RU2226542C2 - Method of treating oils to remove sulfur compounds - Google Patents

Abstract

FIELD: crude oil treatment. SUBSTANCE: removal of sulfur is accomplished by extraction of oil with polar aprotic solvents in centrifugal differential-contact-type extractor with phase jet mixing, rotor rotation speed being 100-320 s^-1. EFFECT: enabled treatment of oil with any sulfur content. 2 cl, 1 dwg, 1 tbl, 5 ex

Description

The invention relates to extraction methods for the purification of oils from sulfur compounds.

Currently, the urgent problem of refining oils with a total sulfur content of more than 2.0 wt.%. The share of sulfur and sour crude oils in Russia in the total production balance is two-thirds (Kharlampidi H.E. Organo-sulfur compounds of oil, refining and modification methods. Soros Educational Journal. 2000, Volume 6, No. 7, p. 42).

A known method of purification of petroleum products from sulfur compounds with a total sulfur content of 1.37 wt.%, Mercaptan sulfur 0.65 wt.%. The extraction is carried out in countercurrent according to the Alders procedure with acetic anhydride with the addition of 5-10 wt.% Water.

The resulting solvent - acetic anhydride: acetic acid: water - has a greater extracting ability than acetic anhydride and acid separately.

The disadvantage of this method is that it is applicable only for the processing of petroleum products with a low content of sulfur compounds, while a highly selective solvent is used. In addition, the process is carried out in an extractor with a large number of theoretical plates, which leads to large dimensions of the apparatus (AS USSR No. 536217, C 10 G 21/06).

Closer to this invention in essence and the achieved result is a method of purification of liquid hydrocarbons from sulfur compounds by extraction with polar aprotic solvents, for example dimethyl sulfoxide, acetonitrile, dimethylformamide and others (SU 819074, C 10 G 21/06, 04/07/1981).

The objective of this technical solution is the purification of oil with a total sulfur content of more than 2.0 wt.%, From sulfur compounds while increasing the productivity of the process.

This technical result is achieved in that the extraction process is carried out by polar aprotic solvents in a centrifugal extractor of differential contact type with jet mixing of phases, with a rotor speed of 100-320.

As polar aprotic solvents, dimethyl sulfoxide (CH ₃ ) ₂ S0, acetonitrile (CH ₃ ) ₂ CON, dimethylformamide (CH ₃ ) ₂ NCHO, dimethylacetamide (CH ₃ ) ₃ NOSH, etc. are used, and Tatarstan oils are used as raw materials with the characteristics presented in the table.

The method is carried out in the extractor shown in the drawing.

The extractor is a cylindrical rotating rotor 1 with a contact in the upper part and settling zones in the lower part, in the upper part of which a telescopic feeding device 2 is mounted.

The contact zone is formed by a package of horizontal partitions 3, 4, 5, rigidly interconnected, and the partition 3 has axial flows 6. An annular nozzle 7 is installed in the partition 4, dividing the volume between the partitions 4 and 5 into a peripheral 8 and a central 9 cavity, and the partition 5 diffuser 10, while the mouth of the nozzle 7 is located above the inlet edge of the diffuser 10. At the base of the settling zone are axial flows for the raffinate 11 and extract 12, each of which is connected to the respective raffinate and extract selection zones 13, 14.

The process is as follows. After starting the rotor 1 at the same time, feedstock (oil) and extractant are supplied through the feed device 2, which enter the contact zone. In this case, the feedstock through axial flows 6 'falls into the peripheral cavity 8, and through the central pipe of the feeding device 2 into the central cavity 9, and the extractant enters the closed cavity formed by the partitions 3 and 4, and then into the nozzle 7, where intense dispersion extractant and its interaction with the feedstock in the input edge of the diffuser 10. The subsequent extraction process is carried out in the volume of the diffuser. The resulting emulsion rushes into the settling zone, where, under the action of a centrifugal field, it separates. The raffinate through the axial overflow 11 is removed from zone 13, and the extractant through the overflow 12 is also removed from zone 14 of the extractor.

Examples of the method.

Example 1. The feedstock with a sulfur content of 3.51 wt.% (Sample 1) is extracted with dimethyl sulfoxide (mass ratio 1: 1) at a rotor speed of 100 s ^-1 . The degree of extraction is 70%. At a rotational speed of 320 s ^{-1, the} degree of recovery is 81%.

Example 2. The feedstock with a sulfur content of 5.4 wt.% (Sample 2) is extracted with dimethyl sulfoxide (mass ratio 1: 1) at a rotor speed of 100 s ^-1 . The degree of extraction is 73%, at a speed of 320 s ^{-1 the} degree of extraction is 82%.

Example 3. The feedstock with a sulfur content of 3.51 wt.% Extracted with dimethylformamide (mass ratio of 1.5: 1) at a rotational speed of 100 ^{r -1} . The degree of extraction of 77%. At a rotational speed of 320 s ^{-1, the} degree of extraction is 86%.

Example 4. The feedstock with a sulfur content of 5.4 wt.% Is extracted with dimethylformamide (mass ratio 1.5: 1) at a rotor speed of 100 ^-1 . The degree of extraction of 83%. At a speed of 320 s ^{-1, the} degree of recovery is 91%.

Example 5. The feedstock with a sulfur content of 5.4 wt.% Extracted with dimethylacetamide (mass ratio of 1.5: 1) at a speed of 100 s ^-1 . The degree of extraction of 68%. At a rotational speed of 320 s ^{-1, the} degree of recovery is 72%.

If the rotor speed is below 100 s ^{-1, the} extractor will choke, i.e. the process cannot be carried out, and at a rotor speed higher than 320 s ^-1 a stable non-stratifying emulsion is formed, which also makes the process of sulfur recovery from the initial solution impossible.

As shown by the experimental results, polar aprotic solvents quite effectively extract sulfur compounds from high-sulfur oils with extractant: initial solution ratios from 1.5 to 1, while the process was carried out continuously in a centrifugal small-sized differential unit-type extractor of large unit power with jet phase mixing. Moreover, with a higher sulfur content in oil, its degree of extraction is higher.

Literature

1. Harlampidi H.E. Organosulfur compounds of oil, purification and modification methods. Soros educational journal. 2000, volume 6, No. 7, s-42.

2. Auth. testimonial. 1525195, application 4365596 / 23-04 from 01/18/08, C 10 G 19/04.

3. Auth. testimonial. 536217, application 2140712/04 dated 04.06.75, C 10 G 21/06.

Claims (2)

1. The method of purification of oil from sulfur compounds by the method of extraction with polar aprotic solvents, characterized in that the process is carried out in a centrifugal extractor of differential contact type with jet mixing of phases at a speed of 100-320 s ^-1 . 2. The method according to claim 1, characterized in that dimethyl sulfoxide, acetonitrile, dimethylformamide, dimethylacetamide are used as polar aprotic solvents.

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