KR820002013B1 - Method for treating sour petroleum distillates - Google Patents

Abstract

Mercaptans in sour petroleum distillate were oxidized by contacting the distillate with mercaptan-oxidizing catalyst in the presence of alkaline reagent and substituted ammonium halide(I, R=C20alkyl, cycloaldyl, aryl, aralkyl, alkaryl; R1=C5-20 straight chain alkyl; X=Cl, Br, F, I).

Description

Natural Petroleum Oil Treatment

The accompanying drawings show a comparison of the prior art of the mercaptan sulfur content with the working time of the present invention.

The present invention relates to a method for treating natural petroleum oil.

Processes for treating natural petroleum fractions by contacting the oil fraction with a supported mercaptan catalyst in an oxidizing atmosphere in the presence of alkaline reagents are well known and widely practiced in the petroleum refining industry. One such method is described in US Pat. No. 2,988,500. This method typically oxidizes unpleasant mercaptans contained in natural petroleum fractions into harmless disulfides, which is commonly referred to as sweeting. The oxidizing agent is mostly air mixed with the natural petroleum fraction to be treated, the alkaline reagent is mainly sodium hydroxide solution, and caustic water solution is supplied continuously or as needed intermittently to the process.

Depending on the oil source from which the oil is extracted, the boiling range of the oil itself, and the method of treating the petroleum to produce the oil, the concentration of the mercaptans contained in the oil will vary widely as well. In general, low boiling petroleum fractions, including natural, direct current and cracked gasoline, contain less complex low boiling mercaptans and are very easily handled in the sweetening process. In particular, the process of the present invention is suitable for the treatment of petroleum fractions such as kerosene, jet fuel, fuel oil, naphtha and the like that boil above 135 ° C. Generally these high boiling fractions contain mercaptans which are very difficult to oxidize, i.e. highly hindered branched chains and aromatic thiols, especially high molecular weight tertiary and multifunctional mercaptans. As can be clearly seen from the examples, the improvement according to the present invention is particularly remarkable when treating the above-mentioned high boiling natural petroleum oil.

An object of the present invention is to provide a novel method of treating natural petroleum oil to improve oxidation of mercaptan contained therein.

It is another object of the present invention to provide a novel process which is particularly suitable for the treatment of high boiling petroleum fractions containing mercaptans which are very difficult to oxidize.

The present invention is an improved process for treating mercaptan-containing natural petroleum fractions by bringing the above-mentioned oxidized fraction in contact with a supported mercaptan oxidation catalyst in the presence of an alkaline reagent and a substituted ammonium halide of the general formula:

[Wherein R is a hydrocarbon group containing up to 20 carbon atoms and is selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl and alkaryl.

R 'is a straight chain alkyl group containing 5-20 carbon atoms, X is chlorine, bromine, fluorine or iodine.]

A very particular example relates to the process of contacting the above-mentioned oils with a charcoal-supported metal phthalocyanine catalyst in the presence of dimethyl benzylalkylammonium chloride, a caustic solution and an alkylsubstituted straight chain alkyl group containing 5-20 carbon atoms.

Another particular example of the invention is the contacting of the above-mentioned oil admixed with air with a charcoal-supported cobalt phthalocyanine monosulfonate catalyst and then the above-mentioned oil in contact with the above-mentioned catalyst with a space of 0.1-10 liquid per hour. A method of treating natural petroleum fractions consisting of dimethylbenzylalkyl ammonium chloride mixed with an aqueous sodium hydroxide solution at a molar ratio of 0.001: 1-1: l, maintained for a time corresponding to the liquid hourly space velocity. It is about. The alkyl substituent of the dimethylbenzyl alkyl ammonium chloride described above is a straight chain alkyl group containing 12-18 carbon atoms.

The method of sweetening natural petroleum fractions has been carried out to date to oxidize mercaptans contained in petroleum fractions in the presence of alkaline reagents. Typically the supported mercaptan oxidation catalyst is first saturated with alkaline reagents and then the alkaline reagents are contacted continuously or intermittently with the catalyst bed and mixed with the natural petroleum fraction as needed. Any suitable alkaline reagent can be used.

