Kinetics of Deep Hydrodearomatization of Diesel Oil from Direct Coal Liquefaction
China Shenhua Coal to Liquid and Chemical Shanghai Research Institute, National Engineering Laboratory of Direct Coal Liquefaction, Shanghai 201108, China
Abstract To study the hydrodearomatics reaction law of diesel oil from direct coal liquefaction, the deep hydrogenation of diesel oil was carried out on a 30 mL continuous hydrogenation experimental apparatus using Pd-Pt hydrogenation catalyst at the operating conditions of pressure 6-12 MPa, temperature 80-240 ℃ and liquid space velocity 0.4-1.2h-1. The results showed that the mass fraction of aromatics in the product oil was reduced to less than 0.01 % under certain hydrogenation conditions. Kinetic equation for hydrodearomatization of diesel oil from direct coal liquefaction was established by combining with external diffusion mass transfer process and the hydrodearomatics reaction process. It is predicted that the effective diffusion coefficient increases firstly and then stabliize to 1, while the aromatic conversion increases and then becomes constant, as the space velocity of the fluid increases. And the higher the reaction temperature is, the greater space velocity of the fluid is required to eliminate the effects of external diffusion. The required reaction temperature and volume space velocity in the hydrogenation of direct liquefied diesel oil could be calculated by kinetics to ensure being less than 0.01% of aromatic hydrocarbon content in the product oil.
