US3850740A - Partial predilution dilution chilling - Google Patents

Partial predilution dilution chilling Download PDF

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US3850740A
US3850740A US00284647A US28464772A US3850740A US 3850740 A US3850740 A US 3850740A US 00284647 A US00284647 A US 00284647A US 28464772 A US28464772 A US 28464772A US 3850740 A US3850740 A US 3850740A
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solvent
oil
dewaxing
cooling zone
cloud point
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US00284647A
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D Gudelis
D Shaw
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ExxonMobil Technology and Engineering Co
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Exxon Research and Engineering Co
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Priority to US00284647A priority Critical patent/US3850740A/en
Priority to AU59205/73A priority patent/AU486973B2/en
Priority to GB3888373A priority patent/GB1440127A/en
Priority to CA179,368A priority patent/CA1012919A/en
Priority to DE2343041A priority patent/DE2343041C2/de
Priority to IT28298/73A priority patent/IT998484B/it
Priority to FR7331106A priority patent/FR2197965B1/fr
Priority to JP9626573A priority patent/JPS573718B2/ja
Priority to NLAANVRAGE7311873,A priority patent/NL186017C/xx
Priority to US05/516,625 priority patent/US4013542A/en
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    • 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
    • C10G73/00—Recovery or refining of mineral waxes, e.g. montan wax
    • C10G73/02—Recovery of petroleum waxes from hydrocarbon oils; Dewaxing of hydrocarbon oils
    • C10G73/06—Recovery of petroleum waxes from hydrocarbon oils; Dewaxing of hydrocarbon oils with the use of solvents
    • 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
    • C10G73/00—Recovery or refining of mineral waxes, e.g. montan wax
    • C10G73/02—Recovery of petroleum waxes from hydrocarbon oils; Dewaxing of hydrocarbon oils
    • C10G73/32—Methods of cooling during dewaxing

Definitions

  • ABSTRACT A dewaxing process is described wherein a residual waxy petroleum oil stock characterized by having a viscosity greater than about 75 SUS at 210F. and containing less than about 10 percent of material boiling below about 950F., is mixed with at least about 0.3 volumes of a dewaxing solvent per volume of residual waxy oil stock, thereby depressing the cloud point of same.
  • the resultant mixture is introduced into a cooling zone. at a temperature above the depressed cloud point of the oil.
  • Precooled dewaxing solvent is incrementally added to the cooling zone which is divided into a plurality of stages with agitation means present in each of the stages.
  • the resultant solvent-oil mixture is cooled and agitated as it passes through the cooling Zone, thereby reducing the temperature of the oil to below its depressed cloud point and precipitating at least a portion of the wax therefrom.
  • a residual oil stock of diminished wax content is thereafter recovered.
  • the waxy oil stock is introduced into the cooling zone in the absence of solvent at a temperature above the cloud point of the oil.
  • Precooled dewaxing solvent is introduced incrementally into the initial stages of the cooling zone, coming into contact with the waxy oil and depressing its cloud point.
  • the oil is gradually cooled to a temperature no less than the depressed cloud point of the oil whereupon additional precooled dewaxing solvent is added to the oil in the remaining stages of the cooling zone, thereby gradually cooling the oil to a temperature below "the depressed cloud point and precipitating at least a portion of the wax therefrom.
  • This invention relates to a process for the dewaxing of a waxy residual petroleum oil stock. More particularly, this invention relates to a solvent predilution dewaxing process wherein a residual waxy petroleum oil stock is admixed with a solvent prior to the cooling of the oil to a temperature below its depressed cloud point.
  • the temperature of the solvent should be the same as that of the main stream at the point of addition. Having the solvent at a lower temperature causes shock chilling of the slurry at that point, with resulting formation of crystal fines, and impairment of filter rate; having the solvent warmer throws an unnecessary additional load on the scraped surface chillers.
  • the bulk of the chilling of the slurry in this well-known process is accomplished through the walls of the scraped surface chillers rather than by means of cold solvents.
  • Dewaxing solvent is introduced into the cooling zone at a plurality of spaced points situated along the cooling zone, coming into contact with the oil.