Alkali metal hydroxides, such as aqueous solutions, such as aqueous sodium hydroxide solution are most widely used. The solution may further contain solubilizers which enhance mercaptan solubility, such as alcohols, in particular ethanol, n-propanol or isopropanol and phenols or cresols. Particularly preferred alkaline reagents are caustic solutions containing 2-30% by weight sodium hydroxide. As the preferred solubilizer, methanol is used, and the alkaline solution may suitably contain 2-100% by volume thereof. Although sodium hydroxide and potassium hydroxide represent the most preferred alkaline reagents, other reagents including titrium hydroxide, rubidium hydroxide and cesium hydroxide are also suitably used.

According to the present invention, in order to improve the oxidation and conversion of mercaptans to disulfides, substituted ammonium halides are mixed with the alkaline reagents described above. It is suitable to use substituted ammonium halides, preferably dimethylbenzyl alkylammonium chloride, with an alkali metal hydroxide or other alkaline reagents in a 0.001: 1-1: 1: 1 molar ratio. Substituted ammonium halides contemplated herein are represented by the following general formula.

[Wherein R is a hydrocarbon group containing up to 20 carbon atoms and is selected from alkyl, cycloalkyl, aryl, aralkyl and alkaryl,

R 'is a straight alkyl group containing 5-20 carbon atoms,

X is chlorine, bromine, fluorine or iodine. Appropriately substituted ammonium halides are therefore dialkylphenylpentyl ammonium chloride, dialkylphenylhexylammonium chloride, dialkylphenyloctylammonium chloride, dialkylphenyldecylammonium chloride, dialkylphenyldodecylammonium chloride, dialkyltetradecylammonium chloride, Dialkylphenylhexadecylammonium chloride, dialkylphenyloctadecylammonium chloride, dialkylphenyleicosylammonium chloride, diallbenzylpentylammonium chloride, dialkylbenzylhexylammonium chloride, dialkylbenzyloctylammonium chloride, dialkylbenzyldecylammonium Chloride, dialkylbenzyldodecylammonium chloride, dialkylbenzyl tetradecylammonium chloride, dialkylbenzylhexadecylammonium chloride, dialkylbenzyloctadecylammonium chloride, dialkylbenzylethylacylammonium chloride, dialkyltolylpentalam Chloride, dialkyltolylhexylammonium chloride, dialkyltolyloctylammonium chloride, dialkyltolyldecylammonium chloride, dialkyltolyldodecylammonium chloride, dialkyltolyltetradecylammonium chloride, dialkyltolylhexadecylammonium chloride, dialkyl Tolyloctadecylammonium chloride, dialkyltolylecosylammonium chloride, dialkylcyclohexyloctylammonium chloride, dialkylcyclohexyldecylammonium chloride, dialkylcyclohexyldodecylammonium chloride, dialkylcyclohexyl tetradecylammonium chloride, dialkylcyclohexyltedecylammonium chloride Alkylcyclohexylhexadecylammonium chloride, dialkylcyclohexyloctadecylammonium chloride and trialkyloctylammonium chloride and the like, wherein the alkyl group is selected from methyl, ethyl and propyl.

The most preferred dimethylbenzylalkylammonium chloride or commercially available from Mason Chemical Company under the trademark Maquats. However, the aforementioned dimethylbenzylalkylammonium chloride first reacts ammonia and C ₁₂ -C ₁₈ carboxylic acid with silica gel at about 500 ° C. to form C ₁₂ -C ₁₈ nitrile, and then contact the nitrile with a nickel catalyst at about 140 ° C. Reduced hydrogen. The C ₁₂ -C ₁₈ amine thus obtained is separated from the reaction mixture and then reacted with 2 molar excess of methylchloride. After neutralizing the reaction mixture, the amine is reacted with 1 molar equivalent of benzylchloride to give the desired dimethyl benzylalkylammonium chloride. It is appropriate to react the methyl chloride as well as the benzyl chloride with the amine in a methanolic solution at a temperature of about 150 ° C. The product can be used as is or further treated on activated carbon to remove impurities.

