Study On The Influence Of Pretreatment On Biomass Pyrolysis Characteristics

Biomass fast pyrolysis is of rapidly growing interest as it is perceived of offer significant logistical and hence economic advantages over other thermal conversion processes. Howerer, the reports on the influence of pretreatment on biomass pyrolysis characteristics are very limited. The main work is with an objective to understand the change in the products distribution and the elemental composition of the liquid oil obtained from pyrolysis, upon biological and chemical pretreatment of original biomass.Three strains of white-rot fungi were selected to biomass pretreatment, Dagui, FW and BP5. Strains Dagui and FW have apparent degradation selectivity for cellulose, whereas strain BP5 has no significant effect on the lignocellulose. Two different chemical processes used for biomass pretreatment are mild acid treatment with H2SO4 and mild alkali treatment with NaOH.Pyrolysis experiments were carried out for pretreatment biomass, and GC/MS was used to analyze the oil components. The study indicates the remarkable influence of pretreatment process on the products distribution and the composition of the liquid oil. However, it was found that the pretreatments do not improved the pyrolysis conversion of biomass.The Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Visible) and thermogravimetric analysis were used to study the changes of lignocellulose composition and structure. Compared to untreated biomass, the oil yields of the treated samples decreased to different degree. This could be explained by the degradation of cellulose and hemicellulose. The composition variation of oil products could be explained by the changes in the sturctrue of lignin. Due to white-rot fungi treatment, the mass losses of biomass reduced and the activation energy decreased too. Theoretically, biological pretreatment can save the energy consumption in biomass pyrolysis.The biological effects of white-rot fungus BP5 on corn stalks were initially studied. The low molecular extracellular substances produced by the strain BP5 were isolated by ultrafiltration. These low molecular weight compounds (less than 5000u) might be involved in the system of Fenton reaction and play an important role during delignification by white-rot fungus.In this paper pyrolysis experiments were carried out for biological and chemical treatment biomass, and the effects of pretreatment on biomass pyrolysis characteristics were initially discussed. It provides valuable references for pretreatment technology study of biomass pyrolysis in future. And also provides experimental evidences for the use of pretreatments for biomass pyrolysis (in situ upgrading) to generate high-quality oil.