Coal tar deep processing technology for directly extracting industrial naphthalene by adding alkali after normal- and reduced-pressure treatments

Abstract

The invention discloses a coal tar deep processing technology for directly extracting industrial naphthalene by adding an alkali after normal- and reduced-pressure treatments. In the technology, coaltar is used as a raw material, the alkali is directly added after normal- and reduced-pressure treatments, wherein a preliminary distillation tower and a distillation front tower adopts negative-pressure operation, and other parts adopt normal-pressure operation. The technology is realized by the following process: crude tar is dehydrated by a dehydration tower and then enters the negative-pressure preliminary distillation tower, separation is carried out by the negative-pressure preliminary distillation tower, asphalt is produced at the bottom of the negative-pressure preliminary distillationtower and enters an asphalt process through a tubular furnace, heavy oil is produced at the top of the negative-pressure preliminary distillation tower, preliminary distillation oil gas produced at the top of the negative-pressure preliminary distillation tower enters a distillation front tower, a naphthalene oil fraction is collected at the bottom of the distillation front tower, phenol oil is produced at the top of the distillation front tower, the naphthalene oil fraction collected at the bottom of the distillation front tower enters a naphthalene tower for further separation, and naphthalene oil is produced at the top of the naphthalene tower. The invention has the advantages of good separation ability, low collection temperature of the preliminary distillation fraction, higher quality of the extracted asphalt and the subsequent naphthalene washing oil, and the invention has the advantages of simple process route, energy saving and environmental protection, and high separation ability.

Description

technical field [0001] The invention relates to the field of coal chemical industry, in particular to a coal tar deep processing technology for directly extracting industrial naphthalene by adding alkali after normal and reduced pressure. Background technique [0002] Coal tar is a dark brown viscous liquid product produced during the dry distillation and gasification of coal. Its components are very complex, containing more than 10,000 varieties, of which more than 500 have been identified. With the development of fine chemical industry, the deep processing of coal tar to obtain high value-added chemical raw materials has been paid more and more attention, and the demand is also increasing. [0003] Atmospheric pressure, one-tower distillation, and double-mixed or triple-mixed fractions are mostly used in China. The coal tar distillation process used is relatively scattered, with high energy consumption, fewer products, and low value for deep processing. At present, the do...

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Problems solved by technology

The actual operation of this process method is difficult, and the separation effect is not obvious

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