JP2018090652A - Crude oil dispersion stabilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crude oil dispersion stabilizer that can disperse or emulsify high-viscosity crude oil to reduce the viscosity, and allows the obtained crude oil dispersion liquid or emulsion to be stable for a long time.SOLUTION: A crude oil dispersion stabilizer contains a vinyl alcoholic polymer, and the vinyl alcoholic polymer has a hydrophobic group at a terminal or side chain.SELECTED DRAWING: None

Description

  The present invention relates to a crude oil dispersion stabilizer containing a vinyl alcohol polymer.

  Crude oil typified by heavy oil is non-conventional oil with higher viscosity than conventional oil, and its rich reserves are expected to contribute to alleviating the problem of oil depletion. However, since heavy oil has high viscosity and poor fluidity, there is a problem that efficient recovery from the oil layer and pipeline transportation are difficult.

  As a method for improving, recovering and transporting the fluidity of such heavy oil, a technique for reducing the viscosity by emulsifying the heavy oil in an aqueous solution using polyvinyl alcohol (PVA) as a dispersion emulsifier is disclosed. (Patent Documents 1 and 2). The methods disclosed in Patent Document 1 and Patent Document 2 effectively emulsify from a heavy oil having an API specific gravity of 30 ° or less to a super heavy oil or bitumen having an API specific gravity of 10 ° or less and extremely high viscosity. It can be lowered. However, according to studies by the present inventors, the emulsion obtained by this method has a high viscosity in a short period of time, precipitates are formed, particles are aggregated and become large, and oil is separated. Such a phenomenon is often seen, and there is a problem that the stability is inferior.

WO2005 / 040669 WO2011 / 023990

  The present invention has been made in order to solve the above-mentioned problems. Crude oil that can be dispersed or emulsified in high-viscosity crude oil to reduce the viscosity, and the obtained crude oil dispersion or emulsion can be stably present for a long time. An object is to provide a dispersion stabilizer.

  The inventors of the present invention have intensively studied to achieve the above object, and as a result, a crude oil having a high viscosity is emulsified by a crude oil dispersion stabilizer containing a vinyl alcohol polymer having a hydrophobic group at its terminal or side chain. And found that the state of the emulsion can exist stably over a long period of time, leading to the present invention.

  An object of the present invention is to provide a crude oil dispersion stabilizer containing a vinyl alcohol polymer, wherein the vinyl alcohol polymer has a hydrophobic group at a terminal or a side chain. It is solved by.

  At this time, the hydrophobic group is preferably a hydrocarbon group, and the hydrophobic group is preferably an alkyl group having 6 to 18 carbon atoms or an aryl group. At this time, the vinyl alcohol polymer preferably has a hydrophobic group at the end, and is preferably used for crude oil having an API specific gravity of 30 ° or less.

  The subject is a crude oil treating agent comprising the crude oil dispersion stabilizer and water, wherein the crude oil treating agent comprises 0.05 to 40 parts by mass of the crude oil dispersion stabilizer with respect to 100 parts by mass of the total amount of the crude oil treating agent. It is also solved by providing.

  The above-mentioned subject is a crude oil dispersion containing the above-mentioned crude oil treating agent and crude oil, comprising 3 to 50 parts by mass of the crude oil treating agent with respect to 100 parts by mass of the total amount of the crude oil dispersion, This can also be solved by providing a crude oil dispersion containing 0.001 to 1 part by weight of polymer and 50 to 97 parts by weight of the crude oil.

  With the crude oil dispersion stabilizer of the present invention, high viscosity crude oil can be dispersed or emulsified to reduce the viscosity, and the resulting crude oil dispersion or emulsion can be stably present for a long time.

