Hydrofinishing method for crude benzol

Abstract

The invention relates to the production field of high purity benzene, toluene and mixed xylene, in particular to a method for treating a hydrorefining crude benzene. The method takes coking crude benzene as raw material, after pretreatment, heavy aromatics are removed directly through a vacuum and de-heavy tower with the pressure at the top of the tower between 0.01MPa and 0.1MPa; pre-hydrotreating reaction and main-hydrotreating reaction are carried out, gas phase material enters a high pressure flash drum after hydrotreating reaction, hydrogen-rich gases are separated, liquid phase material enters a stabilizer and low boiling point hydrocarbon is removed; liquid phase material removed from the low boiling point hydrocarbon enters an aromatics extraction device and high purity benzene, toluene and mixed xylene are obtained through extraction. Under the premise of guaranteeing the yield of benzene, toluene and mixed xylene, the method not only effectively reduces investment cost and the operation cost of devices, but also has the advantages of good product quality, long device running cycle, etc.

Description

technical field [0001] The present invention relates to the production field of high-purity benzene, toluene and mixed xylene; in particular, it relates to a treatment method for hydrogenation of crude benzene, that is, using crude benzene as a raw material, through hydrogenation treatment and extraction of aromatics widely used in the field of petroleum processing, etc. Method to produce high-purity benzene, toluene and mixed xylene products (hereinafter referred to as "triphenyl"). Background technique [0002] The refining of coking crude benzene (mixed aromatics) was first carried out by pickling, which can only partially remove sulfur-containing compounds (mainly thiophene) and other impurities in crude benzene, and the loss of aromatic compounds in the process is relatively large (about 8% to 10%), and its by-product waste acid tar and residues have no effective treatment methods, causing environmental pollution. With the rapid development of the organic chemical indu...

AI Technical Summary

Problems solved by technology

[0002] The refining of coking crude benzene (mixed aromatics) was first carried out by pickling, which can only partially remove sulfur-containing compounds (mainly thiophene) and other impurities in crude benzene, and the loss of aromatic compounds in the process is relatively large (about 8% to 10%), its by-product waste acid tar and residues have no effective treatment methods, causing environmental pollution

With the rapid development of the organic chemical industry, the quality requirements for benzene series aromatic products are very high, and the aromatic products obtained by pickling can no longer meet the needs, and this method has long been eliminated in developed countries

[0003] In the early 1950s, the United States, Britain, Germany, France and other countries successfully developed the crude benzene catalytic hydrogenation refining method. The freezing point of the obtained benzene was 5.2°C-5.4°C, and the mass fraction of thiophene was 1×10 -6 ~10×10 -6 , the quality of benzene is not very high

Although this can effectively improve the yield of triphenyl, the economical efficiency of the device is relatively poor, and the investment and operating costs are relatively high.

The multi-stage evaporator used in this process vaporizes the raw material, and the fourth and fifth evaporators are prone to blockage due to serious olefin polymerization, resulting in shutdown of the device

Images