NO324702B1 - Carbonyl, thiocarbonyl or imine-containing compound as asphaltene dispersants in crude oil - Google Patents

Abstract

A material is described which comprises (a) 0.001% -20% of at least one compound having: (1) at least one carbonyl-, thiocarbonyl- or imine-containing functional group which is not a carboxyl group, (2) at least one polar group 2-10 chemical bonds from a carbonyl, thiocarbonyl, or iminecarbon; and (3) at least 10 carbon atoms; and (b) crude oil.

Description

Background

The present invention relates to a method for dispersing asphaltenes in a petroleum product.

Certain petroleum products, including heavy crude oils, which include materials referred to as "tars", "petroleum tars" or "tar sands" are rich in asphaltenes, metals and resins. The presence of these types of compounds can cause various problems in the recovery, transportation, processing and refining of crude oils, including increased viscosity, formation of stable emulsions, fouling and corrosion. International patent application no. WO95/20637 describes the stabilization of asphaltenes in crude oil using a variety of compounds, including amides and esters. However, the only amides or esters with polar substituents described are those containing 2-hydroxyethyl, 3-hydroxypropyl or 4-hydroxybutyl groups.

The patents CA 2,298,880 C, FR 2,585,032 and GB 2,337,522 also describe methods and chemical compounds for inhibiting the deposition of asphaltenes in crude oil or other fluid hydrocarbons. Inhibitors against the formation of solid organic-based incrustations from fluid hydrocarbon mixtures are also described in NO 308,417 Bl.

US Patent 5,169,411 describes an effective method for inhibiting hydrogen sulphide gas formation during storage or transport of petroleum residues, crude oil and petroleum fuel media using effective amounts of certain imines.

In the Norwegian patent NO 313,714 Bl, a method is described for increasing the efficiency of production chemicals by reducing the number of pressure injection and shut-in operations that are necessary to increase the production rate from an oil well by inhibiting deposit formation in the well.

The problem investigated with the present invention is to find a material which is suitable for improving the processing of petroleum products.

Description of the invention

The present invention relates to a method for dispersing asphaltenes in a petroleum product, characterized in that the method comprises adding to the petroleum product 0.001% to 20% of at least one compound having the formula (V):

where R<14> is C15-C21 alkyl. A preferred method is that 0.01% to 1% of said at least one compound is present. Another preferred method is that R<14> is a C15-C17 alkyl.

The invention further relates to a method for dispersing asphaltenes in a petroleum product, characterized in that the method comprises adding to the petroleum product 0.001% to 20% of at least one compound having the formula where q is 1, 2, 3 or 4; R2 and R<4> are independently from each other hydrogen, alkyl, heteroalkyl, heterocyclic, aryl or arylalkyl; provided that at least one of R<2> and R4 is C15-C21 alkyl. A preferred method is that q=3 and R4 is hydrogen. Particularly preferred is a method where 0.01% to 1% of at least one compound is present.

Detailed description

All percentages are percentages by weight based on the complete composition, unless otherwise noted. A "polar" group is a functional group selected from the following: hydroxy, amino, alkylamino, hydroxylamino, ammonium, alkylammonium, oxime, keto, carboxylation, amide, alkylamide, nitroso, mercapto, alkylthio, alkylsulfonyl, alkylsulfenyl and alkylsulfinyl. An "alkyl" group is a hydrocarbyl group having from 1-22 carbon atoms in a linear, branched or cyclic arrangement. A "difunctional alkyl group" is an alkyl group that has two attachment points, e.g. -CH2-, -CH2CH2-, and -CH2CH2 (CH3)-. Alkyl groups optionally have one or more double or triple bonds. Substitution on alkyl groups by one or more of halo, cyano, alkyl, alkoxy or of the above stated polar groups is permitted; Alkoxy groups can be substituted with one or more halo substituents. A "heteroalkyl" group is an alkyl group in which at least one carbon has been replaced by 0, NR or S, where R is hydrogen, alkyl, heteroalkyl, aryl or arylalkyl. An aryl group is a substituent derived from an aromatic hydrocarbon compound. An aryl group has a total of 6-20 ring atoms, and has one or more rings that are separate or fused. An "arylalkyl" group is an "alkyl" group substituted with an "aryl" group. A "heterocyclic" group is a substituent derived from a heterocyclic compound having from 5-20 ring atoms, at least one of which is nitrogen, oxygen or sulphur. Preferably, the heterocyclic groups do not contain sulphur. Substitution on aryl or heterocyclic groups of one or more of halo, cyano, alkyl, heteroalkyl, alkoxy or of the above-mentioned polar groups is permitted, with substitution of one or more halo groups possible on alkyl, heteroalkyl or alkoxy groups. An "aromatic heterocyclic" group is a heterocyclic group derived from an aromatic heterocyclic compound.

