Single-objective and multiobjective designs for hydrogen networks with fuel cells

Hydrogen network synthesis has always been a popular cost-reduction measure adopted in the petroleum refining industry. Although several mixed-integer nonlinear programming models have already been developed in the past to produce cost-optimal designs, not all relevant units were considered in these studies. In addition, a realistic hydrogen network should clearly be configured on the basis of more than one criterion so as to address both economic and environmental concerns. To circumvent these drawbacks of the available methods, additional unit models for fuel cells and steam reforming plants are incorporated in a comprehensive mathematical program with two objective functions, that is, the total annual cost (TAC) and the global CO₂ emission rate, in the current studies. The trade-off issues between cost reduction and pollution control are addressed by establishing the Pareto front accordingly. Two examples are presented in this paper to demonstrate the feasibility and effectiveness of the proposed approach.