  • High levels of agitation are provided in at least a portion of the solvent-containing stages, thereby providing substantially instantaneous mixing of the solvent and oil, e.g., within a second or less.
  • the oil passes through the cooling zone, it is cooled to a temperature sufficient to precipitate at least a portion of the wax therefrom resulting in the formation of a wax slurry wherein the wax particles have a unique crystal structure, thereby providing superior filtering characteristics such as high filter rates and high dewaxed oil yields. While the process of Ser. No.
  • the process is particularly suitable for dilution chilling dewaxing and comprises, in one embodiment of the invention, prediluting a waxy residual oil with at least about 0.3 volumes ofa predilution solvent per volume of residual oil stock, resulting in the depression of the cloud point of the oil stock.
  • the process feedstock comprises a residual waxy petroleum oil stock characterized by having a viscosity greater than about SUS at 210F. and containing less than about percent of material boiling below about 950F., (all temperatures are reported at atmospheric pressure, unless otherwise stated).
  • the cloud point of the oil is defined as the temperature at which a cloud or haze of wax crystals first appears when an oil is cooled under prescribed conditions (modified ASTM D2500-66 procedure).
  • Predilution refers to the mixing of solvent and oil prior to cooling of the oil to a temperature below its depressed cloud point.
  • the resultant solvent-oil mixture is introduced into a cooling zone divided into a plurality of stages, at a temperature above the depressed cloud point of the oil.
  • Additional dewaxing solvent which may be the same or different than the predilution solvent used to form the initial solvent-oil mixture, is introduced into at least a portion of the stages and high levels of agitation are maintained in at least a portion of the solventcontaining stages thereby providing efficient mixing of solvent and oil.
  • the high levels of agitation referred to above are only necessary during the initial phases of wax crystal nucleation and growth. Once good crystal growth is effected, lower agitation levels may be used, e.g., in the later stages of the cooling zone.
  • the solvent-oil mixture is cooled as it passes through the cooling zone to a temperature below the depressed cloud point of the waxy oil stock, thereby precipitating at least a portion of the wax therefrom, and a residual oil stock of diminished wax content is recovered.
  • the predilution of the oil is conducted in situ, i.e., within the cooling zone itself.
  • the feedstock is introduced into the cooling zone at a temperature above its cloud point and in the substantial absence of solvent.
  • At least about 0.3 volumes of solvent per volume of oil is added to the initial stages of the cooling zone, coming into contact with the oil stock and forming an oil-solvent mixture.
  • the mixture is gradually cooled, as it passes through the initial cooling stages, to a temperature no less than the depressed cloud point of the oil stock.
  • additional solvent is introduced into at least a portion of the remaining stages of the cooling zone, and the oil is further cooled to a temperature below its depressed cloud point thereby precipitating at least a portion of the wax.
  • cooling of the oil may also be employed.
  • other cooling means such as autorefrigeration, wherein cooling is effected in part by vaporization of solvent, may also be employed.
  • the feedstock that is used in the process of the invention comprises a residual waxy oil stock having an initial boiling point above about 800F., with less than about 10 percent (by weight) of material boiling below about 950F. and less than about 50 percent (by weight) of material boiling below about 1,050F.
  • the oil is further characterized by having a viscosity greater than about 75 SUS at 2 lOF. and ranging between about 75 and 300 SUS, preferably between about 100 and 200 SUS and most preferably between about 125 and 175 SUS at 210F.
  • the residual oil contains the most difficulty vaporizable components of petroleum hydrocarbons including asphaltenes and pitch, which are undesirable not only in the finished lubricating oil product, but also in the LII intermediate refining operations, as discussed in more detail infra. It is thus preferred, prior to the dewaxing operation of the subject invention, to remove as much of these components from the residual oil as possible, such as by a deasphalting operation, e.g., propane deasphalting. Further, the residual oil may contain aromatic and polar molecules which would impart undesirable properties to the finished lube oil product. These molecules may be removed by using such process techniques as solvent extraction, comparatively severe hydrogen treatment and the like either before or after the dewaxing step.
