Research For The Distribution Law Of The Thermal Cracked Products From Coked Residue

The thermal-converted kinetic models of vacuum residue and operating factors of delayed coking unit were reviewed in this article. The coking stock from Daqing refinery was studied in a thermal cracking experiment.The reactor used which was made of stainless steel tube(φ25×2.5). Reaction temperature was maintained by the use of DWT-702 precise temperature controllable instrument. Experiments were conducted at different temperature ranged from 430℃to 470℃with the reactor heated by tin bath. The composition of cracking gas was analyzed by gas chromatography, and the reaction residue was separated into n-heptane soluble, n-heptane insoluble—toluene soluble and toluene insoluble. The narrow cut of reactant and product was determined by gas chromatography stimulated distillation with the boiling point range of 30℃. According to the analysis of mass fraction of each narrow cut varied with reaction temperature and time, the narrow cut kinetic model was developed. Reaction apparent activation energy and frequency factor were calculated. The result fitted the experiment data fairly well.The result show that the thermal-converted reaction of vacuum residue may be affected by the presence of recycle oil, much heavy cut would be produced at high reaction temperature, toluene insoluble began to form and accelerated at a relative high speed as the reaction up to some extent.