CN113730934A - Separation and purification device and method for dichloromethane white oil mixed liquid - Google Patents
Separation and purification device and method for dichloromethane white oil mixed liquid Download PDFInfo
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- CN113730934A CN113730934A CN202110918057.XA CN202110918057A CN113730934A CN 113730934 A CN113730934 A CN 113730934A CN 202110918057 A CN202110918057 A CN 202110918057A CN 113730934 A CN113730934 A CN 113730934A
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- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 title claims abstract description 344
- 239000007788 liquid Substances 0.000 title claims abstract description 135
- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000000926 separation method Methods 0.000 title claims abstract description 16
- 238000000746 purification Methods 0.000 title claims abstract description 15
- 230000006835 compression Effects 0.000 claims abstract description 25
- 238000007906 compression Methods 0.000 claims abstract description 25
- 238000005086 pumping Methods 0.000 claims abstract description 21
- 229920006395 saturated elastomer Polymers 0.000 claims description 21
- 239000000463 material Substances 0.000 claims description 14
- 239000007791 liquid phase Substances 0.000 claims description 11
- 239000000047 product Substances 0.000 claims description 11
- 239000002918 waste heat Substances 0.000 claims description 11
- 230000001105 regulatory effect Effects 0.000 claims description 7
- 230000005611 electricity Effects 0.000 claims description 6
- 238000000605 extraction Methods 0.000 claims description 6
- 239000013589 supplement Substances 0.000 claims description 4
- 230000001276 controlling effect Effects 0.000 claims description 3
- 238000010992 reflux Methods 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 3
- 230000001502 supplementing effect Effects 0.000 claims description 3
- 238000005265 energy consumption Methods 0.000 abstract description 5
- 239000000498 cooling water Substances 0.000 abstract description 4
- 238000005516 engineering process Methods 0.000 abstract description 3
- 239000011552 falling film Substances 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 239000011259 mixed solution Substances 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
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- 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
- B01D3/007—Energy recuperation; Heat pumps
-
- 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
- B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
- B01D3/148—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step in combination with at least one evaporator
-
- 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
-
- 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
- C07C7/005—Processes comprising at least two steps in series
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G7/00—Distillation of hydrocarbon oils
- C10G7/006—Distillation of hydrocarbon oils of waste oils other than lubricating oils, e.g. PCB's containing oils
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G7/00—Distillation of hydrocarbon oils
- C10G7/12—Controlling or regulating
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
- C10G2400/14—White oil, eating oil
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- General Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Water Supply & Treatment (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
The invention discloses a device and a method for separating and purifying dichloromethane white oil mixed liquid. A gas phase discharge port of an MVR rectifying tower, a compression system, a saturator, a shell pass of a reboiler and a condensate tank of the device are sequentially communicated through pipelines, the condensate tank is communicated with the saturator through a first pipeline, the condensate tank is communicated with the top of the MVR rectifying tower through a second pipeline, and the condensate tank is communicated with a finished product storage tank through a third pipeline; the vacuum-pumping system is communicated with the saturator through a vacuum-pumping pipe. According to the invention, an MVR energy-saving rectification technology is adopted in the first stage of separation and purification of the dichloromethane and white oil mixed liquor, the latent heat of steam from the top of the MVR rectification tower is utilized and compressed by a two-stage compressor, the pressure and the temperature are increased, the circulating liquid at the bottom of the MVR rectification tower is heated, and the dichloromethane in the circulating liquid is vaporized and liquefied, so that the purpose of primary separation of the mixed liquor is achieved, the use of steam and cooling water is reduced, and the operation energy consumption is saved by 50-70% compared with that of a common separation and purification method.
Description
Technical Field
The invention relates to the technical field of separation and purification, in particular to a device and a method for separating and purifying dichloromethane and white oil mixed liquor.
Background
In the industries of special fibers and lithium battery diaphragms, white oil is usually used as a swelling agent or a pore-forming agent in the wet production process, and methylene dichloride is mostly adopted to elute the white oil on the surface of the special fibers and in the diaphragms in a multi-stage extraction mode due to the safety of methylene dichloride, so that special fiber yarns or microporous structures are formed. The white oil content in the mixed liquid discharged from the production line is usually 2-20 wt%, and the dichloromethane content is 80-98 wt%.
