Investigation On Biomass Fast Pyrolysis And Steam Gasification Of Biomass Char

It is not only a key technique of solution to China energy crisis, but also a hot area of biomass utilization techniques for bio-oil production from biomass fast pyrolysis. However, most researches were focused on increasing main product, bio-oil yield, and utilization of biomass char and syngas attracted few attentions. Therefore, Efficiency of traditional fast pyrolysis technique is low. In order to improve biomass utilization efficiency, integrated utilization should be considered.In this paper, a technique route of changing biomass char into hydrogen-rich gases by steam gasification process was introduced. Subsequently hydrogen was used as material for bio-oil upgrading and utilization efficiency was improved as a result. At the same time biomass material should be pre-cracking to guarantee heat transfer rate between material particles and improve bio-oil yield. In this paper, biomass materials were cracked below 250μm by secondary cracking technique from Clean Production Lab of School of.Environmental Science and Technology of Huazhong University of Science and Technology.In this paper, fast pyrolysis characteristic of pine sawdust and cyanobacterial blooms were investigated in a homemade reactor, while final pyrolysis temperature, heating rate, particle size on products distribution and composition were evaluated. The results showed that proper final pyrolysis temperature, higher heating rate, smaller particle size and proper nitrogen flow rate were beneficial for bio-oil production, and bio-oil yield obtained maximum at final pyrolysis temperature of 500℃, particle size of below 0.25mm, reached 42.97% and 54.97%, respectively. In addition, the results illustrated cyanobacterial blooms bio-oil obtained higher heat value than pine sawdust bio-oil, which achieved at optimized condition.Hydrogen required for material of bio-oil hydrotreatment can obtain by steam gasification of biomass char. Therefore, steam gasification experiments of biomass char were carried out in fixed-bed reactor, and effects of gasification temperature, steam flow rate, particle size of biomass char and solid residence time on dry gases yield and carbon conversion efficiency (CCE) were studied. The results demonstrated that pine sawdust and cyanobacterial blooms appeared the samilar gasification characteristics. The results also suggested higher gasification temperature, longer solid residence time, proper steam flow rate and particle size were favored gasification process, and effect of particle size became more and more negligible with the increase of gasification temperature, and effect of particle size on dry gas yield, CCE and gases composition were negligible at temperature above 750℃. Moreover, solid residence time had no influence on gases composition. At gasification of 850℃, steam flow rate of 1.24g/min and solid residence time of 15 min, dry gas yield reached 2.44Nm3/kg,95.78% and 1.84Nm3/kg,98.82%In order to investigate possibility of bio-oil production from biomass fast pyrolysis and hydrogen production from by-product of biomass fast pyrolysis, pilot experiments were carried out on a integrated apparatus of biomass fast pyrolysis, biomass char steam gasification and pyrolysis gases catalytic reforming, and micron pine sawdust was material. Experimental results suggested the apparatus was qualified for bio-oil and hydrogen production.