LT4037B - Cracking of petroleum products residue - Google Patents

Abstract

Invention can be applied to oil processing and may be used for the viscosity reduction of such oil products such as fuel oil, tar and asphalt. The invention aims to simplify the technology of residual oil products, reduce energy expenditures and reduce the viscosity of residual oil products. The point of the proposed method is as follows: residual oil products are directed to visbreaking and after that the reaction products are distilled in a rectifying column. Fraction of more than 350 degrees Celsius and fraction of more than 500 degrees Celsius are separated. Part of the latter fraction is directed for recirculation and is mixed with the original oil products supplied to the visbreaking. The amount of the recirculation fraction, fluctuate from 1 percent up to 15 percent of the original crude mass.

Description

The invention relates to the field of refining and can be used to reduce the viscosity of residual petroleum products such as fuel oil, tar, asphalt.

Known thermal cracking of heavy (residual) petroleum fractions is a process wherein the mixture of continuously supplied residual petroleum fractions and the circulating fractions in the refining scheme is heated to 400580 ° C with water, stirred and maintained for 0.2-0.6 h at 370-470 ° C. The liquid phase flows from the reactor to the separator, from which part of the residue is diverted for further processing and part to the recirculation circuit. The amount of recirculating fraction is 5- to 20-fold higher than that of the starting fractions (Japanese Application No. 6325637, CI0G9 / 00).

The disadvantage of this known technique is the significant energy cost of recirculation.

Also known is a two-step thermal cracking of heavy hydrocarbons, in which the heavy hydrocarbons are cracked in the first reactor at 400-500 ° C. The reaction products are directed from the first top of the reactor to the rectification column. The residue from the first reactor bottom is led to the second reactor where it is cracked at 510-650 ° C. The cracking products from the second reactor are directed to the same rectification column below the inlet of the first reactor. The column yields a high yield of cracked lubricant. The residue from the bottom of the column recirculates to the first reactor (Japanese Application No.57-135462, CIO G 31/02).

The disadvantages of this known method are high energy costs; and there is virtually no control over the amount of recirculation.

The closest embodiment of the present invention is a process for the processing of heavy viscous hydrocarbons, in which the heavy viscous hydrocarbons are subjected to light cracking and the products thereof are fractionated in a rectification column. The residue from the bottom of the column is extracted with solvent. This results in two or more fractions, including heavy, high asphaltenes and, in any case, one light fraction rich in resins and lubricants. Part of one of the light fractions from the extraction step is combined with heavy viscous hydrocarbons to be subjected to light cracking (U.S. Patent No. 4,440,403, NKI 206-96, C10G9 / 00).

The disadvantages of this technique are the complex technology and the high cost of solvent regeneration.

The object of the present invention is to simplify the technology of refining residual petroleum products, to reduce energy costs and to reduce the viscosity of residual petroleum products.

The object is achieved by refining the residual petroleum products by viscous refining and fractionating the reaction products, including isolation of the fraction more than 350 ° C or more than 500 ° C, mixing part of the isolated fraction with the starting material and re-mixing the resulting mixture. points to visbreaking. Fractions greater than 350 ° C or fractions greater than 500 ° C mixed with residual petroleum products take from 1% by weight to 15% by weight of the starting crude.

The essence of the proposed process is that the residual petroleum products are subjected to visbreaking followed by distillation of the reaction products in a rectification column. It separates a fraction of more than 350 ° C or a fraction of more than 500 ° C. Part of the latter fractions is diverted for recirculation and mixed with primary petroleum products supplied to the viscera. The amount of recirculate fraction greater than 350 ° C or fraction greater than 500 ° C ranges from 1% by weight to 15% by weight of the starting material.

