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Publication numberUS3567639 A
Publication typeGrant
Publication dateMar 2, 1971
Filing dateMay 8, 1967
Priority dateJun 1, 1966
Also published asDE1645873A1
Publication numberUS 3567639 A, US 3567639A, US-A-3567639, US3567639 A, US3567639A
InventorsColin Aaron, Alan Harold Edwards, Keith Campbell Tessier
Original AssigneeExxon Research Engineering Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hydrocarbon-containing compositions
US 3567639 A
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Description  (OCR text may contain errors)

United States Patent 01 :"fice 3,567,639 HYDROCARBON-CONTAINING COMPOSITIONS Colin Aaron and Alan Harold Edwards, Charlton,

Wantage, England, and Keith Campbell Tessier, Westfield, N.J., assignors to Esso Research and Engineering Company No Drawing. Filed May 8, 1967, Ser. No. 636,597 Claims priority, application Great Britain, June 1, 1966, 24,368/ 66 Int. Cl. Cm 1/28 US. Cl. 252--56 7 Claims ABSTRACT OF THE DISCLOSURE A pour point depressant for crude oil, shale oil or a fuel oil which comprises 35-100 wt. percent of residua from the distillation of crude or shale oil is disclosed. The pour point depressant is a copolymer of ethylene and a vinyl or C to C hydrocarbyl substituted vinyl ester of a C to C saturated aliphatic monocarboxylic acid, said copolymer having a number average molecular weight of about 4,000 to 60,000 and containing about 40 to 95 wt. percent ethylene.

This invention relates to fuel compositions based on residua-containing fuels, and other base oils.

Although various pour point depressants are known and have been used, they have been reasonably successful only with middle distillate fuels. It has been found difficult to obtain a potent pour point depressant for shale oils, residua or residua-containing fuels. We have now discovered certain polymers which are potent as pour point depressants in certain hydrocarbons, e.g, residua-containing fuels or crude oils.

According to this invention hydrocarbon-containing compositions comprise a major proportion by weight of a residua-containing fuel, shale oil or a crude oil and a minor proportion by weight of a copolymer of ethylene and vinyl (or hydrocarbyl substituted vinyl) ester of a carboxylic acid, said copolymer having a number average molecular weight of above 3,000 and preferably above 3,500.

The residua-containing fuel is defined as a fuel comprising residua from the distillation of crude oil or shale oil or mixtures thereof. Generally the residua-containing fuel (hereinafter referred to simply as the fuel) will contain from about 35% to 100% by weight of residua, and will usually have kinematic viscosities ranging from 10 to 3,500 cs. at 100 F. However, the viscosity of some particularly waxy fuels may be difficult to measure accurately at 100 F., and it is well known in the art that the viscosity of such fuels is measured by the viscosity at a higher temperature. The viscosity at 100 F. is then obtained by extrapolation using a R.E.F.U.T.A.S. viscosity temperature chart. The extrapolated kinematic viscosity will then fall in the desired range at 100 F. The R.E.F.U.T.A.S temperature viscosity chart was designed by C. I. Kelly, M.S.C. Tech., F.I.C., M. Inst., P.T., A.M.I.A.E. Copyright reserved in Great Britain and U.S.A. by Paird & Tatlock (London) Ltd., 14-17 Cross Street, Hatton Garden, London, E.C.1. Fuels having kinematic viscosities of between 15 and 1500 cs. at 100 F. are preferred, and also fuels wherein at least 60% by weight of the fuel boils above 500 F. at atmospheric pressure are particularly suitable.

The fuels to which this invention applies include therefore, light, medium, heavy and bunker or furnace fuels, the viscosities ranging from about 152000 cs. at 100 F., but usually, however, the maximum viscosity will be about 900 cs. at 100 F. Examples of suitable fuels are described in PB Industrial and Marine Fuels of BS2689: 1957.

3,567,639 Patented Mar. 2, 1971 Crude oils from which the fuels are derived, or shale oil may also be used.

