the pseudocumene rectifying tower, and the complete recycling of working solution and materials is realized.
The combined distillation and separation process for the pseudocumene and the durene has the advantages of reasonable design, safe and reliable process, convenient application, easy maintenance and good popularization and use values.
Drawings
FIG. 1 is a schematic diagram of a durene vacuum liquid ring recovery process apparatus of the present invention.
FIG. 2 is a schematic diagram of the combined distillation and recovery process of pseudocumene and durene according to the present invention.
The reference numerals in the drawings denote:
1. a durene rectification gas pipeline, 2, a vacuum pump, 3, a working fluid intervention nozzle, 4, a vacuum pump gas outlet circuit,
5. a gas-liquid separator 6, a first gas-liquid cavity 7, a working liquid-liquid loop pipeline 8, an intercooler 9, a working liquid inlet,
10. a working fluid spraying pipeline is arranged on the lower portion of the working fluid spraying pipeline,
11. a second gas-liquid cavity, 12, a filler baffle plate, 13 and an exhaust pipe,
14. a separation pipeline 15, a separation tower 16, a durene recovery pipeline 17, a working liquid reflux pipeline,
18. a nozzle pipeline 19, a working fluid replenishing pipeline,
20. a cooling liquid inlet pipeline 21, a cooling liquid return pipeline,
22. a second gas-liquid cavity return pipeline 23, a return valve 24 and a separation flow regulating valve.
a1, passing the pseudocumene through a heavy component pipeline of the reaction liquid after methanol alkylation,
a2, a pseudocumene rectifying tower, a3, a gas phase output pipeline at the top of the pseudocumene rectifying tower, a4, a condensed product pipeline at the top of the pseudocumene rectifying tower,
a5, a reboiler of a durene tower kettle,
a6, a tower top reflux tank of the pseudocumene,
a7, a flow return pump at the top of the pseudocumene column, a8, a reflux pipeline at the top of the pseudocumene column,
a9, a circulating pseudocumene output pipeline,
a10, a trimethyl benzene rectifying tower reboiler,
a11, a pseudocumene column bottom pump, a12, a thirty-four inlet lines,
a13, a durene rectifying tower, a14, a durene tower bottom pump, a15, a durene tower kettle liquid pipe,
a16, a durene rectifying tower top output pipeline, a17, a heavy component removal tower top condenser,
a18, a durene top reflux tank, a19, a durene top reflux pump,
a20, a top reflux pipeline of the durene rectifying tower,
a21, a durene collecting pipeline,
a22, vacuum pressure reducing pipeline, a23, vacuum pump, a24, vacuum pump output pipeline, a25, washing tower,
a26, a washing liquid pipeline,
a27, and a vacuum pump exhaust pipeline,
a28, a return pipeline of a vacuum pump,
a29, a washing liquid pump, a30, a pseudocumene recycle pipeline,
a31, a steam inlet pipe, a32, a condensate outlet pipe,
a33, a pseudocumene rectifying tower bottom section circulating reflux device, a34, a pseudocumene rectifying tower bottom section circulating reflux valve, a35, a third four-lead-in pipeline valve,
a36, a gas exhaust pipeline at the top of the return tank at the top of the pseudocumene column, a37, a pressure control gas exhaust valve at the top of the pseudocumene column,
a38, a pseudocumene column top reflux tank circulation reflux device, a39, a pseudocumene column top reflux tank circulation reflux flow valve, a40 and a circulation pseudocumene output line control valve,
a41, a reflux device at the bottom section of the durene rectifying tower, a42, a reflux valve at the bottom section of the durene rectifying tower, a43, a control valve of a durene tower kettle liquid pipe,
a44, a circulating reflux device of a return tank at the top of the durene tower, a45, a circulating reflux flow valve of the return tank at the top of the durene tower, a46, a control valve of a collecting pipeline of the durene,
a47, a scrubber reflux circulation device, a48, a scrubber reflux flow valve, a49 and a pseudocumene recycle pipeline control valve.
Detailed Description
The combined distillation separation process of pseudocumene and durene according to the present invention will be described in detail below with reference to the accompanying drawings.
Durene, namely 1,2,4, 5-tetramethylbenzene, white crystal, the most main use is to produce pyromellitic dianhydride, the pyromellitic dianhydride can produce polyimide, with the continuous expansion of the polyimide market usage, the demand of durene is increasing day by day, no matter C10 separation method or chemical synthesis method at present, need adopt the rectification technology to realize the concentration of durene finally, durene rectifying column need adopt the higher-quality heat source to realize the rectification separation, subject to heat source restriction and energy consumption balance, durene rectifying column adopts the reduced pressure rectification is the current more reasonable process scheme, but durene material is easy to crystallize at normal temperature, the conventional vacuumizing method can not guarantee the stable operation of long period, the durene discharged by vacuumizing can not be recovered at the same time, cause the waste. The vacuum-pumping rectification process for durene belongs to the blank in the industry at the present stage.
The first embodiment is as follows:
vacuum liquid ring system:
the invention relates to a separation process of durene rectification gas, which is characterized in that the gas phase at the top of a durene rectification tower is vacuumized to realize the reduced pressure distillation of the durene rectification tower, an organic solvent is used as a liquid ring working solution to construct a vacuum liquid ring system, the liquid ring working solution is utilized to circularly absorb durene materials, the liquid ring working solution is separated, and the durene is finally collected.
The organic solvent of the liquid ring working solution adopts pseudocumene.
The process and the equipment adopt an organic solvent as a liquid ring to carry out vacuum-pumping operation on the gas phase of a durene rectifying tower, realize the reduced pressure distillation of durene, and simultaneously recycle durene materials through the absorption action of the organic solvent. The method and the device for vacuumizing the durene rectifying tower meet the operation requirement to the maximum extent, simultaneously avoid the problem that durene crystals block equipment, can realize the recycling of most durene, and have good popularization and application values.
Through spraying the cooling to gaseous durene, the mixed absorption of liquid ring solvent in the vacuum pump, secondary spray absorption and gas-liquid separation realize durene gaseous phase evacuation and material recovery in the separator, include the following steps:
a. vacuum pump inlet spraying cooling
The liquid spraying device is arranged at the inlet of the vacuum pump, and the organic solvent is used for spraying and mixing, so that durene and non-condensable gas entering the vacuum pump are subjected to preliminary cooling;
b. mixed absorption in vacuum pump
Fully mixing a liquid ring formed by an organic solvent in a vacuum pump with durene and non-condensable gas, and realizing primary absorption of the durene by utilizing the intersolubility of the organic solvent;
c. Secondary washing of vacuum pump outlet separator
After the vacuum pump exhausts gas and enters the outlet separator, secondary absorption of durene is realized by spraying and washing with an organic solvent, and finally, non-condensable gas is discharged after gas-liquid separation.
