Multiobjective Optimization of Integrated Green Hydrogen and Biomass Supply Networks for Vacuum Gas Oil and Bio–Oil Coprocessing in Refinery Hydrocracking Units

Abstract

A multiobjective optimization framework is developed for the integrated green hydrogen and biomass supply network design of vacuum gas oil and bio–oil coprocessing in hydrocracking units, to support the low-carbon transformation of refinery hydrogenation processes. A mixed-integer nonlinear programming (MINLP) model is established with dual objectives of minimizing total annual cost (TAC) and total carbon emission (TCE). The ε-constraint method is adopted to generate the Pareto optimal frontier, and the evaluation function method is used to screen the optimal compromise solution balancing economic and environmental performance. Results show that the system achieves a maximum carbon emission reduction of 43.99% with only a 6.91% increase in TAC. The optimal compromise solution realizes a 39.74% TCE reduction with a negligible 0.16% TAC increase compared with the cost-optimal scenario. Green hydrogen related costs account for more than 74% of TAC, which is the dominant factor affecting the supply chain economy, while biomass transportation contributes over 60% of total emissions as the core emission reduction handle. In sensitivity analysis, the optimal supply chain configuration remains stable under fluctuations of green hydrogen price, and the effective implementation interval of carbon tax is 0–75 CNY/t CO2-eq. The proposed framework provides a quantitative basis for integrating renewable feedstocks into refinery.