重油催化裂化沉降器结焦的研究进展

Research progress of coking in disengagers of resid fluid catalytic cracking units

分析了重油催化裂化 (RFCC)沉降器结焦的影响因素和机理。反应油气中含有催化剂颗粒以及油气中重组分的冷凝是沉降器结焦的物理因素 ,而重芳烃、胶质、沥青质的高温缩合和油气中烯烃和二烯烃的环化聚合反应则是沉降器结焦的化学因素。通过对液相重组分高温缩合机理、相分离生焦机理和自由基反应机理等沉降器结焦机理的分析 ,认为沉降器中油气的气、液相分别遵循不同的结焦历程 。

The factors influencing coking within resid fluid catalytic cracking (RFCC) disengagers and the mechanism are analyzed. The physical causes for RFCC disengager coking are the presence of fine catalyst particles existing in the RFCC products and the condensation of heavy fractions of RFCC products. The chemical causes for RFCC disengager coking are the condensation reaction of heavy aromatic hydrocarbon, resins and asphaltene as well as cyclization and polymerization of olefin and diolefin in RFCC products. Different coking courses are followed by the vapor phase and the liquid phase of the RFCC products, separately, on the basis of the analysis on the existing three mechanisms of disengager coking. Therefore, the key step of RFCC disengager coking inhibition is to prevent the condensation of heavy fraction in the RFCC products and to decrease the resident time of RFCC products within the disengagers.