DE2908417C2 - Process for the treatment of acidic petroleum distillates containing mercaptan - Google Patents

Description

Process / ur treatment of acidic petroleum distillates, at which the distillate in the presence of a metal phthalocyanine catalyst with an oxidizing agent at alkaline Reaction conditions are treated are known, for example, from US Pat. No. 2,882,224. This Oxidation processes are used in liquid-liquid treatment systems or with a fixed catalyst layer carried out. In the latter case, the supported catalyst is illuminated with an aqueous alkali solution, which is fed to the process continuously or intermittently.

In the manufacture of the supported metal phthalocyanine catalysts, it is common to use the metal phthalocyanine an alcoholic solution or dispersion of the same to adsorb on an adsorptive carrier. Methanol solutions or dispersions have so far produced the most active catalysts.

The object underlying the invention was now the method for treating a to improve acidic petroleum distillate.

The inventive method for treating mercaptan-containing acidic petroleum distillates in the presence of morpholine and a supported Mctallphthaloeyanin catalyst in an alkaline environment with a Oxidizing agent is characterized in that a catalyst is used which is impregnated a solid adsorptive carrier material with the metal phthalocyanine with the aid of an aqueous impregnation solution or dispersion of this metal phthalocyanine with a content of 5 to 50 ppm by weight Morpholine has been made.

An aqueous sodium hydroxide solution is preferably used as the alkali and air as the oxidizing agent. The preferred amount of metal phthalocyanine on the carrier material, such as activated carbon, is 0.1 to 10% by weight. The preferred metal phthalocyanine is cobalt phthalocyanine monosulfonate or disulfonate.

The adsorptive support materials are those which are generally used as catalyst supports, such as especially the different types of charcoal or activated charcoal produced by the degrading distillation of wood, Peat, lignite, nutshells, bones and other carbonaceous materials have been produced. Other bulky carrier materials are, for example, the naturally occurring clays and silicates, such as diatomaceous earth, Fuüerde, kieselguhr, attapulgus clay, feldspar, montmorillonite, halloysite and kaolin, and also the naturally occurring or synthetically produced heat-exposed inorganic ones Oxides such as alumina, silica, zirconium oxide, thorium oxide and boron oxide or combinations thereof, such as silica-alumina, silica-zirconia and alumina-zirconia. Charcoal and especially activated

ίο Coal is because of its capacity for metal phthalocyanine and preferred for its stability under treatment conditions.

Metal phthalocyanine can be any that are found to be useful in catalysis of sweetening processes

1Ί is known, such as molybdenum, manganese, Iron, cobalt, nickel, platinum, palladium, copper, silver, zinc and tin phthalocyanine. Cobalt phthalocyanine and vanadium phthalocyanine are particularly preferred metal phthalocyanines. The metal phthalo-

jo cyanine is preferably used as a derivative of the same, where the commercially available sulfonated derivatives, such as cobalt phthalocyanine monosulfonate, Cobalt phthalocyanine disulfonate or mixtures thereof are particularly preferred. Even

> 5 other derivatives, especially the carboxylated ones Derivatives of metal phthalocyanines are used.

According to the invention, the solid adsorptive carrier is coated with an aqueous solution or dispersion of the metal phthalocyanine impregnated, this solution also

JIi dem 5 to 50 ppm by weight morpholine (tetrahydro-1,4-isooxazine) contains. Morpholine has now surprisingly proven to be an effective promoter for the by Metal phthalocyanine catalyzed oxidation of mercaptans in an acidic petroleum distillate, but with

j, morpholine concentrations above 50 ppm by weight are not effective enough.

The carrier material is generally in the form of spheres, pills, pellets or granules more uniformly or irregular shape and is

-Hi bene aqueous dispersion and immersed in it impregnated, or the aqueous dispersion can also be sprayed or poured onto the carrier material. In each case the excess solution is separated off and the resulting

4 ^r ) Put material to dry under ambient temperature conditions or dry it at elevated temperature in an oven or in a stream of hot gases. It is generally preferred to absorb up to 25% by weight of metal phthalocyanine on the carrier material.

