Two-stage hydrogenation cracking method for producing industrial chemicals

Abstract

The invention discloses a hydrocracking method for manufacturing industrial chemicals, which is characterized in that: the weighty raw oil and the hydrogen are mixed and then enter the first hydrogenation process region; the hydrogen-rich gas obtained by separating the outflow from the first region enters directly the second hydrocracking reaction region and the liquid enters a fractionator to fractionate; the obtained gas, the naphtha and the tail oil are used as the industrial chemicals and go out of the system and the middle distillate oil single or mixing with other bad distillate oil enters the second hydrogenation process region to crack, and the gas obtained from the second region can be recycled and the liquid enters the fractionator. Compared with the prior art, the invention hasthe advantages of adopting two reaction regions to share a circular hydrogen system, and enabling to transform two or more bad materials into products with high added value.

Description

technical field [0001] The invention relates to the field of petroleum processing, in particular to a two-stage hydrocracking method for producing chemical raw materials. Background technique [0002] With the rapid development of the world economy, the demand for chemical products has increased dramatically, and correspondingly, the demand for chemical raw materials for the production of these chemical products has also increased significantly. The production of chemical raw materials from petroleum fractions is one of the very important means. The most important chemical raw materials are benzene, toluene, xylene, and ethylene, propylene, etc., and the heavy naphtha obtained through hydrocracking of petroleum fractions is benzene, toluene, di An important source of light aromatics such as toluene, the light naphtha and hydrocracking tail oil obtained have the advantages of good quality and high yield of the target product, so it is a high-quality raw material for steam cra...

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Problems solved by technology

[0005] CN01823056.3 discloses a two-stage hydrocracking method, mainly emphasizing the hydrotreating / hydrocracking method of supplementing the hydrogen gas stream. In this method, the raw material oil is all converted into products with a boiling point lower than the raw material oil. This method only considers The energy-saving use of hydrogen in the second stage, if only the new hydrogen of this device is used as the hydrogen in the second stage, the number of processing raw materials in the second stage is very limited, and it is impossible to produce very good chemical raw materials such as hydrocracking tail oil

[0006] US5904835 discloses a parallel hydrocracking method. Although the method uses two series of reaction zones, their feeds are exactly the same, and only a common fractionation system is used. This method can be understood as two sets of hydrocracking units operating in parallel, and cannot Largest production of chemical raw materials

[0007] US2003 / 0221990A1 and US2005 / 0103682A1 disclose a multi-stage hydrocracking method for jet fuel circulation. The hydrocracking method disclosed in these two patents is 3.45-6.9 MPa lower than the first stage and basically free of hydrogen sulfide and hydrogen sulfide. In the case of ammonia, the light products in the first cycle are cracked to produce more gas and naphtha. Due to the large difference in operating pressure in the two reaction zones, two separate hydrogen cycle systems are required , and the second-stage treatment area usually uses expensive noble metal catalysts, and the operation cost is high. This method has the disadvantages of complicated process and high operation cost.

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