Recirculation reduces the initial reaction temperature because the residual petroleum products are more thermally stable than the fraction greater than 350 ° C or the fraction greater than 500 ° C. Therefore, the allowable-to-limit conversion of residual petroleum products is achieved at lower temperatures, which saves energy resources and extends the continuous life of the unit. In addition, lower visbreaking temperatures result in more selective degradation of the high molecular weight compounds and lower degradation of the visbreaking fractions, 180-350 ° C and 350-500 ° C. This ensures lower viscosity of the viscous residue used as a fuel component in the boiler.

The method has been tested on pilot plants.

EXAMPLE

Tar obtained by vacuum rectification of sulfur oil (containing by weight 3% fractions of up to 500 ° C and 10% asphaltenes with a coking ratio of 17,1% by weight and a density of 0,9958 t / m ^{2 3} , relative viscosity at 80 ° C - 430 SK), refers to viscous at 450 ° C and 0.6 MPa. It produces gas, gasoline and residues boiling above 180 ° C from visceral products. Fraction more 180 ° C Conductivity viscosity at 80 ° C - 43.3 SK, stability -1.65.

EXAMPLE

In the first example, the tar is mixed with 1% by weight of the fraction more than 350 ° C and is directed to the visbreak at 450 ° C and 0.6 MPa. Gases, gasoline, fraction 180-350 ° and fraction more than 350 ° C are recovered from the reaction products, and 1% by weight is used for recirculation. The remainder of the latter fraction is mixed with the fraction 180-350 ° C to give the fraction more 180 ° C.

Fraction more 180 ° C relative viscosity at 80 ° C - 42 ° SK, stability -1.70.

EXAMPLE

The tar of the first example is blended with 15 wt.% Fraction at more than 350 ° C and directs it to visbreak at 440 ° C and 0.6 MPa. From the reaction products, gas, gasoline, fraction 180-350 ° C, and fraction more 350 ° C are recovered from the reaction products, which recycle 15% by weight, and mix the residue with fraction 180-350 ° C to obtain fraction more 180 ° C.

Fraction more 180 ° C Conductivity viscosity at 80 ° C - 31 ° SK, stability -1.55.

EXAMPLE

In the first example, the tar is mixed with 5% by weight of the fraction more than 350 ° C and is directed to the visbreaker at 443 ° C and 0.6 MPa. From the reaction products, gas, gasoline, fraction 180-350 ° C, and fraction more 350 ° C are recovered from the reaction products, which recycle 5% by weight and mix the residue with fraction 180-350 ° C to obtain fraction more 180 ° C.

Fraction more 180 ° C Conductivity viscosity at 80 ° C - 25 ° SK, Stability -1.90.

EXAMPLE

In the first example, the tar is blended with 4% by weight of the fraction at greater than 500 ° C and is directed to visbreak at 443 ° C and 0.6 MPa. From the reaction products, gas, gasoline, fraction 180-350 ° C, fraction 350-500 ° C and fraction more 500 ° C are recovered from the reaction products, which are recycled 4% by weight and the residue is mixed with fraction 180-350 ° C and fraction 350 -500 ° C and obtains fraction more 180 ° C.

Fraction more 180 ° C relative viscosity at 80 ° C - 25.5 ° SK, stability -1.85.

If the amount of recirculating material used does not exceed 1% by weight, it has no effect on the process. If the recirculation content is greater than 15% by weight, it increases the viscosity of the fraction over 180 ° C and reduces its stability, which reduces the continuous operation time of the unit.

The use of the present invention enables the production of commercial fuel oil by reducing the distillation fraction to a fraction of more than 180 ° C.

The present invention can be used in industrial combinations of fuel oil processing KT-1/1 type as well as in any visbreaker equipped with external reactors.

Claims (2)

DEFINITION OF INVENTION 1. A process for the processing of residual petroleum products, wherein the residual petroleum products are subjected to viscous cracking, fractionating the reaction products, including separating a fraction of more than 350 ° C or a fraction of more than 500 ° C, characterized in that into visbreaking. 2. A process according to claim 1, wherein the isolated fractions contain from 1% to 15% by weight of the starting material.