The catalyst used in the practice of the present invention may be any of a variety of catalysts known in the treatment art as being effective in promoting the oxidation of mercaptans contained in the natural petroleum fraction to form polysulfide oxidation products. The catalysts described above include metal compounds of tetrapyridino porpyrazine described in US Pat. No. 3,980,582, such as cobalt tetra pyridino porrazine; Porphyrin and metalloporphyrin catalysts such as cobalt tetra phenylporphyrin sulfonate as described in US Pat. No. 2,966,453; Corinoid catalysts as described in US Pat. No. 3,252,392, such as cobalt corin sulfonate and chelated organometallic catalysts as described in US Pat. No. 2,913,426, such as condensation products of aminophenols and Group VIII metals. Metal phthalocyanines are preferred mercaptan oxidation catalysts.

Metal phthalocyanines used to promote oxidation of mercaptans in natural petroleum fractions are typically magnesium phthalocyanine, titanium phthalocyanine, hafnium phthalocyanine, vanadium phthalocyanine, tantalum phthalocyanine, molybdenum phthalocyanine, cobalt phthalocyanine, nickel phthalocyanine, platinum pallocyanine, platinum pallacinine Copper phthalocyanine, silver phthalocyanine, zinc phthalocyanine and tin phthalocyanine. Cobalt phthalocyanine and vanadium phthalocyanine are particularly preferred. Metal phthalocyanines are very frequently used as derivatives thereof. Particular preference is given to commercially available sulfonated derivatives such as cobalt phthalocyanine monosulfonate, cobalt phthalocyanine disulfonate or mixtures thereof. Sulfonated derivatives can be prepared, for example, by reacting cobalt vanadium or other metal phthalocyanines with fuming sulfuric acid. While sulfonated derivatives are preferred, it can be seen that other derivatives, in particular carboxylated derivatives, can be used. Carboxylated derivatives are readily prepared by acting trichloroacetic acid on the metal phthalocyanine.

The metal phthalocyanine catalyst may be adsorbed or impregnated on the solid absorption support by conventional methods or other convenient methods for use in stationary phase processing operations. Generally, a support or carrier of spherical, pill, pellet, granular or other particles of uniform or irregular shape and size is immersed, deposited, suspended or in an aqueous or alcoholic solution or dispersion of a metal phthalocyanine catalyst. It is immersed or contacted by other means such as spraying or spraying an aqueous solution or an alcoholic solution or dispersion onto the adsorption support. In all of the above cases, the mixture obtained by separating the aqueous solution or the dispersion is left to dry at room temperature, or dried by flowing a hot gas at an elevated temperature in an oven or dried by the appropriate method.

In general, up to 25% (by weight) of metal phthalocyanine can be adsorbed onto a solid adsorbent support or carrier material to form a stable catalyst mixture. In general, metal phthalocyanine concentrations of about 2% by weight or more are used, so the benefits of activity given are not enough to ensure the use of high concentrations, but relatively small amounts of 0.1-10% by weight form a suitable active catalyst mixture. However, in view of the significant increase in activity resulting from the use of the substituted ammonium halides of the present invention in relation to the minimum metal phthalocyanine concentration, high concentrations further increase the mercaptan oxidation rate, especially in the treatment of natural petroleum fractions. I think it is effective.

One suitable and convenient method for adsorbing a metal phthalocyanine catalyst to a solid adsorption support or carrier material is to place the support or carrier material in advance in an oil treatment zone or treatment chamber which is a stationary phase, and pass the metal phthalocyanine solution or dispersion through the stationary phase to Consisting of forming a catalyst mixture in situ. This method recycles the solvent or dispersion one or more times so that the desired concentration of metal phthalocyanine is achieved on the adsorption support. Alternatively, the catalyst mixture is inherently formed by pre-positioning the adsorption support into the treatment chamber described above and then filling the treatment chamber with a metal phthalocyanine solution or dispersion to deposit the support for a predetermined period of time.

