WO2009006307A1 - Procédé de récupération de benzène - Google Patents
Procédé de récupération de benzène Download PDFInfo
- Publication number
- WO2009006307A1 WO2009006307A1 PCT/US2008/068592 US2008068592W WO2009006307A1 WO 2009006307 A1 WO2009006307 A1 WO 2009006307A1 US 2008068592 W US2008068592 W US 2008068592W WO 2009006307 A1 WO2009006307 A1 WO 2009006307A1
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- WIPO (PCT)
- Prior art keywords
- working fluid
- membrane
- components
- vacuum
- benzene
- Prior art date
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- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 title claims abstract description 192
- 238000011084 recovery Methods 0.000 title description 2
- 239000012528 membrane Substances 0.000 claims abstract description 65
- 238000000034 method Methods 0.000 claims abstract description 49
- 230000008569 process Effects 0.000 claims abstract description 44
- 230000008016 vaporization Effects 0.000 claims abstract description 3
- 239000012530 fluid Substances 0.000 claims description 73
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 30
- 238000005373 pervaporation Methods 0.000 claims description 30
- 239000012466 permeate Substances 0.000 claims description 20
- 238000009835 boiling Methods 0.000 claims description 18
- 239000000047 product Substances 0.000 claims description 18
- 239000000203 mixture Substances 0.000 claims description 14
- 125000003118 aryl group Chemical group 0.000 claims description 13
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 12
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 12
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 claims description 12
- 238000000605 extraction Methods 0.000 claims description 11
- HYBBIBNJHNGZAN-UHFFFAOYSA-N furfural Chemical compound O=CC1=CC=CO1 HYBBIBNJHNGZAN-UHFFFAOYSA-N 0.000 claims description 8
- LCEDQNDDFOCWGG-UHFFFAOYSA-N morpholine-4-carbaldehyde Chemical compound O=CN1CCOCC1 LCEDQNDDFOCWGG-UHFFFAOYSA-N 0.000 claims description 8
- LQNUZADURLCDLV-UHFFFAOYSA-N nitrobenzene Chemical compound [O-][N+](=O)C1=CC=CC=C1 LQNUZADURLCDLV-UHFFFAOYSA-N 0.000 claims description 8
- UWHCKJMYHZGTIT-UHFFFAOYSA-N Tetraethylene glycol, Natural products OCCOCCOCCOCCO UWHCKJMYHZGTIT-UHFFFAOYSA-N 0.000 claims description 5
- 230000009477 glass transition Effects 0.000 claims description 5
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 5
- 238000000197 pyrolysis Methods 0.000 claims description 5
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 claims description 5
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 4
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 4
- SZXQTJUDPRGNJN-UHFFFAOYSA-N dipropylene glycol Chemical compound OCCCOCCCO SZXQTJUDPRGNJN-UHFFFAOYSA-N 0.000 claims description 4
- -1 hexafluorophosphate Chemical compound 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 3
- 230000005484 gravity Effects 0.000 claims description 2
- 238000005119 centrifugation Methods 0.000 claims 1
- 239000012071 phase Substances 0.000 description 16
- 238000000926 separation method Methods 0.000 description 14
- 239000002904 solvent Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- 238000001704 evaporation Methods 0.000 description 5
- 125000001931 aliphatic group Chemical group 0.000 description 4
- 150000001491 aromatic compounds Chemical class 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 4
- 238000004231 fluid catalytic cracking Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 238000000638 solvent extraction Methods 0.000 description 4
- 238000004821 distillation Methods 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 150000007824 aliphatic compounds Chemical class 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- RWGFKTVRMDUZSP-UHFFFAOYSA-N cumene Chemical compound CC(C)C1=CC=CC=C1 RWGFKTVRMDUZSP-UHFFFAOYSA-N 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 230000037361 pathway Effects 0.000 description 2
- 239000003208 petroleum Substances 0.000 description 2
- 238000004230 steam cracking Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002605 large molecules Chemical class 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000012263 liquid product Substances 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000012465 retentate Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000001577 simple distillation Methods 0.000 description 1
- 239000012855 volatile organic compound Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
- 150000003738 xylenes Chemical class 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/002—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by condensation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
- B01D5/0027—Condensation of vapours; Recovering volatile solvents by condensation by direct contact between vapours or gases and the cooling medium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
- B01D53/229—Integrated processes (Diffusion and at least one other process, e.g. adsorption, absorption)
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/36—Pervaporation; Membrane distillation; Liquid permeation
- B01D61/362—Pervaporation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/144—Purification; Separation; Use of additives using membranes, e.g. selective permeation
-
- 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
- C10G31/00—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for
- C10G31/09—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for by filtration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
- B01D2257/702—Hydrocarbons
- B01D2257/7027—Aromatic hydrocarbons
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2311/00—Details relating to membrane separation process operations and control
- B01D2311/06—Specific process operations in the permeate stream
Definitions
- Benzene is a building block in plastics and basic chemicals. Benzene is used in the synthesis of styrene and cumene, two important intermediaries for polymers and other chemical derivatives, hi refineries and chemical plants, two major sources of benzene are reformate streams (i.e., the product stream from a catalytic reformer) and pyrolysis gasoline streams (i.e., a byproduct of steam cracking in olefins production). Both of these streams are rich in "BTEX" (benzene, toluene, ethylbenzene, and xylenes). Both streams also contain other components, such as normal paraffins (in virgin naphtha), isoparaffins (in reformate), and straight and branched olefins (in pyrolysis gasoline).
