Heavy oil lightening method

Abstract

The invention provides a heavy oil lightening method which comprises the following steps: hydrogen and a heavy oil raw material mixed with a catalyst enter a hydrogenation reactor for hydrogenation reaction to obtain a hydrogenation reaction product; fractionating the obtained hydrogenation reaction product to obtain a light oil product and tail oil; carrying out extraction treatment on the tail oil, so that the obtained extracted oil returns to the hydrogenation reactor to participate in the hydrogenation reaction to form a cycle; wherein a system for realizing the hydrogenation reaction is a dispersion system in which hydrogen is dispersed in an oil phase in a hydrogenation reactor in the form of bubbles with the size of not more than 500 microns. The lightening method provided by the invention has the advantages of high conversion rate, simple process flow and the like.

Description

technical field [0001] The invention belongs to the field of petroleum processing, and in particular relates to a method for lightening heavy oil. Background technique [0002] As petroleum resources continue to become heavy and inferior, heavy oil has become an important raw material for refineries. Efficient conversion and processing of inferior heavy oil resources to produce more clean light oil products has become an important way to cope with the shortage of petroleum resources. According to the change of the hydrocarbon mass ratio of oil products during the processing, the heavy oil lightening process can be divided into two types: hydrogenation and decarburization. Among them, the decarburization process mainly includes catalytic cracking, delayed coking and other processes, which are important The main processing technology for lightening heavy oil accounts for about 83% of the total heavy oil processing volume. However, the high coke yield and the difficulty in full...

AI Technical Summary

Problems solved by technology

Taking the suspended bed hydrogenation process as an example, after hydrogen enters the suspended bed hydrogenation reactor in the form of bubbles, it needs to be transferred to the heavy oil in the liquid phase through the bubble-heavy oil phase interface, and then dissolved (oil-soluble or Water-soluble homogeneous catalyst) or dispersed (solid granular heterogeneous catalyst) catalyst in heavy oil, under a certain operating pressure (mass transfer driving force), the phase between hydrogen bubbles and heavy oil The interfacial area determines the mass transfer rate of hydrogen to heavy oil, and the size of hydrogen bubbles dispersed in heavy oil in the current suspended bed hydrogenation reactor is generally not less than 5 mm, which cannot provide sufficient phase interface for the transfer of hydrogen to heavy oil area, and because of the large bubbles, its buoyancy in heavy oil is also large, the rise is fast, and the residence time is short, resulting in insufficient time for hydrogen to contact and react with heavy oil. Molecular free radicals and hydrogen free radicals can easily cause heavy oil macromolecular free radicals to collide with each other, cause superimposition, and even coking. Therefore, the current suspension bed hydrogenation process is often carried out under relatively high operating pressure (mostly greater than 18MPa). In this way, the driving force for mass transfer of hydrogen to heavy oil can be increased, and the above-mentioned problems such as poor contact reaction between hydrogen and heavy oil and easy coking can be alleviated. However, higher operating pressure often requires higher requirements on equipment and operating processes, which leads to the suspension bed hydrogenation process. Industrial applications are very limited

[0010] In fact, the above-mentioned hydrogenation processes such as the suspended bed generally face the common problem that it is difficult to achieve full contact between heavy oil, hydrogen, and catalysts, which is also the essential reason for the defects of these processes such as high operating pressure and harsh conditions. The reported suspension bed hydrogenation process can realize the effective conversion of heavy oil or reduce the operating pressure of the suspension bed reactor to a certain extent by combining multiple reactors and / or improving the catalyst. However, these processes generally face Due to the complexity of the whole process and other problems, the industrial application is limited

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