US2541682A - Production of para xylene - Google Patents

Production of para xylene Download PDF

Info

Publication number
US2541682A
US2541682A US770587A US77058747A US2541682A US 2541682 A US2541682 A US 2541682A US 770587 A US770587 A US 770587A US 77058747 A US77058747 A US 77058747A US 2541682 A US2541682 A US 2541682A
Authority
US
United States
Prior art keywords
xylene
para
temperature
crystal phase
mother liquor
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.)
Expired - Lifetime
Application number
US770587A
Other languages
English (en)
Inventor
Arnold Jerome Howard
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.)
California Research LLC
Original Assignee
California Research LLC
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
Priority to BE499776D priority Critical patent/BE499776A/xx
Application filed by California Research LLC filed Critical California Research LLC
Priority to US770587A priority patent/US2541682A/en
Priority claimed from GB30000/50A external-priority patent/GB694980A/en
Priority to US206278A priority patent/US2695323A/en
Application granted granted Critical
Publication of US2541682A publication Critical patent/US2541682A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0004—Crystallisation cooling by heat exchange
    • B01D9/0013—Crystallisation cooling by heat exchange by indirect heat exchange
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0004—Crystallisation cooling by heat exchange
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0036—Crystallisation on to a bed of product crystals; Seeding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/004—Fractional crystallisation; Fractionating or rectifying columns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0059—General arrangements of crystallisation plant, e.g. flow sheets
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/14—Purification; Separation; Use of additives by crystallisation; Purification or separation of the crystals
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S203/00—Distillation: processes, separatory
    • Y10S203/19—Sidestream