- reformate streams i.e., the product stream from a catalytic reformer
- pyrolysis gasoline streams i.e., a byproduct of steam cracking in
- the most common method of removing benzene from mixed streams that contain both aromatic and aliphatic compounds with similar boiling points is by distillation combined with a solvent extraction step.
- the feed stream rich in BTEX is first distilled to produce a narrow boiling range cut (called a "heart cut") that contains benzene and aliphatic compounds that have the same boiling range.
- the heart cut stream is then subjected to solvent extraction using a solvent that is selective for the removal of aromatics, thereby producing an essentially pure benzene product
- the BTEX feedstream is first subjected to solvent extraction to provide a product stream of mixed aromatics.
- the mixed aromatics stream is further separated by distillation to produce a highly purified benzene product, since there exists a large difference in the boiling points of benzene and the BTEX component having the closest boiling point, toluene. Both of these methods involve high capital expenditures and are energy intensive.
- pervaporation A membrane process known as "pervaporation” has been shown to be a less energy intensive process for aromatic/aliphatic separation.
- the term pervaporation comes from the words “permeation” and "evaporation” - two of the steps in the process.
- the pervaporation separation process uses a non-porous membrane which, when contacted with a multi-component liquid feed such as a mixed aliphatic and aromatic feedstream, selectively absorbs one or more of the species from the feedstream based upon chemical affinity. The absorbed species then permeate across the membrane under the influence of a concentration gradient that is produced by evaporating the absorbed molecules from the product side of the membrane using a vacuum or sweep gas.
- the permeate vapor emerging on the other side of the membrane is then condensed and recovered as a liquid.
- Temperature and pressure on the product side of the membrane are factors in the ability of a given species to "evaporate" from the membrane. Higher temperatures and better vacuums (less than about 25 mm Hg to about 50 mm Hg) favor evaporation of all species that permeate through the membrane, while lower temperatures and poorer vacuums (greater than about 25 mm Hg to about 50 mm Hg) favor selective evaporation of the lower boiling components from the product side of the membrane. In effect, there is a critical pressure for a given temperature that may allow selective evaporation of components.
- glass transition temperature (Tg) of a polymeric membrane may determine its selectivity toward various species. For instance, in rubbery membranes (i.e. those operating above their Tg), solubility of the feed components into the membrane polymer may govern permeation. Rubbery membranes tend to swell at elevated temperatures making them more effective for the separation of aromatics from non-aromatics but less effective for the selective separation of one aromatic compound (like benzene) from another (like toluene). In glassy membranes (i.e. those operating below their Tg), diffusivity tends to govern permeation, and lower molecular weight species may diffuse faster than higher molecular weight species. Therefore, in glassy membranes (or membranes that have a glassy component) it may be possible to selectively separate benzene from toluene.
- Tg glass transition temperature
- Schucker U.S. Patent 6,273,937, hereinafter the '937 patent
- the process of the '937 patent is capable of separating aromatic molecules from aliphatic molecules at better vacuums (less than about 25 mm Hg to about 50 mm Hg)
- the process is not capable of selectively separating benzene from other BTEX aromatics.
- aromatic extraction solvents e.g., sulfolanes, tetraethylene glycol or propylene carbonate
- further processing via distillation is required to separate the benzene from other aromatics.
- the present disclosure describes a process comprised by passing a feedstream to a permeation unit, wherein the permeation unit comprises a non- porous membrane having a first surface in contact with the feedstream and a second opposing surface in contact with a vacuum, wherein the amount of vacuum in contact with the second opposing surface is at a critical vacuum pressure.
