RU2053844C1 - Catalyst for oxidation of sulfurous compounds - Google Patents

Abstract

FIELD: gas and oil processing industry. SUBSTANCE: catalyst for liquid-phase oxidation of sulfurous compounds in aqueous-alkaline medium consists of, wt.-%: cobalt phthalocyanine 10-20; alkaline metal benzoate 0.1-2.0; polypropylene or its mixture with low-pressure polyethylene taken at the ratio (25-75):(75-25) the rest. EFFECT: enhanced quality of catalyst. 2 tbl

Description

 The invention relates to heterogeneous phthalocyanine catalysts for liquid-phase oxidation of sulfur compounds in an aqueous alkaline medium and can be used in the gas and oil refining, chemical, pulp and paper industries for the neutralization of aqueous process condensates, sulfur-alkaline effluents, as well as for the regeneration of mercaptide-containing alkaline solutions when cleaning light hydrocarbons.

 A known catalyst for the oxidation of sulfur compounds in an aqueous alkaline medium containing the following components, wt. cobalt sulfophthalocyanine 1; activated carbon 3.4 and polyethylene the rest (see US patent N 3396123, CL 252-426, 1968).

 The main disadvantages of this catalyst are its low stability and low catalytic activity in the process of oxidation of sulfur compounds in an aqueous alkaline medium.

 By the technical nature and the achieved result, the closest to the invention is a heterogeneous catalyst for the oxidation of sulfur compounds in an aqueous alkaline medium containing cobalt phthalocyanine or its derivatives and a thermoplastic polymer (polyethylene, polypropylene or polystyrene) as a carrier in the following ratio of components, wt. cobalt phthalocyanine or its derivatives 3-20, the rest polymer (see auto St. St. N 1041142, class B 01 J 37/04, 1983).

 Of these media, the most affordable and technologically advanced in manufacture is high pressure polyethylene (LDPE).

The disadvantage of the catalyst in PEVD is its rather low heat resistance, not allowing to carry out the process of decontamination effluents at temperatures above 80 ^C. Further, the catalyst carrier on the plastic is not resistant to hydrocarbon exposure that may get into the oxidation reactor, along with sewage in emergency situations, leads to loss of strength and activity.

 Polystyrene also has low heat resistance, and in addition, it is a scarce material.

 Of these media, polypropylene is the most resistant to high temperatures and aromatic hydrocarbons.

 The disadvantage of the catalyst on a polypropylene carrier is the difficulty of its manufacture, because due to high temperatures during extrusion, partial thermal degradation of cobalt phthalocyanine is observed, accompanied by the release of gaseous products and a partial decrease in catalyst activity. In addition, working conditions worsen and the atmosphere is polluted.

 The aim of the invention is the creation of such a catalyst, which would simultaneously have high heat resistance, catalytic activity and improved manufacturability.

 This goal is achieved by the fact that in the composition of the catalyst containing cobalt phthalocyanine and polyolefin, an additional salt of benzoic acid, for example, sodium benzoate or potassium, is additionally introduced, in the following ratio, wt.

Cobalt phthalocyanine 10-20
Salt of benzoic acid 0.1-2.0 Polyolefin The rest of the cobalt phthalocyanine is pretreated with a salt of benzoic acid, for example sodium benzoic acid or potassium, by vigorous stirring, and polypropylene or a mixture of low-pressure polypropylene and polyethylene is used preferably, in the following ratio: (25-75) :( 75-25).

 A distinctive feature of the proposed catalyst is an additional component, the salt of benzoic acid, for example, sodium benzoate or potassium benzoate, which is pre-treated with cobalt phthalocyanine, and polypropylene or a mixture of polypropylene and low pressure polyethylene in the above ratio are used.

 Salts of benzoic acid, sodium benzoate or potassium are known products used as chemicals.

 PRI me R 1. The catalyst composition, wt. Cobalt phthalocyanine 12 Sodium benzoate 0.5 Polypropylene 87.5 is prepared as follows. 60 g of cobalt phthalocyanine are mixed with 2.5 g of sodium benzoate in an Anger high-speed paddle mixer. Mixing time 5 min. Then add 437.5 g of polypropylene, previously stabilized by the system: topanol "KA" 0.3 wt. dilauryl thiodipropionate 0.5 wt. calcium stearate 0.2 wt. and stirred for 15 minutes The composition is homogenized in a laboratory single-screw extruder ET-30 with an optimal extrusion mode in zones 150-170-190-180. The resulting tow is cooled and crushed into granules with sizes of 3-5 mm.