At present, the recovery of dichloromethane white oil mixed liquid generally adopts one-level atmospheric distillation + one-level negative pressure rectification mode to carry out separation and purification, and the dichloromethane boiling point is low, is evaporated out earlier at the rectification in-process, because dichloromethane content is great in the mixed liquid, need consume a large amount of steam, and the dichloromethane steam of evaporating simultaneously has a large amount of cooling water and low temperature water cooling of needs, and there is the great problem of energy consumption in the current rectification technique.
Disclosure of Invention
The invention aims to provide a dichloromethane white oil mixed liquid separation and purification device and a dichloromethane white oil mixed liquid separation and purification method, which can reduce energy consumption.
A separation and purification device for a dichloromethane white oil mixed liquid comprises an MVR rectifying tower, a compression system, a reboiler, a heat compensator, a condensate tank, a vacuum pumping system and a saturator; the device comprises a liquid phase discharge port of an MVR rectifying tower, a heat compensator and a tube pass of a reboiler, wherein the liquid phase discharge port of the MVR rectifying tower, the tube pass of the heat compensator and the tube pass of the reboiler are sequentially communicated through pipelines, a gas phase discharge port of the MVR rectifying tower, a compression system, a saturator, a shell pass of the reboiler and a condensate tank are sequentially communicated through pipelines, the condensate tank is communicated with the saturator through a first pipeline, a first valve is arranged on the first pipeline, the condensate tank is communicated with the top of the MVR rectifying tower through a second pipeline, a second valve is arranged on the second pipeline, the condensate tank is communicated with a finished product storage tank through a third pipeline, and a third valve is arranged on the third pipeline; the vacuum-pumping system is communicated with the saturator through a vacuum-pumping pipe.
Further, the device still includes charge pump and pre-heater, the feed inlet of charge pump, pre-heater and MVR rectifying column is linked together through the pipeline in proper order.
Furthermore, a liquid phase discharge port of the MVR rectifying tower is provided with a residual liquid pump and a residual liquid regulating valve or a frequency converter, and the frequency converter is electrically connected with the residual liquid pump.
Furthermore, a waste heat exchanger is further arranged on a pipeline section between the feeding pump and the preheater, the preheater is communicated with the waste heat exchanger, and the waste heat exchanger is communicated with the outlet end of the residual liquid pump.
Further, the device still includes the controller and is used for detecting the first level sensor of liquid level in the MVR rectifying column, the controller with first level sensor and converter electricity are connected, or work as the raffinate governing valve is the solenoid valve, the controller with first level sensor and raffinate governing valve electricity are connected.
Furthermore, the device also comprises a second liquid level sensor for detecting the liquid level in the condensate tank, the third valve is an electromagnetic valve, and the controller is electrically connected with the second liquid level sensor and the third valve.
Further, the vacuum pumping system comprises a liquid ring vacuum pump, and a pumping port of the liquid ring vacuum pump is communicated with the saturator through the vacuum pumping pipe; the sealing liquid of the liquid ring vacuum pump is dichloromethane, the circulating liquid tank of the liquid ring vacuum pump is communicated with the condensate tank through a liquid discharge pipe, and a liquid discharge valve for opening or closing the liquid discharge pipe is arranged on the liquid discharge pipe; the device also comprises a third liquid level sensor for detecting the liquid level in the circulating liquid tank of the liquid ring vacuum pump, the liquid discharge valve is an electromagnetic valve, and the controller is electrically connected with the third liquid level sensor and the liquid discharge valve.
Furthermore, an air suction valve for opening or closing the vacuum tube is arranged on the vacuum tube, a pressure sensor is arranged on a pipeline section of the vacuum tube between the air suction valve and the saturator, the air suction valve is an electromagnetic valve, and the controller is electrically connected with the pressure sensor and the air suction valve.
