Steam Reforming Of Bio-oil For Hydrogen Production Over Ni-based Catalysts

Hydrogen is regarded as one of the most potential clean energy in the 21st century.Demand for hydrogen has been getting heavier as the rise of a hydrogen economy.At present,most hydrogen is produced by high temperature reforming of non-renewable fossil fuels such as coal,natural gas and naphtha from petroleum.However,this not only causes a lot of greenhouse gas emissions and environmental pollution,but also accelerates the shortage of fossil fuels.Biomass has the characteristics of carbon neutrality,and it has been considered as an alternative feedstock for hydrogen production due to its advantages of renewability,diversity,abundance and environmental friendliness.At present,there are two main methods for hydrogen production derived from biomass:biomass gasification and steam reforming of bio-oil from biomass pyrolysis.The cost of hydrogen production from biomass gasification is relatively higher due to the stricter requirements for production facilities and technology conditions.It is obvious that bio-oil with relatively higher energy density is easy to transport and store.Therefore,steam reforming of bio-oil is considered to be a feasible solution to industrialized hydrogen production in the future.The effect of replacement of ?-Al2O3 by La2O3 was studied on Ni catalysts for hydrogen production via acetic acid steam reforming.The La/(La+Al)weight ratio ranged from 0 to 1 in the catalyst support prepared by co-precipitation method.Over the Ni/La-3A1 catalyst(the La/(La+Al)weight ratio at 0.25),the carbon conversion and hydrogen yield reached 100%and 72.2%,respectively,which was obviously higher than other catalysts at 700 ?,S/C = 1 and LHSV = 10 h-1.The effects of S/C,LHSV and stability test were studied in detail over Ni/La-3Al catalyst,whose high activity maintained for more than 30 h.Ni/La-3Al catalyst was chosen to study the catalytic activity for typical single model compound and model compounds of bio-oil.It was found that the catalyst exhibited good activity at 700 ?:Hydroxyacetone completely converted with the hydrogen yield of 85.5%.Phenol had a slightly lower conversion of 90.5%and the hydrogen yield was 77.3%.Furfural conversion reached 95.0%with the hydrogen yield of 81.0%,model compounds conversion was 94.3%and the hydrogen yield achieved 80.3%.Meanehile,the catalytic activity for model compounds decreased about 25%after 15 h in the stability test of the catalyst.Ni supported on activated rice husk biochar with different handing methods was selected to investigate the catalytic reactivity during acetic acid steam reforming.Ni/BC4(biochar activated by KOH alkalization and HN03 reflux)catalyst performed best among all the catalysts,the carbon conversion and hydrogen yield achieved 91.2%and 71.2%,respectively.But in the stability test of the Ni/BC4 catalyst,the reactivity with the carbon conversion more than 80%and hydrogen yield no less than 60%maintained only for 325 min,indicating that the catalytic stability of Ni supported on activated biochar needs to be improved.