 PRI me R 2. Similarly to method 1 prepare catalysts containing, by weight. cobalt phthalocyanine 10, 12, 20, sodium benzoate or potassium 0.1; 0.5; 2.0; the rest is a mixture of stabilized polypropylene and polyethylene ND in the ratios: 25:75, 50:50, 75:25. PP stabilizers are the same.

 In the manufacture of catalysts containing the proposed additive, there is almost no emission of volatile products in the zone of exit of the melt from the extruder, and the bundle is dense, elastic, without bubbles and breaks.

 During the extrusion of a known catalyst, a large amount of volatile products is released, the granules are porous and brittle (see composition 4, table. 1).

PRI me R 3. 75 ml of a model solution of sodium sulfide, similar in composition to the effluent after purification of the propane-propylene fraction from hydrogen sulfide containing 0.3 wt. sodium sulfide (in terms of sulfur), the rest of the water is oxidized with atmospheric oxygen in the presence of 18 g of catalyst granules prepared according to examples 1, 2. Oxidation is carried out in a glass reactor with a diameter of 30 mm and a high 300 mm, equipped with a reflux condenser, a contact thermometer with a system automatic temperature regulation taps for oxygen supply and discharge of the solution, ^at 40 ° C, atmospheric pressure, oxygen feed rate into the reactor 2 l / min for 30 min. The residual content of sodium sulfide (in terms of sulfur) is determined potentiometrically according to GOST 22985-90. The results of the experiments are given in table. 2.

 PRI me R 4. 75 ml of an alkaline solution of amyl mercaptide, similar in composition to the solution after purification of the butane-butylene fraction containing, by weight. sodium mercaptide 0.108 (in terms of sulfur); sodium hydroxide 10.0 and water the rest, oxidized for 10 min under the conditions described in example 2. The content of mercaptide sulfur in the oxidized solution is determined potentiometrically according to GOST 22985-90. The results are shown in table. 2.

 From the above table. 1, 2 of the data shows that the proposed catalyst in comparison with the known one has advantages in manufacturing technology, a sharp decrease in catalyst degradation, and has a higher catalytic activity in the process of liquid-phase oxidation of sulfur compounds (e.g. sodium sulfide and mercaptide) in an aqueous alkaline medium.

 With the introduction of sodium benzoate or potassium above the claimed limit, the achieved improvement in the properties of the catalyst remains at the same level, therefore, an increase in concentration above 2.0% is impractical.

The selected ratio of polypropylene and polyethylene in the mixture varies depending on the following factors:
the presence or scarcity of raw materials;
the required operating temperature of the catalyst (from 80 to 110 ^about C);
the need to reduce the temperature regimes of catalyst processing in the manufacture of packed catalyst elements.

 The use of the proposed catalyst allows to increase the degree of conversion of sodium sulfide by 10-18% sodium amyl mercaptide by 8-15% and thereby obtain an economic effect.

 In patent studies, it was found that the claimed combination of features has novelty.

 In the process of laboratory studies, it was found that the catalyst obtained in the described manner has a higher activity, heat resistance and manufacturability in manufacturing in comparison with the known, which is not obvious and does not follow from the properties of the components used.

 The catalyst can be used in industrial processes for the neutralization of sulfur-alkaline effluents and aqueous sulfide-containing process condensates, during the demercaptanization of liquefied hydrocarbon gases and gasoline fractions.

 Based on the foregoing, the authors and the applicant concluded that the developed technical solution meets the criteria of the invention.

 Due to the fact that the industrial production of the inventive catalyst at the Moscow Oil Refinery has already been prepared, we ask you to speed up the patent examination and the grant of a patent for the claimed invention.

Claims (1)

A catalyst for the oxidation of sulfur compounds containing cobalt phthalocyanine and a polyolefin, characterized in that it additionally contains an alkali metal benzoate salt, and as a polyolefin - polypropylene or its mixture with low pressure polyethylene, taken in a mass ratio (25-75) :( 75 -25), in the following ratio of components, wt.%:
Cobalt Phthalocyanine - 10 - 20
Alkali metal benzoic acid salt - 0.1 - 2.0
Polypropylene or its mixture with low-pressure polyethylene - Else

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