Further, the compression system comprises a first-stage compressor and a second-stage compressor which are connected in series, the fourth pipeline is communicated with the inlet end of the first-stage compressor and/or the inlet end of the second-stage compressor, and the total compression ratio of the first-stage compressor to the second-stage compressor is 1.8-3; the single machine compression ratio is 1.1-1.8, the first-stage compressor back pressure is 45-58 kpa, and the second-stage compressor back pressure is 60-80 kpa.
A method for separating and purifying dichloromethane white oil mixed liquor uses the device for separating and purifying dichloromethane white oil mixed liquor; the method comprises the following steps:
feeding the dichloromethane white oil mixed liquor at a bubble point of the MVR rectifying tower, allowing part of dichloromethane to vaporize after entering the MVR rectifying tower, separating from the top of the MVR rectifying tower, compressing by a compression system to increase the temperature and pressure of dichloromethane vapor, allowing the dichloromethane white oil mixed liquor to enter a saturator to supplement part of dichloromethane condensate to prepare dichloromethane saturated vapor, supplementing part of dichloromethane condensate to prepare dichloromethane saturated vapor, and allowing the dichloromethane saturated vapor to enter a shell pass of a reboiler;
white oil and unvaporized dichloromethane are separated from the bottom of the MVR rectifying tower, part of mixed liquid of the white oil and the unvaporized dichloromethane which is discharged from the bottom of the MVR rectifying tower enters a tube pass of a reboiler after being subjected to heat compensation by a heat compensator, the mixed liquid exchanges heat with dichloromethane saturated steam, the dichloromethane saturated steam in a shell pass of the reboiler is condensed and liquefied and flows into a condensate tank, the mixed liquid in the tube pass of the reboiler is partially vaporized in the process, and mixed liquid and steam in the tube pass of the reboiler both enter the MVR rectifying tower; the dichloromethane material in the condensate tank is discharged in three parts, one part of the dichloromethane material is supplemented into a saturator through a first pipeline and used for preparing dichloromethane saturated steam, the flow of the part is fixed and is realized by fixing the opening degree of a first valve, the other part of the dichloromethane material returns to the top of the MVR rectifying tower through a second pipeline and is used for controlling the temperature of the top of the tower to ensure the purity of the recycled dichloromethane, the reflux quantity of the part is adjusted by setting the opening degree of the second valve, the rest part of the dichloromethane material is output into a dichloromethane finished product storage tank as a finished product through a third pipeline, the discharge quantity of the part is adjusted by the opening degree of a third valve, and the opening degree of the third valve is controlled according to the liquid level in the condensate tank;
the condensate tank is communicated with the inlet end of the compression system through a fourth pipeline, and the opening degree of the fourth valve is set to balance the internal pressure of the condensate tank;
the vacuum pumping system controls the pressure in the saturator.
The temperature and pressure of the dichloromethane steam at the top of the MVR rectifying tower are raised after the dichloromethane steam is compressed by a two-stage compressor, the dichloromethane steam enters a saturator to obtain saturated dichloromethane steam through replenishing condensate, the obtained dichloromethane saturated steam enters a reboiler forwards and exchanges heat with the heated white oil at the bottom of the tower and the unvaporized dichloromethane mixed liquid, the dichloromethane saturated steam is condensed and liquefied at the reboiler, the heated white oil and the unvaporized dichloromethane mixed liquid are evaporated through a falling film, most dichloromethane is vaporized, the vaporized dichloromethane is discharged from the top of the tower, so that the heat of the dichloromethane steam at the top of the MVR rectifying tower is recycled, namely, the MVR energy-saving rectifying technology is adopted in the first stage of the separation and purification of the dichloromethane white oil, bubble point feeding under controlled pressure is adopted, and the latent heat of the steam discharged from the top of the MVR rectifying tower is compressed by the two-stage compressor, the pressure and the temperature are improved, the circulating liquid at the bottom of the MVR rectifying tower is heated, the dichloromethane in the circulating liquid is vaporized and liquefied, the purpose of preliminarily separating the mixed liquid is achieved, the use of steam and cooling water is reduced, and the operation energy consumption is saved by 50-70% compared with that of a common separation and purification method.
Drawings
Fig. 1 is a schematic structural diagram of a dichloromethane and white oil mixed liquid separation and purification device of the invention.