d. Circulating cooling of working fluid of vacuum pump
After the part of the working fluid of the vacuum pump which is taken out is separated from the separator, the working fluid returns to the inlet of the vacuum pump after being cooled by the cooler, so that the cyclic utilization of the working fluid is realized
In order to realize the recycling of durene materials, a discharge replacement pipeline is arranged at the bottom of the gas-liquid separator, a durene-containing liquid ring medium is periodically replaced, durene is recovered after separation, and the working stability of a vacuum pump liquid ring is ensured.
Preferably, in the step a, the liquid spraying device realizes the atomization and the injection of the organic solvent through the nozzle, realizes the mixing and the temperature reduction with the vacuumized gas in the vacuum pump, and simultaneously avoids the blockage of the inlet of the vacuum pump due to the temperature reduction and crystallization of durene.
Preferably, in the step b, the organic solvent serving as a liquid ring in the vacuum pump is further contacted with the vacuuming gas in the working cavity, and part of durene is dissolved in the organic solvent.
Preferably, in the step c, the vacuumized gas enters the gas-liquid separator through the outlet of the vacuum pump, and is fully mixed with the organic solvent sprayed by the separator, so that most of durene in the vacuumized gas is dissolved in the organic solvent. And the gas is discharged from the top of the separation cavity after the entrained liquid drops are separated by the filler wire mesh partition plate in the middle of the separator.
Preferably, the vacuum pump in the step d realizes recycling of the liquid ring working medium through gas-liquid separation, and in order to ensure stable operation, an intercooler is arranged and the normal operation temperature is ensured by cooling with circulating water.
Preferably, the liquid ring medium containing durene is replaced periodically, the working solution discharged from the bottom of the gas-liquid separator is subjected to secondary separation, the working solution is recycled after being separated, and the durene material is recycled.
The invention ensures the safety of the process operation to the maximum extent, and effectively recovers durene materials in the vacuumized gas, thereby obtaining good social and economic benefits. The concrete advantages are as follows:
the method comprises the following steps of (A) using an organic solvent as a working medium, and performing vacuum-pumping operation on durene gas phase by using a liquid ring vacuum pump, wherein the minimum pressure can be reduced to 5KPa, and the operation is stable and reliable;
and (II) the organic solvent is fully contacted with the vacuumized material, so that the durene in the material is fully recovered, and the economic benefit is considerable.
And thirdly, the device has simple process, simple and convenient operation and easy realization, and is suitable for popularization and application in the industry.
Equipment:
the equipment for realizing the separation process of the durene rectification gas has the structure that: a vacuum pump 2 is connected with the downstream of the durene rectification gas pipeline 1, a working fluid intervention nozzle 3 is arranged between the durene rectification gas pipeline 1 and the vacuum pump 2,
the vacuum pump 2 outputs a vacuum pump air outlet path 4, the downstream of the vacuum pump air outlet path 4 is connected to a first gas-liquid cavity 6 of a gas-liquid separator 5, the bottom of the first gas-liquid cavity 6 is communicated with a working liquid-liquid ring pipeline 7, an intercooler 8 is arranged on the working liquid-liquid ring pipeline 7, and the downstream end of the working liquid-liquid ring pipeline at the downstream of the intercooler 8 is connected with a working liquid inlet 9 of the vacuum pump in a backflow mode;
the working liquid spraying pipeline 10 is communicated to the first gas-liquid cavity 6 of the gas-liquid separator 5;
the gas-liquid separator 5 is provided with a second gas-liquid cavity 11, a filler baffle plate 12 is arranged between the first gas-liquid cavity 6 and the second gas-liquid cavity 11 of the gas-liquid separator 5,
the top of the second gas-liquid cavity 11 is communicated with an exhaust pipe 13, and the exhaust pipe 13 is communicated with the outside;
the bottom of the second gas-liquid cavity 11 is communicated with a separation pipeline 14, the downstream of the separation pipeline 14 is communicated to a separation tower 15, the bottom of the separation tower 15 is communicated with a durene recovery pipeline 16, the top of the separation tower 15 is communicated with a working liquid return pipeline 17, and the downstream of the working liquid return pipeline 17 converges to a working liquid spraying pipeline 10;
the working fluid spraying pipeline 10 is divided into nozzle pipelines 18, and the nozzle pipelines 18 are communicated with the working fluid intervention nozzles 3;
the upstream of the working fluid spraying pipeline 10 is introduced into a working fluid supplement pipeline 19.
The intercooler 8 is provided with a cooling liquid inlet pipeline 20 and a cooling liquid return pipeline 21, the cooling liquid inlet pipeline 20 and the cooling liquid return pipeline 21 are communicated with a heat exchange shell pass of the intercooler, and a working liquid loop pipeline is arranged on a heat exchange tube pass of the intercooler;
a first gas-liquid cavity 6 and a second gas-liquid cavity 11 of the gas-liquid separator are horizontally arranged side by side, and a filler baffle plate 12 is longitudinally arranged between the first gas-liquid cavity and the second gas-liquid cavity in a separated manner; the filler of the filler partition plate is provided with a gas-liquid micropore channel which is communicated with the first gas-liquid cavity and the second gas-liquid cavity.
A second gas-liquid cavity return pipeline 22 is arranged in a second gas-liquid cavity 11 of the gas-liquid separator, the second gas-liquid cavity return pipeline 22 is communicated to the top of the second gas-liquid cavity from the bottom of the second gas-liquid cavity through the outside of the gas-liquid separator along the second gas-liquid cavity return pipeline, a return valve 23 is arranged on the second gas-liquid cavity return pipeline, and a return valve signal linkage control is connected with a separation flow regulating valve 24 on the separation pipeline 14.
The equipment mainly comprises a vacuum pump, a gas-liquid separator, a durene separation tower, an intercooler and a nozzle.
The vacuum pump adopts an organic solvent as a liquid ring, and vacuum is formed in the liquid ring to realize the vacuum pumping of gas. The inlet of the spray nozzle is connected with the spray nozzle, the outlet of the spray nozzle is connected with the gas-liquid separator, and the working liquid inlet of the spray nozzle is connected with the intercooler.
The gas-liquid separator 5 is used for separating the vacuum pump working solution carried by the vacuum-pumping gas and the gas, and simultaneously, the durene material in the gas is dissolved and recovered through the full contact of the organic solvent working solution and the vacuum-pumping gas by the internal spraying device. The material inlet is connected with the outlet of a vacuum pump, the outlet is a vacuumizing gas discharge port, the working liquid inlet is connected with a working liquid outlet connected with an intercooler, and the working liquid discharge port is connected with a durene tower 3.