Preferably, the heterocyclic groups in compounds used according to the present invention are aromatic heterocyclic groups.

According to the present invention, at least one compound has: (1) at least one carbonyl-, thiocarbonyl- or imine-containing functional group that is not a carboxyl group; (2) at least one polar group 2-10 chemical bonds from a carbonyl, thiocarbonyl or imine carbon; and (3) at least 10 carbon atoms; is added to a petroleum product, where the total amount of said compounds is from 0.001%-20%, preferably from 0.001%-10%, more preferably from 0.01%-10%, more preferably from 0.01%-1%, and most preferably from 0.02%-0.2%.

A carbonyl, thiocarbonyl, or imine-containing functional group is any functional group, other than carboxyl, that contains a carbonyl, thiocarbonyl, or imine functionality, including but not limited to amide, ester, keto, imine, thioester, thioamide, aldehyde, carboxylate, carbamate, xanthate, carbamide, guanidine, thiourea and β-ketoester. "Carbonyl, thiocarbonyl or imine carbon" is each carbonyl, thiocarbonyl or imine carbon of a carbonyl, thiocarbonyl or imine containing functional group, i.e. the carbon atom of a C=W functionality, where W is 0, S or N. I in some cases a carbonyl, thiocarbonyl or imine containing functional group has more than one carbonyl, thiocarbonyl or imine carbon, e.g. has a p-ketoester group 2 carbonyl atoms. According to the present invention, the difference between a carbonyl, thiocarbonyl or imine carbon and a polar group will be measured by the number of covalent chemical bonds which are either between: (1) the atom in the polar group through which it is tested (e.g. the oxygen in hydroxy; the nitrogen of amino, hydroxylamino, ammonium or nitroso; or sulfur or sulfur-containing groups); or (2) a C=W carbon in the polar group (eg the carbonyl carbon of amide or the imine carbon of oxime); and a carbonyl, thiocarbonyl or imine carbon.

E.g. in oleyl acetoacetate the carbonyl carbon in the keto group is two bonds from the carbonyl carbon in the ester group, while in N-(2-hydroxyethyl)stearamide the oxygen in the hydroxy group is 4 bonds from the amide carbonyl carbon. Preferably, at least one polar group in a compound according to the present invention is located 2-8 chemical bonds from a carbonyl, thiocarbonyl or imine carbon, more preferably from 2-7 chemical bonds, and most preferably 2, 3, 4, 5 or 6 chemical bonds from a carbonyl, thiocarbonyl or imine carbon. Preferably, a carbonyl-, thiocarbonyl- or imine-containing functional group is selected from the group consisting of amide, ester, imine, thioester, thioamide, carbamate, carbamide and thiourea. Preferably, a carbonyl-, thiocarbonyl- or imine-containing functional group is not part of a heterocyclic ring. Preferably, a compound used according to the invention is aliphatic. Preferably, a compound used according to the invention is acyclic.

A compound used in the material or method according to the present invention is preferably represented by formula (I):

where Y is C1-C3 difunctional alkyl, O, S, NR3 or is absent; Z is hydrogen (in which case R<2> is absent), 0, S, NR<4> or is absent; W is 0, S or NR<5>; R<1>, R<2>, R<3>, R<4> and R<5> are independently hydrogen or organic functional groups; and at least one of Y, R<1>, R<2>, R<3>, R4 and R<5> is substituted with at least one polar group 2-10 chemical bonds from carbonyl, thiocarbonyl or imine carbon. Preferably R<1>, R<2>, R<3>, R4 and R<5> are independently hydrogen, alkyl, heteroalkyl, heterocyclic, aryl or arylalkyl. Preferably at least one of R<1>, R<2>, R<3>, R<4> and R<5> has at least 7 carbon atoms, more preferably at least 9 carbon atoms, more preferably at least 11 carbon atoms, and most preferably at least 15 carbon atoms. Preferably, only the carbonyl-, thiocarbonyl- or imine-containing functional group is an amide group, and at least one of R<1>, R<2>, R3, R4 and R<5> is a linear alkyl group substituted with only a single hydroxy group at the carbon farthest from the amide carbonyl carbon, at least one of R<1>, R<2>, R<3>, R4 and R<5>, have at least 15 carbon atoms and no hydroxy groups.