Definitions

  • This invention relates to the recovery of para xylene from a xylene rich fraction consisting essentially of a complex mixture of xylenes with aromatic and non-aromatic hydrocarbons boiling in the same range as the para xylene. More particularly, the invention involves the production of para xylene from a mixture of nonaromatic petroleum hydrocarbons.
  • a complex hydrocarbon fraction with which the present invention is concerned primarily and from which para xylene may be recovered typically contains only a minor proportion of para xylene.
  • the proportion of para xylene in such mixtures seldom is more than 30% by volume and usually is less than about 21% by volume of the hydrocarbon fraction but should be more than about of the xylene present in the mixture.
  • the major portion of the mixture comprises aromatic hydrocarbons boiling Within 11 F. of the para xylene and including from at least about 5% up to as much as 20% or more of ethyl benzene based on the entire hydrocarbon fraction.
  • the ethyl benzene content may be from 50 to 100% by volume of the para xylene content.
  • the xylene fraction usually contains at least about 5% and up to 20% or more (based on the entire hydrocarbon fraction) of unsulfonatable hydrocarbons of unknown constitution.
  • parafiinic which may boil as much as 50 F. below the para xylene and not more than a'bout20 F. above the para isomer.
  • paraillnic hydrocarbons may be present in amounts of from 25 to 100% by volume based on the para xylene content and include acyclic saturated hydrocarbons which either boil within the range or form constant boiling mixtures with ahe xylenes.
  • Examples of such paraiiinic hydrocarbons are various isomeric octanes and nonanes. The presence of cyclic paraiins, i. e., naphthenes boiling from 50 F. below to 20 F.above para xylene is not precluded.
  • Spannagel Patent No. 1,940,065 allegedly recovers para xylene by crystallization but first purifies the xylene fraction by distilling off any aliphatic hydrocarbons, ethyl benzeneand the like, boiling below para and meta xylene," to avoid the complicating'eiects of these impurities.
  • ortho xylene also is removed and an intermediate meta, para xylene cut boiling from 13G-140 C., and evidently free of complieating hydrocarbon impurities, ls utilizedY in the crystallization step.
  • para xylene is separated from the above-described xylene-rich hydrocarbon mixtures by chilling to a temperature of from -75 to 120 F., preferably from 80 F. to -l10 F. and more desirably to a temperature below 80 F. and just above that representedl by one of the following v equations:
  • T2V minimum temperature in F.
  • X equals per cent paraillns in feed
  • Y equals per cent ethyl benzene in feed
  • Z equals per cent ortho xylene in feed.
  • T2 minimum temperature in F.
  • X per cent paraflins in feed
  • Y per cent ethyl benzene in feed
  • Z per cent of meta xylene in the feed.
  • T2 minimum temperature in F.
  • X per cent parafflns in feed
  • Y per cent ethyl benzene in feed.
  • para xylene is produced and recovered from non-aromatic petroleum hydrocarbons.
  • a suitable xylene fraction is obtained by aromatization, preferably by the so-called hydroforming process in which a naphthenic petroleum fraction is aromatized and xylenes are produced.
  • hydroforming process in which a naphthenic petroleum fraction is aromatized and xylenes are produced.
  • 'Ihis type of process is well-known in the petroleum industry.
  • careful coordination of feed stocks and hydroforming conditions is necessary to obtain best results and to yield a preferred xylene fraction for recovery of para xylene in accordance with this invention.
  • the present invention is particularly adapted to the treatment of an equilibrium xylene mixture from hydroformed non-aromatic petroleum fractions.
  • equilibrium xylene mixture is here utilized to designate a xylene fraction containing ortho, meta and para xylenes in the equilibrium proportions resulting from hydroforming or other suitable aromatization process, that is, in which the relative proportions are about o:m:p::2:6:2.
  • the additional ethyl benzene and parafns hereinbefore described are also present.
  • the invention is particularly adapted to the treatment of this specific type of mixture, it will be understood that the invention is also applicable to other xylene fractions of the compositions hereinbefore described. To avoid prolixity, the remainder 0f this description will be made with reference to xylene fractions derived from hydroforming operations.V
  • FEED STOCKS Naphthenic hydrocarbon mixtures from naphthene-type petroleum crude oils comprise one preferred type of feed stock.
  • vSuch mixtures are normally termed straight run distillates in the petroleum industry, although other aromatizable hydrocarbons or dstillates may be substituted therefor.