1. A feed pump; 2. a preheater; 3. an MVR rectifying tower; 4. a first stage compressor; 5. a secondary compressor; 6. a reboiler; 7. a heat compensator; 8. a condensate tank; 9. a circulation pump; 10. a residual liquid pump; 11. a condensate pump; 12. a vacuum pumping system; 121. a liquid ring vacuum pump; 13. a saturator; 14. a raffinate regulating valve; 15. a liquid outlet pipe; 16. a first pipeline; 161. a first valve; 17. a second pipeline; 171. a second valve; 18. a third pipeline; 181. a third valve; 19. a finished product storage tank; 20. vacuumizing a tube; 201. an air extraction valve; 21. a waste heat exchanger; 22. a liquid discharge pipe; 221. a drain valve; 23. a pressure sensor; 24. a fourth pipeline; 241. and a fourth valve.
Detailed Description
The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.
As shown in fig. 1, a device for separating and purifying a dichloromethane white oil mixed solution comprises an MVR rectifying tower 3, a compression system, a reboiler 6, a heat compensator 7, a condensate tank 8, a vacuum pumping system 12 and a saturator 13; a liquid phase discharge port of the MVR rectifying tower 3, a tube pass of the heat compensator 7 and a tube pass of the reboiler 6 are sequentially communicated through pipelines, a gas phase discharge port of the MVR rectifying tower 3, a compression system, a saturator 13, a shell pass of the reboiler 6 and a condensate tank 8 are sequentially communicated through a pipeline, the condensate tank 8 is communicated with the saturator 13 through a first pipeline 16, a first valve 161 is arranged on the first pipeline 16, the condensate tank 8 is communicated with the top of the MVR rectifying tower 3 through a second pipeline 17, a second valve 171 is arranged on the second pipeline 17, the condensate tank 8 is communicated with a finished product storage tank 19 through a third pipeline 18, a third valve 181 is arranged on the third pipeline 18, the condensate tank 8 is communicated with an inlet end of the compression system through a fourth pipeline 24, and a fourth valve 241 is arranged on the fourth pipeline 24; the evacuation system 12 communicates with the saturator 13 through an evacuation tube 20.
In the invention, after the top dichloromethane vapor of the MVR rectifying tower 3 is compressed by a compression system, the temperature and the pressure are increased, the vapor enters a saturator 13 to obtain saturated dichloromethane vapor through replenishing condensate, the obtained dichloromethane saturated vapor enters a reboiler 6 forwards to exchange heat with the heated bottom white oil and the unvaporized dichloromethane mixed liquid, the dichloromethane saturated vapor is condensed and liquefied, the heated white oil and the unvaporized dichloromethane mixed liquid are evaporated through a falling film, most dichloromethane in the dichloromethane is vaporized, the vaporized dichloromethane is discharged from the top of the tower, thus the heat of the top dichloromethane vapor of the MVR rectifying tower 3 is recycled, namely, the MVR energy-saving rectification technology is adopted in the first stage of the separation and purification of the dichloromethane white oil mixed liquid, bubble point feeding under controlled pressure is adopted, and the vapor latent heat ejected from the MVR rectifying tower 3 is compressed by a two-stage compressor, the pressure and the temperature are improved, the circulating liquid at the bottom of the MVR rectifying tower 3 is heated, dichloromethane in the circulating liquid is vaporized and liquefied, the purpose of preliminarily separating the mixed liquid is achieved, the use of steam and cooling water is reduced, and the operation energy consumption is saved by 50-70% compared with that of a common separation and purification method.
The device still includes charge pump 1 and pre-heater 2, and the feed inlet of charge pump 1, pre-heater 2 and MVR rectifying column 3 is linked together through the pipeline in proper order, squeezes the material into MVR rectifying column 3 in through charge pump 1, and pre-heater 2 heats up the material to MVR rectifying column 3's bubble point.
A liquid phase discharge port of the MVR rectifying tower 3 is provided with a residual liquid pump 10 and a residual liquid regulating valve 14 or a frequency converter, the frequency converter (not shown in the figure) is electrically connected with the residual liquid pump 10, and the load of the residual liquid pump 10 or/and the opening degree of the residual liquid regulating valve 14 are/is regulated according to the liquid phase height at the bottom of the MVR rectifying tower 3.
