Based on process characteristics and operation economic demands of heavy oil catalytic pyrolysis in two-stage riser

a multi-objective optimization model

which attempted to maximize yields of propylene and gasoline as well as to minimize yield of dry gas simultaneously

was developed with consideration of process principle model and various constraints. The model was solved by a standardized normal constraint method to formulate a complete set of uniformly distributed Pareto-optimal solutions. Numerical simulations show that the multi-objective optimization could comprehensively and quantitatively describe optimal trade-off among yields of propylene

gasoline and dry gas

as well as influence of operation variables and constraints on product distribution

which could offer guidelines for optimal operation of TMP process.