Abstract: An improved fluid catalytic cracking unit(FCCU)riser-regenerator model combined with carbon-monoxide(CO)combustion was proposed,since multiple steady states of FCCU would change as CO conversion changed with different amounts of CO combustion promoter added.Due to the conservative consumption of CO combustion promoter which contains Pt as the active component in refineries,the amount of the added combustion promoter would significantly affect the economics.Thus,based on the heat balance of the high-efficiency regenerator,heat generation and removal curves were determined and three steady states were found,two of which were thermally stable satisfying the slope condition.From the analysis of the influence of different amounts of CO promoter on the multiple steady states,it was pointed out that the varying distance between the two high steady states resulting from different amounts of CO combustion promoter added would influence the severity of the control system design.

Key words: FCCU, multiple steady states, thermal stability, CO combustion promoter

摘要： 考虑到一氧化碳(CO)助燃剂作为调控系统CO燃烧状况的操作手段会影响催化裂化装置的多稳态,在已有的烧焦罐式高效再生催化裂化装置反应-再生系统动态机理模型的基础上,扩展了再生器内CO燃烧的机理模型,并将CO助燃剂的添加量与再生器内CO的燃烧状态进行定量的关联。在对再生器进行热量衡算的基础上,绘制出再生器的放出-移出热量曲线,确定了系统的3个稳态操作点,并根据放热反应器稳态热稳定性斜率条件分析了稳态点的热稳定性。针对炼厂CO助燃剂添加量设计较为保守的问题,分析了减少助燃剂添加量对系统操作的影响,指出CO助燃剂的添加量会影响到系统两个高温稳态点之间的操作空间从而影响到装置控制系统设计的苛刻度。

关键词: 催化裂化, 多稳态, 热稳定性, CO助燃剂