The durene separation tower is used for rectifying and separating the working solution discharged by the gas-liquid separator 5, so that durene materials are separated, and meanwhile, the working solution is recovered. The inlet of the durene separating tower is connected with a working liquid discharge port of the gas-liquid separator, the top outlet of the durene separating tower is the recycled working liquid, and the bottom outlet of the durene separating tower is the recycled durene material.
The intercooler is used for cooling the working fluid circulated by the vacuum pump. The inlet of the vacuum pump is connected with the working liquid outlet of the gas-liquid separator, and the outlet of the vacuum pump returns to the working liquid inlet of the vacuum pump. And circulating water is fed and returned.
The nozzle is installed at the inlet of the vacuum pump, and the working liquid is sprayed to enable the vacuumized gas to be preliminarily cooled. The nozzle line is connected with the working liquid line.
[ Process flow ]
1. Vacuumizing gas spraying cooling
The vacuumizing gas is sprayed with working liquid to be preliminarily mixed and cooled through a nozzle arranged at an inlet before entering a vacuum pump, and the precooled and crystallized durene and the working liquid are mixed to enter a vacuum pump cavity in the cooling process.
2. Preliminary absorption of four materials in vacuum pump
The vacuumized gas enters the cavity of the vacuum pump and is fully contacted with the organic solvent serving as the working solution, and the durene in the gas is partially dissolved in the working solution.
3. Working solution washing and separation
The outlet gas of the vacuum pump enters a gas-liquid separator, and is fully mixed by spraying working liquid, so that durene materials in the gas are further absorbed, and then the gas is discharged through a top outlet after passing through a filler partition plate in the middle of the separator. One part of the working liquid is sent to an intercooler through a circulating pipeline, and the other part of the working liquid is sent to a durene separation tower through a bottom replacement pipeline.
4. Rectification separation of displacement working fluid
The working solution for dissolving durene enters the middle part of the durene separation tower, the working solution solvent is separated from the top and then returns to the gas-liquid separator through rectification separation, and the durene material at the bottom is recycled.
5. Cooling of circulating working fluid
Because the temperature of the vacuum-pumping gas is higher, in order to ensure the normal operation of the vacuum pump, the circulating working fluid is cooled by circulating water, and the stability of the temperature in the vacuum pump is maintained.
The process route is as follows:
the gas of will evacuating spouts into the working solution in the nozzle, mix the back and tentatively cool down and get into the vacuum pump import, evacuating gas and working solution fully contact in the vacuum pump cavity, and during partial durene dissolved the working solution, the residual gas discharged from the vacuum pump export, get into gas-liquid separator, spray through the secondary of working solution, with gaseous intensive mixing, further absorb the durene in the gas, then gaseous through packing baffle layer separation mist entrainment back, from the discharge of separation cavity top. Part of the bottom working solution is sent to an intercooler through a circulating pipeline, cooled to below 40 ℃ by using circulating water and returned to the inlet of the vacuum pump, so as to maintain the stability of the working temperature of the vacuum pump; the other part enters a durene separation tower through a replacement pipeline, and working solution is recovered after durene is separated.
Through the process route, durene gas-phase vacuumizing is completed, and durene is dissolved and absorbed by the working medium in the liquid ring vacuum pump, so that the durene material in the vacuumized gas is recycled.
Example two:
the combined distillation separation process of pseudocumene and durene comprises the following steps:
a combined distillation and separation process for pseudocumene and durene comprises a pseudocumene rectification section and a durene rectification section,
introducing heavy components of reaction liquid of the methanol-alkylated pseudocumene, after three-phase separation, of the oil phase subjected to lightness removal into a pseudocumene rectifying tower for pseudocumene rectifying section treatment;
the pressure distillation is adopted in the pseudocumene rectifying section,
the gas phase at the top of the pseudocumene rectifying tower is used as a heat source to heat the bottom liquid of the durene rectifying tower so as to realize the utilization of the heat source,
cooling the gas phase at the top of the pseudocumene rectifying tower by a durene rectifying tower kettle, returning to the top of the pseudocumene condensing reflux section for condensing reflux and collecting pseudocumene;
the durene rectification working section adopts reduced pressure distillation,
part of the bottom liquid of the pseudocumene rectifying tower is boiled and refluxed to the bottom of the pseudocumene rectifying tower, the other part is introduced into the durene rectifying tower,
durene rectifying column sets up the top of the tower condensation reflux and collects durene, wherein:
condensing the product at the top of the durene rectifying tower by a condenser, then feeding the product into a durene tower top reflux tank, connecting the top of the durene tower top reflux tank with a vacuum pump, connecting the downstream of the air flow of the vacuum pump with a washing tower, outputting the top of the washing tower by the vacuum pump for exhausting, shunting the bottom liquid of the washing tower, refluxing one part of the liquid to the vacuum pump, pumping out the other part of the liquid by a washing tower bottom washing liquid pump, refluxing and introducing the other part of the liquid to the pseudocumene rectifying tower,
introducing the pseudocumene liquid collected in the pseudocumene working section into a washing tower as a washing liquid working solution to enter the washing tower to wash the gas phase in the washing tower;
the bottom of the durene tower top reflux tank is partially pumped by a reflux pump to reflux the durene rectifying tower top, and the other part is pumped to collect durene.
Part of the bottom product of the pseudocumene rectifying tower in the pseudocumene rectifying section is introduced into a durene rectifying tower to be used as working liquid of a vacuum liquid ring system,
part of the pseudocumene of the product collected in the pseudocumene rectification section is introduced into a washing tower of the durene rectification section to be used as a liquid supplement of a working liquid of a vacuum liquid ring system,
in the durene reduced pressure distillation link, the pseudocumene and the durene are produced at the top of the durene rectifying tower, the pseudocumene and the durene are condensed and then sent to a top reflux tank of the durene rectifying tower,