- the process also includes absorbing selectively one or more components from the feedstream into the membrane at the first surface, wherein the one or more components comprises benzene.
- the process also includes permeating the one or more components from the first surface to the second opposing surface by influence of a concentration gradient across the membrane, wherein the concentration gradient across the membrane is maintained by use of the vacuum in contact with the second opposing surface.
- the process also includes vaporizing the one or more components at the second opposing surface while under critical vacuum pressure.
- the process also includes condensing the one or more components into a product stream.
- the process also includes separating the product stream comprising the one or more components, so as to separate benzene from the other components.
- the present disclosure describes a pervaporation apparatus comprised by a permeation unit, a vacuum source, a fluid pump, a working fluid, a decanter vessel, and a flash drum.
- the permeation unit in the pervaporation apparatus is further comprised by a non-porous polymeric membrane having a first surface and a second opposing surface.
- Figure 1 illustrates a schematic of an embodiment of the process apparatus described in the disclosure.
- FCC Fluid catalytic cracking
- Naphtha is a mixture of hydrocarbons obtained in the refining of petroleum, in some instances by FCC. Naphtha is often referred to as petroleum ether.
- Reformate is the product stream from a catalytic reformer.
- a feedstream comprised of one or more components, wherein one of the components comprises benzene may be passed into a permeation unit 14 through a line 10.
- the feedstream may be reformate in one embodiment.
- the feedstream may be pyrolysis gasoline.
- the feedstream may be FCC naphtha.
- the permeation unit 14 may contain a non-porous, polymeric selective membrane 11 possessing a first surface 11a and an opposing second surface lib.
- a portion of the feedstream that has a chemical affinity to the selective membrane 11 may come into contact with the selective membrane 11 at first surface 11a, absorb into membrane 11, and permeate across membrane 11 from the first surface 11a to the opposing second surface lib.
- a concentration gradient maintained by a vacuum condition on the side of the opposing second surface lib may drive the absorbing and permeation process.
- the vacuum condition may be a critical vacuum condition for benzene in an embodiment.
- the membrane is operated at a temperature below the membrane's glass transition temperature (Tg). In some embodiments, the operating temperature of the membrane is about O 0 C to about 300 0 C.
- the permeate Upon crossing through the selective membrane 11, the permeate may become volatilized from the second surface lib due to the vacuum condition generated on the opposing side surface lib of the permeation unit 14.
- the vacuum condition may be a critical vacuum pressure.
- the vaporous permeate may exit the permeation unit 14 through line 13 driven by the pressure differential of the partial vacuum.
- the lean retentate may exit permeation unit 14 through line 12.
- the vaporous permeate may optionally be cooled in line 13 by a chilled condenser operating at a temperature below the boiling point of the permeate at the operating vacuum in an embodiment.
- a partial vacuum may be generated by a Venturi nozzle 15 connected to the permeation unit 14 by line 13.
- Venturi nozzles are well known in the art.
- the pressure produced in a Venturi nozzle is defined by Bernoulli's equation (Formula 1):
- V 1 the velocity of the working fluid at the entrance of the nozzle
- V 2 the velocity of the working fluid at the narrowest point of the nozzle
- a Venturi nozzle 15 may be a circular-arc with a converging-diverging pathway.
- the converging-diverging pathway is known in the art to cause an increase in the velocity of flow of a working fluid as it passes through the restriction in the nozzle, thereby creating a corresponding decrease in fluid pressure.
- the decrease in fluid pressure creates a suction, or vacuum, for drawing a fluid connected to the nozzle.
- the temperature of the working fluid operates in the range of about O 0 C to about 15O 0 C. In other embodiments, the working fluid operates in the temperature range of about 0 0 C to about 100°C. In still other embodiments, the working fluid operates in the temperature range of about 25 0 C to about 15O 0 C.
- the working fluid may be pumped by fluid pump 21 through line 22 into the Venturi nozzle 15 at a velocity that produces a desired vacuum and therefore a pressure gradient across the non-porous membrane 11.
- the vacuum obtained by passing the working fluid through the Venturi nozzle may reach a value that is a critical vacuum.
- the critical vacuum in this disclosure is defined as a vacuum pressure that lies between the vapor pressure of benzene and the vapor pressure of toluene at the conditions existing on the second surface lib of the membrane.
- a vacuum at the critical vacuum on the second surface side lib of the non-porous membrane 14 advantageously may favor the desorption of benzene from the opposing second surface lib of the membrane 11 over other aromatics such as toluene.