  • the residual oil is derived from a raw lube oil stock, the major portion of which boils above about 650F.
  • This oil stock can be vacuum distilled with the resultant overhead and sidestreams being termed distillates and the bottoms being termed residua or residual oil stocks.
  • distillates are therefore included in the term residual as used herein.
  • the crude sources from which the instant feedstocks may be obtained are exemplified by the paraffinic crudes such as Aramco, Kuwait, the Panhandle, North Louisiana, Tia Juana and the like.
  • the wax content of the feedstock as defined by the amount of material to be removed to produce an oil with a pour point in the range of +25 to 0F. will vary between about 5 and 35 wt. percent based on total feed, preferably between about 10 and 30 wt. percent.
  • the initial pour and cloud points of the oil will range, respectively, between about and 175F. and about and 180F.
  • the predilution solvent is selected from any of the dewaxing solvents known in the prior art such as the aliphatic ketones having from three to six carbon atoms, e.g., acetone, methylethyl ketone (MEK), methylisobutyl ketone (MlBK) and the like, the lower molecular weight hydrocarbons such as ethane, propane, butane and propylene, as well as mixtures of the foregoing ketones and mixtures of the ketones with hydrocarbon compounds such as propylene, and aromatics such as benzene and toluene.
  • the dewaxing solvents known in the prior art such as the aliphatic ketones having from three to six carbon atoms, e.g., acetone, methylethyl ketone (MEK), methylisobutyl ketone (MlBK) and the like
  • the lower molecular weight hydrocarbons such as ethane, propane, but
  • halogenated low molecular weight hydrocarbons such as the C -C chlorinated hydrocarbons, e.g., dichloromethane, dichloroethane and mixtures thereof, may be used.
  • effective predilution solvents include toluene, MlBK, MEK/toluene, MEK/MIBK and the like.
  • the depressed cloud point of the oil is dependent, in part, upon the degree of predilution of the oil with solvent and will preferably range between about 50 and l75F., most preferably between about 50 and F.
  • the amount of predilution solvent added to the oil will be dependent, in part, on the nature of the feedstock, the cooling zone, the extent of cooling within the cooling zone, i.e., approach to the filtration temperature, and the desired final ratio of solvent to oil in the wax/oil/solvent slurry withdrawn from the cooling zone.
  • Preferred amounts of predilution dewaxing solvent range between about 0.3 and 2.0 volumes per volume of residual oil stock, most preferred between about 0.5 to 1.5 volumes of solvent per volume of oil stock.
  • the dewaxing solvent that is used during the phase of the dewaxing operation conducted at a temperature below the depressed cloud point of the oil may be the same as or different than the predilution solvent and is selected from the same group of solvents mentioned in connection with the predilution solvents.
  • suitable dewaxing solvent mixtures include methylethyl ketone/methylisobutyl ketone, methylethyl ketone/toluene and propylene/acetone.
  • the preferred solvents are the C -C ketones with methylethyl ketone being particularly preferred. It is noted that when the dewaxing solvent is MEK, a particularly preferred predilution solvent comprises toluene or MIBK.
  • the predilution process has been found to be specific to waxy residual oils as described hereinabove, and is, in fact, detrimental to the dewaxing of light distillates.
  • the term light distillates refers to a feedstock having a 90 percent or end boiling point as high as about 1,050F. and containing at least 50 percent (by weight) of material boiling below about 1,050F.
  • these light distillates usually contain more than about percent (by weight) of material boiling below about 950F. but contain less than about 5 percent (by weight) of material boiling below about 650F.
  • the distillate is further 1 characterized by having a viscosity at 210F below about 75 SUS.
  • predilution techniques in dilution chilling dewaxing reduce the overall viscosity of the oil stock in the critical early stages of crystal nucleation and growth thereby removing diffusion limitations to crystal growth and facilitating the development of larger particles.
  • wax crystallizing from such high boiling, high molecular weight feedstocks comprises highly branched paraffins and naphthenes, which have very low crystal growth rates.