  • the hydrocarbons present in this preferred feed stock are believed to consist largely of cyclo-aliphatic hydrocarbons with six carbon atoms in the cyclo-aiphatic ring and with aliphatic side chains attached to the ring. Some five and seven carbon atom cyclo-aliphatic rings may be present. Both the number of side chains and the length of each chain attached to the foregoing rings vary among the many compounds normally present in a petroleum hydrocarbon mixture.
  • these variables are a function of the average molecular weight or, more particularly, the boiling range and distillation -curve .of the petroleum fraction.
  • a naphthenic hydrocarbon mixture consisting essentially of hydrocarbons having from six to twelve carbon atoms in the molecule and preferably composed at least predominantly of hydrocarbons containing from seven to eight carbon atoms at present is regarded as a more desirable feed stock.
  • the fraction selected desirably should boil within the range of from about 180 F. to about 420 F. and preferably from about 180 F. to about 320 F. In some instances an even more narrow cut boiling from 230 F. to 275 F. is preferred. Open chain paraillnic hydrocarbon fractions of these boiling ranges are not precluded.
  • an initial step in the exemplary process comprises aromatization of the particular petroleum feed stock selected.
  • a naphthenic hydrocarbon mixture is utilized, the conversion of hydrocarbons to aromatics is believed to occur by dehydrogenation of the six carbon atom rings from cyclo-aliphatic to aromatic while leaving alkyl groups attached to the residual nucleus.
  • the preferred aromatization process knownas hydroforming is characterized by aromatization in the presence of controlled amounts of hydrogen and a vanadium oxide or ⁇ molybdenum oxide catalyst.
  • a hydrocarbon feed such as a naphthenic petroleum distillate, boiling within the range of F. to 320 F., and obtained, for instance. by fractional distillation of a crude petroleum (from Kettleman Hills Oil Field in California) is passed at from about 900 F. to about 1200 F., desirably about 1000 F., over a vanadium oxide-alumina or molybdenum oxide-alumina catalyst.
  • Space rate desirably is from 0.1 to about 2.0 volumes of liquid hydrocarbon feed per volume of catalyst per hour, and it is preferred to maintain a partial pressure of hydrogen in the reaction zone Vof from about 30 to about 300 pounds per square inch.
  • the reaction product from such a hydroforming operation will contain not only the desired xylenes and additional aromatic hydrocarbon but also aliphatic hydrocarbons boiling over a wide range, including C4 and like materials. Initially, therefore, it' is necessary to recover a xylene fraction from this reaction mixture.
  • Fig. 1 is a schematic flow sheet of a typical process and suitable apparatus for practicing the process of this invention.
  • Figs. 2 and 3 illustrate graphically the effect of parafns upon crystallization temperature and recovery of para xylene.
  • Figs. 4 and 5 illustrate the eiTect of ethyl benzene on crystallization temperaturey and recovery of para xylene
  • Fig. 6 reveals the influence of relative proportions of the xylene isomers on crystallization recovery of para xylene.
  • Fig. 7 shows the effect of ortho xylene concentration on optimum crystallization temperatures and at different ratios of ortho to meta xylenes.
  • a naphthenic hydrocarbon feed is introduced by way of line l to a hydroforming unit and non-aromatic petroleum hydrocarbons such as the naphthenic petroleum distillate boiling within the range of 18o-320 F., as previously described, is converted to a complex aromatic hydrocarbon fraction.
  • the particular hydroforming operation is that previously described and exemplied as a preferred process.
  • the hydrocarbon eiiiuent iiows by way of line I2 to a fractionating column I3 where separation is effected. As here shown, the fractionation is effected in a single column although a multiplicity of fractionating units may be utilized.
  • C4 and lighter hydrocarbons are taken as overhead through line
  • C9 and heavier hydrocarbons are discharged as bottoms by way of line I 8.
  • the xylene-rich hydrocarbon mixture from which para xylene is to be recovered is withdrawn from fractionating column I3 by way of lziie I9 and ows through cooler 2
  • the ortho xylene content of a fraction prepared by hydroforming is less than the preferred ratio, and as here shown ortho xylene is added to the hydrocarbon mixture in surge tank 22 by line 23, and the ortho to meta xylene ratio is thereby adjusted to approximately 1:2.
  • the blended hydrocarbon mixture so formed then flows by way of lines 24 and 28 through heat exchanger 21 Where the temperature of the mixture is initially lowered, most desirably by indirect heat exchange with mother liquor from the crystallization operation. This mother liquor flows through inlet and outlet conduits 28 and 29, but for purposes of simplicity connections with the mother liquor lines are not shown.
