RU2603635C1 - Method for demercaptanisation of hydrocarbon material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of alkaline demerptanisation of hydrocarbon material with subsequent oxidation-catalyst regeneration of mercaptide-saturated alkaline agent or direct oxidation of mercaptans contained in hydrocarbon raw material with atmospheric oxygen in presence of an alkaline agent and a heterogeneous catalyst for oxidation of sulphur compounds. Method is characterised by that alkaline agent used is aqueous solution of alkali, containing polar organic compounds, formed due to deep oxidation of mercaptides by treatment of mercaptide-containing alkaline solution with atmospheric oxygen in presence of highly active heterogeneous catalyst KSM-X on a polymer support. High activity of KSM-X catalyst during oxidative regeneration mercaptide-containing alkaline solution and efficiency of obtained alkaline agent due to water-soluble polar oxygen-containing products of oxidation mercaptides contained therein simplifies technology of process of demercaptanisation of hydrocarbons, significantly reduces size of process equipment, reduces capital and operating costs for its implementation as compared to existing methods.

EFFECT: demercaptanisation of hydrocarbon material.

1 cl, 2 tbl, 2 exl

Description

The invention relates to methods for demercaptanization of hydrocarbons (dry and liquefied hydrocarbon gases, gasoline and kerosene fractions, light oils, gas condensates, lubricating oils, etc.) and can be used in gas, oil refining, oil and petrochemical industries. Known methods for the purification of hydrocarbons - gasolines, gas condensates from mercaptans with aqueous alkali solutions containing polar organic additives: methanol and dimethyl sulfoxide or dimethylformamide [2], ethanol and acetone with formaldehyde [3]; or ethanol with a ketone selected from the group methyl ethyl ketone, methyl butyl ketone, acetophenone and cyclohexanone [4].

These methods are associated with the continuous consumption of organic solvents and with additional costs for their separation from the product being cleaned and regeneration.

Also known are methods for purifying hydrocarbon feedstocks (HCS) from mercaptans with alkali solutions containing 0.5-4.0 vol.% Ethylene glycol as polar organic additives. % [5], polyethylene glycol [6], followed by catalytic regeneration of the mercaptide-containing alkaline solution by oxidation of the mercaptides to disulfides in the presence of phthalocyanine catalysts.

The disadvantage of these methods is the contamination of the product to be purified with partially hydrocarbon-soluble organic additives and alkali, which leads to the need for subsequent water washing of the demercaptanized feed and the formation of the corresponding sulfur-alkaline effluents.

In terms of technical nature and the achieved result, the closest to the proposed method is the method of demercaptanization of hydrocarbons [7] by extraction of mercaptans with an alkaline extractant followed by oxidative regeneration of an extractant saturated with mercaptides in the presence of a homogeneous or heterogeneous catalyst for the oxidation of sulfur compounds, in which, as an alkaline extractant or additive to a known extractant use the product of the interaction of alkali (NaOH, KOH) with acidic impurities of high-boiling hydrocarbon fractions (VUV) obtained in the process of oxidative-catalytic purification of VUV from mercaptans by treatment with atmospheric oxygen in the presence of a heterogeneous catalyst KSM [8] according to the patent of the Russian Federation [9], selected as a prototype of the proposed method for producing an alkaline agent.

The disadvantage of the method [7] is the need for preliminary production of an alkaline extractant by reacting solid alkali (NaOH, KOH) with acidic impurities of VUV during its oxidative-catalytic purification from mercaptans according to the patent [9]. This complicates its use for demercaptanization of light hydrocarbon raw materials that do not contain acidic impurities characteristic of VUV, and makes it difficult to implement this method due to the need to use solid alkali in the synthesis of alkaline extractant from acidic impurities of VUV according to the RF patent [9].

The objective of the present invention is to remedy these disadvantages. According to the invention, this is achieved by using for the regeneration of a mercaptide-containing alkaline solution of a more active catalyst for the oxidation of sulfur compounds [1] on a polymer carrier, which includes cobalt dichlorophthalocyanine and metal oxides of variable valence (hereinafter referred to as KSM-X catalyst), which allows to obtain an effective alkaline agent available method in the process of demercaptanization of hydrocarbons due to a deeper oxidation of mercapt contained in an aqueous solution of KOH or NaOH rows to the polar oxygenate product, significantly accelerating the oxidation of mercaptides, compared with an alkali solution not containing such oxygen-containing products.

Water-soluble products of deep oxidation of sulfur compounds (mercaptides and organic sulfides) contained in a regenerated aqueous solution of alkali (NaOH or KOH) are used as polar organic products that enhance the efficiency of the alkaline agent, which are formed during the processing of a mercaptide-containing alkaline solution with air in the presence of a KSM-X catalyst. by reactions (1-9):

2RSK + 0.5O ₂ + H ₂ O → RSSR + 2KOH (one) RSSR + 1 / 2O ₂ → RSOSR (2) RSOSR + 1 / 2O ₂ → RSO ₂ SR (3) RSO ₂ SR + 1 / 2O ₂ → RSO ₂ SOR (four) RSO ₂ SOR + 1 / 2O ₂ → RSO ₂ SO ₂ R (5) RSO ₂ SO ₂ R + H ₂ O → RS (O) OH + RS (O ₂ ) OH (6) ROH + RSH → RSR + H ₂ O (7) RSR + 1 / 2O ₂ → RS (O) R (8) RS (O) R + 1 / 2O ₂ → RS (O ₂ ) R (9)

Table 1 shows the approximate composition of polar oxygen-containing products of deep oxidation of sulfur compounds contained in an alkaline reagent.

