Catalytic Pyrolysis Of Triglycerides For Liquid Biofuel

Compared with traditional biomass energy resources,triglycerides have gained intense attention for its simplicity and flexibility in storing and transporting as well as the high energy density.Catalytic pyrolysis of triglycerides has been thought as one of the most promising technologies for liquid biofuel.The pyrolysis of soybean oil has been studied in a self-made reactor under nitrogen atmosphere.The effects of pyrolysis temperature and feed rate have been studied over the yield and composition of the liquid products.The optimum pyrolysis temperature is 450°C and feed rate is 0.75ml·min-1.The pyrolysis liquid products were distilled and classified into gasoline fraction,diesel fraction and oil sludge according to the distillation temperature range of fossil fuel.The sum of gasoline fraction and diesel fraction was defined as biofuel in this paper.The maximum yield of biofuel 50.8%was achieved under the optimum operating conditions,and it mainly consisted of alkanes,alkenes and carboxylic acids.The catalytic pyrolysis of soybean oil has been studied using metal oxides as catalysts.The effect of catalyst types,catalytic pyrolysis temperatures and the mass ratio of catalysts to oil were studied on the base of the yields and composition of pyrolysis products.It was found that basic metal oxides CaO and MgO have good decarboxylation effects.And the acid value has been decreased from 80.8mgKOH·g-1 to 20.2 and 43.0mgKOH·g-1 in the presence of 10wt%CaO and 10wt%MgO respectively,moreover,the biofuel yield has increased from 50.8%to 54.2%and 58.4%respectively.With the increasing addition of CaO,the acid value of the pyrolysis liquid was decreased and the yield was increased.The biofuel yield was 55.6%and the acid value was 8.0mgKOH·g-1 in the presence of 20wt%CaO.Molecular sieves ZSM-5 and MCM-41 have been selected as catalysts for the catalytic pyrolysis of soybean oil in a tublar reactor.The effect of catalyst types,Si/Al ratio and metal modification catalysts on the liquid yield and composition were studied.Higher biofuel yield was gained in the presence of MCM-41,and the catalytic activity was enhanced by introducing Al into the framework.Catalyst La-Al-MCM-41 has a good deoxygenation result,and the pyrolysis liquid oil was characterized by a lower oxygen content(6.0%).The liquid product went throuth a deeper crack in the presence of Ni-Al-MCM-41,and the yield of biofuel has been increased to 57.9%.With the increasing of La content,the deoxygennation activity was enhanced,and the biofuel yield was also increased.The pyrolysis characteristics of soybean oil were investigated using thermogravimetric analysis-Fourier transform infrared spectrometer(TG-FTIR).The basic oxide CaO and the mesoporous molecular sieve MCM-41 were added into the soybean oil to study the catalytic pyrolysis characteristics.As a result,the final pyrolysis temperature was raised,and the main pyrolysis region was widened,as well as the maximum weight lose rate was decreased.The CaO had a good deoxygenated effect and the production of phenols would be restrained by MCM-41.