マトリックス法を用いた製油所副生水素の環境負荷分析

抄録

In recent years, hydrogen is expected as an attractive energy to achieve a low-carbon society. By-product hydrogen in oil refinery is one of the promising resources to produce hydrogen. It is needed to evaluate an environmental burden, especially CO₂ emission, of the by-product hydrogen. Analysis of the environmental burden in oil refinery is complicated because manufacturing processes in oil refinery have some recurrent flows. A matrix method is useful to analyze consistently environmental burdens on refinery processes including recurrent flows. In this study, the method is applied to investigate CO₂ emissions of by-product hydrogen in oil refinery in Japan. The emission is analyzed for two different hydrogen concentration of off-gas. The effect of changing feedstock of hydrogen production unit(HPU) is analyzed from LPG of an internal production material to natural gas of an external raw material. The result shows that most of CO₂ burdens emitted from some processes which require a lot of heat energy in the refinery. The study also estimates CO₂ emissions of the by-product hydrogen, which is about the same amount as that of the gasoline.