  The crude oil dispersion stabilizer of the present invention is characterized by containing a vinyl alcohol polymer having a hydrophobic group at its terminal or side chain. It was revealed that a crude oil dispersion or emulsion having a low viscosity can be obtained by dispersing or emulsifying a crude oil having a high viscosity with the crude oil dispersion stabilizer of the present invention. The crude oil dispersion or emulsion thus obtained does not increase in viscosity in a short time and is excellent in stability. As can be seen from the comparison results of Examples and Comparative Examples described later, in Comparative Example 1 (heavy oil) using unmodified PVA, the viscosity of the crude oil dispersion increased after 6 hours. In Comparative Example 2 (bitumen) using unmodified PVA, sediment was formed in the crude oil dispersion, and the viscosity could not be measured. On the other hand, in Examples 1-8 using a crude oil dispersion stabilizer containing a vinyl alcohol polymer having a hydrophobic group at the terminal or side chain, the dispersion stability of the crude oil was excellent. Accordingly, it is possible to efficiently recover the crude oil from the oil reservoir. In addition, transportation by pipeline is also possible.

  The crude oil in the present invention includes crude oil such as heavy oil, bitumen (oil sand), tar, and pitch. A crude oil having a high viscosity can be dispersed or emulsified by the crude oil dispersion stabilizer of the present invention. The crude oil is preferably a crude oil having an API specific gravity of 30 ° or less. That is, a crude oil dispersion stabilizer used for crude oil having an API specific gravity of 30 ° or less is a preferred embodiment of the present invention.

  The vinyl alcohol polymer used in the present invention has a hydrophobic group at the terminal or side chain (hereinafter sometimes abbreviated as “modified PVA”). The hydrophobic group is not particularly limited, and a hydrocarbon group such as an alkyl group, a cycloalkyl group, or an aryl group is preferably used. These hydrocarbon groups may have a substituent. Among these, the hydrophobic group is more preferably an alkyl group having 6 to 18 carbon atoms or an aryl group.

  Examples of the alkyl group having 6 to 18 carbon atoms include n-hexyl group, isohexyl group, 2-ethylhexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group and n-dodecyl group. Can be mentioned. Examples of the aryl group having 6 to 18 carbon atoms include a phenyl group, a naphthyl group, and an anthryl group.

  Hereinafter, a vinyl alcohol polymer having a hydrophobic group at the terminal (hereinafter sometimes abbreviated as “terminal-modified PVA”) will be described. There is no restriction | limiting in particular about the manufacturing method of terminal modified PVA, A various method is employable. For example, (1) a method in which a vinyl ester is polymerized by coexisting a compound having a functional group such as an alcohol, aldehyde, or thiol having a hydrophobic group as a chain transfer agent, and (2) vinyl is obtained. Examples thereof include a method of introducing a hydrophobic group to the terminal of the alcohol polymer by a chemical reaction. As a method for obtaining terminal-modified PVA more economically and efficiently, a vinyl ester such as vinyl acetate in the presence of a chain transfer agent having a hydrophobic group, particularly a thiol having a C 6-18 alkyl group or aryl group. The method of polymerizing the compounds and then saponifying is preferred (see JP-A-59-166505, JP-A-1-240501, JP-B-61-41924 and JP-A-7-292025).

  Examples of the chain transfer agent having a hydrophobic group include n-hexyl aldehyde, n-octyl aldehyde, 2-ethyl-hexyl aldehyde, n-caprin aldehyde, n-decyl aldehyde, n-undecyl aldehyde, n-lauryl aldehyde, C6-C18 aldehydes such as n-tridecyl aldehyde, cetyl aldehyde, palmityl aldehyde, stearyl aldehyde; or n-hexyl mercaptan, n-octyl mercaptan, n-decyl mercaptan, n-dodecyl mercaptan, n-octadecyl mercaptan Mercaptans having an alkyl group or aryl group having 6 to 18 carbon atoms such as thiophenol can be used. Especially, as a chain transfer agent, the mercaptan which has a C6-C18 alkyl group or an aryl group is used suitably. The number of carbon atoms is more preferably 8 or more.