Vi beer, so that a stable catalytic composition forms. A suitable and convenient method is to have the solid support in a beforehand The treatment zone or chamber for the petroleum distillate is arranged as a fixed layer and the aqueous one

^r > 5 sends metal phthalocyanine solution or dispersion through the layer to form the catalyst in situ. This method allows the aqueous solution or dispersion to be used one or more times up to the desired concentration of the metal phthalocyanine

bo attributed to the carrier. According to another In turn, the carrier can be arranged beforehand in the treatment room for the petroleum distillate after which the chamber is filled with the aqueous metal phthalocyanine solution or dispersion to

hi the wearer himself for a predetermined period of time to be soaked, the catalyst also forming in situ. In the procedure according to the Invention are mercaptans, which in an acidic

Petroleum distillate are contained, oxidized to harmless disulfides. The catalyst is initially with the saturated alkaline reagent, and this is then at least intermittently the acidic petroleum distillate admixed, which is passed over the catalyst in order to achieve the desired alkali concentration on the catalyst maintain. As the alkali, there is an alkali metal hydroxide in aqueous solution such as an aqueous solution of sodium hydroxide or potassium hydroxide, preferably. The solution can also contain a solubility improver to promote mercaptan solubility, such as an alcohol and especially methanol, ethanol, n-propanol and isopropanol, as well as phenols and Cresols. A particularly preferred alkaline reagent is an aqueous solution with 2 to 30% by weight Alkali metal hydroxide such as sodium hydroxide. The solubility improver is when one is used is, preferably methanol, and the alkaline solution can expediently 2 to JOO% by volume of which included. Other suitably used alkalis are lithium hydroxide, rubidium hydroxide and cesium hydroxide.

The process is usually carried out at ambient temperature, although elevated temperatures can also be used can be used, which are generally not above 150 C. The procedure can be performed at press of up to 69 bar, although atmospheric pressure or essentially atmospheric pressure completely sufficient. A liquid hourly space flow rate of 1 to 100 is sufficient to achieve the desired reduction in the mercaptan content of an acidic petroleum distillate.

Air is preferably used as the oxidizing agent, although oxygen or other oxygen-containing ones are also used Funds can be used. The mixture of petroleum distillate, alkaline reagent and oxidizing agent can be sent up or down through the catalyst layer. In some cases it can the air can be guided in countercurrent to the petroleum distillate. In still other cases, the petroleum distillate and separately introducing the alkaline reagent into the treatment zone.

The catalyst is active and stable in the process according to the invention. Accordingly, the catalyst in a fixed layer used to treat a large volume of sour petroleum distillate will. Although the metal phthalocyanine is somewhat soluble in alkaline solution, it will, however, on the solid retained adsorptive carrier material. However, if about metal phthalocyanine leached from the carrier or otherwise gets into the alkaline solution, it can easily be reused in this solution be returned in the proceedings. In some cases, additional information may be required To introduce metal phthalocyanine for adsorption on the solid support.

The acidic petroleum distillates vary widely in their composition depending on the source of the petroleum, from which the distillate originates, the boiling range of the distillate and possibly the methods of processing of crude oil to obtain the distillate. The method according to the invention is particularly suitable for the treatment of petroleum distillates that boil above 135 C, such as kerosene, Jet fuel and fuel oil in a treatment system with a fixed catalyst layer. These higher boiling distillates generally contain the more difficult to oxidize mercaptans; H. the branched-chain and aromatic thiols which are insoluble in alkali, especially the higher molecular weight tertiary ones and polyfunctional mercaptans. In addition, the method according to the invention is also useful for the treatment of lower boiling distillates such as natural, straight-run and cracked gasoline Petrol.

example 1

To produce a supported metal phthalocyanine catalyst used in the process according to the invention, activated adsorptive carbon particles were impregnated with a common aqueous dispersion of cobalt phthalocyanine monosulfonate and morpholine. The dispersion was prepared in such a way that 0.31 ml of an aqueous morpholine solution containing 2000 ppm by weight of morpholine was diluted to 25 ml with water. To this solution, 150 mg of cobalt phthalocyanine monosulfonate was added and the mixture was stirred to form a slurry. The sludge was then further diluted by adding 100 ml of water and gave an impregnation dispersion, which is hereinafter referred to as a solution and which contained 5 ppm by weight of morpholine. It was stirred for a further 5 minutes. 100 cm ^{3 of} the coal particles with an average bulk density of 0.25 g / cm ¹ and with a particle size in the 10 to 30 mesh range were then immersed in the impregnation solution. The solution was stirred for 5 minutes and then kept under quiet conditions for an hour. The impregnating solution was then evaporated to dryness on a steam bath, and the impregnated particles were then heated to 100 ° C

j-) dried in an oven for one hour. The so obtained catalyst is referred to as catalyst A hereinafter. Those labeled as Catalysts B, C and D. Catalysts were prepared accordingly, with the exception that the impregnation solution Contained 10, 16 and 2000 ppm morpholine, respectively.