  • wax crystallizing from lower boiling distillate feedstocks generally contains predominantly normal paraffins, which have relatively high crystal growth rates and would therefore not be as sensitive to diffusion limitations.
  • a preferred dewaxing aid comprises a Ziegler type mixed normal alpha olefin copolymer described in more detail in U.S. Ser. No. 164,892, filed July 21, 1971, having a number average molecular weight between about 2,000 and 60,000 or higher, and having pendant side chains of C and higher.
  • a particularly preferred dewaxing aid composition comprises 38 wt. percent nhexene-l, 26percent n-hexadecene-l, 21 percent noctadecene-l and 15 percent n-eicosene-l.
  • Other dewaxing aids may also be used such as polymeric higher alkyl methacrylates, long-chain alkyl 1,2-oxiranes, po-
  • lymerized higher fatty acid esters of vinyl alcohol a mixture of at least two homopolymers of a C C alpha olefin, a Friedel-Crafts condensation product of a halogenated hydrocarbon such as chlorinated paraffin wax with an aromatic hydrocarbon such as naphthalene, mixtures thereof and the like.
  • FIG. 1 is a simplified flow scheme of a preferred embodiment of the dewaxing process of the subject invention.
  • FIG. 2 is a graph relating filter :rate to the amount of predilution in MEK/toluene dilution chilling dewaxing of an Aramco 2,500 bright stock.
  • a waxy lubricating oil stock is taken from tankage and introduced into predilution mixing zone 1 via line 28 while dewaxing solvent is introduced therein via 1ine-29QAfter a sufficient contact time, the resultant solvent-oil mixture is introduced via line 2 into cooling zone 3, at a temperature above the depressed cloud point of the feedstock.
  • heating means may be provided in mixing zone 1 to ensure that the feed temperature is above the depr'essed cloud point of the oil prior to introduction into the cooling zone.
  • the cooling zone is depicted herein as a vertical cooling tower; however, it is noted that the design is not limited to this configuration.
  • the solventoil mixture enters the cooling tower and into the first stage of the cooler, i.e., 4(a).
  • Dewaxing solvent is passed from storage tank 5 through line 6, and heat exchangers 7 and 8, where the solvent temperature is reduced to that sufficient to cool the oil to the desired temperature.
  • Coolant enters the heat exchangers 7 and 8 through lines 24 and 25, respectively and leaves through lines 26 and 27. It will be apparent to those skilled in the art that the exact solvent temperature employed will depend upon the amount of oil to be cooled and the amount of solvent to be added to the oil, i.e., the degree of oil dilution which is sought during the filtration step.
  • the solvent leaves the heat exchanger 8, through line 9, and enters manifold 10.
  • the manifold comprises a series of spaced solvent inlet points 11 to the several stages of the cooling tower 3.
  • the rate of solvent flow through each inlet is regulated by flow control means (not shown) and is adjusted, so as to maintain a desired temperature gradient along the height of the cooling tower.
  • the incremental solvent addition is such that the chilling rate of the oil is below about lF./minute and most preferably between about 1 and 5F./minute.
  • the amount of solvent added thereto will be sufficient to provide a liquid/solid weight ratio between about 5/1 and 100/1 at the dewaxing temperature and a solvent/oil volume ratio between about 1.0/1 and 7/1.
  • The-first portion or increment of solvent enters the first stage, 4a, of the cooling tower 3, where it is substantially instantaneously mixed with oil due to the action of the agitator 12a.
  • the agitator is driven by a variable speed motor 13 and the degree of agitation, as defined in more detail below, is controlled by variation of the motor speed, with due allowance for the flow rate through the cooling tower. It is noted that while a rotating blade is shown as the agitation source, any other mixing means that is able to produce the high levels of agitation required can be used herein.
  • the oil-solvent mixture may pass upwardly or downwardly through the cooling tower 3 (downwardly flow only has been shown).