- Operation at a critical vacuum may allow benzene to volatilize from the opposing second surface lib of the non-porous membrane 11 and inhibit the volatilization of toluene and other aromatics.
- a critical vacuum value may be determined using a mathematical model derived by Ji and co workers (W. Ji; S. K. Sikdar, and S. T. Hwang, "Modeling of Multicomponent Pervaporation for Removal of Volatile Organic Compounds from Water," J. Mem. Sd., 93(1994), 1-19): (Formula 2).
- j i %rr i - l b -p- ) (2)
- Xi mole fraction of i in the polymer at the second opposing surface of the membrane
- pi partial pressure of i in the permeate vapor (Pa)
- Setting the vacuum to be the critical vacuum may prevent other aromatics from being desorbed from the non-porous membrane 11 in an embodiment of the process described.
- the passage of working fluid through the Venturi nozzle 15 creates a suction on the permeate in the permeation unit 14 and draws the permeate into the working fluid where the permeate mixes intimately with the working fluid flowing through the Venturi nozzle to create a product stream.
- the working fluid may be an extraction solvent having selectivity for extraction of aromatic compounds over non- aromatic compounds.
- Working fluid-containing permeate, some dissolved and some entrained, exits Venturi nozzle 15 through line 16.
- the working fluid/permeate which comprises a product stream, enters decanter vessel 17, wherein the flow separates into two liquid phase portions: a heavier extract phase 18 and a lighter phase 19, allowing selective separation of benzene from other components in the product stream.
- the heavier phase 18 is comprised of the working fluid and dissolved benzene.
- lighter phase 19 is a raff ⁇ nate phase, which is comprised of all the other components that are poorly soluble in the working phase liquid.
- separation of 18 from 19 occurs by gravity in the decanter vessel.
- the decanter vessel is alternately comprised as a centrifuge for separation of 18 and 19.
- the decanter vessel 17 may operate at about atmospheric pressure. Operation of the decanter vessel 17 either above or below atmospheric pressure may be advantageous in certain instances, and such operation remains within the spirit and scope of the disclosure.
- the lighter phase raffinate 19 exits the decanter vessel 17 through midline 20.
- the heavier extract phase 18 exits decanter vessel 17 through line 23.
- the heavier extract phase 18 is then heated by heat exchanger 24 to above the normal boiling point of benzene, whereupon the heavier extract phase 18 exits the exchanger 24 through line 25.
- the heated heavier extract phase 18 then enters into a flash drum 26, wherein benzene vaporizes away from the working fluid in a flash heating process.
- flash drum 26 may be operated at about atmospheric pressure. In other embodiments, flash drum 26 may be operated at a partial vacuum to facilitate the flashing process and reduce the energy needs of heat exchanger 24, as will be evident to one skilled in the relevant art.
- working fluids for benzene separation may include, but are not limited to, those selected from the group consisting of propylene carbonate, ethylene carbonate, N-methyl pyrrolidone, tetramethylene sulfone, tetraethylene glycol, N-formyl morpholine, furfural, nitrobenzene, dipropylene glycol, glycerol, diethylene glycol, ethylene glycol, l-butyl-3-methylimidazolium hexafluorophosphate, and mixtures thereof. These non-limiting examples may beneficially demonstrate affinity for selective extraction of aromatic molecules over non- aromatic molecules.
- Vaporized benzene exits the flash drum 26 through a line 27.
- the vaporized benzene is condensed by heat exchanger 28 and exits the system as a liquid product stream through line 29.
- the heat exchanger 28 is a chilled condenser operated at a temperature below the boiling point of benzene at the operating vacuum of flash drum 26.
- the lean working fluid exits the flash drum 26 through line 30, is cooled by heat exchanger 31, and is recycled to fluid pump 21 through a line 32. Integration of the heat exchangers discussed in this embodiment may provide advantageous energy cost savings.
- a method of providing a critical vacuum for a pervaporation system that does not use a vacuum pump or a steam ejector is disclosed. This disclosure is based on the use of a converging-diverging (Venturi) nozzle that uses a high boiling point aromatic extraction solvent as the working fluid instead of steam.
- a permeation membrane module whose permeate side is connected to the throat of the Venturi nozzle is also disclosed.
- Working fluid passing through the nozzle pulls a vacuum, in some embodiments a critical vacuum, by adjustment of the flow rate of working fluid through the Venturi nozzle that is sufficient to selectively permeate and volatilize benzene from the surface of the membrane.
