Experimental Study On Two-stage Catalytic Steam Reforming Of Bio-Oil

Steam catalytic reforming of bio-oil is one of the promising technologies of bio-oil application.Ni-based catalysts are widely used in bio-oil reforming for hydrogen or synthesis gas due to the high activity and low cost.However,Ni-based catalysts have the disadvantage of deactivation because of carbon deposit.Many researches have been launched for catalyst modification and process optimization and some progress have been achieved in solving this problem.Inspired by the two-stage reaction scheme,in this paper a two-stage catalytic steam reforming of bio-oil scheme has been put forward combining low-temperature pre-reforming and high-temperature Ni-based catalytic reforming.Pre-reforming can improve the effect of Ni-based catalyst reforming bio-oils in an economical and energy-saving way.In order to study the influence of inexpensive and readily available Fe/bio-char pre-reforming catalysts on the reforming effect,the different combinations of Fe/bio-char and Ni-Ca/?-Al₂O₃ catalysts were set up with pre-reforming temperature from 350 to 600?.The preduced tars were analysed with UV spectrophotometer?UV?and gas chromatography-mass spectrometry?GC-MS?while the gas products were analysed with gas chromatography?GC?.In addition,in order to explore the effect of Fe/bio-char pre-reforming on the catalytic activity of Ni-based catalysts,the spent Ni-based catalysts from different catalytic reforming reactions were evaluated in the same steam reforming process as fresh catalysts.The catalysts before and after the reaction have been characterized.The effect of Fe/bio-char as pre-reforming catalyst on the two-stage reforming progress was studied on a scheme of Ni based catalytic steam reforming of bio-oil.Ni-Ca/?-Al₂O₃catalyst was used on the second stage at high temperature while Fe/bio-char catalyst was put on the first stage where the temperature was relatively low?350-600??.Different combination schemes of two catalysts were investigated.The produced tars were characterized with ultraviolet?UV?fluorescence spectroscopy and GC-MS while the produced gases were characterized with GC.The results indicated that significant portions of naphthalenes and polycyclic aromatic compounds in the volatiles from the first stage reforming could turn into furans,Phenols and non-aromatics with the present of Fe/bio-char.The optimized components of volatiles could facilitate the performance of Ni based catalyst on the second stage and increase the syngas yield during the whole reforming process.In addition,Fe/bio-char showed great effect on restraining the coke formation on Ni based catalyst at high first-stage temperature?550-600??.During the two-stage reforming reaction of bio-oil,the catalytic activity of Ni-based catalysts especially the ones prepared at low pre-reforming temperatures has increased.