Preferably, a compound used according to the present invention is not in the form of a salt having an anion and a cation, i.e. a salt which is not a zwitterion; more preferably the compound is a neutral compound. Preferably, only the carbonyl-, thiocarbonyl- or imine-containing functional group is an ester or keto group, and at least one of R<1>, R<2>, <R3,><R4> and R5 is a linear alkyl group substituted with only a single hydroxy group at the carbon farthest from the ester or ketocarbonyl carbon, at least one polar group is present that is not the single hydro group or keto group, most preferably, the compound has an alkyl substituent having at least 15 carbon atoms. Preferably, W, Y and Z are not all 0, or all S.

An "organic functional group" is a functional group that does not contain metal atoms and has from 1-22 carbon atoms, hydrogen atoms, and optionally hetero atoms, including but not limited to nitrogen, oxygen, sulfur, phosphorus and halogen atoms. An organic functional group optionally contains double and triple bonds, rings, which are linked or fused, and if the group is completely or partially acyclic, the acyclic part can be linear or branched. Preferably, an organic functional group is an alkyl, heteroalkyl, aryl, arylalkyl, heterocyclic or heterocyclic alkyl group. In a preferred embodiment of this invention, at least one of the organic functional groups is a C2-C22 alkyl or heteroalkyl group, more preferably a C7-C22 alkyl or heteroalkyl group, more preferably a C8-C22 alkyl or heteroalkyl group, and most preferably a C15-C22 alkyl group. Preferably, alkyl or heteroalkyl groups are unsubstituted. A compound used according to the invention optionally contains other carbonyl-, thiocarbonyl- or imine-containing functional groups of one or more of the organic functional groups, preferably in a total of 1-3-carbonyl-, thiocarbonyl- or imine-containing functional groups . Preferably, a polar group is a hydrogen bond donor, e.g. hydroxy, amino, alkylamino, ammonium, hydroxylamino, oxime, sulfonic acid or amide. More preferably, a polar group is hydroxy, amino, alkylamino or hydroxylamino. Most preferably, a polar group is hydroxy or hydroxylamino.

In a preferred embodiment of the invention, a compound of formula (I) is represented by formula (II):

wherein X is 0, S, N, NH or NR7; R<6> and R<7> are independently alkyl, heteroalkyl, aryl, heterocyclic or arylalkyl; and n is 1 or 2.

It will be obvious to those skilled in the art that n=l where X is 0, S, NH or NR7; and N=2 where X is N.

Preferably, R<6> is C2-C22_alkyl, more preferably C7-C22-alkyl, more preferably C9-C22-alkyl, and most preferably C15-C22_alkyl. Preferably, Y is -CH2CH2-, or

-CH 2 CH(CH 3 ) -.

Preferably, R<2> is alkyl or arylalkyl.

Preferably, W=0, and Z is 0 or NR<4>.

Compounds of formula (II) where Y is -CH2CH2-, or

-CH2CH (CH3)-, W is 0 and Z is 0 or NR4 can be derived from the reaction with a fatty amine, thiol or alcohol, R<6>XH, with an acrylate or methacrylate ester, or an acrylamide or methacrylamide. Preferably, X=NH and the compound of formula (II) is derived from an unsubstituted C15-C22 alkylamine, R<6>NH2, preferably one which is an oil-soluble amine. In one embodiment, the alkylamine is a tertiary-alkyl-primary-amine, i.e. a primary amine where the alkyl group is linked to the amino group through a tertiary carbon. Examples of commercially available tertiary-primary-amines are

Primene™ amines available from Rohm and Haas Company, Philadelphia, PA.

