The whole margin of a chemical process can be evaluated by the economic benefits of operation optimization

and based on steady-state optimization and dynamic optimization it can be further divided into control margin for dynamic operation and process margin for achievable economic benefits

both of which are relevant to control performance of the chemical process. In this paper

multi-objective dynamic optimization was implemented for a chemical process with design margin

whose optimization objectives were the achievable economic benefits of operating point and the control performance of dynamic process. The control structure described by 0-1 variables and control parameters were the optimization variables to form a mixed-integer dynamic optimization. Constrained NSGA-Ⅱ was used to solve the multi-objective dynamic optimization problem. Based on the Pareto optimal solution set

the relationship between control margin

process margin and control performance was analyzed. The case study of FCCU showed that

for a chemical process with design margin

when control performance was improved

the process would need more control margin but less process margin

which meant less achievable economic benefits from operation optimization. Through the trade-off between control margin and process margin

an optimum operating point and control scheme could be found to fulfill both process and control demand.