Coal tar heavy fraction fluidized-bed hydrocracking method and system thereof

Abstract

The invention relates to the field of coal chemical industry, in particular to a coal tar heavy fraction fluidized-bed hydrocracking method. The method comprises the following steps: the raw materials of coal tar heavy fractions are mixed with hydrogen and then enter a fluidized-bed reactor from the bottom thereof, and a supported catalyst enters the fluidized-bed reactor from the top thereof; under the action of the supported catalyst, the coal tar heavy fractions and the hydrogen carry out hydrocracking reaction in the fluidized-bed reactor; and the obtained reaction product is delivered from the top of the fluidized-bed reactor and then subject to gas-liquid separation, the separated hydrogen returns to the fluidized-bed reactor to be recycled, and the separated liquid product is subject to distillation separation to obtain gaseous hydrocarbon, gasoline fractions, diesel fractions and tail oil. In the invention, by directly adopting the fluidized-bed hydrocracking method, the coal tar heavy fractions can keep light weight, the yield of the fuel oil product hydrogenated by coal tar can be effectively increased, and blockage phenomenon of a catalyst bed layer can be effectively eliminated; and the method of the invention has the characteristics of simple and reasonable process, long-term operation, a small amount of the catalyst adopted, low cost, high yield of the oil generated by the product and good quality.

Description

technical field [0001] The invention belongs to the technical field of coal chemical industry, and in particular relates to a method and system for ebullating bed hydrocracking of heavy fractions of coal tar. Background technique [0002] In the process of petroleum processing, fluidized bed hydrocracking is one of the main methods to lighten various inferior heavy oils and residual oils. In order to meet the rapid growth of market demand for light fuel oil, more than 20 sets of heavy oil and residual oil fluidized bed hydrocracking units have been put into industrial production in various countries. Ebullating bed hydrocracking technology has the remarkable characteristics of wide adaptability to high viscosity, high carbon residue, high bitumen, high metal residue, uniform temperature in the reactor, high catalyst utilization rate, long operation period and flexible operation of the unit. Ebullating bed hydrocracking technology has become one of the main development direc...

AI Technical Summary

Problems solved by technology

This production method is actually a combined process of fixed bed and ebullating bed. However, due to the high impurity content in tar, and the reaction is easy to coke under high temperature conditions, the catalyst bed is seriously blocked. To maintain long-term operation, the catalyst needs to be replaced frequently. A large amount of catalyst is used, which increases the cost and complicates the process

In addition, the product from the switching reactor contains a considerable amount of water, which directly enters the hydrogenation reactor without treatment, which has a great impact on the activity of the catalyst (especially the catalyst containing molecular sieves), which will greatly reduce the activity of the catalyst

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