pumping the gas at the top of the durene tower from the reflux tank to a washing tower by a vacuum pump, outputting the gas at the top of the washing tower by the vacuum pump for exhaust, shunting the liquid at the bottom of the washing tower, pumping one part of the gas back to a vacuum pump for circulating and pumping into the washing tower, pumping the other part of the gas out of the washing tower by a washing liquid pump at the bottom of the washing tower for refluxing and introducing into a pseudocumene rectifying tower as the circulating working liquid of a vacuum liquid ring system,
the washing tower is simultaneously introduced with the liquid supplement of the pseudocumene working solution,
part of the bottom of the durene tower top reflux tank is pumped by a reflux pump to reflux the durene rectifying tower top, and the other part of the bottom of the durene tower top reflux tank is pumped by a reflux pump to collect durene;
the pseudocumene working solution and the working solution supplement liquid are circulated to assist in separating and collecting the durene in the durene vacuum reduced pressure distillation process, and the flow of the pseudocumene working solution forms a vacuum liquid ring system.
The reaction liquid of the pseudocumene after methanol alkylation comes from an upstream process, and the upstream process comprises the following steps:
(1) reaction section
After carrying out dehydration pretreatment on the pseudocumene from the tank area, mixing the pseudocumene with the collected pseudocumene produced in the pseudocumene rectification working section, entering a pseudocumene feeding buffer tank, boosting the pressure to 2.0MPaA through a pseudocumene feeding pump, entering a pseudocumene heater, and carrying out heat exchange with a reaction product to heat the pseudocumene to 340 ℃;
after the mixed methanol in the methanol feeding buffer tank is boosted to 2.0MPaA by a methanol feeding pump, the mixed methanol enters a methanol feeding heater to be heated to 160 ℃ and is divided into two parts: one part of the mixed solution enters the inlets of a second bed layer and a third bed layer of the alkylation reactor, and the reaction temperature of the catalyst bed layer is controlled; the other part of the mixed raw material and the mixed pseudocumene are mixed and enter a reaction feeding vaporizer, the vaporized mixed raw material enters a reaction feeding and discharging heat exchanger to be overheated to 370 ℃, and then enters an alkylation reactor to react methanol and pseudocumene under the action of a catalyst to generate durene; in order to ensure the control of reaction heat, the pseudocumene in the material of the alkylation reactor adopts an excess circulation process, and the reaction product contains part of the circulating pseudocumene which does not participate in the reaction;
the reaction product from the alkylation reactor is heat-exchanged to 170 ℃ by a steam generator and a low-pressure steam generator, then enters a thermal high-pressure separation gas-liquid separation tank, the pressure of the reaction system is maintained at 2.0MPaA by adjusting the discharge amount of purge gas, the discharged purge gas is sent to a torch, the gas phase and the liquid phase are cooled to 70 ℃ by a thermal high-pressure separation gas cooler and a reaction product air cooler respectively, the gas phase and the liquid phase enter a three-phase separation tank for gas-liquid-oil three-phase separation, and the separated water phase enters a methanol recovery tower; the oil phase enters a feed preheater of the debutanizer to exchange heat with the rich durene solution and then enters the debutanizer;
(2) rectification section
The water phase from the three-phase separator enters a methanol recovery tower, the gas-phase methanol at the top of the tower is condensed by a condenser at the top of the tower, enters a reflux tank at the top of the methanol recovery tower, and is divided into two parts after being boosted by a reflux pump at the top of the methanol recovery tower: one part is taken as overhead reflux; the other part is mixed with a methanol raw material to be used as reaction feed; the tower bottom water is pressurized by a tower bottom pump of the methanol recovery tower, cooled to 40 ℃ by a tower bottom cooler of the methanol recovery tower and then sent out of a boundary area;
the oil phase from the three-phase separator enters a light component removal tower, the gas phase at the top of the tower is condensed by an air cooler at the top of the tower, then enters a reflux tank at the top of the light component removal tower, and is divided into two parts after being boosted by a reflux pump at the top of the light component removal tower: one part is taken as overhead reflux; the other part is taken as a product by a light hydrocarbon cooler and is cooled to 40 ℃ and then is sent out of the boundary area, and the main components in the tower bottom liquid are pseudocumene, durene and a small amount of heavy components;
the reaction liquid of the pseudocumene produced by the upstream process after methanol alkylation is obtained and used as a heavy component, the heavy component respectively passes through a pseudocumene rectification section and a durene rectification section, the pseudocumene and the durene are respectively recovered, and finally the residual heavy component is pumped out of a battery limit.
The device comprises the following steps:
a device for realizing the combined distillation and separation process of pseudocumene and durene has the structure that:
the end of a reaction liquid heavy component pipeline a1 after methanol alkylation of the pseudocumene is communicated to the tower body of a pseudocumene rectifying tower a2,
a gas phase output pipeline a3 at the top of the pseudocumene rectifying tower is communicated to a5 shell pass of a durene tower kettle reboiler a, the tail end of the shell pass heat exchange outputs a pseudocumene overhead condensation product pipeline a4,
the tail end of a pseudocumene overhead condensation product pipeline a4 is communicated with the top of a pseudocumene column overhead reflux tank a6,
the bottom of the pseudocumene column top reflux tank a6 is communicated with a pseudocumene column top reflux pipeline a8 through a pseudocumene column top reflux pump a7, and the top reflux pipeline a8 of the pseudocumene column is communicated with the top of a pseudocumene rectifying column a2 in a reflux manner;
the overhead reflux line a8 of the pseudotritoluene tower is branched and output to a circulating pseudotritoluene output line a 9;
the bottom of the pseudocumene rectifying tower a2 is communicated with a pseudocumene rectifying tower reboiler a10 reflux pseudocumene rectifying tower a2 tower bottom section;
the bottom of the pseudocumene rectifying tower a2 is communicated with a three-four introducing pipeline a12 through the bottom pump a11 of the pseudocumene rectifying tower,
the tail end of the three-four introducing pipeline a12 is communicated with the body of the durene rectifying tower a13,
the bottom of the durene rectifying tower a13 is communicated with a durene tower kettle reboiler a5 tube side through a durene tower bottom pump a14, the reboiling end of the durene tower kettle reboiler is communicated with the bottom section of the durene rectifying tower a13,
a durene tower bottom pump a14 shunts and outputs a durene tower kettle liquid pipe a 15;
an output pipeline a16 at the top of the durene rectifying tower is communicated with a shell pass of a condenser a17 at the top of the de-heavy tower, the tail end of the output pipeline at the top of the condensed durene rectifying tower is communicated with the top of a reflux tank a18 at the top of the durene rectifying tower,
