Catalytic Steam Reforming Of Bio-oil For Hydrogen Production Based On Catalysts Development

The shortage of fossil fuels and concerns about environment protection have been bringing clean energy to be one of the topic issues around the world.Hydrogen is the most abundant element in the world and safely used in many industrial aspects.However,the most cost effective hydrogen production is still derived from natural gas steam reforming in industry,which emits large amounts of greenhouse gases.Biomass is the only renewable and carbon-neutral fuel resources in the world,and its derived fuels are considered as promising alternatives to fossil fuels.Steam reforming of bio-oil via biomass pyrolysis is one of the most important pathway for hydrogen production technologies from biomass.Acetic acid was chosen as the bio-oil model compound for steam reforming research.A comparative research on the catalytic activity of La2O3 and ?-Al2O3 supported Ni and Co catalysts was conducted.Supported on the special La2O3,Ni and Co showed higher H2 and CO2 selectivities due to the basicity and CO2 absorption characteristics compared with that on?-Al2O3.Moreover,Ni catalysts performed better than Co with the lower CH4 selectivity.Ni/La2O3 presented the best activity towards hydrogen production by totally converting acetic acid with a hydrogen yield of 80.9%at 700?,which was stably maintained for 38 h.Adopting Ni as the active metal,the catalyst support,byproduct biochar,were produced from fast pyrolysis with lauan biomass as raw material for the simulated bio-oil steam reforming research.The surface property of lauan biochar was enhanced by activation pretreatment and a lot of pore structure was observed in the activated biochar.The pore structure mainly centered below 10 nm and around 4 nm.After loading the active metal Ni,the developed catalyst displayed fine reaction activity.Especially at high temperature,the hydrogen yield achieved almost 100%at 700 ?.The ZhunDong coal ash with a special chemical composition was selected as a guard catalyst,and packed in front of nickel-based catalysts,in order to surpress the catalyst deactivation.During the reaction,the model compounds passed through coal ash and were preliminarily reformed to smaller molecular intermediates containing more CO and CH4,which were then further reformed over the following nickel-reforming catalyst.The improved reaction system succeeded in effectively converting the complex simulated bio-oil into hydrogen and exhibited high activity.For 15 wt.%Ni/?-Al2O3 catalyst with coal ash packing,the catalyst lifetime was extended to 8 h,with simulated bio-oil almost completely converted into hydrogen.In addition,coke deposition was suppressed.The ZhaoTong coal ash with a special chemical composition was selected as the catalyst support to load Ni catalyst,aiming at the development of a high performance and low cost catalyst for the hydrogen production via the catalytic steam reforming of renewable bio-oil.The conversion of acetic acid reached more than 95%and the hydrogen yield over 80%at 700?.The improvement of coal ash supported reforming catalysts were studied aiming at the efficient and inexpensive catalysts.By comparing the catalytic activities of different coal ashes based on the chemical composition,the effects of AAEM(alkali and alkaline earth metals)and Fe were confirmed and ZhunDong coal ash was selected.The catalytic activity of coal ash was effectively improved by adding Fe and increasing the hydrogen selectivity.With a lower Ni loading amount and catalyst cost,the superior activity of 10Ni-Fe/ZhunDong coal ash was maintained for 10 h,with the carbon conversion of acetic acid and H2 yield at 100%and 89.6%,respectively.