The specified alkaline reagent is an alkaline solution insoluble in hydrocarbons, characterized by the following physicochemical parameters:

Appearance - viscous liquid

Color - Russet

The concentration of total alkali,% mass, from 1 to 50

Density, kg / dm ³ , from 1.05 to 1.5

A distinctive feature of the proposed method is the acceleration of the oxidation of mercaptides in the presence of an alkaline agent containing water-soluble polar oxygen-containing oxidation products of mercaptides, which are formed by treating the mercaptide-containing alkaline solution with air in the presence of a highly active heterogeneous catalyst KSM-X.

This distinguishing feature determines the significant differences of the proposed method from the prototype and the prior art in this field, because the proposed method for producing these polar products by direct oxidation of mercaptides during the regeneration of an alkaline solution and their use to accelerate the oxidation of mercaptides is not described in the literature and allows, in comparison with the prototype, to improve the technology for the process of demercaptanization of hydrocarbons, to reduce capital costs for demercaptanization by reducing the size of used technological equipment.

The proposed method was tested in laboratory conditions on a model solution of ethanethiol in alkaline solutions and in an alkaline reagent in the presence of heterogeneous catalysts on a polymer carrier [10], [8], [1] and without a catalyst. Below are examples and results of the experiments.

Example 1

The effectiveness of an alkaline reagent containing polar oxygen-containing oxidation products of mercaptides and a conventional alkaline solution that does not contain such products is evaluated by the degree of non-catalytic oxidation of mercaptide sulfur under the following conditions: the volume of a 10% alkaline solution or alkaline reagent with sodium ethyl mercaptide is 50 ml, the temperature of the experiments 40 ° C, the oxidation time is 30 minutes, the initial concentration of mercaptide sulfur is 0.273 wt. % Alkaline regeneration is judged by the change in the residual content of mercaptide sulfur over time by potentiometric titration according to GOST 22985-90. The test results are given in table. 2.

From the above experiments No. 1 and 2 of the table. 2 data shows that the proposed alkaline reagent is significantly more active compared to a conventional alkaline solution and in the non-catalytic oxidation of mercaptide sulfur.

Example 2

The efficiency of oxidative regeneration of a mercaptide-containing alkaline solution is evaluated by the degree of oxidation of mercaptide sulfur in the presence of an aqueous alkali solution or an alkaline reagent solution containing polar oxygen-containing products of the oxidation of mercaptides in a composition with the proposed catalyst [1] for HDPE (KSM-X) with a ratio of copper oxide (II ) and / or manganese (IV) oxide and / or nickel (II) oxide and / or cobalt (III) oxide to cobalt phthalocyanine and / or its water-insoluble derivative of cobalt dichlorophthalocyanine equal 1: 1, as well as in the composition used with the HDPE catalysts used in the prototype [9]: [8] (KSM) with an optimal ratio of titanium dioxide to cobalt phthalocyanine and / or its water-insoluble derivative equal to 1: 1 and a catalyst [10 ] (COP). The conditions for testing the catalysts: the mass of the catalyst is 5 g, the volume of a 10% solution of sodium hydroxide with sodium ethyl mercaptide is 50 ml, the temperature of the experiments is 40 ° C, the oxidation time is 30 minutes, the initial concentration of mercaptide sulfur is 0.273 wt. % The activity of the catalysts is judged by the change in the residual content of mercaptide sulfur over time by potentiometric titration according to GOST 22985-90.

The compositions of the catalysts prepared according to Example 1 and the results of their tests for catalytic activity in the oxidation reactions of mercaptide sulfur are given in table. 2.

From the above table. 2 data shows that the oxidation state of mercaptide sulfur in the claimed alkaline agent is significantly higher both in the presence of the claimed heterogeneous catalyst KSM-X and used in the prototype [9] catalysts KSM or KS (see experiments No. 3-20, 21-22 and 23-30) than in a conventional aqueous alkaline solution. In this case, the most effective composition of the tested is the claimed composition of the catalyst KSM-X with an alkaline agent obtained by the proposed invention in a more affordable way than in the prototype [9].

Thus, the proposed method for the demercaptanization of hydrocarbon raw materials has significantly higher performance characteristics that simplify the technology for the process of demercaptanization of hydrocarbons by accelerating the regeneration of the mercaptide-containing alkaline solution or the process of oxidative deodorization of hydrocarbons, reduce the size of processing equipment, that is, reduce capital and operating costs for the implementation these processes compared to known the method of the prior art.

Information sources

1. Patent 2529500

2. A.S. CCCP No. 1694625

3. A.S. CCCP No. 1583435

4. A.S. CCCP No. 1579927

5. A.S. CCCP No. 1773930

6. A.S. CCCP No. 1268604

7. Patent 2173330

8. Patent 2110324

9 Patent 2110555

10. A.S. No. 1041142

Claims (1)

The method of alkaline demercaptanization of hydrocarbon feedstock followed by oxidation-catalytic regeneration of an alkaline agent saturated with mercaptides with an alkaline agent or direct oxidation of mercaptans contained in hydrocarbon feedstock with atmospheric oxygen in the presence of an alkaline agent and a heterogeneous catalyst for the oxidation of sulfur compounds, characterized in that an alkaline aqueous solution containing alkali agent is used containing polar organic compounds formed by the deep oxidation of mercaptides pr processing merkaptidsoderzhaschego alkaline solution with atmospheric oxygen in the presence of a highly active heterogeneous catalyst KSM-X on the polymeric support.