Process design and analysis of a net-zero carbon emissions hydrocracking unit integrating co-processing technique with green hydrogen and electricity

To mitigate carbon emissions from refineries, it is feasible to integrate established technologies such as green hydrogen, green electricity, bio-gas, and bio-oil co-processing into hydrocracking (HC) units. To clarify the contribution of these technologies to carbon reduction in HC units, three scenarios are proposed: Scenario 1 involves coupling green hydrogen and green electricity with HC units; Scenario 2 builds upon Scenario 1 by incorporating bio-gas; and Scenario 3 integrates co-processing technology into Scenario 1. The carbon emissions of the three scenarios are analyzed and compared based on the life cycle concept. The results show that for traditional HC units, carbon emissions at the input reaches 876.98 t/h, with vacuum gas oil and hydrogen constituting the majority at 96.7%. Under Scenario 1, carbon emissions at the input of the HC unit are reduced by 45.44 t/h, whereas Scenario 2 yields a reduction of 52.61 t/h. Remarkably, Scenario 3 achieves a substantial reduction of 272.56 t/h. The sensitivity analysis results indicate that carbon emissions are most sensitive to the bio-oil co-processing ratio and least sensitive to the penetration ratio of green electricity. Therefore, the adoption of co-processing technology is deemed most effective to reduce carbon emissions from HC units.