- the extraction solvent in an embodiment is one that has selectivity for benzene over other similar boiling point chemicals. Benzene may be removed from the extraction solvent by a flashing process, either at atmospheric or reduced pressure, and collected as a product stream.
- the present disclosure is also embodied as a pervaporation apparatus which is demonstrated schematically in Figure 1.
- the pervaporation apparatus may be configured to separate benzene from a mixture of other components.
- the pervaporation apparatus may be comprised by a permeation unit 14, a vacuum source, a fluid pump 21, a working fluid, a decanter vessel 17, and a flash drum 26.
- a mixture of one or more components, one of which comprises benzene, enters permeation unit 14 through line 10.
- the permeation unit 14 may be comprised by a non-porous, polymeric membrane 11 having a first surface 11a and an opposing second surface lib in an embodiment.
- the operating temperature of the polymeric membrane 11 is maintained below the membrane's glass transition temperature (Tg) in some embodiments.
- the operating temperature of the polymeric membrane 11 is maintained from about O 0 C to about 300°C.
- the vacuum source is comprised by a Venturi nozzle 15, through which the working fluid flows to create a vacuum.
- the pervaporation apparatus may contain a line 12 in an embodiment to remove the mixture of components not permeated across membrane 11.
- the pervaporation apparatus advantageously may utilize a working fluid demonstrating affinity for selective extraction of aromatic molecules over non-aromatic molecules, wherein the working fluid is selected from the group, including but not limited to, propylene carbonate, ethylene carbonate, N-methyl pyrrolidone, tetramethylene sulfone, tetraethylene glycol, N-formyl morpholine, furfural, nitrobenzene, dipropylene glycol, glycerol, diethylene glycol, ethylene glycol, l-butyl-3-methylimidazolium hexafluorophosphate, and mixtures thereof.
- the working fluid is selected from the group, including but not limited to, propylene carbonate, ethylene carbonate, N-methyl pyrrolidone, tetramethylene sulfone, tetraethylene glycol, N-formyl morpholine, furfural, nitrobenzene, dipropylene glycol, glycerol, diethylene glyco
- Venturi nozzle 15 is operated to maintain the second opposing membrane surface lib at a reduced pressure condition, hi certain embodiments, the reduced pressure condition may be a critical vacuum for benzene.
- a mixture of one or more components, wherein one of the components comprises benzene travels from membrane surface lib into the working fluid inside the Venturi nozzle 15 through line 13.
- the working fluid exits the Venturi nozzle 15 through line 16 and contains the one or more components of the permeate, wherein one of the components comprises benzene.
- the working fluid may operate within a temperature range of about O 0 C to about 150°C in some embodiments.
- the working fluid may operate within a temperature range of about 0°C to about 100°C. In still other embodiments, the working fluid may operate within a temperature range of about 25 0 C to 150°C.
- Working fluid is supplied to Venturi nozzle 15 from fluid pump 21 through line 22. [0033] Upon leaving the Venturi nozzle 15, the working fluid containing a mixture of one or more components, one of which comprises benzene, travels through line 16 and collects in a decanter vessel 17 and may separate into a mixture of two immiscible phases 18 and 19.
- the decanter vessel 17 may be alternately be embodied as a centrifuge in certain instances. Decanter vessel 17 may optionally be heated, cooled, or operated under a reduced pressure condition in some embodiments.
- the lighter phase 19 may be comprised by one or more components insoluble in the working fluid
- the heavier phase 18 may be comprised by the working fluid and one or more components, one of which comprises benzene.
- Lighter phase 19 may be removed from decanter vessel 17 through midline 20 in an embodiment.
- the heavier phase 18 comprised by the working fluid and one or more components, one of which comprises benzene, may travel through lines 23 and 25 to flash drum 26 after passing through heat exchanger 24.
- Heat exchanger 24 may be used to heat the working fluid solution of one or more components, one of which comprises benzene.
- heat exchanger 24 may heat the working fluid solution of one or more components, one of which comprises benzene, to above the normal boiling point of benzene.
