RU2469067C1 - Method for obtaining low-sulphur oil coke - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: low-sulphur oil coke obtaining method involves the following: preparation of coking raw material by mixing the initial raw material first with heavy gas oil of catalytic cracking in quantity of not less than 30% per initial raw material with further primary heating of the obtained raw material up to 280-320°C and enrichment with heavy coking gas oil fractions by introducing the recirculated substance of heavy coking gas oil from distillate products in quantity of not less than 30% per the obtained raw material mixture to the bottom of rectifying column and supply of the obtained mixture to the reactor after secondary heating up to coking temperature, which differs by the fact that as initial raw material there used is tar oil mixed with bitumen; at that, the bitumen content is not more than 30%.

EFFECT: method allows increasing the yield of low-sulphur oil coke due to new composition of initial raw material.

1 cl, 1 tbl

Description

The invention relates to methods for producing low-sulfur petroleum coke by delayed coking and can be used in the oil refining industry.

A known method of producing low-sulfur petroleum coke, including aromatization of the feedstock - tar by mixing it with heavy catalytic cracking gas oil (THCK) or heavy coking gas oil recycle (THC) or pyrolysis resin or a mixture thereof in an amount of 4-15% for the feedstock and further delayed coking of the obtained raw materials (Pat. RF No. 2206595, IPC ⁷ СВВ 55/00, op. June 20, 2001).

The disadvantage of this method is the low yield of coke to the coking feedstock.

Closest to the proposed method in technical essence and the achieved result is a method for producing low-sulfur petroleum coke, including the preparation of coking feedstock by mixing the feedstock first with heavy catalytic cracking gas oil, taken in an amount of 23-30% of the feedstock, followed by primary heating of the obtained feedstock to 280-320 ° C and enrichment with fractions of heavy coke oven gas oil by introducing 10-30% per coke heavy coke oven gas recycle from distillate products learned raw material mixture to the bottom of the distillation column and feeding the resulting mixture into the reactor after secondary heating to the coking temperature (US Pat. RF No. 2408650, IPC ⁷ C10B 55/00, op. 10.01.2011).

The disadvantage of this method is the low yield of coke to the coking feedstock.

The present invention is aimed at increasing the yield of petroleum coke.

This is achieved by the fact that in the method for producing low-sulfur petroleum coke, including the preparation of coking feedstock by mixing the feedstock first with heavy catalytic cracking gas oil, taken in an amount of at least 30% of the feedstock, followed by primary heating of the obtained feedstock to 280-320 ° C and enrichment of coking heavy gas oil fractions by introducing at least 30% of heavy coking gas oil recirculate from distillate products to the resulting raw material mixture into the bottom of the distillation column and bottom after the secondary mixture is heated to the coking temperature, according to the invention, a mixture of tar and asphalt is used as feedstock, while the asphalt content is not more than 30%.

The use of a mixture of tar and asphalt with the content of the latter of not more than 30% in the initial raw material, and then mixing the resulting raw material mixture with heavy catalytic cracking gas oil in an amount of at least 30%, and then with coking heavy gas oil in an amount of at least 30% allows to increase the yield of low-sulfur coke with the preservation of its qualitative characteristics.

The method is as follows

In the feedstock - a mixture of tar and asphalt with a content of the latter 22-30%, a diluent is added - heavy catalytic cracking gas oil in an amount of 30-40% for the feedstock, then the resulting feed mixture is preheated in heat exchangers and in a convection furnace to a temperature of 280-320 ° C and fed to the bottom of the distillation column, where it, as a result of contact with the coking vapors coming from a working reactor with a temperature of 400-420 ° C, is heated to a temperature of 360-380 °, while enriching them with heavy fractions - recycle t heavy coker gas oil in an amount of 30-40% on the resulting raw material mixture. The amount of heavy coking gas oil recycle introduced into the raw material mixture is controlled by varying the temperature of the coking vapors entering the bottom of the distillation column from a working reactor, or by changing the place of introduction of the raw material mixture into it. The newly obtained raw material mixture - the secondary raw material is fed to the furnace for heating to the coking temperature of 485-505 ° C, and then to the coking reactor.

The following are specific examples of the implementation of the proposed method.

In the experiments, products with the following quality indicators were used:

- tar: density 994 kg / m ³ , coking ability 13.8%, sulfur content 0.92%, vanadium content 0.006%;

- recycle - heavy coking gas oil (THC): density 963 kg / m ³ , coking ability 0.55%;

- heavy catalytic cracking gas oil (THCK): density 1036 kg / m ³ , coking ability 3.46%;

- asphalt: density 1016 kg / m ³ , sulfur content - 1.23%, vanadium content 0.009%, coking property 19.4%;

- visbreaking residue: density 1003 kg / m ³ , sulfur content 1.2%, vanadium content 0.008%, coking property 15.8%.

The proposed method is illustrated by the following examples, which are given in the table. These tables were obtained experimentally by coking on a pilot plant a raw material mixture prepared according to the prototype and the proposed method at a pressure of 0.1 MPa and a temperature of 495 ° C at the outlet of the furnace.

Table The indicators of the method of producing low-sulfur coke The composition of the raw materials and indicators of the method for producing low-sulfur coke Examples The composition of the coking feed Feedstock,% THCK,% of feedstock THC,% of the resulting raw mix Recirculation ratio The output of coke for feedstock,% 1 - prototype Tar - 55 thirty thirty 1.3 27.0 Visbreaking balance - 22 2 - proposed Tar - 55 thirty thirty 1.3 29.0 Asphalt - 22 3 - proposed Tar - 50 40 40 1.4 31,0 Asphalt - 30

The table shows that the yield of coke by the proposed method increased by 2-4%.

Thus, the proposed method due to the new composition of the feedstock allows to increase the yield of low-sulfur petroleum coke.

Claims (1)

A method of producing low-sulfur petroleum coke, including the preparation of coking feedstock by mixing the feedstock first with heavy catalytic cracking gas oil, taken in an amount of at least 30% for the feedstock, followed by primary heating of the obtained feedstock to 280-320 ° C and enrichment of coking heavy gas oil fractions by introducing a recycle of heavy coking gas oil from distillate products in an amount of not less than 30% of the obtained raw material mixture to the bottom of the distillation column and feeding the resulting mixture to the reaction op after secondary heating to carbonization temperatures, characterized in that the feedstock is a mixture of asphalt and tar, with asphalt content is not more than 30%.