the bottom of the durene tower top reflux tank a18 is pumped and divided into two paths by a durene tower top reflux pump a19, one path is communicated with a durene rectifying tower top reflux pipeline a20 and is refluxed and communicated with the durene rectifying tower a13 tower top section, and the other path is output and communicated with a durene collecting pipeline a 21;
the top output of the durene top reflux tank a18 is communicated with a vacuum decompression pipeline a22,
the end of the vacuum decompression line a22 is connected to a vacuum pump a23, the vacuum pump a23 is connected downstream to a vacuum pump output line a24,
the end of the vacuum pump output line a24 is communicated with the tower body of the washing tower a25,
the circulating pseudocumene output pipeline a9 branches and outputs a washing liquid pipeline a26, the downstream end of the washing liquid pipeline a26 is communicated with the tower top section of a washing tower a25,
an exhaust pipeline a27 of a vacuum pump is output from the tower top of the washing tower a 25;
the bottom of the washing tower a25 is divided into two paths, wherein, a return pipeline a28 of a vacuum pump is communicated with a vacuum decompression pipeline a22 and flows back into a vacuum pump a 23; the other path is pumped out by a washing liquid pump a29 and is communicated with a pseudocumene rectifying tower body by a pseudocumene return line a30 in a backflow mode.
In the device, a vacuum liquid ring system is formed by matching a flow of introducing durene rectification working section from a pseudocumene rectification working section and refluxing pseudocumene in the pseudocumene rectification working section with a vacuum pump.
The bottom of the pseudocumene rectifying tower is communicated with a tube pass reflux pseudocumene rectifying tower bottom section of a pseudocumene rectifying tower reboiler a 10; the shell side of the trimethyl benzene rectifying tower reboiler is connected with a steam inlet pipe a31 and a condensate outlet pipe a 32;
the bottom section of the pseudocumene rectifying tower is provided with a pseudocumene rectifying tower bottom section circulating reflux device a33, the bottom section circulating reflux device of the pseudocumene rectifying tower is provided with a pseudocumene rectifying tower bottom section circulating reflux valve a34, and the bottom section circulating reflux valve of the pseudocumene rectifying tower is jointly controlled by a three-four introducing pipeline valve a35 on a three-four introducing pipeline;
the tank top of the tower top reflux tank of the pseudocumene column is communicated with a tank top exhaust pipeline a36 of the tower top reflux tank of the pseudocumene column, and a pressure control exhaust valve a37 of the tower top reflux tank of the pseudocumene column is arranged on the tank top exhaust pipeline a36 of the tower top reflux tank of the pseudocumene column;
the tank body of the top reflux tank of the pseudocumene column is provided with a pseudocumene column top reflux tank circulating reflux device a38, a pseudocumene column top reflux tank circulating reflux flow valve a39 on the pseudocumene column top reflux tank circulating reflux device, and a circulating pseudocumene output line control valve a40 on a pseudocumene column top reflux tank circulating reflux flow valve joint control circulating pseudocumene output line.
The bottom section of the durene rectifying tower is provided with a durene rectifying tower bottom section reflux device a41, the durene rectifying tower bottom section reflux device is provided with a durene rectifying tower bottom section reflux valve a42, and the durene rectifying tower bottom section reflux valve jointly controls a durene tower kettle liquid pipe control valve a43 on a durene tower kettle liquid pipe;
the body of the durene top reflux tank is provided with a durene top reflux tank circulating reflux device a44, the durene top reflux tank circulating reflux device is provided with a durene top reflux tank circulating reflux flow valve a45, and the durene top reflux tank circulating reflux flow valve jointly controls a durene collection pipeline control valve a46 on a durene collection pipeline;
the tower bottom section of the washing tower is provided with a washing tower circulating reflux device a47, the washing tower circulating reflux device is provided with a washing tower circulating reflux flow valve a48, and the washing tower circulating reflux flow valve is linked with a pseudocumene return pipeline control valve a49 on the pseudocumene return pipeline.
The embodiment of the combined distillation and recovery process of pseudocumene and durene comprises the following steps:
1. combined distillation process
The method changes the normal pressure distillation of the pseudocumene rectifying tower into the pressurized distillation, changes the normal pressure distillation of the durene rectifying tower into the reduced pressure distillation, uses the gas phase of the pseudocumene rectifying tower as a heat source to heat the durene tower kettle liquid, realizes the comprehensive utilization of the heat source of the two towers, and saves the steam consumption. In order to realize the durene reduced pressure distillation operation, the gas phase at the top of the tower needs to be vacuumized.
2. Durene evacuation
Because durene is easy to crystallize at the temperature lower than 80 ℃, in order to avoid crystallization blockage of vacuum-pumping equipment, pseudocumene can be selected as a working solution, durene is recovered during vacuum-pumping operation, a washing tower is arranged at an exhaust port for secondary washing, all gases in the vacuum-pumping material are recovered, and the absorbed solution returns to a pseudocumene rectifying tower for repeated separation and utilization.
3. Novel combined distillation process scheme for pseudocumene and durene
Brief introduction of the flow:
the pseudocumene rectifying tower is heated by steam, the working pressure of the rectifying tower is 0.1MPa (G), and the gas phase temperature at the top of the rectifying tower is controlled to be about 190 ℃. The gas phase at the top of the pseudocumene tower is sent to a reboiler of a durene tower kettle, the temperature of the durene tower kettle is heated to about 150 ℃, the gas phase pressure at the top of the durene tower is controlled to about 10KPa through vacuum pumping operation, and the rectification separation of durene can be realized at the temperature of 120 ℃ at the top of the pseudocumene tower.
The vacuum pump adopts the pseudocumene recovered from the pseudocumene tower top, one part of the pseudocumene is used as a working solution for recycling, the other part of the pseudocumene is subjected to secondary washing and recovery in a washing tower, and the pseudocumene is returned to the pseudocumene tower for re-separation and recovery after absorption.
The process has the advantages that:
1. by changing the operating pressure of the two rectifying towers, the heat coupling is realized, the heating steam of the durene tower is saved, and the consumption of cooling water on the top of the pseudocumene tower is reduced.
2. The gas phase at the top of the durene tower is vacuumized, pseudocumene is selected as the working solution of the vacuum equipment, the durene can be absorbed while vacuumizing is realized, and the durene crystallization is prevented from blocking pipeline equipment.
3. The pseudocumene solution after absorbing durene can return to the pseudocumene rectifying tower, and the complete recycling of working solution and materials is realized.

