RU2241732C1 - Method of purification of hydrocarbonaceous raw material from mercaptans - Google Patents

Abstract

FIELD: gas-production industry; petroleum and oil refining industries; purification of hydrocarbonaceous raw material from mercaptans.

SUBSTANCE: the invention is dealt with the methods of purification of hydrocarbonaceous raw material from mercaptans. The method provides for purification of hydrocarbonaceous raw material or commercial hydrocarbon fractions from mercaptans, in particular from high-boiling tertiary mercaptans and may be used in gas, petroleum and oil refining industries. The method realized by oxidation of mercaptans by oxygen-bearing gas in an alkaline medium in presence of a phthalocyanine catalyst, ethanolamine and a promoting additive in the form of copper complexes with dinatrium salt etgyldiaminetetraacetic acid (Trilon B)used in amount of 50-90 % against the weight of the catalyst. The method allows at a long duration of the promoting additive action to achieve and keep a high degree of purification of hydrocarbonaceous raw material from mercaptans.

EFFECT: the method ensures high degree of purification of hydrocarbonaceous raw material from mercaptans.

2 cl, 2 tbl, 2 ex

Description

The present invention relates to the field of purification of hydrocarbons from mercaptans and can be used in the gas, oil and oil refining industries.

A known method of purification of hydrocarbons from mercaptans, where to the alkaline solution of the phthalocyanine catalyst is added as a promoter sodium phosphate or phosphates of other alkali metals in an amount of 0.01-1% [1]. Despite the obvious cheapness of such a promoter, this method does not find wide application due to the low degree of purification.

A catalyst for the oxidation of mercaptans is also known, where a promoter, ammonium molybdate, is added to an alkaline solution of the phthalocyanine catalyst [2]. This catalyst does not provide a high oxidation rate of mercaptans, in particular high boilers.

Of interest is the method of demercaptanization of kerosene, in which mercury ions and thiosulfate ions, or cyanide ions are proposed as a promoting additive for the oxidation of difficultly oxidized high-boiling tertiary mercaptans [3]. Despite the relatively high degree of purification, the high toxicity of the components of the proposed promoter is noteworthy.

Closest to the proposed method according to the technical nature and the achieved result is a method of purification of hydrocarbon materials from mercaptans, in particular high boiling tertiary mercaptans. In this method, in an alkaline solution of a phthalocyanine catalyst, it is proposed to use a promoting additive - bromides of metals of variable valency I, VI, VII groups of the Periodic system or their complexes with ethanolamines [4]. Metal bromides are used in an amount of 10-100% by weight of the phthalocyanine catalyst.

The main disadvantage of this purification method is the gradual decrease in the degree of purification as a result of prolonged use of a promoting additive in an alkaline solution of a phthalocyanine catalyst.

The objective of the present invention is to achieve and maintain a high degree of purification of hydrocarbons from high boiling mercaptans with prolonged use of a promotional additive.

According to the invention, the task is achieved by cleaning hydrocarbons from mercaptans by oxidizing mercaptans with an oxygen-containing gas in an alkaline medium in the presence of a phthalocyanine catalyst and a promoting additive. It is proposed to use a complex of a copper salt with a disodium salt of ethylenediaminetetraacetic acid (EDTA or Trilon B) in an amount of 50-90% by weight of a phthalocyanine catalyst as a promoting additive.

Distinctive features of the proposed method is the use as a promoting additive complex of a salt of copper with Trilon B in an amount of 50-90% by weight of the phthalocyanine catalyst.

These distinctive features of the proposed method determine the novelty and inventive step in comparison with the prior art. The use of a complex of copper with trilon B as a promoting additive allows one to achieve and maintain a high degree of purification from high boiling tertiary mercaptans during prolonged operation of the promoter as part of an alkaline solution of a phthalocyanine catalyst. There is no information in the literature about the promoting additive - the complex of copper salt with Trilon B.

The water-soluble phthalocyanine catalysts proposed for use in the invention, such as cobalt disulfophthalocyanine (DSPA), cobalt tetrasulfophthalocyanine (TSPA), cobalt dichlorodioxidisulfophthalocyanine (DCHODSPFC) and other highly reactive oxygen catalysts, a sufficiently high oxidation rate of mercaptans.

The alkaline solution proposed for use is an aqueous solution of sodium hydroxide or potassium hydroxide with a concentration of 10-15 wt.% And ethanolamines with a concentration of 3-8% by weight. Alkalis and ethanolamines belong to the well-known group of bases and are intended for ionization of mercaptans, which precedes the stage of oxidation of mercaptans.

The proposed method is tested in laboratory conditions by the example of purification of a model mixture of n-dodecane and tert-dodecyl mercaptan, as well as the kerosene fraction of the Samara refinery.

Preparation of initial solutions of the catalyst complex

The solution of the catalyst complex (50 ml) consists of three parts. Each of the three solutions is prepared separately in the following sequence.

Solution 1. Dissolve 0.00138 g of copper sulfate in 15 ml of water. Then, with stirring, 0.0025 g of Trilon B is slowly added.

