Liquid-phase hydrogenation reactor and hydrogenation process

Abstract

The invention relates to a liquid-phase hydrogenation reactor and a hydrogenation process, the liquid-phase hydrogenation reactor comprises an inner cylinder and a reactor shell, the inner cylinder is conical, the top and the bottom of the inner cylinder are open, the edge of the bottom of the inner cylinder is hermetically connected with the inner wall of the reactor, and a plurality of small holes are formed in the wall of the inner cylinder; a ceramic membrane tube bundle is vertically arranged in the axial direction of the reactor and is communicated with external hydrogen; the inner cylinder is filled with a hydrogenation catalyst I, the annular cavity is filled with a hydrogenation catalyst II, and the activity of the hydrogenation catalyst I is higher than that of the hydrogenation catalyst II; the reactor raw material inlet communicates with the top of the inner cylinder; the materials flow in the inner cylinder from top to bottom; the materials flow in the annular cavity from top to bottom. According to the method, the contact time of the material and the catalyst in the whole hydrogenation reaction process can be effectively controlled, so that the temperature rise of a catalyst bed layer is more uniform, the problems of severe heat release and reaction conversion rate inhibition in the reaction process are solved, and higher hydrogenation reaction rate and conversion rate in the whole liquid-phase hydrogenation reaction process are achieved.

Description

technical field [0001] The invention belongs to the fields of chemical industry and petrochemical industry, and specifically relates to a liquid-phase hydrogenation reactor and a hydrogenation process. Background technique [0002] Liquid phase hydrogenation technology is a new type of hydrogenation technology, which is to dissolve hydrogen in the raw material oil in advance, and to meet the hydrogenation required by the hydrogenation reaction through a large amount of liquid phase circulation, which overcomes the hydrogen diffusion in the conventional trickle bed hydrogenation reaction Due to the influence of mass transfer, the hydrogenation reaction is carried out in the kinetic control zone. Therefore, compared with the traditional fixed-bed gas / liquid / solid three-phase hydrogenation process, the liquid phase hydrogenation process has a fast hydrogenation reaction rate and a high reaction rate. High efficiency, low energy consumption, low investment and many other advanta...

AI Technical Summary

Problems solved by technology

However, the following problems still exist in the conventional downflow liquid-phase hydrogenation reactor and reaction process: (1) The concentration of reactants in the fresh material in the early stage of the reaction is high, the hydrogen content is high, the driving force of the reaction process is large, and the initial activity of the catalyst is also high , and the contact between the material and the catalyst in the liquid-phase hydrogenation process is relatively sufficient, so there are problems such as severe reaction heat release, large temperature rise, and difficult control of the process; (2) In the later stage of the reaction, due to the high reaction temperature, if it is still The hydrogenation reaction occurs on the active catalyst, causing the problems of fast reaction rate, side reaction and cracking reaction. Therefore, a catalyst with appropriate activity should be used in the later stage of the reaction to control the reaction rate and improve the reaction yield. (3) Since the late stage of the reaction is still a liquid-phase hydrogenation reaction process, the gas products generated by the reaction are still dissolved in the liquid material, that is, the conventional reaction is adopted in the liquid-phase hydrogenation reaction process It is difficult to separate by the stripping method of the reactor, which requires a large stripping surface area. If the reaction gas is not stripped out in time and removed, the reaction conversion rate in the later stage of the reaction will be reduced, so that the ideal hydrogenation cannot be achieved. Reaction depth; (4) During the reaction process, with the flow of materials in the hydrogenation reactor and the consumption of hydrogen, the dissolved and dispersed state of hydrogen in the oil has gradually changed, resulting in the hydrogen bubbles dissolved around the oil molecules. When the reaction occurs, the bubbles that have not reacted gradually coalesce into large bubbles, so that the oil cannot continuously provide hydrogen during the hydrogenation reaction, and it will also increase the side reaction or cracking reaction

[0008] In summary, most of the liquid-phase hydrogenation reactors in the prior art are based on the method of dissolving hydrogen or hydrogen dissolving components, and the method of supplementing hydrogen to improve the reaction efficiency. The external stripping facilities will flash the hydrogen sulfide and ammonia generated by the reaction. These methods do not solve the problem of severe exothermic reaction, uneven temperature rise, low reaction conversion rate in the later stage, and when the required conversion rate is reached during the liquid phase hydrogenation reaction. Therefore, it is necessary to further develop new liquid-phase hydrogenation reactors and liquid-phase hydrogenation reaction processes.

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