  • where it is reduced to crystallizing temperature by mixing with previously cooled xylene stock.
  • the xylene stock is retained at crystallizing temperature until the desired crystal form is obtained, that is, until shock crystals are largely removed by remelting and recrystallization or by equilibrium exchange with larger crystals which will be retained and recovered satisfactorily in subsequent filtering operations.
  • a residence time of about twenty minutes is preferred.
  • Crystallizing temperature is maintained in soaking tank 3
  • circulation pump 33 forces the xylene through temperature-controlled chillers 34, 36 and 31 connected in parallel, as shown, by valve-controlled inlet lines 38, 39 and 4I.
  • circulation pump 33 is designed and controlled to force the xylene mixture through the chiller It has been found that recovery of para xylene minutes or more residence time at crystallizingtemperatures.
  • the xylene stream flows into a suitable heat insulated soaking or tubes at a suflicient velocity and under adequate pressure to cause turbulent ow.
  • turbulent flow here is used in the kcommonly accepted hydraulic sense.
  • Such turbulent flow is adapted to prevent or minimize localized shock cooling of the xylenes at the surface of the heat exchange tubes in coolers 34, 36 and 31. Additionally, crystal growth and adherence on the walls of such heat exchange tubes is reduced to a minimum by the use of high velocities, especially those exceeding the minimum for turbulent flow. For example, supercooling may be effected in the heat exchange tubes and the supercooled liquid returned to the crystallization tank before crystal formation is completed. After reduction to a crystallization temperature at least as low as that to be maintained in soaking tank 3
  • any suitable refrigerant is supplied to the chillers by Way of inlet header 25 and outlet 30.
  • Liquefied ethylene, ethane or methane are examples of suitable refrigerants.
  • temperature controls 35 are provided in the refrigerant discharge line of each of the chillers to regulate the flow of refrigerant therethrough. Desirably, these controls are responsive to the temperature of the xylene mixture in discharge lines 42, 43 and 44 respectively.
  • the slurry of para xylene crystals in the remaining liquid hydrocarbon mixture is conveyed by suitable means, as indicated by line 41, to a crystal separation and recovery unit.
  • crystal separation and purification are eiected by a combination of centrifugal lters and an agitated tank washer. Initially the crystals in slurry from tank 3
  • washing fiuid any suitable washing fiuid may be utilized, such as isopentane, alcohol or the like, but as here shown a para xylene saturated hydrocarbon mixture is -introduced by way of valve-controlled line 52 with the slurry and the mixture intimately contacted by agitators 53. The resultant slurry flows through outlet line 54 to a second centrifugal filter 56. In order to maintain and control the temperature in washer I, a portion of the washing liquid in stream 54 is by-passed through valvecontrolled line 51, heater 58 and return line 59 to washing tank 5
  • is separated in the second stage centrifugal filter 56, and the purified crystals removed and transferred to melting tank 63 as indicated by line 64.
  • the ltrate from this second stage separation is discharged by way oi' line 66.
  • 'I'his filtrate comprises a xylene fraction saturated withv respect to para xylene at ltration temperature. A portion thereof flows by way o f valve-controlled line 52 to be utilized as the washing liquid in tank 5
  • the remainder of the nitrate from unit 56 passes by way of recycle line 61 through heat exchanger 21, and preferably is blended with the xylene feed stock, before it is introduced into soaking tank 3
  • Purified crystals ofpara xylene in tank 63 are melted and passed to storage 68 by way of line 89. A portion of the melted stock is by-passed through valve-controlled line 1I, heater 12 and return line 13, the heated xylene serving to melt crystals fed to the system. Heat is supplied by hot water or any other suitable fluid introduced through the line 'I4 and discharged through line 15.
  • 'I'he two-stage filtration and crystallization system preferablyis operated with first-stage filter 48 maintained at a lower temperature than second-stage lter 56.
  • is allowed Ato melt so that the filtrate from unit 56 is para xylene of the desired purity, thereby furnishing a wash liquid rich in para xylene by way of valve-controlled line 52 for removing entrained less-pure mother liquor from the crystals in washer 5
  • Temperature in such a washing operation may be from about +20 F. to +35 F. although lower temperatures may be used, depending upon purity and yields desired.