In a preferred embodiment of the invention, the compound of formula (I) is an imine having a polar group 2-10 chemical bonds from the imine carbon. In this embodiment, W=NR<5>, Z is hydrogen or is absent (ie, ZR2 is hydrogen or R<2>, and Y is absent, resulting in the structure depicted in formula (III):

where at least one of R<1>, R<2> and R<5> contains a polar group 2-10 chemical bonds from the imine carbon. Preferably, the polar group is hydroxy. Preferably, R<5> is a C15-C22 alkylamine. In one embodiment, the alkylamine is a tertiary-alkyl-primary-amine.

In a preferred embodiment of the invention, the imine compound of formula (III) is selected from the group consisting of:

wherein R<8>, R<9> and R1<0> are independently hydrogen or alkyl; R<11> is C2-C22-alkyl; R<12> is hydrogen or alkyl; m is 0 or 1; and k is 1, 2 or 3.

Preferably R<11> is C7-<C>22_alkyl, more preferably C9-C22-alkyl, and most preferably C15-C22_alkyl.

In a preferred embodiment of the invention, the compound of formula (I) is an amide having a polar group 2-10 chemical bonds from the amide carbonyl carbon. In this embodiment, W=0, Z is NR 4 , and Y is C 1 -C 3 difunctional alkyl or is absent, resulting in the structure depicted in formula (IV):

where at least one of Y, R<1>, R<2> and R<4> contains a polar group 2-10 chemical bonds from the amide carbon. Preferably, the polar group is hydroxy. In a preferred embodiment of

invention, the amide compound of formula (IV) is selected from the group consisting of:

where R<4> and R<2> are as defined herein; R<13> is H or OH;

j is 1 or 2; p is 1, 2 or 3; and q is 1 or 2, 3 or 4.

Preferably at least one of R<4> and R2 is C8-C2i-alkyl, more preferably at least one of R<4> and R2 is C15-C2i-alkyl.

Preferably one of R<4> and R2 is hydrogen.

In another preferred embodiment of the invention, the t amide of formula (IV) has formula (V):

where R<14> is C15-C2i-alkyl. Preferably, R<14> is C15-C17alkyl, most preferably acyclic linear alkyl, including but not limited to the alkyl group of oleic acid (heptadec-8 (Z)-en-l-yl), n-heptadecyl, and mixtures of C15- C17 acyclic linear alkyl groups, e.g. dialkyl mixtures that exist in naturally occurring Ci6-Ci8 fatty acids.

In a preferred embodiment of the invention, the compound of formula (I) is an ester having a polar group 2-10 chemical bonds from the ester carbonyl carbon. In this embodiment, W=0; Y is C1-C3 difunctional alkyl or is absent or is absent; and Z is 0, resulting in the structures depicted in formula (VI):

where R<1> and R<2> are organic functional groups, and at least one of Y, R<1> and R<2> is substituted with at least one polar group 2-10 chemical bonds from the ester carbon. In a preferred embodiment of the invention, Y is absent, and at least one of R<1> and R<2> has at least 15 carbon atoms. Preferably, the polar group is hydroxy.

In another preferred embodiment of the invention, an ester of formula (VI) is represented by formula (VII):

where R<15> is alkyl, heteroalkyl, aryl, heterocyclic or arylalkyl; R<17> is hydrogen or alkyl; X is as defined previously; R<16> is hydrogen or methyl; and o is 1 or 2.

It will be obvious to those skilled in the art that o=1 when X is 0, S, NH or NR7, and o=2 when X is N. Preferably R<15> is C7-<C>22<->alkyl, more preferably C9 -C22-alkyl, and most preferably C15-C22-alkyl. Preferably R<17> is hydrogen, methyl or hydroxymethyl. Compounds of formula (VII) are typically derived from reaction of a fatty amine, thiol or alcohol, R<15>XH, with an acrylate or methacrylate hydroxyalkyl ester. Preferably X=NH and the compound of formula (VII) is derived from an unsubstituted C15-C22 alkylamine, R<15>NH2, preferably one which is an oil-soluble amine'. In one embodiment, the alkylamine is a tertiary-alkyl-primary-amine.