  • additional prechilled solvent is introduced to each of the several stages 4, through inlets 1 1 so as to maintain substantially the same temperature drop from one mixing stage to the next and at the same time to provide the desired degree of dilution. It should be noted that any number of stages up to 50 may be employed; however,
  • the cooling of the oil stock continues to a temperature substantially below the depressed cloud point of the oil stock, thereby precipitating at least a portion of the wax therefrom and forming a wax-oil-solvent mixture.
  • the oil-solvent solution with precipitated wax passes from the final stage of the cooling tower through line 14 to wax separation means 15. If desired the wax-oil solvent mixture may be further cooled by conventional means not shown. Any suitable separation means such as filtration or centrifugation may be employed.
  • the wax-solvent mixture is removed through line 16 and the solvent recovered therefrom in a suitable separating system 19, which preferably comprises stripping with an inert gas such as nitrogen, steam or air, or straight distillation.
  • the solvent leaves the separator 19 through line 17 and the wax exits through line 18.
  • the oil-solvent mixture leaves separator through line 20 and passes to oil separation means 21. Any suitable means to effect this separation may be used, such as distillation, selective adsorption, or stripping with an inert gas such as nitrogen, air or steam.
  • the solventfree oil is removed from the separator and recovered through line 22.
  • the solvent is removed through line 23 and may be recycled directly to the dilution chilling tower or first scrubbed to remove impurities before reuse.
  • the degree of agitation during the initial stages of crystal nucleation and growth, must be sufficient to provide substantially instantaneous mixing of solvent and oil, i.e., preferably within a second or less.
  • the degree of agitation required in the process can be achieved by increasing the agitator rpm, when all other mixing variables, e.g., flow rates through the mixer, vessel and agitator design, viscosity of the ingredients and the like, are maintained constant, so that the modified Reynolds Number (Perry, Chemical Engineers Handbook, 3rd, pp. 1224, McGraw-Hill, New York, 1959), Me, which is defined by the equatron:
  • 1 liquid density, pound/feet n agitator speed, revolution/second u liquid viscosity, pound/feet second ranges between about 200 and about 150,000.
  • the dimensionless ratio of cooling tower diameter to agitator diameter is between about 15/1 and about 10/1 and the ratio of the impeller blade length to impeller blade width ranges from about 0.75 to 2 and preferably from about 1 to 1.5.
  • the ratio of the mixing stage height to the diameter of the stage will generally range from about 0.2/1 to about l/l.
  • a turbine type agitator is preferred, however, other types of agitators such as propellers may be used.
  • the cooling tower may or may not be baffled, but a baffled tower is preferred.
  • Each stage will generally contain from about two to eight baffles and preferably from two to four baffles, located about the outer periphery of each stage,
  • the width of the baffles may range from about 5 to 15 percent of the diameter of the tower.
  • the dimentional ratio of the crosssection of the restricted flow opening to the crosssection of the tower will be between about H20 and about l/200.
  • the cooling tower of the present invention is preferably operated at a pressure sufficient to prevent flashing of the solvent. Atmospheric pressure is sufficient when the ketones are employed as solvent; however, superatmospheric pressures are required when low molecular weight hydrocarbons such as propyleneacetone and related autorefrigerative solvents are used. As noted above, however, in situations where propylene-acetone and related autorefrigerative type solvents are used, low pressures will be required.
  • a process combining both vaporization of the solvent to provide in situ refrigeration and direct cooling from cold dewaxing solvent is disclosed in US. Pat. No. 3,658,688 patented Apr. 25, 1972, the disclosures of which are incorporated herein by reference.
  • the recovered lube oil products may, if so desired, be subjected to various finishing operations such as clay contacting, hydrofinishing, acid treatment and the like.
  • EXAMPLE 1 A laboratory experiment was performed in a 6 inches diameter single stage batch unit provided with a 2 inches diameter flat-bladed turbine impeller, a means for solvent introduction and an overflow device to maintain a constant volume of slurry. This batch unit does not completely duplicate continuous multi-staged operations but has been found to give approximately EXA P equivalent results.
  • M LE 2 The feedstock used in this example was a deasphalted Thefexpehmhhts dlsclosed 1h E pl 1 Supra; were phenol-extracted residual distillation fraction from an rerun m a wmmuous 16 Stage pll'ot compnsed of Arabian light crude.