- Flash drum 26 may be operated at atmospheric pressure in an embodiment. In another embodiment, flash drum 26 may be operated at a reduced pressure condition to advantageously lower the temperature of the flashing process. Following flashing, vaporized benzene travels though line 27 before being condensed by heat exchanger 28. The condensed benzene may be collected as a product stream through line 29. Lean working fluid may be passed back to fluid pump 21 after passing through heat exchanger 31 and line 32.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Water Supply & Treatment (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
L'invention concerne un procédé qui comprend le passage d'un courant d'alimentation sur une unité de perméation comprenant une membrane comportant une première surface en contact avec le courant d'alimentation et une seconde surface en contact avec un vide, la quantité de vide en contact avec la seconde surface étant à un niveau de vide critique, absorbant sélectivement un ou plusieurs composants du courant d'alimentation dans la membrane sur la première surface, le ou les composants comprenant du benzène, en faisant pénétrer le ou les composants de la première surface vers la seconde surface sous l'influence d'un gradient de concentrations à travers la membrane qui est maintenu par l'utilisation d'un vide critique en contact avec la seconde surface, en vaporisant le ou les composants sur la seconde surface qui est sous vide critique, en condensant le ou les composants dans des courants de produit, et en séparant le ou les composants de façon à séparer sélectivement le benzène.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US94689007P | 2007-06-28 | 2007-06-28 | |
US60/946,890 | 2007-06-28 |
Publications (1)
Publication Number | Publication Date |
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WO2009006307A1 true WO2009006307A1 (fr) | 2009-01-08 |
Family
ID=40226486
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/US2008/068592 WO2009006307A1 (fr) | 2007-06-28 | 2008-06-27 | Procédé de récupération de benzène |
Country Status (1)
Country | Link |
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WO (1) | WO2009006307A1 (fr) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20190249630A1 (en) * | 2018-02-14 | 2019-08-15 | Saudi Arabian Oil Company | Onboard fuel separation for octane-on-demand using membrane distillation |
US10478778B2 (en) | 2015-07-01 | 2019-11-19 | 3M Innovative Properties Company | Composite membranes with improved performance and/or durability and methods of use |
CN110538480A (zh) * | 2019-09-25 | 2019-12-06 | 上海电气集团股份有限公司 | 一种冷凝系统及冷凝方法 |
US10618008B2 (en) | 2015-07-01 | 2020-04-14 | 3M Innovative Properties Company | Polymeric ionomer separation membranes and methods of use |
US10737220B2 (en) | 2015-07-01 | 2020-08-11 | 3M Innovative Properties Company | PVP- and/or PVL-containing composite membranes and methods of use |
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US6273937B1 (en) * | 2000-03-29 | 2001-08-14 | Trans Ionics Corporation | Membrane pervaporation and vapor permeation system |
US6896717B2 (en) * | 2002-07-05 | 2005-05-24 | Membrane Technology And Research, Inc. | Gas separation using coated membranes |
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- 2008-06-27 WO PCT/US2008/068592 patent/WO2009006307A1/fr active Application Filing
Patent Citations (3)
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US6273937B1 (en) * | 2000-03-29 | 2001-08-14 | Trans Ionics Corporation | Membrane pervaporation and vapor permeation system |
US6899743B2 (en) * | 2002-06-12 | 2005-05-31 | Membrane Technology And Research, Inc. | Separation of organic mixtures using gas separation or pervaporation and dephlegmation |
US6896717B2 (en) * | 2002-07-05 | 2005-05-24 | Membrane Technology And Research, Inc. | Gas separation using coated membranes |
Non-Patent Citations (1)
Title |
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SHE ET AL.: "Concentration of dilute flavor compounds by pervaporation: permeate pressure effect and boundary layer resistance modeling", JOURNAL OF MEMBRANE SCIENCE, vol. 236, no. 1-2, 15 June 2004 (2004-06-15), pages 193 - 202, XP004507037 * |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10478778B2 (en) | 2015-07-01 | 2019-11-19 | 3M Innovative Properties Company | Composite membranes with improved performance and/or durability and methods of use |
US10618008B2 (en) | 2015-07-01 | 2020-04-14 | 3M Innovative Properties Company | Polymeric ionomer separation membranes and methods of use |
US10737220B2 (en) | 2015-07-01 | 2020-08-11 | 3M Innovative Properties Company | PVP- and/or PVL-containing composite membranes and methods of use |
US20190249630A1 (en) * | 2018-02-14 | 2019-08-15 | Saudi Arabian Oil Company | Onboard fuel separation for octane-on-demand using membrane distillation |
US10697412B2 (en) * | 2018-02-14 | 2020-06-30 | Saudi Arabian Oil Company | Onboard fuel separation for octane-on-demand using membrane distillation |
CN110538480A (zh) * | 2019-09-25 | 2019-12-06 | 上海电气集团股份有限公司 | 一种冷凝系统及冷凝方法 |
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