The preferred ethylene comonomers are vinyl (or bydrocarbyl, e.g. C to C hydrocarbyl, substituted vinyl) esters of C to C carboxylic acids. The carboxylic acid is preferably aliphatic, and saturated and preferably monocarboxylic. Thus, one may use vinyl propionate, vinyl hexoate, vinyl octanoate, vinyl dodecanoate, vinyl behenoate, isopropenyl acetate, or octadecyl myristoate. The particularly preferred ester is vinyl acetate. The resulting polymer should contain from to 40 weight percent, preferabl 90 to 60 weight percent, of ethylene.

One method of preparing the copolymers involves feeding the monomers into a tubular reactor which has been previously purged with nitrogen. A small amount of oxygen, usually 0.005 to 0.05 wt. percent based on the weight of ethylene is also introduced into the reactor. Alternatively a peroxide initiator, e.g. di-t-butyl peroxide, or a mixture of peroxide initiator and oxygen may be introduced into the reactor in place of oxygen alone. A solvent (e.g. benzene, water, saturated hydrocarbons, methanol) may also be employed in the reaction. The pressure is maintained between 60 and 2700 atmospheres (900 and 40,000 p.s.i.g.), preferably between and 2000 atmospheres (2,000 and 30,000 p.s.i.g.). The temperature should be maintained between 40 C. and 300 C., preferably between 70 C. and 250 C.

Another method of preparing the copolymers is via a batch process. Such a process requires a solvent for the reactants, the solvent being for example toluene or hexane. The preferred solvent however is benzene. The reaction initiator may be any peroxy compound, preferably di-tbutyl peroxide. The temperature of the polymerisation reaction is dependent upon the particular peroxide initiator employed and should be high enough for suflicient decomposition of the initiator to occur. This temperature will usually be between 40 C. and 300 C.

For the preferred initiator, i.e. di-tert-butyl peroxide, the most suitable temperature is between 130 C. and C. The pressure should be between 60 and 1000 atmospheres (900 and 15,000 p.s.i.g.), and preferably being between 75 and 470 atmospheres (1100 and 7000 p.s.i.g.). The autoclave or similar equipment containing the solvent, initiator and vinyl or hydrocarbyl substituted vinyl ester is purged with nitrogen and then with ethylene before charging with a sufficient amount of ethylene to yield the desired pressure when heated to the reaction tempertaure. During the polymerization addition ethylene is added to maintain the pressure at the desired level. Further amounts of initiator and/ or solvent, and/ or vinyl and hydrocarbyl substituted vinyl ester may also be added during the reaction. On completion of the reaction free solvent and unreacted monomers are removed by stripping or some other suitable process yielding the desired polymer.

The copolymers useful in the invention preferably have a number average molecular weight from 3,000 to 60,000 as measured by Vapour Phase Osmometry (using a Mechrolab Vapour Phase Osmometer model 301A) and/or Membrane Osmometry (using a Mechrolab 1 Membrane Osmometer model 501). The number average Heehrolab Inc., 1062 Linda Vista Avenue, Mountain View, Calif.

J tween 0.005 and 0.5% by weight based on the weight of fuel, shale oil, or crude oil.

The copolymer can also be applied down oil wells to crude oil to inhibit the formation of paraffin deposits, or to dissolve existing deposits on the sides of the well casing. The copolymer can also be added to crude oils or residua above ground to facilitate their movement through pipe lines. Thus, for example, the copolymer can be added to any North African crude, to lower the pour points so that they can be more readily pumped.

The blending of the above-mentioned copolymers in fuels, crude oils etc., can be facilitated by first forming copolymer concentrates in suitable hydrocarbon blend stocks. Examples of suitable solvents are those containing a high proportion of aromatic hydrocarbons, e.g. toluene, xylene, kerosene extract, this extract being the highly aromatic fraction separated from a crude kerosene by a liquid sulphur dioxide extraction process. Further suitable solvents are slack waxes, which are the waxes obtained without purification or refining from lubricating oil dewaxing processes. Such suitable slack waxes will usually have melting points between 20 C. and 62 C. and oil contents of to 50 wt. percent.