  • Example 1 the Aramco 2,500 bright stock waxy raffinate, described in Example 1. was introduced into the chilling zone in the absence of solvent. Dilution chilling was performed with F. MEK/toluene (55/45 LV'/() and the effect of varying the feed temperature on effective predilution and performance is shown in Table IV below.
  • EXAMPLE 5 This example illustrates the detrimental effect of predilution on a phenol extracted light distillate feedstock from a Western Canadian Crude.
  • the feedstock KETONE DILUTION CHILLING DEWAXING ARAMCO 2500 BRIGHT OCK EFFECT OF PREDILUTION ON DWO FILTER RATE Lab single stage simulation of 16 stage dilution chilling. Same solvent composition used for predilution and subcloud point cooling. Dilchill solvent temperature 20F. Agitation 770 rpm (2" impeller) chilling rate 2F/minute Solvent/feed to filter 4/1.
  • EXAMPLE 4 This example demonstrates the performance advantage obtained by in situ predilution. The experiments were carried out in the laboratory single stage unit, and
  • the initial feed pour and cloud points were F. and F. respectively, and it required the removal of 22 percent dry wax to yield a lubricating oil with a 0F. pour point.
  • the process conditions are disclosed in Table V. The data typify the effect of predilution on light distillates.
  • the feed was introduced into the 16 stage dilution chilling pilot unit, described in Example 2, at l35F., while in another instance the feed was introduced into the 16 stage pilot unit at 155F. under in situ predilution conditions.
  • Table VI Other conditions, and the deleterious effect on performance of in situ predilution obtained by elevating the feed temperature is illustrated in Table VI below.
  • Feed temperature F. initial wax cloud point reached at: stage number I 4 stage temperature.
  • waxy residual petroleum oil stock is characterized by containing less than about 10 percent (weight) of material boiling below about 950F., at atmospheric pressure, and less than about 50 percent (weight) of material boiling below about l,050F., at atmospheric pressure.
  • step (a) is a dewaxing solvent and is selected from the group consisting of aliphatic ketones containing from 3 to 6 carbon atoms per molecule, the lower molecular weight hydrocarbons, aromatic compounds, halogenated lower molecular weight hydrocarbons and mixtures thereof.
  • step (a) is a dewaxing solvent and is the same as or different than the dewaxing solvent used in step (c).
  • step (c) 7. The process of claim 1 wherein the dewaxing solvent used in step (c) is prechilled prior to introduction into said cooling zone.

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  • Engineering & Computer Science (AREA)
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US00284647A 1972-08-29 1972-08-29 Partial predilution dilution chilling Expired - Lifetime US3850740A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US00284647A US3850740A (en) 1972-08-29 1972-08-29 Partial predilution dilution chilling
AU59205/73A AU486973B2 (en) 1972-08-29 1973-08-14 A process forthe dewaxing ofa waxy residual petroleum oil stock
GB3888373A GB1440127A (en) 1972-08-29 1973-08-17 Dewaxing petroleum oils
CA179,368A CA1012919A (en) 1972-08-29 1973-08-22 Partial predilution dilution chilling
DE2343041A DE2343041C2 (de) 1972-08-29 1973-08-25 Verfahren zum Entwachsen von wachshaltigen Rückstandsölen
IT28298/73A IT998484B (it) 1972-08-29 1973-08-28 Processo di deparffinazione mediante raffreddamento con prediluizione parziale e diluizione
FR7331106A FR2197965B1 (en(2012)) 1972-08-29 1973-08-28
JP9626573A JPS573718B2 (en(2012)) 1972-08-29 1973-08-29
NLAANVRAGE7311873,A NL186017C (nl) 1972-08-29 1973-08-29 Werkwijze voor het ontparaffineren van een paraffinehoudend aardolieresidu.