  These terminal-modified PVAs are obtained by polymerizing vinyl ester monomers using a conventionally known method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, and the like. It can be produced by saponifying an ester polymer. From the industrial viewpoint, preferred polymerization methods are solution polymerization, emulsion polymerization and dispersion polymerization. In the polymerization operation, any one of a batch method, a semi-batch method, and a continuous method can be employed.

  Examples of vinyl ester monomers that can be used for polymerization include vinyl acetate, vinyl formate, vinyl propionate, vinyl caprylate, vinyl versatate, and among these, vinyl acetate is an industrial viewpoint. To preferred.

  When the vinyl ester monomer is polymerized, the vinyl ester monomer may be copolymerized with other monomers as long as the gist of the present invention is not impaired. It is preferable to polymerize alone. Examples of other monomers that can be used include α-olefins such as propylene, n-butene, and isobutylene; acrylic acid and salts thereof, methyl acrylate, ethyl acrylate, n-propyl acrylate, and i-acrylate. Acrylic acid esters such as propyl, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate; methacrylic acid and salts thereof; methyl methacrylate, Methacrylic acid such as ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate Acid esters Acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetone acrylamide, acrylamide propanesulfonic acid and its salt, acrylamidopropyldimethylamine and its salt or its quaternary salt, N-methylolacrylamide and its Acrylamide derivatives such as derivatives; methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and its salts, methacrylamidepropyldimethylamine and its salts or quaternary salts thereof, N-methylolmethacrylamide and Methacrylamide derivatives such as derivatives thereof; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl Vinyl ethers such as ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether; nitriles such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride and vinyl fluoride; Vinylidene halides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid, and salts or esters thereof; vinyltrimethoxysilane, etc. Vinylsilyl compounds; polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, polyoxyethylene (meth) acrylic acid amide, polyoxypropylene (meth) acrylic Acid amide, polyoxyethylene (1- (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl ether, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether Oxyalkylene group-containing monomers such as isopropenyl acetate and the like.

  In the present invention, modified PVA having a high content of 1,2-glycol bonds obtained by polymerizing a vinyl ester monomer under a temperature condition higher than usual can also be used. In this case, the content of 1,2-glycol bonds is preferably 1.9 mol% or more, more preferably 2.0 mol% or more, and even more preferably 2.1 mol% or more.

  For the saponification reaction of vinyl ester polymers, alcoholysis or hydrolysis using conventionally known basic catalysts such as sodium hydroxide, potassium hydroxide and sodium methoxide, or acidic catalysts such as p-toluenesulfonic acid. Decomposition reaction can be applied. Examples of the solvent used for the saponification reaction include alcohols such as methanol and ethanol; esters such as methyl acetate and ethyl acetate; ketones such as acetone and methyl ethyl ketone; aromatic hydrocarbons such as benzene and toluene. Can be used alone or in combination of two or more. Among them, it is convenient and preferable to perform the saponification reaction in the presence of sodium hydroxide, which is a basic catalyst, using methanol or a mixed solution of methanol and methyl acetate as a solvent.

  Hereinafter, a vinyl alcohol polymer having a hydrophobic group in a side chain (hereinafter sometimes abbreviated as “side chain-modified PVA”) will be described. There is no restriction | limiting in particular about the manufacturing method of side chain modified PVA, A various method is employable. For example, at least one monomer selected from an α-olefin having 6 to 18 carbon atoms or an N- (meth) acrylamide derivative is copolymerized with a vinyl ester monomer, and the resulting copolymer is saponified. This method is preferably employed. Examples of the α-olefin having 6 to 18 carbon atoms include 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene and the like. Examples of N- (meth) acrylamide derivatives having 6 to 18 carbon atoms include N-octyl (meth) acrylamide, N-decyl (meth) acrylamide, and N-dodecyl (meth) acrylamide. The number of carbon atoms is more preferably 8 or more.

  Examples of vinyl ester monomers include vinyl acetate, vinyl formate, vinyl propionate, vinyl caprylate, vinyl versatate, and among these, vinyl acetate is preferred from an industrial viewpoint.

