Bio-oil steam reforming, partial oxidation or oxidative steam reforming coupled with bio-oil dry reforming to eliminate CO_2 emission

摘要

Biomass is carbon-neutral and utilization of biomass as hydrogen resource shows no impact on atmospheric CO_2 level. Nevertheless, a significant amount of CO_2 is always produced in biomass gasification processes. If the CO_2 produced can further react with biomass, then the biomass gasification coupled with CO_2 reforming of biomass will result in a net decrease of CO_2 level in atmosphere and produce the chemical raw material, syngas. To achieve this concept, a "Y" type reactor is developed and applied in bio-oil steam reforming, partial oxidation, or oxidative steam reforming coupled with CO_2 reforming of bio-oil to eliminate the emission of CO_2. The experimental results show that the reaction systems can efficiently suppress the emission of CO_2 from various reforming processes. The different coupled reaction systems generate the syngas with different molar ratio of CO/H_2. In addition, coke deposition is encountered in the different reforming processes. Both catalysts and experimental parameters significantly affect the coke deposition. Ni/La_2O_3 catalyst shows much higher resistivity toward coke deposition than Ni/Al_2O_3 catalyst, while employing high reaction temperature is vital for elimination of coke deposition. Although the different coupled reaction systems show different characteristic in terms of product distribution and coke deposition, which all can serve as methods for storage of the carbon from fossil fuels or air.