A suitable composition of such copolymer/solvent blends is 5 to 50% by weight of copolymer, and 95 to 50% by weight of solvent. Thus, for example, particularly suitable blends have been found to be a blend of to 30 e.g. by Weight of an ethylene/vinyl acetate copolymer and 90 to 70% e.g. 75% of a slack wax or a kerosene extract. These compositions can be readily blended into fuels to the required concentrations, e.g. up to 1% by weight, at temperatures of about 40 C. and above.

The copolymers may also be used in the fuels, crude oils, etc. in conjunction with other additives commonly used in fuels, e.g. rust-inhibitors, demulsifying agents, corrosion inhibitors, anti-oxidants or dispersants, or other flow improvers or pour depressants.

EXAMPLE 1 In this example, two copolymers were used, and added in different concentrations to two different fuels.

Copolymer A was a random copolymer of ethylene (67 weight percent and vinyl acetate (33 weight percent) having a number average molecular weight of 13,000 as measured by Vapour Phase Osmometry using chloroform as solvent at 37 C. Copolymer B was a random copolymer of ethylene (82 weight percent) and vinyl acetate (18 weight percent) having a number average molecular weight of 12,000 as measured by Vapour Phase Osmometry using benzene as solvent at 37 C. Both A and B were separately blended with a slack wax so that the blends contained 25% by Weight of A and 25% by weight of B respectively. The slack wax had a melting point of 40 C. and contained 29 wt. percent of oil. The copolymer/slack wax blends were separately blended into two different residual-containing fuel oils C and D having the following characteristics. Fuel oil C contained 32% by weight of distillate fraction boiling between 350 and 680 F., and 68% by weight of residuum with a boiling point of 680+ F., and it had a kinematic viscosity of 43.2 cs. at 100 F. Fuel oil D had an initial boiling point Copolymer eoneen- Upper pour tration, Flow point, F. point, F.

Weight percent 0 D C D Additive:

None 65 25 20 O. 1 25 -15 25 -15 0. 01 30 10 30 25 0. 05 20 10 20 30 O. 01 30 5 5 20 EXAMPLE 2 A 1 gallon stainless steel magnetically stirred autoclave was charged with 840 ml. of benzene and then purged with nitrogen then with ethylene. The autoclave was then heated to 150 C. and pressurised with ethylene to 900 p.s.i.g. 220 g. of vinyl acetate was then introduced via a metering pump over a period of 2 hours. Concurrently a solution of 22 g. of di-tert butyl peroxide in 66 g. of benzene was introduced to the reactor over a period of 3 hours. The temperature was maintained at 150 C. and the pressure at 900 p.s.i.g. during the reaction. After the addition of the peroxide was completed the reaction mass was maintained at 150 C. and 900 p.s.i.g. for an additional 30 minutes. On completion of the reaction the mixture was cooled and the pressure released. Free solvent and unreacted monomers were removed by stripping to give copolymer E.

EXAMPLE 3 Following the procedure given in Example 2, the following copolymers were made using the charges and reaction conditions given in Table I:

TABLE I Polymer preparation G H I J K L Reaction pressure,

p.s.i.g 1, 350 2, 000 3,000 3, 000 4, 000 3,000 Reaction temperature,

150 150 150 135 150 85 Initial charges:

Benzene, ml l, 000 800 800 800 800 800 Vinyl acetate, ml. 80 80 80 S0 Feed rates, ml.,hr

Vinyl acetate 170 140 210 250 Over total time,

hours 1% 2 1% 1% 1% 1% Initiator di-tert butyl peroxide Initiator, n11 l 50 l 20 2 20 2 20 Z 20 3 120 Over total time,

hours 1% 2% 1% 1 5 1% 1 Soak time, hours Polymers H I K L l Lauroyl peroxide. 2 23 wt. di-tert butyl peroxide in benzene. 3 13.8 wt. lauroyl peroxide in benzene.