  As a saponification reaction of the obtained copolymer, the same method as described in the explanation of the terminal-modified PVA can be used.

  The saponification degree of the modified PVA is preferably 70 to 99.9 mol%, more preferably 80 to 99.5 mol%, still more preferably 85 to 99 mol%. When the degree of saponification is less than 70 mol%, the solubility of PVA in water may be reduced. The degree of saponification of the modified PVA can be measured according to JIS-K6726 (1994).

The upper limit of the viscosity average degree of polymerization (hereinafter sometimes simply referred to as the degree of polymerization) of the modified PVA is usually 4000 or less, preferably 2000 or less, and particularly preferably 1000 or less. When the viscosity average polymerization degree is larger than 4000, the productivity of the modified PVA may be lowered. Although there is no restriction | limiting in particular about the minimum of a viscosity average polymerization degree, From a viewpoint from which dispersion stability becomes favorable, 100 or more are preferable, 150 or more are more preferable, and 200 or more are still more preferable. The viscosity average degree of polymerization of the modified PVA is a value measured according to JIS-K6726 (1994). That is, after the modified PVA is re-saponified to a degree of saponification of 99.5 mol% or more and purified, it can be obtained from the intrinsic viscosity [η] (liter / g) measured in water at 30 ° C. by the following formula.
P = ([η] × 10000 / 8.29) ^{(1 / 0.62)}

  The modified amount of the modified PVA is preferably 0.01 to 10 mol%. When the modification amount is less than 0.01 mol%, it may be difficult to disperse the crude oil, and the crude oil dispersion may be separated in a short time. The modified amount of the modified PVA is more preferably 0.05 mol% or more, and still more preferably 0.2 mol% or more. On the other hand, when the modification amount exceeds 10 mol%, the solubility of PVA may be lowered, more preferably 5 mol% or less, and still more preferably 2 mol% or less. The modified amount of the modified PVA can be obtained by proton NMR measurement.

  As described above, the vinyl alcohol polymer used in the present invention has a hydrophobic group at the terminal or side chain. From the viewpoint of further improving the dispersion stability of crude oil, the vinyl alcohol polymer is used. It is preferable that has a hydrophobic group at the terminal.

  The crude oil dispersion stabilizer of the present invention may be added directly to the crude oil, but is preferably used as a crude oil treatment agent obtained by mixing with water. At this time, it is preferable that 0.05 to 40 parts by mass of the crude oil dispersion stabilizer is included with respect to 100 parts by mass of the total amount of the crude oil treating agent. From the viewpoint of further improving the dispersion stability of the crude oil, the lower limit of the crude oil dispersion stabilizer is more preferably 0.1 parts by mass or more. On the other hand, the upper limit of the crude oil dispersion stabilizer is more preferably 30 parts by mass or less, and still more preferably 20 parts by mass or less. In the present invention, a preferred embodiment is a crude treatment agent containing 0.05 to 40 parts by mass of the crude oil dispersion stabilizer and 60 to 99.95 parts by mass of water with respect to 100 parts by mass of the total amount of the crude treatment agent It is. From the viewpoint of further improving the dispersion stability of crude oil, a crude oil treatment agent containing 0.1 to 30 parts by mass of the crude oil dispersion stabilizer and 70 to 99.9 parts by mass of water is a more preferred embodiment. A crude oil processing agent containing 0.1 to 20 parts by mass of the crude oil dispersion stabilizer and 80 to 99.9 parts by mass of water is a more preferred embodiment.

  The crude oil treating agent is preferably an aqueous solution containing a crude oil dispersion stabilizer. The crude oil treating agent may contain a solvent other than water such as alcohol as long as it does not impair the effects of the present invention, and may contain stabilizers, surfactants and the like that are usually used.