  • Mother liquor from first stage filter 48 is discharged by way of outlet conduit 11, and in the embodiment here illustrated passes to fractionating column 18 wherein an ortho xylene fraction is separated by distillation.
  • ortho xylene is removed from the l0 distillation as a bottoms fraction by way of discharge line 19.
  • a portion of the ortho xylene desirably is recycled by way of valve-controlled line 23 to feed surge tank 22 in an amount sumcient to adjust the ortho xylene content of the feed as previously disclosed herein.
  • the remainder of the ortho xylene flows to storage by way 'of valve-controlled line 8
  • Overhead from superfractionator 18 passes by way of line 82 to'storage 83.
  • This overhead fraction consistsv of a mixture of xylenes, primarily meta xylene with minor amounts of ortho and para xylenes as well as with parafhns and ethyl benzene contained in the original feed stock.
  • a preferred method of superfractionation is to operate the fractionating unit continuously at a given constant feed rate while (1) removing overhead distillate and bottoms at a constant ratio corresponding to the feed rate and in a relative proportion such that the desired purity of the ortho xylene may be maintained, and (2) maintaining a constant volume of liquid and still bottoms by controlling the rate of heat inputthereto.
  • Maintenance of the constant volume of bottoms may be effected, for example, by a constant level control which increases the amount of steam admitted to the still heating unit when the level of the still bottoms begins to rise, and decreases steam input when the volume of bottoms begins to drop below the predetermined level.
  • Figs. 2 and 3 illustrate that the presence of paralllns tends to decrease para xylene recoveryat any given' temperature, but that this decrease in recovery is avoidable by further reducing crystallization temperature 'within the limits and in the manner hereinA disclosed; that is, by lower- 12 TABLE I Eect of paramns on the recovery of para ing the temperature 0.3 F. for each per cent of b renin Feedo parafns present.
  • An agitated chilling vessel adding the unsulfonatable residue (that is, the was provided for cooling the feed stock by inparaiiinic hydrocarbons) of a xylene fraction I ternal refrigeration by direct addition of Dry formed by hydroforming a petroleum hydrocarbon Ice.
  • unsulfonatable residue that is, the was provided for cooling the feed stock by inparaiiinic hydrocarbons
  • a xylene fraction I ternal refrigeration by direct addition of Dry formed by hydroforming a petroleum hydrocarbon Ice.
  • By utilrated CO2 mechanical agitation was utilized to izing this particular mixture of paraillns, repreaid in controlling the temperature of the charge sentative results were obtained without the necesstock and in reducing agglomeration of the sity of identifying the exact composition and prosolid CO2. portions of the different parafilnic components.
  • the centrifugal pump, agitator and pipe lines were suitably insulated to maintain low temperatures. Means for' measuring temperatures in the agitator and of the inlet and outlet of the centrifuge were provided. In operation, the whole system was gradually cooled to the desired crystallization temperature by addition of solid CO: to the agitator and continuous recirculation of the xylene mother liquor through the agitator and centrifugal filter.
  • the method of separating paraxylene from catalytically reformed naphtha which comprises fractionally distilling said naphtha to separate a xylene rich fraction having a boiling range from about 270 F. to about 300 F., passing said fraction into a cooling zone and cooling it to a temperature in the range F. tof-120 F.
  • a cyclic process for recovering paraxylene from a hydrocarbon liquid comprising substantial amounts of orthoxylene, metaxylene and paraxylene comprising the steps of cooling ing a paraxylene content substantially greater than that of the mother liquor, filtering the wash liquid from the crystal phase, withdrawing'the I0 washed crystal phase as a product, conducting the washing and second mentioned llltering steps at temperatures substantially above the temperature of the cooling zone such that a substantial portion of the crystal phase is melted during said steps, returning a portion of the ltrate Iromthe second mentioned ltering step to the .cooling 16 zoneduring, a. succeeding cycle and utilizing the remainder as the major component of the specied wash liquid to wash the crystal phase produced in the succeeding cycle of operation.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (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)
US770587A 1947-08-26 1947-08-26 Production of para xylene Expired - Lifetime US2541682A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE499776D BE499776A (en(2012)) 1947-08-26
US770587A US2541682A (en) 1947-08-26 1947-08-26 Production of para xylene
US206278A US2695323A (en) 1947-08-26 1951-01-16 Production of para xylene