A waste heat exchanger 21 can be further arranged on the pipeline section between the feed pump 1 and the preheater 2, the preheater 2 is communicated with the waste heat exchanger 21, and the waste heat exchanger 21 is communicated with the outlet end of the residual liquid pump 10. Therefore, the high-temperature liquid phase flowing out of the bottom of the liquid phase discharge port of the MVR rectifying tower 3 can be utilized for preliminarily heating the material, and the energy is saved.
The waste heat exchanger 21, the preheater 2 and the heat compensator 7 can be plate heat exchangers, shell and tube heat exchangers or wound tube heat exchangers.
The preheater 2 and the heat compensator 7 are heated by an external heat source, wherein the external heat source can be heat compensating steam, heat conducting oil, electric heating, and the like.
The MVR rectifying tower 3 can be a random packed tower or a regular packed tower.
The saturator 13 is a container for supplementing condensate to the steam compressed by the compressor to form saturated steam.
The reboiler 6 may employ a falling film evaporator.
The liquid outlet of condensate tank 8 can be equipped with drain pipe 15, can be equipped with condensate pump 11 on drain pipe 15, and condensate pump 11 takes out condensate tank 8 material and divides three routes, and the saturator 13, the top of the tower of returning of the same kind, the ejection of compact of the same kind are gone back to one kind, and condensate pump 11 can be a pump, also can be two pumps or three pumps, when three pumps, sets up respectively on each way of material.
In this embodiment, the number of the condensate pumps is one, and the outlet ends of the condensate pumps 11 are respectively provided with three branches, one of the three branches is communicated with the saturator 13 through a first pipeline 16, the other branch is communicated with the top of the MVR rectifying tower 3 through a second pipeline 17, and the remaining branch is communicated with a finished product storage tank 19 through a third pipeline 18.
The evacuation system 12 may include a liquid ring vacuum pump 121, a water ring vacuum pump, or an oil-free vacuum pump.
In this embodiment, the vacuum pumping system 12 includes a liquid ring vacuum pump 121, an air pumping port of the liquid ring vacuum pump 121 is communicated with the saturator 13 through an evacuation tube 20, a sealing liquid of the liquid ring vacuum pump 121 may be dichloromethane, a circulating liquid tank of the liquid ring vacuum pump 121 is communicated with the condensate tank 8 through a drain tube 22, and the drain tube 22 is provided with a drain valve 221 for opening or closing the drain tube.
The compression system may have various configurations, which are not limited herein, such as: the compression system can comprise a first-stage compressor 4 and a second-stage compressor 5 which are connected in series, a fourth pipeline 24 is communicated with the inlet end of the first-stage compressor 4 and/or the inlet end of the second-stage compressor 5, and the total compression ratio of the first-stage compressor 4 to the second-stage compressor 5 can be 1.8-3; the single compressor compression ratio can be 1.1-1.8, the backpressure of the primary compressor 4 can be 45-58 kpa, the backpressure of the secondary compressor 5 can be 60-80 kpa, and in the embodiment, the fourth pipeline 24 is communicated with the inlet ends of the primary compressor 4 and the secondary compressor 5.
In order to realize systematic automation, the device can also include the controller (not shown in the figure) and be used for detecting the first level sensor (not shown in the figure) of liquid level in the MVR rectifying column 3, raffinate governing valve 14 can be the solenoid valve, the controller is connected with first level sensor and raffinate governing valve 14 electricity, adjust the size of 14 opennesses of raffinate governing valve through the height of liquid level in the MVR rectifying column 3, liquid level is too high in the MVR rectifying column 3 is detected as first level sensor, the controller is adjusted 14 openness of raffinate governing valve and is some greatly.
In another practical mode, the raffinate regulating device 14 may be in a normally open state, and the controller is electrically connected to the first liquid level sensor and the frequency converter, and when the first liquid level sensor detects that the liquid level in the MVR rectifying tower 3 is too high, the controller regulates the load of the raffinate pump 10 to be increased.