The polymers prepared in Examples 2 and 3 have the following properties:

POLYMER PROPERTIES 1 Number average molecular Weight measured in toluene solution at 37 C. using a Mechrolab Vapour Phase Osmometer, Model 301A.

2 Weight/volume percent solution in toluene at 100 F.

3 0.02 weight percent of copolymer in fuel oil C as defined in Example I.

4 25 Weight percent copolymer concentrates in toluene were first prepared and these concentrates were used for preparing the fuel oil blends.

b Intrinsic viscosity of 0.17, toluene at 50 C.

EXAMPLE 4 Copolymers I, K and L from Example 3 were blended into residuum M. This residuum has an initial boiling point of 647 F. at atmospheric pressure and a viscosity at 122 F. of 121 Saybolt Furol seconds.

COPOLYMERS IN FUEL M Upper Weight, pour Copolymer 1 percent point None 105 0. 1 90 1 25 weight percent additive concentrates in toluene were used as in Example 3.

EXAMPLE 5 A 25 wt. percent concentrate of copolymer B in a slack wax (as described in Example I) was blended into three crude oils giving the following results.

Upper Upper pour pour Crude oil point point 1 N 70 60 l 25 -5 Q 0 -15 residua from the distillation of crude or shale oil, and

about .001 to 10 wt. percent of a pour depressing copolymer of ethylene and an ester selected from the group consisting of vinyl esters and C to C hydrocarbyl substituted vinyl esters, of C to C saturated aliphatic monocarboxylic acids, said copolymer having a number average molecular weight in the range of about 4,000 to 60,000 and containing about to wt. percent ethylene.

2. A composition according to claim 1, wherein said oil is crude oil and said ester is a vinyl ester.

3. A composition according to claim 2, wherein said molecular weight is in the range of 4,000 to 20,000.

4. A composition according to claim 3, wherein said ester is vinyl acetate.

5. A composition according to claim 1, wherein said oil is fuel oil having at least 60 wt. percent boiling above 500 F. at atmospheric pressure and having a viscosity between 15 and 3,500 cs. at F., and said ester is vinyl ester.

6. A composition according to claim 5, wherein said molecular weight is in the range of 4,000 to 20,000.

7. A composition according to claim 6, wherein said ester is vinyl acetate and said molecular weight is above 5,000.

References Cited UNITED STATES PATENTS 3,048,479 8/ 1959 Ilnyckyj et al. 44--62 3,093,623 6/1963 Ilnyckyj 44-62 3,126,364 3/1964 Ilnyckyj 4462 3,192,165 6/1965 Fields et a1. 44-62 3,254,063 5/1966 Il-nyckyj 4462 3,236,612 2/1966 Ilnyckyj 4462 3,262,873 7/1966 Tiedje et a1 208-33 3,393,144 7/1968 Button et a1. 208-33 PATRICK P. GARVIN, Primary Examiner Y. H. SMITH, Assistant Examiner US. Cl. X.R. 4462

