三维有序大孔Fe_2O_3为载氧体的生物质热解气化实验研究

Biomass pyrolysis/gasification using three dimensional ordered macroporous(3DOM) Fe_2O_3 as an oxygen carrier

采用无皂乳液聚合法制备单分散聚苯乙烯(PS)微球,并以硝酸盐为原料、柠檬酸为络合剂制备前驱体溶液,通过浸渍和焙烧得到三维有序大孔(3DOM)Fe2O3,并通过SEM、XRD、BET和压汞仪对3DOM Fe2O3进行表征。采用热重-质谱联用的方法,以3DOM Fe2O3为载氧体,对生物质在氦气气氛下的热解气化进行研究,探讨3DOM Fe2O3载氧体在生物质热解气化过程中代替纯氧、富氧空气或水蒸气作为生物质气化剂的可能性,并与普通分析纯Fe2O3与生物质热解气化的实验结果进行对比,分析3DOM Fe2O3在提高载氧体反应活性方面的作用。结果表明,制备的3DOM Fe2O3呈现排列规整的三维有序多孔形貌,层与层间通过三维孔道相连,并呈交替排列。通过与分析纯Fe2O3的XRD谱图对比,发现制得的3DOM Fe2O3为纯Fe2O3,无其他杂质相的存在。热重-质谱分析结果表明,Fe2O3作为载氧体在高温段促成了生物质气化反应的发生。与分析纯的Fe2O3作对比,当载氧体为三维有序大孔结构时,生物质的最大失重率提高了7.1%,气化阶段的最大失重速率提高了0.29%/min,CO、CO2、CH4在高温段出现两个连续的析出峰。

Polystyrene spheres were prepared by soap free emulsion polymerization method, then three dimensional ordered macroporous （3DOM） oxides Fe203 were successfully prepared after impregnation and calcination using nitrates as raw materials and citric acid as complexing agent. The samples were characterized by the techniques of scanning electron microscopy （SEM）, X-ray diffraction （XRD）, BET and mercury porosimetry. Pyrolysis and gasification of biomass with Fe203 as oxygen carriers in helium atmosphere were carried out in a thermogravimetric analyzer coupled with mass spectrometry （ TG-MS ）. The possibility of 3DOM Fe203 functioning as gasification agent in biomass gasification substituted for pure oxygen, oxygen-enriched air or steam were investigated. Furthermore, a comparison experiment was carded out by using analytically pure Fe203 to analysis the high-performance of 3DOM Fe203. The characterization results showed that 3DOM Fe203 presented a three-dimensional ordered macroporous morphology, its tiers were arranged alternatively and connected through three-dimensional pore structures. By contrast with the XRD pattern of analytically pure Fe203. TG-MS results showed that Fe203 contributed to biomass gasification in high temperature stage. When used 3DOM Fe203 as oxygen carrier, the maximum weight loss and maximum weight loss rate raised 7.1% and 0.29%/min in the gasification stage, respectively, meanwhile two generation peaks of CO, CO2, and CH4 anoeared in the MS curves.