The device can also comprise a second liquid level sensor (not shown in the figure) for detecting the liquid level in the condensate tank 8, the third valve 181 is an electromagnetic valve, the controller is electrically connected with the second liquid level sensor and the third valve 181, and when the second liquid level sensor detects that the liquid level in the condensate tank 8 is too high, the controller controls the opening degree of the third valve 181 to be larger, so that the discharge amount is larger.
The device can also include a third liquid level sensor (not shown in the figure) for detecting the liquid level in the circulating liquid tank of the liquid ring vacuum pump 121, the liquid discharge valve 221 is an electromagnetic valve, the controller is electrically connected with the third liquid level sensor and the liquid discharge valve 221, when the third liquid level sensor detects that the liquid level in the circulating liquid tank is too high, the controller controls the opening degree of the liquid discharge valve 221 to be larger, so that the flow of dichloromethane liquid in the circulating liquid tank into the condensate tank 8 is larger.
The evacuation pipe 20 may further include an evacuation valve 201 for opening or closing the evacuation pipe, a pressure sensor 23 is disposed on a pipeline section of the evacuation pipe 20 between the evacuation valve 201 and the saturator 13, the evacuation valve 201 is an electromagnetic valve, the controller is electrically connected to the pressure sensor 23 and the evacuation valve 201, and the liquid ring vacuum pump 121 always handles an open state, so that when the pressure sensor 23 detects that the pressure in the saturator 13 is too high, the controller opens the evacuation valve 201, and the liquid ring vacuum pump 121 evacuates the saturator 13 to reduce the pressure in the saturator 13.
In this embodiment, a method for separating and purifying a dichloromethane white oil mixed solution uses the above device for separating and purifying a dichloromethane white oil mixed solution; the specific process is as follows:
the method comprises the following steps of enabling dichloromethane white oil mixed liquor to pass through a preheater 2 by using a feed pump 1 to reach the bubble point of an MVR rectifying tower 3 for feeding, enabling part of dichloromethane to be vaporized after entering the MVR rectifying tower 3 and then separated from the top of the MVR rectifying tower 3, enabling the dichloromethane to pass through a primary compressor 4 and a secondary compressor 5 to improve the temperature and pressure of dichloromethane steam, enabling the dichloromethane white oil mixed liquor to enter a saturator 13 to supplement part of dichloromethane condensate to prepare dichloromethane saturated steam, enabling the dichloromethane saturated steam to supplement part of dichloromethane condensate to prepare dichloromethane saturated steam, and enabling the dichloromethane saturated steam to enter the shell pass of a reboiler 6;
white oil and unvaporized dichloromethane are separated from the bottom of the MVR rectifying tower 3, part of mixed liquid of the white oil and the unvaporized dichloromethane from the bottom of the MVR rectifying tower 3 passes through a circulating pump 9, is subjected to heat compensation by a heat compensator 7 and then enters a tube pass of a reboiler 6, the mixed liquid exchanges heat with saturated dichloromethane vapor, the saturated dichloromethane vapor in a shell pass of the reboiler 6 is condensed and liquefied and flows into a condensate tank 8, part of dichloromethane in the mixed liquid in the tube pass of the reboiler 6 is vaporized and evaporated from the top of the MVR rectifying tower 3, and the rest part of dichloromethane is introduced into the top of the MVR rectifying tower 3 to continue circulation; the dichloromethane in the condensate tank 8 is discharged by a condensate pump 11, the pumped material is divided into three parts, one part of the dichloromethane is supplemented into a saturator 13 through a first pipeline 16 for preparing saturated dichloromethane vapor, the flow of the part is fixed and is realized by fixing the opening degree of a first valve 161, the other part of the dichloromethane returns to the top of the MVR rectifying tower 3 through a second pipeline 17 for controlling the temperature at the top of the tower to ensure the purity of the recycled dichloromethane, the reflux quantity of the part is adjusted by setting the opening degree of a second valve 171, the rest part of the dichloromethane enters a dichloromethane finished product storage tank 19 as a finished product through a third pipeline 18, the discharge quantity of the part is adjusted by the opening degree of a third valve 181, and the opening degree of the third valve 181 is controlled according to the liquid level in the condensate tank 8;
the condensate tank 8 is communicated with the inlet end of the compression system through a fourth pipeline 24, and the opening degree of a fourth valve 241 is set to balance the internal pressure;
discharging a part of mixed liquid of white oil and unvaporized dichloromethane from the bottom of the MVR rectifying tower 3 through a residual liquid pump 10;
the vacuum pumping system 12 continues to operate, with the suction valve 201 open, depending on the pressure in the saturator 13;
wherein the absolute pressure at the bottom of the MVR rectifying tower 3 is controlled to be 20-50 kpa, and the pressure drop of the rectifying tower is 0-2 kpa.
