The Study Of Coke Formation Mechanism In The Co-processing Of Bio-oil And Petroleum Fractions

Co-processing is a kind of the most important process of a modern refinery because of its flexibility to different feedstock and product demands. However, this process is confined to laboratory and pilot scale because of high coke formation and catalyst deactivation. Therefore, it needs to study the behavior of coke formation to reduce coke formation.In order to study the reaction mechanism of different oxygen-containing functional groups, acetic acid, cyclopentanone and guaiacol were selected as bio-oil model compounds to study the coke formation using a fixed-bed reactor. The effects of temperature and WHSV on the coke yield were investigated. The liquid products obtained in the cracking of bio-oil model compounds were analyzed and the possible cracking pathway was proposed to explain the formation of those products.The coke deposited on the catalyst had been characterized using different analytical techniques (elementary analysis, XRD, SEM, TG, IR, GC-MS and NMR spectroscopy). The results indicated that coke mostly consisted of polycyclic aromatic hydrocarbons. The coke formation was mainly due to the polymerization and polycondensation of large amounts of aromatic compounds.The feed and product in co-processing process are divided into four virtual assemblies by using the lumped method. The reaction time, reaction temperature and WHSV were researched, the five parameters of the model were calculated through mathematical simulation, and then the lumping kinetic model of liquid fraction was established.