Claims (8)

1. The equipment for realizing the separation process of durene rectification gas is characterized by comprising the following structural components in parts by weight: a vacuum pump is connected with the downstream of the durene rectification gas pipeline, a working fluid intervention nozzle is arranged between the durene rectification gas pipeline and the vacuum pump,
the vacuum pump outputs a pump-out gas path of the vacuum pump, the downstream of the pump-out gas path of the vacuum pump is connected to a first gas-liquid cavity of the gas-liquid separator, the bottom of the first gas-liquid cavity is communicated with a working liquid-liquid loop pipeline, an intercooler is arranged on the working liquid-liquid loop pipeline, and the downstream end of the working liquid-liquid loop pipeline at the downstream of the intercooler is connected with a working liquid inlet of the vacuum pump in a backflow mode;
the working liquid spraying pipeline is communicated to a first gas-liquid cavity of the gas-liquid separator;
the gas-liquid separator is provided with a second gas-liquid cavity, a filler clapboard is arranged between the first gas-liquid cavity and the second gas-liquid cavity of the gas-liquid separator,
the top of the second gas-liquid cavity is communicated with an exhaust pipe, and the exhaust pipe is communicated to the outside;
the bottom of the second gas-liquid cavity is communicated with a separation pipeline, the downstream of the separation pipeline is communicated to a separation tower, the bottom of the separation tower is communicated with a durene recovery pipeline, the top of the separation tower is communicated with a working liquid return pipeline, and the downstream of the working liquid return pipeline converges to a working liquid spraying pipeline;
the working fluid spraying pipeline is communicated with the working fluid intervention nozzle;
the upstream of the working solution spraying pipeline is introduced into a working solution supplementing pipeline.
2. The equipment for realizing the separation process of durene rectification gas according to claim 1, which is characterized in that:
the intercooler is provided with a cooling liquid inlet pipeline and a cooling liquid return pipeline, the cooling liquid inlet pipeline and the cooling liquid return pipeline are communicated with a heat exchange shell pass of the intercooler, and a working liquid loop pipeline is arranged on a heat exchange tube pass of the intercooler;
a first gas-liquid cavity and a second gas-liquid cavity of the gas-liquid separator are horizontally arranged side by side, and a filler partition plate is longitudinally arranged between the first gas-liquid cavity and the second gas-liquid cavity in a partitioned manner;
and a second gas-liquid cavity return pipeline is arranged in a second gas-liquid cavity of the gas-liquid separator, a return valve is arranged on the second gas-liquid cavity return pipeline, and the return valve is in signal linkage control connection with a separation flow regulating valve on the separation pipeline.
3. A combined distillation and separation process of pseudocumene and durene is characterized by comprising a pseudocumene rectification section and a durene rectification section,
introducing heavy components of reaction liquid of the methanol-alkylated pseudocumene, after three-phase separation, of the oil phase subjected to lightness removal into a pseudocumene rectifying tower for pseudocumene rectifying section treatment;
the pressure distillation is adopted in the pseudocumene rectifying section,
the gas phase at the top of the pseudocumene rectifying tower is used as a heat source to heat the bottom liquid of the durene rectifying tower so as to realize the utilization of the heat source,
cooling the gas phase at the top of the pseudocumene rectifying tower by a durene rectifying tower kettle, returning to the top of the pseudocumene condensing reflux section for condensing reflux and collecting pseudocumene;
the durene rectification working section adopts reduced pressure distillation,
part of the bottom liquid of the pseudocumene rectifying tower is boiled and refluxed to the bottom of the pseudocumene rectifying tower, the other part is introduced into the durene rectifying tower,
durene rectifying column sets up the top of the tower condensation reflux and collects durene, wherein:
condensing the product at the top of the durene rectifying tower by a condenser, then feeding the product into a durene tower top reflux tank, connecting the top of the durene tower top reflux tank with a vacuum pump, connecting the downstream of the air flow of the vacuum pump with a washing tower, outputting the top of the washing tower by the vacuum pump for exhausting, shunting the bottom liquid of the washing tower, refluxing one part of the liquid to the vacuum pump, pumping out the other part of the liquid by a washing tower bottom washing liquid pump, refluxing and introducing the other part of the liquid to the pseudocumene rectifying tower,
introducing the pseudocumene liquid collected in the pseudocumene working section into a washing tower as a washing liquid working solution to enter the washing tower to wash the gas phase in the washing tower;
the bottom of the durene tower top reflux tank is partially pumped by a reflux pump to reflux the durene rectifying tower top, and the other part is pumped to collect durene.
4. The combined distillation separation process of pseudocumene and durene according to claim 3, wherein:
part of the bottom product of the pseudocumene rectifying tower in the pseudocumene rectifying section is introduced into a durene rectifying tower to be used as working liquid of a vacuum liquid ring system,
part of the pseudocumene of the product collected in the pseudocumene rectification section is introduced into a washing tower of the durene rectification section to be used as a liquid supplement of a working liquid of a vacuum liquid ring system,
in the durene reduced pressure distillation link, the pseudocumene and the durene are produced at the top of the durene rectifying tower, the pseudocumene and the durene are condensed and then sent to a top reflux tank of the durene rectifying tower,
pumping the gas at the top of the durene tower from the reflux tank to a washing tower by a vacuum pump, outputting the gas at the top of the washing tower by the vacuum pump for exhaust, shunting the liquid at the bottom of the washing tower, pumping one part of the gas back to a vacuum pump for circulating and pumping into the washing tower, pumping the other part of the gas out of the washing tower by a washing liquid pump at the bottom of the washing tower for refluxing and introducing into a pseudocumene rectifying tower as the circulating working liquid of a vacuum liquid ring system,
the washing tower is simultaneously introduced with the liquid supplement of the pseudocumene working solution,
part of the bottom of the durene tower top reflux tank is pumped by a reflux pump to reflux the durene rectifying tower top, and the other part of the bottom of the durene tower top reflux tank is pumped by a reflux pump to collect durene;
the pseudocumene working solution and the working solution supplement liquid are circulated to assist in separating and collecting the durene in the durene vacuum reduced pressure distillation process, and the flow of the pseudocumene working solution forms a vacuum liquid ring system.
5. The combined distillation separation process of pseudocumene and durene according to claim 3 or 4, wherein: the reaction liquid of the pseudocumene after methanol alkylation comes from an upstream process, and the upstream process comprises the following steps:
(1) reaction section
After carrying out dehydration pretreatment on the pseudocumene from the tank area, mixing the pseudocumene with the collected pseudocumene produced in the pseudocumene rectification working section, entering a pseudocumene feeding buffer tank, boosting the pressure to 2.0MPaA through a pseudocumene feeding pump, entering a pseudocumene heater, and carrying out heat exchange with a reaction product to heat the pseudocumene to 340 ℃;
after the mixed methanol in the methanol feeding buffer tank is boosted to 2.0MPaA by a methanol feeding pump, the mixed methanol enters a methanol feeding heater to be heated to 160 ℃ and is divided into two parts: one part of the mixed solution enters the inlets of a second bed layer and a third bed layer of the alkylation reactor, and the reaction temperature of the catalyst bed layer is controlled; the other part of the mixed raw material and the mixed pseudocumene are mixed and enter a reaction feeding vaporizer, the vaporized mixed raw material enters a reaction feeding and discharging heat exchanger to be overheated to 370 ℃, and then enters an alkylation reactor to react methanol and pseudocumene under the action of a catalyst to generate durene; in order to ensure the control of reaction heat, the pseudocumene in the material of the alkylation reactor adopts an excess circulation process, and the reaction product contains part of the circulating pseudocumene which does not participate in the reaction;