The metal phthalocyanine catalyst can be adsorbed or impregnated with the well-known general solid adsorbent material generally used as a catalyst support. Preferred adsorbents include various charcoal, peat, lignitite, nutshells, bones and carbonaceous materials produced by the dry distillation of wood, in particular porous particles having increased adsorption by heat treatment or chemical treatment or both treatments. Charcoal with is preferred. This is called charcoal or charcoal. In addition, the above-mentioned adsorbent materials include natural clays and silicates such as diatomaceous earth, clay, kiesel, attapulgus clay, feldspar, montmorillonite, halosite and kaolin; Non-reactive inorganic oxides such as alumina, silica, zirconia, toria and boria, or combinations thereof, such as silica-alumina, silica-zirconia, and anlumina-zirconia, produced by natural or synthetic materials. Any particular solid adsorbent material is selected according to its ability under its conditions of use. For example, in the treatment of the natural petroleum fraction described above, the solid adsorbent carrier material should be insoluble or inert to the petroleum fraction in the alkaline reaction conditions of the treatment zone. In the latter case charcoal, in particular activated carbon, is preferred because of its capacity for metal phthalocyanines and stability under treatment conditions.

The method of the present invention can be carried out according to the processing conditions of the known art. This method is usually performed at room temperature, although high temperatures up to about 105 ° C. are suitably utilized. Atmospheric pressure is quite moderate but it is carried out at a pressure of 69 atm. A contact time corresponding to the hourly space velocity of a liquid of 0.1-10 is effective to achieve the desired reduction of the mercaptan content in the natural petroleum fraction, with the optimum contact time being the size of the treatment zone, the amount of catalyst contained therein and the amount of catalyst to be treated. It depends on the nature of the oil.

As mentioned above, the sweetening of the natural petroleum fraction is carried out by oxidizing its mercaptan content to disulfide. The process is therefore carried out in the presence of an oxidizing agent, preferably air, although oxygen or other oxygen-containing gas may be used. The natural petroleum fraction is passed upwards or downwards through the catalyst bed. Natural petroleum fractions can contain sufficient air. Generally, however, added air is mixed with the oil and charged together into the treatment zone. In some cases, it may be advantageous to charge the air separately into the treatment zone and backflow separately in the opposite direction to the oil.

Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1

The natural petroleum fraction treated in this example and the following examples is kerosene fraction having a boiling point of 178-218 ° C. at 742 mmHg. Kerosene has a specific gravity of 0.3031 and contains 443 ppm mercaptan sulfur. Kerosene was charged downward into a vertical tubular reactor via a cobalt phthalocyanine mono sulfonate catalyst supported on 100 cc charcoal placed as a stationary phase. The catalyst phase consisted of 1% by weight cobalt phthalocyanine mono sulfonate adsorbed on 10-30 mesh activated carbon particles. The kerosene was charged at 0.5 liquid hourly space velocity under 4 atmospheres of air providing about 2 times the stoichiometric amount of oxygen required to oxidize the mercaptan contained in kerosene.

In this example showing a known example, the catalyst phase was first soaked with about 10 cc of 8% sodium hydroxide aqueous solution and then 10 cc of the above-described solution was charged onto the catalyst mixed with the kerosene charged thereto at 12 hour intervals. Treated kerosene was analyzed periodically for mercaptan sulfur. In the accompanying drawings, the mercaptan sulfur content of the treated kerosene is plotted against the number of operating hours (dashed lines).

Example 2

In this example, the mercaptan-containing kerosene fraction described above according to the invention is treated as described in Example 1, except that dimethylbenzyl-n-alkylammonium chloride is mixed with an aqueous sodium hydroxide solution to treat 0.01 mole dimethylbenzyl. A -n-alkylammonium chloride solution was prepared. Diethylbenzyl-n-alkylammonium chloride,

Dimethylbenzyldodecylammonium chloride (61%)

Dimethylbenzyltetradecylammonium chloride (23%)

Dimethylbenzylhexadecylammonium chloride (11%)

Dimethylbenzyloctadecylammonium chloride (5%)

Consists of

Treated kerosene was periodically reanalyzed for mercaptan sulfur.

The mercaptans sulfur content of the treated kerosene indicated for run time (solid line in the figure) demonstrates that the activity was improved and significantly stable by the examples of the present invention.

Claims (1)

A method of treating a mercaptan-containing natural petroleum fraction consisting of contacting the natural petroleum fraction with an supported mercaptan oxidation catalyst in the presence of an alkaline reagent and a substituted ammonium halide of the general formula:

Food, [R is a hydrocarbon group containing up to 20 carbon atoms and is selected from alkyl, cycloalkyl, aryl, aralkyl and alkaryl. R 'is a straight chain alkyl group containing 5-20 carbon atoms X is chlorine, bromine, fluorine or iodine.]

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