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US770587A US2541682A (en) 1947-08-26 1947-08-26 Production of para xylene
GB30000/50A GB694980A (en) 1950-12-07 1950-12-07 Recovery of para xylene from hydrocarbon mixtures by fractional crystallisation
US206278A US2695323A (en) 1947-08-26 1951-01-16 Production of para xylene

Publications (1)

Publication Number Publication Date
US2541682A true US2541682A (en) 1951-02-13

Family

ID=32303025

Family Applications (2)

Application Number Title Priority Date Filing Date
US770587A Expired - Lifetime US2541682A (en) 1947-08-26 1947-08-26 Production of para xylene
US206278A Expired - Lifetime US2695323A (en) 1947-08-26 1951-01-16 Production of para xylene

Family Applications After (1)

Application Number Title Priority Date Filing Date
US206278A Expired - Lifetime US2695323A (en) 1947-08-26 1951-01-16 Production of para xylene

Country Status (2)

Country Link
US (2) US2541682A (en(2012))
BE (1) BE499776A (en(2012))

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2603667A (en) * 1950-01-26 1952-07-15 Phillips Petroleum Co Fractional crystallization
US2614134A (en) * 1950-06-21 1952-10-14 Standard Oil Dev Co Purification of crystalline substances
US2651665A (en) * 1950-06-10 1953-09-08 Standard Oil Dev Co Recovery of pure paraxylene
US2659763A (en) * 1950-09-16 1953-11-17 California Research Corp Xylene separation
US2665316A (en) * 1950-10-21 1954-01-05 Standard Oil Dev Co Recovery of durene
US2672487A (en) * 1949-05-28 1954-03-16 Standard Oil Dev Co Para xylene separation process
US2695323A (en) * 1947-08-26 1954-11-23 California Research Corp Production of para xylene
US2724007A (en) * 1952-07-30 1955-11-15 Exxon Research Engineering Co Para xylene separation process
US2747001A (en) * 1950-06-09 1956-05-22 Phillips Petroleum Co Crystal purification process
US2750433A (en) * 1951-03-20 1956-06-12 California Research Corp Hydrocarbon analysis and control in crystallization processes
US2766309A (en) * 1952-05-23 1956-10-09 Exxon Research Engineering Co Wash technique for paraxylene process
US2773129A (en) * 1955-07-27 1956-12-04 Itt Flat-bank crossbar switch
US2790018A (en) * 1954-06-09 1957-04-23 Exxon Research Engineering Co Recovery of para xylene by crystallization
US2795635A (en) * 1953-08-28 1957-06-11 Phillips Petroleum Co Centrifuge
US2795634A (en) * 1953-05-01 1957-06-11 Standard Oil Co Recovery of ortho-and para-xylenes from c8 aromatic mixtures
US2823241A (en) * 1954-03-22 1958-02-11 Exxon Research Engineering Co Method for washing a filter cake
US2824147A (en) * 1949-03-21 1958-02-18 Ici Ltd Separation of xylenes
US2827503A (en) * 1953-05-01 1958-03-18 Standard Oil Co Recovery of para-xylene from solutions containing the xylene isomers
DE1034633B (de) * 1954-05-20 1958-07-24 Basf Ag Verfahren zur Zerlegung organischer Stoffgemische durch fraktionierte Kristallisation
US2848516A (en) * 1953-03-16 1958-08-19 Phillips Petroleum Co Crystal purification method
US2866833A (en) * 1953-09-14 1958-12-30 Standard Oil Co Paraxylene purification system
US2881230A (en) * 1955-09-26 1959-04-07 Phillips Petroleum Co Fractional crystallization process
DE972036C (de) * 1952-10-03 1959-05-14 Metallgesellschaft Ag Verfahren zur Abtrennung von p-Xylol aus seinen technischen Gemischen
US2952825A (en) * 1955-07-05 1960-09-13 Marlan E Bourns Electrical resistor
US4662990A (en) * 1984-12-19 1987-05-05 Hanover Research Corporation Apparatus for recovering dry solids from aqueous solids mixtures
US5094722A (en) * 1989-10-11 1992-03-10 Sumikin Chemical Co., Ltd. Process for the purification of a dimethylphenol isomer
US5152875A (en) * 1990-04-10 1992-10-06 Hoechst Aktiengesellschaft Separation of m- and p-dichlorobenzene
US5498822A (en) * 1994-04-04 1996-03-12 Mobil Oil Corporation Single temperature stage crystallization of paraxylene
US6147272A (en) * 1994-12-29 2000-11-14 Institut Francais Du Petrole Process for separating paraxylene comprising at least two crystallization stages at high temperature

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2815288A (en) * 1953-09-04 1957-12-03 Phillips Petroleum Co Crystal purification
DE1934721C3 (de) * 1969-07-09 1974-01-17 Fried. Krupp Gmbh, 4300 Essen Verfahren zum Abtrennen von Flüssigkeitsfilmen von p-Xylol-Kristallen
US8877014B2 (en) 2012-12-14 2014-11-04 Uop Llc Split-shell fractionation columns and associated processes for separating aromatic hydrocarbons

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1940065A (en) * 1927-12-15 1933-12-19 Ig Farbenindustrie Ag Separatrion and purification of ortho, meta and para xylene
US2383174A (en) * 1940-02-17 1945-08-21 United Gas Improvement Co Recovery of valuable hydrocarbons
US2398526A (en) * 1943-08-07 1946-04-16 Allied Chem & Dye Corp Isolation of para-xylene
US2400883A (en) * 1941-01-06 1946-05-28 Koppers Co Inc Method of refining light-oil products
US2435792A (en) * 1944-09-07 1948-02-10 Standard Oil Dev Co Chemical process

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE499776A (en(2012)) * 1947-08-26

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1940065A (en) * 1927-12-15 1933-12-19 Ig Farbenindustrie Ag Separatrion and purification of ortho, meta and para xylene
US2383174A (en) * 1940-02-17 1945-08-21 United Gas Improvement Co Recovery of valuable hydrocarbons
US2400883A (en) * 1941-01-06 1946-05-28 Koppers Co Inc Method of refining light-oil products
US2398526A (en) * 1943-08-07 1946-04-16 Allied Chem & Dye Corp Isolation of para-xylene
US2435792A (en) * 1944-09-07 1948-02-10 Standard Oil Dev Co Chemical process