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3682249 *Jan 8, 1971Aug 8, 1972Paul W FischerMethod for inhibiting the deposition of wax from wax-containing soluble oils and micellar dispersions and soluble oil and micellar compositions inhibited thereby
US3792984 *Jun 25, 1970Feb 19, 1974Texaco IncFuel oil blending to improve pour reduction
US3841850 *Oct 16, 1972Oct 15, 1974Exxon Research Engineering CoHydrocarbon oil containing ethylene copolymer pour depressant
US3850587 *Nov 29, 1973Nov 26, 1974Chevron ResLow-temperature flow improves in fuels
US3862825 *Jul 9, 1970Jan 28, 1975William M SweeneyLow pour point gas fuel from waxy crudes
US3880613 *Feb 7, 1972Apr 29, 1975Raam R MohanHigher alkyl trimethyl ammonium salt liquid hydrocarbon compositions
US3947368 *Feb 25, 1971Mar 30, 1976Texaco Inc.Ethylene-vinyl ester copolymer
US3961916 *Feb 28, 1974Jun 8, 1976Exxon Research And Engineering CompanyWax crystallization inhibitors, fuel oil, ethylene-vinyl ester copolymers
US4010006 *Oct 18, 1973Mar 1, 1977Exxon Research And Engineering CompanyFuel oil additive, blend of ethylene-vinyl acetate copolymer and acylpolystyrene
US4115343 *Jun 7, 1976Sep 19, 1978Rhone-Poulenc IndustriesEthylene-vinyl acetate copolymers, foam inhibitors
US4149984 *Dec 15, 1977Apr 17, 1979Rohm GmbhLubricating oil additives
US4156434 *Jan 24, 1977May 29, 1979Texaco Inc.Low pour point fuel compositions
US4417038 *Dec 4, 1981Nov 22, 1983Basf AktiengesellschaftEthylene-alkyne copolymers, their preparation and their use as additives to petroleum distillates
US4564460 *Aug 9, 1982Jan 14, 1986The Lubrizol CorporationHydrocarbyl-substituted carboxylic acylating agent derivative containing combinations, and fuels containing same
US4575526 *Mar 12, 1985Mar 11, 1986The Lubrizol CorporationHydrocarbyl substituted carboxylic acylaging agent derivative containing combinations, and fuels containing same
US4613342 *Oct 16, 1985Sep 23, 1986The Lubrizol CorporationHydrocarbyl substituted carboxylic acylating agent derivative containing combinations, and fuels containing same
US4906682 *Sep 7, 1988Mar 6, 1990Rohm GmbhEthylene-vinyl ester copolymer emulsions
US4932980 *Jul 25, 1988Jun 12, 1990Rohm GmbhPolymeric fluidizer for middle distillates
US5078917 *Nov 1, 1989Jan 7, 1992Functional Products IncorporatedEthylene-vinyl acetate copolymers and terpolymers
US5141663 *Dec 24, 1990Aug 25, 1992Olin CorporationDissolving alkylene-vinyl ester copolymer in a base fluid mixture of polyalkylene glycol esters and polyalkylene glycols
US6010989 *Sep 4, 1998Jan 4, 2000Clariant GmbhEthylene-vinyl ester interpolymer; paraffin dispersant; aliphatic or cyclic ester or ether solubilizer
US6099601 *Feb 20, 1997Aug 8, 2000Basf AktiengesellschaftEthylene-vinyl formate copolymers, process for their preparation, their use as flow improvers, and fuel and propellant compositions comprising them
US6235069 *May 24, 2000May 22, 2001Basf AktiengesellschaftEthylene-vinyl formate copolymers, process for their preparation, their use as flow improvers, and fuel and propellant compositions comprising them
US6495495Aug 9, 2000Dec 17, 2002The Lubrizol CorporationBlend of such as ethylene-vinyl acetate copolymer and naphthenic oil; preventing filter blockage due to wax formation
US7708876Jul 11, 2006May 4, 2010Oiltreid Limited Liabilities CompanyHeavy fuel oil
USB407812 *Oct 18, 1973Mar 23, 1976 Title not available
WO1992004428A1 *Aug 6, 1991Mar 19, 1992Olin CorpFire resistant hydraulic fluid composition
WO2012170242A1May 30, 2012Dec 13, 2012Dow Global Technologies LlcMethod t0 make an aqueous pour point depressant dispersion composition
Classifications
U.S. Classification508/475, 44/393
International ClassificationC10L1/18, C08L91/00, C10L1/22, C10L1/16, C10L1/20, C10L1/197, C08L31/04
Cooperative ClassificationC08L91/00, C08L31/04, C10L1/1641, C10L1/236, C10L1/165, C10L1/207, C10L1/195, C10L1/1973
European ClassificationC08L31/04, C10L1/197B