【摘要】 催化裂化装置中CO助燃剂需要周期性分时段添加,属于连续生产过程中的间歇操作,因而助燃剂添加量具有参数和变量的双重特性,与助燃剂添加量相匹配的主风流量成为一个操作周期内控制再生器内CO燃烧状况的连续操作变量。通过对主风流量控制回路中再生器稀相床温差、再生器出口烟气氧含量以及二密相床再生温度三个潜在被控变量的稳态灵敏度分析及控制效果评价,发现当CO助燃剂添加量接近欠量范围时,装置主风流量回路宜选择稀相床温差作为被控变量以保证系统的安全运行,但会显著地增加操作成本,因此应避免助燃剂添加量处于欠量状况下的操作;当加载有适量助燃剂时,装置仅可以选择再生器出口烟气氧含量作为被控变量;而当助燃剂添加量比较充足时,再生器出口烟气氧含量与二密相床再生温度均可作为被控变量,此时更宜选择烟气氧含量以保证较大范围助燃剂添加量下控制系统的连续运行。更多还原

【Abstract】 CO combustion promoters are added manually and periodically in Fluid Catalytic Cracking units, which belongs to the batch operation of continuous processes, so the amount of added CO promoters is of both the characteristics of parameters and variables. The combustion air flow rate matching the amount of added CO promoters is a continuous manipulated variable for CO combustion. Based on the comparisons including steady-state sensitivity and dynamic control effect among the potential controlled variables which include the temperature difference of dilute-phase fluidized bed in regenerator, oxygen content in flue gas and dense bed temperature in regenerator, the following conclusions can be found. The controlled variable should be the temperature difference of dilute-phase fluidized bed in regenerator in order to guarantee the safety when CO promoters are relatively inadequate, but the operation cost will be increased meanwhile, therefore, the operation in an inadequate range of CO promoters is not suggested. When the amount of CO promoters is moderate, the oxygen content in flue gas should be selected as controlled variable. Besides, when the system is charged with abundant amount of CO promoters, the oxygen content in flue gas or the dense bed temperature can be selected as controlled variable, but it is better to choose the oxygen content in flue gas as controlled variable for a more smooth control in a wide range of CO promoters.更多还原