  In the present invention, the method for dispersing or emulsifying crude oil using the crude oil treating agent is not particularly limited. A method of mixing the crude oil treatment agent and crude oil as a pretreatment for pipeline transportation is a preferred embodiment, and a method of injecting the crude oil treatment material into an oil layer to obtain a dispersed or emulsified crude oil dispersion is also preferred. Embodiment. A crude oil reforming method using the crude oil treating agent is also a preferred embodiment.

  In the present invention, the mixing ratio when the crude oil is dispersed or emulsified using the crude oil treatment agent is not particularly limited, but the mass ratio of the crude oil treatment agent to the crude oil (crude oil treatment agent / crude oil) is 3/97 to Preferably it is 50/50. From the viewpoint of further improving the dispersion stability of crude oil, the mass ratio is more preferably 5/95 to 40/60.

  Moreover, in this invention, it is a crude oil dispersion containing the said crude oil processing agent, Comprising: 3-50 mass parts of the said crude oil processing agent is contained with respect to 100 mass parts of whole quantity of a crude oil dispersion, The said vinyl alcohol polymer is 0. A crude oil dispersion containing 0.001 to 1 part by mass and 50 to 97 parts by mass of the crude oil is a preferred embodiment. From the viewpoint of further improving the dispersion stability of the crude oil, the content of the crude oil treating agent with respect to 100 parts by mass of the total amount of the crude oil dispersion is preferably 5 to 40 parts by mass. It is preferable that it is 60-95 mass parts. The content of the vinyl alcohol polymer is preferably 0.05 to 0.8 parts by mass from the viewpoint of further improving the dispersion stability of the crude oil. The crude oil dispersion thus obtained is preferably used as an energy source.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely using an Example, this invention is not limited to these Examples.

[Synthesis of terminal hydrophobic group-containing PVA]
<PVA-1 to 3>
Vinyl alcohol polymers (PVA-1 to 3) having an alkyl group at the terminal were synthesized by the method described in Example 1 of JP-B-61-41924. Table 1 shows the types of mercaptans used in the synthesis, vinyl alcohol unit content (degree of saponification) and viscosity average degree of polymerization measured according to JIS-K6726 (1994), and the amount of modification determined by ¹ H-NMR measurement. Show.

<PVA-4>
A vinyl alcohol polymer (PVA-4) having a phenyl group at the terminal was synthesized by the method described in Example 1 of JP-A-7-292025. Table 1 shows the types of mercaptans used in the synthesis, vinyl alcohol unit content (degree of saponification) and viscosity average degree of polymerization measured according to JIS-K6726 (1994), and the amount of modification determined by ¹ H-NMR measurement. Show.

[Synthesis of side chain hydrophobic group-containing PVA]
<PVA-5>
(1) 630 parts by mass of vinyl acetate, 6.2 parts by mass of 1-dodecene, and 1766 parts by mass of methanol are charged into a reactor equipped with a stirrer, a reflux condenser, an argon inlet, and an initiator addition port, and argon bubbling is performed. The system was purged with argon for 30 minutes. The temperature of the reactor was increased, and when the internal temperature reached 60 ° C., 1.0 part by mass of 2,2′-azobisisobutyronitrile was added to initiate polymerization. After polymerization at 60 ° C. for 4.8 hours, the polymerization was stopped by cooling. The polymerization rate when the polymerization was stopped was 60%. Subsequently, unreacted monomers were removed while sometimes adding methanol under reduced pressure at 30 ° C. to obtain a methanol solution (concentration 55.6%) of polyvinyl acetate into which 1-dodecene was introduced.