Solution 2. At first, 0.01 g of sodium hydroxide is dissolved in 10 ml of water. Then, 0.005 g of the IVKAZ phthalocyanine catalyst is dissolved.

Solution 3. 5 g of sodium hydroxide are dissolved in 25 ml of water. Then 1.5 monoethanolamine.

After preparation, solution 2 is added to solution 1. Solution 3 is added to the mixture of solutions 1 and 2. The result is 50 ml of a solution of the catalyst complex containing 0.0073 wt.% Complex of copper with Trilon B, 0.01 wt.% Catalyst IVKAZ, 3 wt.% Monoethanolamine, and 10 wt.% Caustic soda.

Example 1. In a reactor with a stirrer load 100 ml of dodecane containing 0.2 wt.% Tert-dodecyl mercaptan in terms of sulfur and 50 ml of the catalyst complex. The composition and procedure for preparing the catalyst complex are described previously.

The oxidation is carried out at atmospheric pressure, a temperature of 50 ° C with air supply through a bubbler at a speed of 0.2 l / min, for 30 minutes. In this case, mercaptans turn into disulfides. After decantation, the catalyst complex is separated from hydrocarbons and reused in subsequent cycles to clean new portions of hydrocarbons.

The results of experiments on the purification of dodecane from mercaptans during the first six purification cycles when using a complex of copper and trilon B as a promoting additive are presented in Table 1. Here, for comparison, data are presented on the purification of dodecane from mercaptan under the same conditions when copper bromide is used as a promoting additive.

From the experimental data given in Table 1, it can be seen that when purifying a model mixture of n-dodecane from tert-dodecyl mercaptan, the use of a promoting additive in the form of a complex of copper and trilon B salts in an alkaline solution of a phthalocyanine catalyst allows a rather high degree of purification to be achieved (lowering the content of mercaptan sulfur with 0.2 to 0.008 wt.%). In addition, the presence of this promoter allows you to maintain the achieved high degree of purification with prolonged use of the promoter (cycles I-IV) in an alkaline solution of the phthalocyanine catalyst compared to the use of the known promoter (CuBr), when the degree of purification gradually decreases (residual mercaptan sulfur content from 0.008 wt. .% increased to 0.0745 wt.%).

Example 2. In a stirred reactor, 100 ml of the kerosene fraction of the Samara Oil Refinery containing 0.0326 wt.% Mercaptan sulfur and 50 ml of the catalyst complex are loaded, the composition and preparation of the catalyst complex are described previously. The conditions for purification of the kerosene fraction are the same as in example 1.

The results of experiments on the purification of the kerosene fraction from mercaptans during the first six cleaning cycles when using a complex of copper salt and trilon B as a promoting additive are given in Table 2. Here, for comparison, data are presented on the purification of the kerosene fraction from mercaptans under the same conditions when using the previously known copper bromide as a promoting additive.

From the experimental data given in Table 2, it can be seen that when purifying the kerosene fraction of the Samara refinery from mercaptans, the use of a promoting additive of a complex of copper and trilon B salts in an alkaline solution of a phthalocyanine catalyst allows a rather high degree of purification to be achieved (a decrease in the content of mercaptan sulfur of 0.0326 wt.% up to 0.0018 wt.%). In addition, the use of this promoter allows you to maintain the achieved high degree of purification with prolonged use of the promoter (cycles I-VI) in an alkaline solution of a phthalocyanine catalyst, compared with the use of the known promoter (CuBr), when the degree of purification gradually decreases (the residual content of mercaptan sulfur from 0 , 0020 wt.% Increased to 0.0220 wt.%).

Sources of information

1. US patent No. 2999806, 12.09.61. “Purification of hydrocarbon distillates from mercaptans.” Universal Oil Products Co. R.Zh. Chemistry, VII, No. 19, 1962, 19 M 201.

2. Patent of the GDR, cl. In 01 J 31/22, No. 134195, declared 09/23/77, No. 201118, publ. 02/14/79. “The catalyst and its use.” R.Zh. Chemistry, 21 L 205, 1979.

3. US patent No. 3271294. “Oxidation of mercaptans”, R.Zh. Chemistry, St. Volume 19P, No. 5, 1968.

4. Auth. certificate No. 513069, the application. 05.22.74. “A method for the purification of hydrocarbons from mercaptans”. A.M. Mazgarov, G.V. Tukov, V.A. Fomin, A.G. Ahmadullina. BI No. 17, 1976, p. 89.

Claims (2)

1. The method of purification of hydrocarbon feeds from mercaptans by oxidation with an oxygen-containing gas in an alkaline medium in the presence of a phthalocyanine catalyst, ethanolamine with a promoting additive, characterized in that complexes of copper with disodium salt of ethylenediaminetetraacetic acid (Trilon B) are used as a promoting additive. 2. The method according to claim 1, characterized in that the promoting additive is used in an amount of 50-90% by weight of the phthalocyanine catalyst.