Pretreatment method for deep processing of coal tar

Abstract

The invention relates to a pretreatment method for deep processing of coal tar. A technology for carrying out deslagging, ammonia water removing, dephenolizing and desalting separation on the coal tar through centrifugal separation, gas backwashing filtering, distilling and high-voltage electric field is adopted, the pretreatment method is applicable to the pretreatment of high-temperature coat tar, medium-temperature coal tar and low-temperature coat tar, the separated ammonia water can be recycled, and phenols are sold as a chemical raw material directly or after the phenols are refined, so that the problems that wastewater containing ammonia and phenol is discharged, a hydrogen source of energy is wasted due to phenol hydrogenation, and the like are avoided, and the added value of the coal tar is increased.

Description

technical field [0001] The invention relates to a coal tar raw material pretreatment method, in particular to a coal tar deep processing pretreatment method, which belongs to the technical field of chemical industry. Background technique [0002] With the crisis of oil resources, the way to seek new oil resources has become the focus of people's attention, so the coal tar processing industry has attracted people's attention again. In addition to the development of new uses for traditional coal tar processed products such as naphthalene, anthracene, phenols and asphalt, coal tar products further processed through hydroprocessing have become more market-competitive products. [0003] The technology of hydrogenation of coal tar to produce light fuel oil has been developed rapidly. Rational processing and utilization of coal tar can not only provide the demand for various chemical raw materials, but also relieve the pressure of shortage of petroleum resources and increase the ad...

AI Technical Summary

Problems solved by technology

The existing problem is: coal tar is a complex mixture of polar and non-polar substances, there are both van der Waals forces and hydrogen bonds between molecules, and cyclone separation can only partially separate non-ideal substances, phenols Hydrogen bonds can also be formed with water. Therefore, the water in coal tar is difficult to remove through cyclone separation. In addition, coal ash adheres to the tar and its density is relatively small and cannot be separated by cyclone. In addition, the separated water contains Ammonia, phenols and other substances pollute the environment. The present invention first removes mechanical impurities by means of centrifugal separation and filtration, so that the removal rate of 10 μm reaches 98%, and then removes ammonia, water, and phenols through distillation, and finally performs secondary Or the three-stage electric desalination system removes the salt in the coal tar, and the residual moisture in the coal tar is removed by flash evaporation

[0005] (1) In the coal tar pretreatment unit, the whole distillate oil of the raw material to be processed is purified by water removal, dust removal, and desalination, and then enters the next unit; (2) In the coal tar high-efficiency separation unit, the pretreated coal tar enters the fractionation tower , Fractional distillation of the phenol oil fraction at 170-210°C and the naphthalene oil fraction at 210-230°C, the phenol oil and naphthalene oil are further refined to produce fine chemicals phenol and naphthalene, the light oil fraction at 230 ° C, and the delayed coking products are light fuel oil and pitch coke, and the pitch coke is used as the final The product, light fuel oil, enters the fixed bed hydrogenation unit; (4) in the fixed bed hydrogenation unit, the light oil fraction of coal tar <170°C, the remaining fraction after refining phenol oil and naphthalene oil, and delayed coking light fuel oil Mixed as the raw material for hydrogenation, the hydrogenated products are rectified to obtain the final product gasoline and diesel oil, and a small amount of tail oil is recycled for hydrogenation. This patent firstly separates and removes dust through cyclone, and then enters the dehydration tower for dehydration. After dehydration, the coal tar enters the fractionation tower , the desalination treatment is mentioned in the summary of the invention. There are no desalination treatment facilities and specific desalination methods in the flow chart. In addition, dehydration and tar separation are carried out in two towers, which increases the investment in equipment. Coking before hydrogenation makes part of the coal tar Turning into coke, the comprehensive utilization rate of coal tar is not high

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