Hydrofining Process of Coal Tar Based on Four Kinds of Catalyst Grading

Abstract

Although the mechanism of coal tar hydrogenation technology has not been fully revealed, many enterprises have realized the industrialization of this technology through the reference of crude oil hydrogenation technology. Therefore, it will be very helpful for the development of this technology to present a research result close to industry. Based on four kinds of catalyst gradations, the hydrogenation experiments of different processes and a series of 1200 h long-term experiments were carried out in a four-tube fixed bed reactor with coal tar distillate (IBP ≈ 360 °C) as the raw material. First, based on the product composition of different reactor outlets, the composition changes and main reaction process of coal tar in four reactors were summarized. It was found that the reactions in the four reactions are different and related. The hydrogenation of olefins mainly takes place in the first reaction (230 °C, hydrofining guard catalyst and hydrodemetallization catalyst). Most of the oxygenated compounds were transformed in the second reactor (320 °C, hydrogenation catalyst I) but not completely. The hydrogenation of aromatics is mainly concentrated in the third and fourth reactors, but there are already signs of this reaction in the second reactor. Second, the influence of different process conditions on the product properties and the material balance under different process conditions were summarized. Finally, the stability of the grading system is verified by the long-term experiments.

Co-production of Naphthenic Oil and Phenolic Compounds from Medium- and Low-Temperature Coal Tar

“…10 Wang et al 11 reported that the reaction parameters and feed nitrogen could strongly influence the ability of catalysts (NiMo/Al 2 O 3 and NiW/USY). Similarly, Niu et al 12 examined the effects of process conditions chiefly on the product properties. To compete with petroleum-based fuels, many researchers have pursued producing light fraction oils from coal-based oils.…”

Transformation of Basic and Non-basic Nitrogen Compounds during Heavy Oil Hydrotreating on Two Typical Catalyst Gradations

“…The catalyst grading scheme can be based on different catalysts’ physical and chemical properties and their distribution in each reactor. Different catalyst gradations result in a great difference in the activities and selectivities. , The difference in chemical properties is mainly due to the different content of substances in each catalyst, and the differences in physical properties are manifested in the surface area, pore size, and shape . Former studies on HDN reactions mainly used modeling compounds and light oil such as gasoline and diesel oil.…”