The above is not relevant and is applicable to the prior art.
While certain specific embodiments of the present invention have been described in detail by way of illustration, it will be understood by those skilled in the art that the foregoing is illustrative only and is not limiting of the scope of the invention, as various modifications or additions may be made to the specific embodiments described and substituted in a similar manner by those skilled in the art without departing from the scope of the invention as defined in the appending claims. It should be understood by those skilled in the art that any modifications, equivalents, improvements and the like made to the above embodiments in accordance with the technical spirit of the present invention are included in the scope of the present invention.
Claims (10)
1. The device for separating and purifying the dichloromethane and white oil mixed liquid is characterized in that: comprises an MVR rectifying tower, a compression system, a reboiler, a heat compensator, a condensate tank, a vacuum pumping system and a saturator; the device comprises a liquid phase discharge port of an MVR rectifying tower, a heat compensator and a tube pass of a reboiler, wherein the liquid phase discharge port of the MVR rectifying tower, a compression system, a saturator, a shell pass of the reboiler and a condensate tank are sequentially communicated through pipelines, the condensate tank is communicated with the saturator through a first pipeline, a first valve is arranged on the first pipeline, the condensate tank is communicated with the top of the MVR rectifying tower through a second pipeline, a second valve is arranged on the second pipeline, the condensate tank is communicated with a finished product storage tank through a third pipeline, a third valve is arranged on the third pipeline, the condensate tank is communicated with an inlet end of the compression system through a fourth pipeline, and a fourth valve is arranged on the fourth pipeline; the vacuum-pumping system is communicated with the saturator through a vacuum-pumping pipe.
2. The apparatus of claim 1, wherein the apparatus comprises: the device still includes charge pump and pre-heater, the feed inlet of charge pump, pre-heater and MVR rectifying column is linked together through the pipeline in proper order.
3. The apparatus of claim 2, wherein the apparatus comprises: and a liquid phase discharge port of the MVR rectifying tower is provided with a residual liquid pump and a residual liquid regulating valve or a frequency converter, and the frequency converter is electrically connected with the residual liquid pump.
4. The apparatus of claim 3, wherein the apparatus comprises: and a waste heat exchanger is also arranged on a pipeline section between the feed pump and the preheater, the preheater is communicated with the waste heat exchanger, and the waste heat exchanger is communicated with the outlet end of the residual liquid pump.
5. The apparatus of claim 3, wherein the apparatus comprises: the device still includes the controller and is used for detecting the first level sensor of liquid level in the MVR rectifying column, the controller with first level sensor and converter electricity are connected, or work as the raffinate governing valve is the solenoid valve, the controller with first level sensor and raffinate governing valve electricity are connected.
6. The apparatus of claim 5, wherein the apparatus comprises: the device still including be used for detecting the second liquid level sensor of liquid level in the condensate tank, the third valve is the solenoid valve, the controller is connected with second liquid level sensor and third valve electricity.
7. The apparatus of claim 5, wherein the apparatus comprises: the vacuum pumping system comprises a liquid ring vacuum pump, and an air pumping port of the liquid ring vacuum pump is communicated with the saturator through the vacuum pumping pipe; the sealing liquid of the liquid ring vacuum pump is dichloromethane, the circulating liquid tank of the liquid ring vacuum pump is communicated with the condensate tank through a liquid discharge pipe, and a liquid discharge valve for opening or closing the liquid discharge pipe is arranged on the liquid discharge pipe; the device also comprises a third liquid level sensor for detecting the liquid level in the circulating liquid tank of the liquid ring vacuum pump, the liquid discharge valve is an electromagnetic valve, and the controller is electrically connected with the third liquid level sensor and the liquid discharge valve.
