How is the catalyst poisoned in direct coal liquefaction? What are the symptoms after poisoning?

The main reasons for catalyst poisoning in coal liquefaction are as follows: 1. Resins and polycyclic aromatic hydrocarbons present in the crude oil obtained from coal liquefaction coking on the catalyst surface. 2. Ash in coal and metals in the oil tend to deposit on the catalyst surface and in its pores, ultimately leading to blockage of the catalyst pores and poisoning of the active sites, thereby rendering the catalyst inactive. 3. Heterocyclic compounds containing nitrogen get strongly adsorbed on the catalyst surface, reducing its activity. 4. A lack of H2S causes metal sulfides to be reduced by H2, losing their activity. Symptoms of poisoning include a decrease in reaction rate, or even complete failure to participate in the reaction. This post was last edited by Ma Hai on 2009-1-18 at 20:19

In fact, the catalysts used in current common direct liquefaction processes are all disposable catalysts, which is a different concept from catalyst beds in traditional chemical engineering. Catalysts in traditional chemical processes serve as carriers for the reaction process and are reused; as a result, the issue of catalyst poisoning arises, meaning that their catalytic efficiency decreases or is lost after certain reactions take place； However, in current direct liquefaction processes, the catalyst and one of the reactants, coal powder, are added in proportions corresponding to that of coal powder, and they end up as residue after the reaction. Specifically, HTI uses synthetic iron catalysts, while NEDOL uses natural pyrite or synthetic iron catalysts; therefore, in actual direct liquefaction processes, there is no such issue as catalyst poisoning.

Reply to 2# Cold-Blooded Wolf: My current research topic is related to coal liquefaction; it’s very important, so thank you

Students on the 4th floor, ask the moderator for more advice; he knows a lot

Reply to 4# Jian@Beibei: What specific research topic is it?