the reaction product from the alkylation reactor is heat-exchanged to 170 ℃ by a steam generator and a low-pressure steam generator, then enters a thermal high-pressure separation gas-liquid separation tank, the pressure of the reaction system is maintained at 2.0MPaA by adjusting the discharge amount of purge gas, the discharged purge gas is sent to a torch, the gas phase and the liquid phase are cooled to 70 ℃ by a thermal high-pressure separation gas cooler and a reaction product air cooler respectively, the gas phase and the liquid phase enter a three-phase separation tank for gas-liquid-oil three-phase separation, and the separated water phase enters a methanol recovery tower; the oil phase enters a feed preheater of the debutanizer to exchange heat with the rich durene solution and then enters the debutanizer;
(2) rectification section
The water phase from the three-phase separator enters a methanol recovery tower, the gas-phase methanol at the top of the tower is condensed by a condenser at the top of the tower, enters a reflux tank at the top of the methanol recovery tower, and is divided into two parts after being boosted by a reflux pump at the top of the methanol recovery tower: one part is taken as overhead reflux; the other part is mixed with a methanol raw material to be used as reaction feed; the tower bottom water is pressurized by a tower bottom pump of the methanol recovery tower, cooled to 40 ℃ by a tower bottom cooler of the methanol recovery tower and then sent out of a boundary area;
the oil phase from the three-phase separator enters a light component removal tower, the gas phase at the top of the tower is condensed by an air cooler at the top of the tower, then enters a reflux tank at the top of the light component removal tower, and is divided into two parts after being boosted by a reflux pump at the top of the light component removal tower: one part is taken as overhead reflux; the other part is taken as a product by a light hydrocarbon cooler and is cooled to 40 ℃ and then is sent out of the boundary area, and the main components in the tower bottom liquid are pseudocumene, durene and a small amount of heavy components;
the reaction liquid of the pseudocumene produced by the upstream process after methanol alkylation is obtained and used as a heavy component, the heavy component respectively passes through a pseudocumene rectification section and a durene rectification section, the pseudocumene and the durene are respectively recovered, and finally the residual heavy component is pumped out of a battery limit.
6. An apparatus for carrying out a combined distillation separation process of pseudocumene and durene according to claim 3 or 4, characterized in that the apparatus is structured as follows:
the heavy component pipeline end of the reaction liquid after the methanol alkylation of the pseudocumene is communicated with the tower body of the pseudocumene rectifying tower,
the gas phase output pipeline at the top of the pseudocumene rectifying tower is communicated with the shell pass of the durene tower kettle reboiler, the heat exchange tail end of the shell pass outputs a pseudocumene overhead condensation product pipeline,
the tail end of a condensation product pipeline at the top of the pseudocumene tower is communicated with the top of a reflux tank at the top of the pseudocumene tower,
the bottom of the tower top reflux tank of the pseudocumene column is communicated with a tower top reflux pipeline of the pseudocumene column through a pseudocumene column tower top reflux pump, and the tower top reflux pipeline of the pseudocumene column is communicated with the tower top of the pseudocumene rectifying tower in a reflux manner;
a flow-dividing output circulation pseudocumene output pipeline is arranged on the tower top reflux pipeline of the pseudocumene tower;
the bottom of the pseudocumene rectifying tower is communicated with a pseudocumene rectifying tower reboiler to reflux the bottom section of the pseudocumene rectifying tower;
the bottom of the pseudocumene rectifying tower is communicated with a third inlet pipeline and a fourth inlet pipeline through the output of a pseudocumene tower bottom pump,
the tail ends of the three-four inlet pipelines are communicated with a durene rectifying tower body,
the bottom of the durene rectifying tower is communicated with a durene tower kettle reboiler tube side through a durene tower bottom pump, the reboiling end of the durene tower kettle reboiler tube side is communicated with the bottom section of the durene rectifying tower in a backflow mode,
a durene tower bottom pump shunts and outputs a durene tower kettle liquid pipe;
the output pipeline at the top of the durene rectifying tower is communicated with the shell pass of a condenser at the top of the de-heavy tower, the tail end of the output pipeline at the top of the condensed durene rectifying tower is communicated with the top of a reflux tank at the top of the durene rectifying tower,
the bottom of the durene tower top reflux tank is pumped into two paths by a durene tower top reflux pump, one path is communicated with a durene rectifying tower top reflux pipeline and is communicated with the durene rectifying tower top section in a reflux way, and the other path is output and communicated with a durene collecting pipeline;
the tank top output of the durene top reflux tank is communicated with a vacuum decompression pipeline,
the tail end of the vacuum decompression pipeline is communicated with a vacuum pump, the downstream of the vacuum pump is communicated with an output pipeline of the vacuum pump,
the tail end of the output pipeline of the vacuum pump is communicated with the body of the washing tower,
the circulating pseudocumene output pipeline divides the flow and outputs a washing liquid pipeline, the downstream end of the washing liquid pipeline is communicated with the top section of the washing tower,
an exhaust pipeline of a vacuum pump is output from the top of the washing tower;
the bottom of the washing tower is divided into two paths, wherein one path of vacuum pump return pipeline is communicated to a vacuum decompression pipeline and flows back to a vacuum pump; the other path is pumped out by a washing liquid pump and communicated with the pseudocumene rectifying tower body in a reflux way through a pseudocumene return pipeline.
7. The apparatus of claim 6, wherein the apparatus comprises:
the bottom of the pseudocumene rectifying tower is communicated with a tube pass reflux pseudocumene rectifying tower bottom section of a pseudocumene rectifying tower reboiler; the shell side of the trimethyl benzene rectifying tower reboiler is connected with a steam inlet pipe and a condensate outlet pipe;
the bottom section of the pseudocumene rectifying tower is provided with a pseudocumene rectifying tower bottom section circulating reflux device, the bottom section circulating reflux device of the pseudocumene rectifying tower is provided with a pseudocumene rectifying tower bottom section circulating reflux valve, and the bottom section circulating reflux valve of the pseudocumene rectifying tower is jointly controlled by three-four inlet line valves on three-four inlet lines;
the tank top of the tower top reflux tank of the pseudocumene column is communicated with a tank top exhaust pipeline of the tower top reflux tank of the pseudocumene column, and a pressure control exhaust valve of the tower top reflux tank of the pseudocumene column is arranged on the tank top exhaust pipeline of the tower top reflux tank of the pseudocumene column;
the tank body of the top reflux tank of the pseudocumene column is provided with a top reflux tank circulating reflux device of the pseudocumene column, a top reflux tank circulating reflux flow valve of the pseudocumene column on the top reflux tank circulating reflux device of the pseudocumene column, and a circulating pseudocumene output line control valve on a top reflux tank circulating reflux flow valve joint control circulating pseudocumene output line of the pseudocumene column.
8. The apparatus for the combined distillation separation process of pseudocumene and durene according to claim 7, wherein:
the bottom section of the durene rectifying tower is provided with a durene rectifying tower bottom section reflux device which is provided with a durene rectifying tower bottom section reflux valve, and the durene rectifying tower bottom section reflux valve is in joint control with a durene tower kettle liquid pipe control valve on a durene tower kettle liquid pipe;
the body of the durene top reflux tank is provided with a durene top reflux tank circulating reflux device, the durene top reflux tank circulating reflux device is provided with a durene top reflux tank circulating reflux flow valve, and the durene top reflux tank circulating reflux flow valve jointly controls a durene collecting pipeline control valve on a durene collecting pipeline;
the tower bottom section of the washing tower is provided with a washing tower circulating reflux device, a washing tower circulating reflux flow valve is arranged on the washing tower circulating reflux device, and the washing tower circulating reflux flow valve is linked with a pseudocumene return pipeline control valve on the pseudocumene return pipeline.
CN202010486240.2A 2020-06-01 2020-06-01 Combined distillation and separation process of pseudocumene and durene Active CN111558230B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010486240.2A CN111558230B (en) 2020-06-01 2020-06-01 Combined distillation and separation process of pseudocumene and durene