US05/516,625 US4013542A (en) 1972-08-29 1974-10-21 Partial predilution dilution chilling

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FR (1) FR2197965B1 (en(2012))
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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4013542A (en) * 1972-08-29 1977-03-22 Exxon Research And Engineering Company Partial predilution dilution chilling
US4115243A (en) * 1977-07-05 1978-09-19 Texaco Inc. Solvent dewaxing process
US4115244A (en) * 1977-07-05 1978-09-19 Texaco Inc. Solvent dewaxing process
US4115242A (en) * 1977-07-05 1978-09-19 Texaco Inc. Solvent dewaxing process
US4140620A (en) * 1977-07-05 1979-02-20 Texaco Inc. Incremental dilution dewaxing process
US4514280A (en) * 1975-06-02 1985-04-30 Exxon Research And Engineering Co. Dewaxing waxy oil by dilution chilling employing static mixing means
EP0356081A1 (en) * 1988-08-12 1990-02-28 Exxon Research And Engineering Company Method for reducing the cloud point of materials using an ultrafiltration separation process
US5167847A (en) * 1990-05-21 1992-12-01 Exxon Research And Engineering Company Process for producing transformer oil from a hydrocracked stock
WO1995007327A1 (en) * 1993-09-10 1995-03-16 Exxon Research & Engineering Company Controlling chilling tower profile for dilution chilling dewaxing of 600n waxy oil

Citations (8)

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US2410483A (en) * 1944-11-13 1946-11-05 Mid Continent Petroleum Corp Processes of dewaxing oils
US2486014A (en) * 1945-07-06 1949-10-25 Atlantic Refining Co Hydrocarbon oil dewaxing
US3006839A (en) * 1959-01-06 1961-10-31 Shell Oil Co Dewaxing hydrocarbon oil
US3038854A (en) * 1959-02-09 1962-06-12 Texaco Development Corp Solvent dewaxing
US3642609A (en) * 1969-11-13 1972-02-15 Exxon Research Engineering Co Dewaxing waxy oil by dilution chilling
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US3681230A (en) * 1970-07-10 1972-08-01 Exxon Research Engineering Co Immiscible filtration of dilution chilled waxy oils
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US4013542A (en) * 1972-08-29 1977-03-22 Exxon Research And Engineering Company Partial predilution dilution chilling
US4514280A (en) * 1975-06-02 1985-04-30 Exxon Research And Engineering Co. Dewaxing waxy oil by dilution chilling employing static mixing means
US4115243A (en) * 1977-07-05 1978-09-19 Texaco Inc. Solvent dewaxing process
US4115244A (en) * 1977-07-05 1978-09-19 Texaco Inc. Solvent dewaxing process
US4115242A (en) * 1977-07-05 1978-09-19 Texaco Inc. Solvent dewaxing process
US4140620A (en) * 1977-07-05 1979-02-20 Texaco Inc. Incremental dilution dewaxing process
EP0356081A1 (en) * 1988-08-12 1990-02-28 Exxon Research And Engineering Company Method for reducing the cloud point of materials using an ultrafiltration separation process
US5167847A (en) * 1990-05-21 1992-12-01 Exxon Research And Engineering Company Process for producing transformer oil from a hydrocracked stock
WO1995007327A1 (en) * 1993-09-10 1995-03-16 Exxon Research & Engineering Company Controlling chilling tower profile for dilution chilling dewaxing of 600n waxy oil
US5401383A (en) * 1993-09-10 1995-03-28 Exxon Research & Engineering Co. Controlling chilling tower profile for dilution chilling dewaxing of 600N waxy oil

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GB1440127A (en) 1976-06-23
NL186017C (nl) 1990-09-03
CA1012919A (en) 1977-06-28
DE2343041C2 (de) 1986-12-04
NL186017B (nl) 1990-04-02
DE2343041A1 (de) 1974-03-07
AU5920573A (en) 1975-02-20
NL7311873A (en(2012)) 1974-03-04
JPS4960302A (en(2012)) 1974-06-12
FR2197965B1 (en(2012)) 1979-10-19
IT998484B (it) 1976-01-20
FR2197965A1 (en(2012)) 1974-03-29
JPS573718B2 (en(2012)) 1982-01-22

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