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2695323A (en) * 1947-08-26 1954-11-23 California Research Corp Production of para xylene
US2824147A (en) * 1949-03-21 1958-02-18 Ici Ltd Separation of xylenes
US2672487A (en) * 1949-05-28 1954-03-16 Standard Oil Dev Co Para xylene separation process
US2603667A (en) * 1950-01-26 1952-07-15 Phillips Petroleum Co Fractional crystallization
US2747001A (en) * 1950-06-09 1956-05-22 Phillips Petroleum Co Crystal purification process
US2651665A (en) * 1950-06-10 1953-09-08 Standard Oil Dev Co Recovery of pure paraxylene
US2614134A (en) * 1950-06-21 1952-10-14 Standard Oil Dev Co Purification of crystalline substances
US2659763A (en) * 1950-09-16 1953-11-17 California Research Corp Xylene separation
US2665316A (en) * 1950-10-21 1954-01-05 Standard Oil Dev Co Recovery of durene
US2750433A (en) * 1951-03-20 1956-06-12 California Research Corp Hydrocarbon analysis and control in crystallization processes
US2766309A (en) * 1952-05-23 1956-10-09 Exxon Research Engineering Co Wash technique for paraxylene process
US2724007A (en) * 1952-07-30 1955-11-15 Exxon Research Engineering Co Para xylene separation process
DE972036C (de) * 1952-10-03 1959-05-14 Metallgesellschaft Ag Verfahren zur Abtrennung von p-Xylol aus seinen technischen Gemischen
US2848516A (en) * 1953-03-16 1958-08-19 Phillips Petroleum Co Crystal purification method
US2795634A (en) * 1953-05-01 1957-06-11 Standard Oil Co Recovery of ortho-and para-xylenes from c8 aromatic mixtures
US2827503A (en) * 1953-05-01 1958-03-18 Standard Oil Co Recovery of para-xylene from solutions containing the xylene isomers
US2795635A (en) * 1953-08-28 1957-06-11 Phillips Petroleum Co Centrifuge
US2866833A (en) * 1953-09-14 1958-12-30 Standard Oil Co Paraxylene purification system
US2823241A (en) * 1954-03-22 1958-02-11 Exxon Research Engineering Co Method for washing a filter cake
DE1034633B (de) * 1954-05-20 1958-07-24 Basf Ag Verfahren zur Zerlegung organischer Stoffgemische durch fraktionierte Kristallisation
US2790018A (en) * 1954-06-09 1957-04-23 Exxon Research Engineering Co Recovery of para xylene by crystallization
US2952825A (en) * 1955-07-05 1960-09-13 Marlan E Bourns Electrical resistor
US2773129A (en) * 1955-07-27 1956-12-04 Itt Flat-bank crossbar switch
US2881230A (en) * 1955-09-26 1959-04-07 Phillips Petroleum Co Fractional crystallization process
US4662990A (en) * 1984-12-19 1987-05-05 Hanover Research Corporation Apparatus for recovering dry solids from aqueous solids mixtures
US5094722A (en) * 1989-10-11 1992-03-10 Sumikin Chemical Co., Ltd. Process for the purification of a dimethylphenol isomer
US5152875A (en) * 1990-04-10 1992-10-06 Hoechst Aktiengesellschaft Separation of m- and p-dichlorobenzene
US5498822A (en) * 1994-04-04 1996-03-12 Mobil Oil Corporation Single temperature stage crystallization of paraxylene
US6147272A (en) * 1994-12-29 2000-11-14 Institut Francais Du Petrole Process for separating paraxylene comprising at least two crystallization stages at high temperature

Also Published As

Publication number Publication date
US2695323A (en) 1954-11-23
BE499776A (en(2012))

Similar Documents

Publication Publication Date Title
US2541682A (en) Production of para xylene
US2533232A (en) Production of para xylene
DE69512227T2 (de) Einstufiges kristallisationsverfahren bei konstanter temperatur zur rückgewinnung von paraxylol
US3775288A (en) Combination of dilution chilling with scraped surface chilling in dewaxing lubricating oils
US2398526A (en) Isolation of para-xylene
US2511711A (en) Process for separating a mixture of isomeric xylenes
US2665316A (en) Recovery of durene
US2672487A (en) Para xylene separation process
US2780663A (en) Fractional crystallization and crystal washing
US2866833A (en) Paraxylene purification system
US3916018A (en) Separation of paraxylene
US3959978A (en) Separation process by fractional crystallization
US2820070A (en) Method for recovering paraxylene
US2795634A (en) Recovery of ortho-and para-xylenes from c8 aromatic mixtures
US2383174A (en) Recovery of valuable hydrocarbons
US2816938A (en) Fractional crystallization under pressure
US2413674A (en) Multistage method of purifying styrene
US3590091A (en) Crystallization and purification of 2,6-dmn
US3212281A (en) Fractional crystallization
US2985694A (en) Multistage xylene separation process
US2527824A (en) Manufacture of xylene isomers
US2438368A (en) Method of purifying benzene
US6525235B2 (en) Method for manufacturing 2,6-dimethylnaphthalene
US2659763A (en) Xylene separation
US3067125A (en) Dewaxing process