In addition to dispersing asphaltenes, the material according to the invention will typically also increase emulsion breaking capacity, reduce viscosity, reduce sediment formation, reduce surface fouling and reduce corrosion. For the extraction of crude oil, the material according to the present invention can be injected directly into an injection well, or preferably diluted with solvent before injection. Suitable solvents include, but are not limited to, petroleum distillates such as kerosene and gaseous oils; linear and branched aliphatic solvents such as pentane, hexane, mixtures of nonanes and 2-ethylhexanes; cycloaliphatic compounds known as naphtha; aromatic solvents such as toluene, xylenes and commercial aromatic solvent mixtures; esters; ethers; alcohols such as ethanol, iso-propanol, octanol and dodecanol; ketones such as acetone, cyclohexanone and acetophenone; and other polar solvents. Preferred dilutions are 0.01-50% by weight of the compound in the solvent, with more preferred dilutions being 0.01-20% by weight, more preferred dilutions being 0.1-10% by weight, and most preferred dilutions 1-10% by weight.

Examples

Example 1; (2- hydroxyethyl) amides

Performance Criteria and Test Methods: Asphaltene Dispersion Test Tube Method: This test requires a previously prepared dispersion of asphaltenes in xylenes (Aromatic 150 solvent) or asphaltenic heavy crude oil diluted in xylenes (Aromatic 150 solvent) at a known concentration. A solution of an additive formulation (0.1 ml, the active ingredient was typically 5-10% by weight, making the treatment rate 500-1000 ppm) was transferred to a 15.0 ml graduated glass centrifuge tube, and hexanes were added as that the total volume was 10.0 ml. To this mixture of additive and hexanes, an asphaltene stock solution (0.1 mL) was added. The test tube was closed, shaken vigorously for approx. 1 min., or 40-60 times by hand, and set aside. The volume of precipitated asphaltenes deposited at the bottom of the tube was measured at 10, 30, 60, 90 minutes and 1440 (24 hour) intervals. If no additive was used, the volume of the asphaltenes that precipitated in the first 0.5-1 h was 0.4-0.5 ml (4-5%) and it was actually important initially to adjust the concentration of the asphaltene stock solution so that under these conditions with a dilution with paraffinic solvents a 4-5 vol% asphaltenic precipitation occurred. If additives were an effective dispersant of asphaltenes, no precipitate was formed up to 24 h (grading=2; good). In some cases, no precipitation was observed for more than 24 h to several days (grading=2+; excellent). If the additive did not have dispersing properties, an almost immediate precipitation of asphaltenes occurred (grading=0; poor). Results for several (2-hydroxyethyl)amides are listed in Table 1. Results for several other amide or imine compounds are reported in Table 2.

"DEA"=diethanolamine, "MEA"=monoethanolamine. Mackamid™ amides are commercial products available from Mclntyre Group Limited (University Park, IL).

Treatment amount is the concentration of the amide in the crude oil.

"HEA"=2-hydroxyethyl acrylate; AROMATIC 150 SOLVENT is a solvent mixture boiling in the range of 184-204°C containing xylene isomers available from Exxon Mobil Chemical Co., Houston, Texas.

The results presented in Table 1, entries 1) to 6), and Table 2, entry 3), show that amides where the only other polar group (other than amide) is a 2-hydroxyethyl, 3-hydroxypropyl, or 4-hydroxybutyl group are effective dispersants only as they are substituted with an alkyl group having at least 15 carbons.

Claims (6)

1. Process for dispersing asphaltenes in a petroleum product, characterized in that the method comprises adding to the petroleum product 0.001% to 20% of at least one compound having the formula (V): where R<14> is C15-C21 alkyl. 2. The method in accordance with claim 1, characterized in that 0.01% to 1% of said at least one compound is present. 3. The method in accordance with claim 2, characterized in that R<14> is a C15-C17 alkyl. 4. Procedure for dispersing asphaltenes in a petroleum product, characterized in that the method comprises adding to the petroleum product 0.001% to 20% of at least one compound having the formula where q is 1, 2, 3 or 4; R<2 > and R 4 are independently from each other hydrogen, alkyl, heteroalkyl, heterocyclic, aryl or arylalkyl; provided that at least one of R<2> and R4 is C15-C21 alkyl. 5. The method in accordance with claim 4, characterized in that q=3 and R<4> is hydrogen. 6. The method in accordance with claim 5, characterized in that 0.01% to 1% of at least one compound is present.