Method of purifying tetrahydronaphthalene in coking crude benzene hydrogenation solution

Abstract

The invention discloses a method of purifying tetrahydronaphthalene in a coking crude benzene hydrogenation solution. The method comprises reduced pressure distillation, esterification reaction, sulfonation reaction and secondary reduced pressure distillation. Through the reasonably controlled and operated pressure, temperature and reflux ratio, the continuous educed pressure distillation and chemical subtraction can be used to greatly reduce the purification difficulty, the separating effect can be significantly improved, tetrahydronaphthalene, obtained after the separation, is higher in quality, higher in purity and higher in extraction ratio, the extraction ratio and purity in a raffinate can reach up to above 98%, and the additional value of a by-product in the raffinate can be effectively improved, the recovering level of the tetrahydronaphthalene can be significantly improved, and the problem that the tetrahydronaphthalene is high in purification difficulty can be effectively improved; furthermore, the whole tetrahydronaphthalene extracting process is low in energy consumption, the equipment investment is low, the advanced technology can be realized, the process structure is simple, and the good economic benefit and social benefit can be realized, therefore the method is easy to popularize and use.

Description

technical field [0001] The invention belongs to the technical field of rectification and separation, and in particular relates to a method for purifying tetralin from coking crude benzene hydrogenation liquid. Background technique [0002] Coking crude benzene is a by-product produced in the coal coking process, which is rich in important compounds such as benzene, toluene and xylene, and is an important way to obtain pure benzene at present. Due to the continuous rise of oil prices and the rapid development of my country's economy, the market demand for pure benzene and its downstream products is also increasing. In the 1990s, various enterprises adopted this hydrogenation device to process coking crude benzene one after another. After hydrogenation reaction of coking crude benzene, benzene, toluene and xylene with high purity can be obtained. However, after hydrodesulfurization The treated heavy component raffinate also contains many important organic compounds, mainly in...

AI Technical Summary

Problems solved by technology

In the early days, companies generally treated the above-mentioned heavy component raffinate as cheap solvent oil, which caused a lot of waste. With the increasing scarcity of natural resources, in order to further increase the added value of products and increase the market competition of enterprises Due to the power and economic benefits, some enterprises have also adopted distillation and purification technology to extract tetralin from the hydrogenation residue of coking crude benzene. However, in the actual extraction process, it was found that the tetralin in the hydrogenation of coking crude benzene Purification, its process conditions are essentially different from the purification of refined naphthalene hydrogenation synthesis liquid. Its purification is more difficult, and the waste distance between components is small. The purity of the tetralin is low, the content of the extracted tetralin is low, and the quality of the obtained tetralin is poor. If one wants to obtain high-quality tetralin that meets the market demand through rectification, it is not only necessary to increase the reflux ratio , it is also necessary to increase the number of trays, and the energy consumption and equipment investment in the distillation process are relatively high