8. The apparatus of claim 5, wherein the apparatus comprises: the vacuum tube is provided with an air extraction valve for opening or closing the vacuum tube, a pressure sensor is arranged on a pipeline section of the vacuum tube between the air extraction valve and the saturator, the air extraction valve is an electromagnetic valve, and the controller is electrically connected with the pressure sensor and the air extraction valve.
9. The apparatus of claim 1, wherein the apparatus comprises: the compression system comprises a first-stage compressor and a second-stage compressor which are connected in series, the fourth pipeline is communicated with the inlet end of the first-stage compressor and/or the inlet end of the second-stage compressor, and the total compression ratio of the first-stage compressor to the second-stage compressor is 1.8-3; the single machine compression ratio is 1.1-1.8, the first-stage compressor back pressure is 45-58 kpa, and the second-stage compressor back pressure is 60-80 kpa.
10. A method for separating and purifying dichloromethane white oil mixed liquid is characterized in that: the methylene dichloride white oil mixed liquor separation and purification device of any one of claims 1 to 9 is used; the method comprises the following steps:
feeding the dichloromethane white oil mixed liquor at a bubble point of the MVR rectifying tower, allowing part of dichloromethane to vaporize after entering the MVR rectifying tower, separating from the top of the MVR rectifying tower, compressing by a compression system to increase the temperature and pressure of dichloromethane vapor, allowing the dichloromethane white oil mixed liquor to enter a saturator to supplement part of dichloromethane condensate to prepare dichloromethane saturated vapor, supplementing part of dichloromethane condensate to prepare dichloromethane saturated vapor, and allowing the dichloromethane saturated vapor to enter a shell pass of a reboiler;
white oil and unvaporized dichloromethane are separated from the bottom of the MVR rectifying tower, part of mixed liquid of the white oil and the unvaporized dichloromethane which is discharged from the bottom of the MVR rectifying tower enters a tube pass of a reboiler after being subjected to heat compensation by a heat compensator, the mixed liquid exchanges heat with dichloromethane saturated steam, the dichloromethane saturated steam in a shell pass of the reboiler is condensed and liquefied and flows into a condensate tank, the mixed liquid in the tube pass of the reboiler is partially vaporized in the process, and mixed liquid and steam in the tube pass of the reboiler both enter the MVR rectifying tower; the dichloromethane material in the condensate tank is discharged in three parts, one part of the dichloromethane material is supplemented into a saturator through a first pipeline and used for preparing dichloromethane saturated steam, the flow of the part is fixed and is realized by fixing the opening degree of a first valve, the other part of the dichloromethane material returns to the top of the MVR rectifying tower through a second pipeline and is used for controlling the temperature of the top of the tower to ensure the purity of the recycled dichloromethane, the reflux quantity of the part is adjusted by setting the opening degree of the second valve, the rest part of the dichloromethane material is output into a dichloromethane finished product storage tank as a finished product through a third pipeline, the discharge quantity of the part is adjusted by the opening degree of a third valve, and the opening degree of the third valve is controlled according to the liquid level in the condensate tank;
the condensate tank is communicated with the inlet end of the compression system through a fourth pipeline, and the opening degree of the fourth valve is set to balance the internal pressure of the condensate tank;
the vacuum pumping system controls the pressure in the saturator.
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| CN105693460A (en) * | 2016-03-14 | 2016-06-22 | 江苏乐科节能科技股份有限公司 | Heat-pump distillation technology for recycling dichloromethane solvent |
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| CN105693460A (en) * | 2016-03-14 | 2016-06-22 | 江苏乐科节能科技股份有限公司 | Heat-pump distillation technology for recycling dichloromethane solvent |
| WO2017177763A1 (en) * | 2016-04-11 | 2017-10-19 | 山东万圣博科技股份有限公司 | System and method for separating n-methyl-2-pyrrolidone/chloroform |
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Application publication date: 20211203 |