A comparative catalyst was prepared as above except that the cobalt phthalocyanine was adsorbed on the activated carbon support from a methanol dispersion according to known methods.

For this purpose, 150 mg of cobalt phthalocyanine monosulfonate were mixed with 50 ml of methanol and stirred for 5 minutes. The resulting dispersion was then diluted to 300 ml with methanol, with stirring for an additional 5 minutes. 100 cm ¹ of the activated carbon particles were immersed in the methanol dispersion, and the dispersion was stirred for 5 minutes and then held for one hour under quiescent conditions. The methanol dispersion was then evaporated to dryness on a steam bath, and the resulting

>'. impregnated particles were then dried in an oven at 100 ° C. for one hour. This catalyst is referred to as catalyst E hereinafter.
The catalysts produced in this way were one

Wi comparison stc.st. The test was carried out in an air atmosphere under ambient conditions of temperature and pressure. In each test there was 13.3 cm x ^{1 of} catalyst moistened with 5 cm 'of aqueous sodium hydroxide solution (pH 14)

hi and 100 cm ^{1 of} an acidic crosine contained in a closed glass container which was inserted into a mechanical shaker. The reaction mixture was in contact with the catalyst 30

Shaken minutes, after which the kerosene was analyzed with regard to the residual mercaptan content. There were three different acidic kerosene each, namely

Table I.

with a content of 164, 407 and 832 ppm by weight of mercaptan sulfur are used. The test results are compiled in Table I below.

Line, min. Mercaptanschv. -.fei.
Catalyst Λ Weight ppm
Catalyst B Catalyst C Catalyst u Catalyst ii 0
30th 164
6th 164
> 164
6th 164 164
8th /.•It. Min. Mertaptanschuelel.
Catalyst Λ (icwichii-ppm
Kulak salor 15 Catalyst (. Catalyst I) Catalyst ii 0
30th 407
12th 407
6th 407
9 407
30th 407
19th Line. Min. Mercaptan sulfur,
Catalyst Λ Cicwichlv-npm
Catalyst B Catalyst C Catalyst I) Catalyst E.

832 2 832 22nd 15th example

A catalyst prepared like Catalyst B was used in a comparative test with a catalyst compared to the prior art such as catalyst E had been prepared. In any case became 100 cm 'of the catalyst as a fixed layer in a vertical glass tube reactor arranged, eggs was kept at ambient temperature (23 C). Before starting each test, the The catalyst layer was washed with an aqueous sodium hydroxide solution of K) Be. Air was in the system an amount of 100 cnrVh. and the air was mixed with the acidic kerosene charge. The mixture was down through the catalyst bed at a liquid hourly space flow rate of 1 carried out over a period of 20 hours. The reactor outlet was

832
33

832 20

periodically decreased and with regard to the mercaptan sulfur content analyzed. The results are summarized in Table II below.

Table Il Mercaptan sulfur, Weight ppm Time, hours Catalyst B Catalyst E. 448 448 0 4th 5 1 6th 8th 5 6th Il 10 8th 14th 15th 9 17th 20th

Claims (2)

Patent claims: 1. Process for the treatment of acidic petroleum distillates containing mercaptan, in the presence of morpholine and a supported metal phthalocyanine catalyst in an alkaline environment with an oxidizing agent, characterized in that one a catalyst used by impregnation of a solid adsorptive carrier material with the metal phthalocyanine with the aid of an aqueous impregnation solution or dispersion of this metal phthalocyanine with a content of 5 to 50 ppm by weight of morpholine. 2. The method according to claim 1, characterized in that a catalyst is used in its production the solid adsorptive carrier material with 0.1 to 10% by weight of metal phthalocyanine has been impregnated from the impregnation solution or dispersion.