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010486240.2A CN111558230B (en) 2020-06-01 2020-06-01 Combined distillation and separation process of pseudocumene and durene

Publications (2)

Publication Number Publication Date
CN111558230A CN111558230A (en) 2020-08-21
CN111558230B true CN111558230B (en) 2021-08-31

Family

ID=72075128

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010486240.2A Active CN111558230B (en) 2020-06-01 2020-06-01 Combined distillation and separation process of pseudocumene and durene

Country Status (1)

Country Link
CN (1) CN111558230B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112691400B (en) * 2020-12-30 2023-09-19 中冶焦耐(大连)工程技术有限公司 Vacuum system and process for three-mixed fraction decompression tar distillation tower
CN114159819B (en) * 2021-11-26 2023-03-28 铜陵金泰化工股份有限公司 Processing technology and device for propylene glycol vacuum rectification production

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS611628A (en) * 1984-06-15 1986-01-07 Mitsubishi Oil Co Ltd Method for concentrating durene
CN86105297A (en) * 1985-08-14 1987-02-11 林德股份公司 The method of scrubbing gas to recover hydrocarbons
CN101362672A (en) * 2008-09-28 2009-02-11 黄健雄 Apparatus and method for continuously preparing trimethyl benzene and tetramethylbenzene in single tower by heavy aromatic hydrocarbon one step method
CN104314841A (en) * 2014-10-16 2015-01-28 泸州北方化学工业有限公司 Liquid ring vacuum pump technology for producing organosilicone monomer
CN104437055A (en) * 2014-11-25 2015-03-25 中冶焦耐工程技术有限公司 Negative-pressure ammonia distillation process and equipment for deaminizing ammonia before vacuum pump
CN108191595A (en) * 2018-02-11 2018-06-22 常熟联邦化工股份有限公司 For detaching C10The distillation system of heavy aromatics
CN109966997A (en) * 2017-12-28 2019-07-05 江苏正丹化学工业股份有限公司 A kind of method and its reactor of pseudocumene alkylation production durol

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100990059B1 (en) * 2003-10-20 2010-10-26 미츠비시 가스 가가쿠 가부시키가이샤 Process for producing pyromellitic acid
ITPI20100114A1 (en) * 2010-10-11 2012-04-12 Sime S R L EQUIPMENT AND PROCESS FOR SEPARATING 1,2,4 TRIMETHYLBENZENE (PSEUDOCUMENE) FROM A MIXTURE CONTAINING AROMATIC HYDROCARBONS
CN202289515U (en) * 2011-09-08 2012-07-04 中国石油天然气集团公司 Refining system for circulating 1,3-propanediol in continuous production process of polytrimethylene terephthalate
KR101966135B1 (en) * 2017-12-07 2019-04-05 한국에너지기술연구원 Vacuum Distillation System for Alkylenecarbonate Purification Associated with Carbon Dioxide Capture Process

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS611628A (en) * 1984-06-15 1986-01-07 Mitsubishi Oil Co Ltd Method for concentrating durene
CN86105297A (en) * 1985-08-14 1987-02-11 林德股份公司 The method of scrubbing gas to recover hydrocarbons
CN101362672A (en) * 2008-09-28 2009-02-11 黄健雄 Apparatus and method for continuously preparing trimethyl benzene and tetramethylbenzene in single tower by heavy aromatic hydrocarbon one step method
CN104314841A (en) * 2014-10-16 2015-01-28 泸州北方化学工业有限公司 Liquid ring vacuum pump technology for producing organosilicone monomer
CN104437055A (en) * 2014-11-25 2015-03-25 中冶焦耐工程技术有限公司 Negative-pressure ammonia distillation process and equipment for deaminizing ammonia before vacuum pump
CN109966997A (en) * 2017-12-28 2019-07-05 江苏正丹化学工业股份有限公司 A kind of method and its reactor of pseudocumene alkylation production durol
CN108191595A (en) * 2018-02-11 2018-06-22 常熟联邦化工股份有限公司 For detaching C10The distillation system of heavy aromatics

Also Published As

Publication number Publication date
CN111558230A (en) 2020-08-21

Similar Documents

Publication Publication Date Title
CN111558230B (en) Combined distillation and separation process of pseudocumene and durene
CN111437619A (en) Multi-tower differential pressure energy-saving anhydrous alcohol distillation system and anhydrous alcohol energy-saving production method
CN110218151B (en) Device and method for preparing propyl propionate through tower kettle flash evaporation type heat pump reaction rectification
CN113274755B (en) Process and device for preparing oxygen by phase thermal decomposition of sulfuric acid in iodine-sulfur cycle
CN110256202B (en) Four-tower four-effect crude methanol refining process method
CN105906512B (en) A kind of the single column separating technology and device of phenylenediamine isomer
CN108863719A (en) Steam infiltration-alkaline process coupling prepares the method and device of sodium methoxide
WO2021047392A1 (en) Process method for preparing acetic acid by carbonylating methanol by means of reactor thermally coupled with rectifying tower
CN212594064U (en) Durene rectification separator
CN114380692A (en) Preparation method of energy-saving electronic grade carbonic ester
CN110862330B (en) Efficient energy-saving rectification process for recycling DMAC waste liquid
CN105771551B (en) A kind of separation method of ammonia and carbon dioxide
CN102471194A (en) Method and system for producing methanol and dimethyl ether
CN210117345U (en) Four-tower four-effect crude methanol refining process system
WO2023060906A1 (en) Novel process of absorption and stabilization unit and comprehensive utilization method of products therefrom
CN209210671U (en) Steam infiltration-alkaline process coupling prepares the device of sodium methoxide
CN112979516B (en) Energy-saving methyl mercaptan synthesis device
CN212818177U (en) Multi-tower differential pressure energy-saving anhydrous alcohol distillation system
CN105771589B (en) A kind of separator of ammonia and carbon dioxide
CN213760550U (en) Two-tower double-heat-pump integrated 1-butene refining energy-saving device
CN210796289U (en) High-efficient low energy consumption sodium methoxide purification equipment
CN103664616A (en) Method and device for producing benzyl benzoate
CN109646977B (en) Reactive distillation coupling tower and application thereof in preparation of formic acid
CN111848401A (en) Device and process for refining dimethyl carbonate by energy coupling with partition wall tower
CN218089444U (en) Device for extracting and purifying carbon tetraolefin

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant