What are the main influencing factors on the top cover of a hydrogenation reactor?

1. The acid value of the raw materials is high, with naphthenic acid being the most significant. Naphthenic acid reacts with Fe to form oil-soluble iron naphthenate; at certain temperatures, this iron naphthenate reacts with hydrogen sulfide to produce solid FeS, which covers the catalyst bed and results in the formation of a layer on the upper part of the bed. Generally, the Fe ion level should be kept below 2 mg/kg. It is best to keep it within 1 mg/kg. 2. The influence of metals in the raw materials. In addition to Fe, organic calcium forms a hard shell on the catalyst surface, which increases the reactor pressure drop and can also cause the catalyst to clog, affecting its removal; generally, the concentration of Ca ions should be kept below 1 mg/kg. 3. The impact of dry raw materials. As the boiling range increases, the content of cyclic hydrocarbons, especially polycyclic aromatic hydrocarbons, rises rapidly; the BMCI value increases as well, which accelerates the reaction leading to coking and carbon deposition, resulting in the formation of a layer on the top. 4. Influence of nitrogen content in raw materials. Nitrides are inherently unstable, undergoing condensation to form coke with a crust forming on top.

Well explained, I’ve learned something, thank you