Method for conversion of low-hydrogen heavy oil to light fractions by hydrogenation with hydrogen-supplying hydrocarbons

Abstract

The invention relates to a method for conversion of low-hydrogen heavy oil to light fractions by hydrogenation with hydrogen-supplying hydrocarbons, which is a process for conversion of heavy oil such as coal pitch by hydrogenation with hydrogen-supplying hydrocarbon stream enriched in hydrogen-supplying hydrocarbons. The method has the effects of inhibiting condensation coking speed, increasing liquid product yield in the process of conversion of coal tar heavy oil to light fractions, improving product quality, reducing reaction temperature increase and enhancing stability and safety of device operation. The hydrogen-supplying hydrocarbon stream can be hydrogenation reaction effluents in partial hydrogenation saturation process of bicyclic aromatic hydrocarbons or polycyclic aromatic hydrocarbons or oil products enriched in partial saturated aromatic hydrocarbons obtained in the separation process of bicyclic aromatic hydrocarbons or polycyclic aromatic hydrocarbons. The precursor substance of hydrogen-supplying solvent oil is coal tar fractions with boiling points of 350-450 DEG C, and the hydrogen-supplying solvent oil mainly comprises hydrocarbon components with ordinary boiling points of 350-450 DEG C. The combination of the method for conversion of coal tar heavy oil to light fractions by hydrogenation and method for conversion of coal tar light fractions by hydrogenation constitutes a novel combined process for conversion of full-range fractions of coal tar by hydrogenation.

Description

technical field [0001] The present invention relates to a method for hydrogenation and lightening of low-hydrogen-content heavy oil using hydrogen-donating hydrocarbons; in particular, the present invention relates to a method for using hydrogen-donating hydrocarbons for coal tar heavy oil (gum-rich oil with a conventional boiling point greater than 450° C. In the hydrogenation and lightening reaction process, the presence of hydrogen-donating hydrocarbons can disperse coal tar heavy oil and crack small molecules to reduce its polycondensation probability and improve the overall raw material The hydrocarbon hydrogen content reduces the hydrogenation load, accelerates the hydrogen transfer rate and inhibits the condensation of coal tar heavy oil pyrolysis fragments, etc., which can improve the retention rate of pyrolysis molecules (that is, increase the yield of light oil products), reduce the condensation solid yield, Shorten the reaction process time, reduce the total tempera...

AI Technical Summary

Problems solved by technology

[0017] ③ One of the disadvantages is that "coal tar fractions with a conventional boiling point of 370-450°C" are rich in polycyclic aromatic hydrocarbons and colloids, have poor thermal stability, and poor hydrogen supply capacity. The ability to inhibit coking during the heating process is poor, and the coal tar and heavy oil heating furnace tubes are easy to coke;

[0018] ④ The second disadvantage is that "coal tar fraction with a conventional boiling point of 370-450°C" is rich in polycyclic aromatic hydrocarbons, colloids, and has poor hydrogen supply capacity. Effectively inhibit the "thermal condensation reaction" of cracking fragments, high coke yield and high gas yield;

[0019] ⑤ The third disadvantage is that the "coal tar fraction with a conventional boiling point of 370-450°C" is rich in polycyclic aromatic hydrocarbons and colloids, which itself is an excellent raw material for hydrorefining, which can be converted into excellent hydrocracking Raw materials, such processing has high liquid yield and low gas yield; patent application 201010217358.1 directly introduces the 370-450°C fraction in coal tar into the hydrocracking process, making it undergo non-ideal hydrofining-hydrocracking process, because the dominant function of the suspension bed hydrocracking process in patent application 201010217358.1 is "cracking", which is suitable for the suspension bed hydrogenation catalyst and reaction system function (apparent hydrofinishing function and hydrocracking function) of coal tar heavy oil, It is usually not optimal for coal tar fractions at 370-450°C. For example, the regional operating temperature of the suspended bed hydrogenation process of coal tar heavy oil is usually as high as 420-450°C, which is much higher than that of the fixed-bed hydrotreating process of coal tar fractions. The normal operating temperature range of 370-420°C in the fixed-bed hydrocracking process must have a high probability of cracking reaction;

[0020] ⑥ The fourth disadvantage is that, compared with the hydrocracking process of petroleum-based heavy oil, the hydrogen content of solvent oil is much lower, and the hydrogen consumption of solvent oil hydrogenation reaction is much larger, and the heat of reaction is much larger, that is to say, its heat carrier Efficiency (the ability to control the temperature rise of the overall reaction process) is much lower;

[0021]⑦The fifth disadvantage is that the polycyclic aromatic hydrocarbons contained in the "coal tar fraction with a conventional boiling point of 370-450°C", large colloid molecules, high viscosity, and thermal movement low speed;

[0022] During the hydrocracking process of petroleum-based heavy oil suspension bed, the components acting as solvent oil have high hydrogen content, rich bicyclic or polycyclic hydrocarbons, rich Partially saturated aromatic hydrocarbon macromolecules, solvent oil itself contains rich hydrogen transfer hydrocarbons and / or hydrogen donating hydrocarbons, strong anti-coking function during thermal processing, low hydrogen consumption and low reaction heat during hydrocracking, compared with the aforementioned patent application 201010217358.1 Describes the hydrocracking method of medium and low temperature coal tar heavy oil. The solvent oil used in patent application 201010217358.1 has low hydrogen content and low hydrogen supply capacity. Big disadvantage is obvious

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