(2) 3.75 parts by mass of ion-exchanged water and 199 parts by mass of methanol were added to 540 parts by mass of the methanol solution of polyvinyl acetate into which 1-dodecene obtained in (1) was introduced (1-dodecene in the solution). Was added to 300 parts by mass of polyvinyl acetate), sodium hydroxide methanol solution (concentration 12.8%) was added, and saponification was performed at 40 ° C. (saponified 1-dodecene was introduced). Polyvinyl acetate concentration 40%, moisture content 0.5 mass%, molar ratio of sodium hydroxide to vinyl acetate unit in polyvinyl acetate introduced with 1-dodecene 0.0075). Since a gelled product was formed in about 15 minutes after the addition of the sodium hydroxide methanol solution, this was pulverized by a pulverizer and further allowed to stand at 40 ° C. for 45 minutes to promote saponification. After neutralizing the remaining alkali by adding methyl acetate to this, it was washed well with methanol soxhlet, and dried at 40 ° C. for 12 hours in a vacuum dryer to thereby remove the side chain hydrophobic group-containing PVA (PVA-5). Obtained. Table 1 shows the content of 1-dodecene (modified amount) determined by ¹ H-NMR measurement, the content of vinyl alcohol units (degree of saponification) and the viscosity average polymerization degree measured according to JIS-K6726 (1994). Show.

Example 1
To a glass screw tube, 6 parts by mass of a 0.5% by mass aqueous solution of PVA-1 and 14 parts by mass of heavy oil (35 ° C. viscosity 580 mPa · s, API specific gravity 11.6) are added, and a magnetic stirrer is used. The mixture was stirred at 1500 rpm for 15 minutes to prepare a crude oil dispersion. The viscosity (A) of the crude oil dispersion immediately after production and the viscosity (B) of the crude oil dispersion after 6 hours at 35 ° C. were measured at 35 ° C. using a B-type viscometer. The obtained results are shown in Table 2. Table 2 shows the value of (B / A) as an index of dispersion stability.

Examples 2-8
A crude oil dispersion was prepared and evaluated in the same manner as in Example 1 except that the type of PVA, the concentration of PVA, the type of crude oil, and the dispersion composition were changed as shown in Table 2. The bitumen used in Examples 7 and 8 is from Canada (viscosity at 35 ° C., 66100 mPa · s, API specific gravity of 7.6). The obtained results are shown in Table 2.

Comparative Example 1
A crude oil dispersion was prepared and evaluated in the same manner as in Example 1 except that unmodified PVA (polymerization degree 300, saponification degree 88 mol%) was used instead of PVA-1 used in Example 1. The obtained results are shown in Table 2.

Comparative Example 2
A crude oil dispersion was prepared and evaluated in the same manner as in Comparative Example 1 except that bitumen was used instead of the heavy oil used in Comparative Example 1. The obtained crude oil dispersion immediately formed a sediment, and its viscosity could not be measured. The obtained results are shown in Table 2.

Claims (7)

  A crude oil dispersion stabilizer containing a vinyl alcohol polymer, wherein the vinyl alcohol polymer has a hydrophobic group at a terminal or a side chain.   The crude oil dispersion stabilizer according to claim 1, wherein the hydrophobic group is a hydrocarbon group.   The crude oil dispersion stabilizer according to claim 1 or 2, wherein the hydrophobic group is an alkyl group having 6 to 18 carbon atoms or an aryl group.   The crude oil dispersion stabilizer according to any one of claims 1 to 3, wherein the vinyl alcohol polymer has a hydrophobic group at a terminal.   The crude oil dispersion stabilizer according to any one of claims 1 to 4, which is used for crude oil having an API specific gravity of 30 ° or less.   It is a crude oil processing agent containing the crude oil dispersion stabilizer and water in any one of Claims 1-5, Comprising: The said crude oil dispersion stabilizer is 0.05-40 mass with respect to 100 mass parts of whole quantity of a crude oil processing agent. Crude oil processing agent.   A crude oil dispersion comprising the crude oil treatment agent according to claim 6 and crude oil, wherein the vinyl alcohol polymer comprises 3 to 50 parts by mass of the crude oil treatment agent with respect to 100 parts by mass of the total amount of the crude oil dispersion. A crude oil dispersion containing 0.001 to 1 part by mass of the crude oil and 50 to 97 parts by mass of the crude oil.