Study On Directional Solvolysis Liquefaction For Forestry Biomass

Lignocellulosic biomass is an ideal alternative ti traditional energy because of its various anvantages such as abundance,nonpollution,geographically ubiquitous,potentially cheap,converting liquid fuel directly which is incomparable among the resources.It consists of holocellulose and lignin.Solvolysis reaction is an important thermochemical conversion technology for value-added chemicals from lignocellulosic biomass.In traditional sovolysis reaction,biomass was decomposed at a “black box” model.Most of studies focus on improving the yields and the fuel properties of liquefied products,ignoring the molecular transformation pathways of biomass（holocellulose and lignin）and leading to production of unpredictable oxygenated compounds.There are nearly 300 oxygenated compounds in pyrolytic oils,but each only accounts for a small portion,which leads difficulties in separation and upgrading process.The objective of this study was to explore the relationship between the anatomy structure of biomass and the reaction mechanism of sovolysis,which contributes to discover a selective reaction pathway for the formation of high quality liquefied products that benefit for further upgrading process.Bamboo,poplar（hardwood）and masson pine（softwood）are chosen as raw materiais for the liquefaction experiment.Liquefaction reaction has reacted in different reactionintensity,respectively: 120 ℃(P_max=0.8 MPa),140 ℃(P_max=1.3 MPa),160 ℃(P_max=2.2 MPa),180 ℃(P_max=3.2 MPa),200 ℃(P_max=4.8 MPa),220 ℃(P_max=6.5 MPa).The productions are methyl glycoside and phenolics.They are tested by Gas Chromatography-Mass Spectrometry（GC-MS）,High Performance Liquid Chromatography（HPLC）.The liquefaction residues are tested by X-ray Diffraction（XRD）,Scanning Electron Microscope（SEM）,Fourier Infrared Spectrum（FTIR）,Thermo-Gravimetric（TG-DTG）.The main results are summarized as follows:（a）The laws and the optimal reaction conditions of liquefaction reaction of lignocellulosic biomass were all determined.Researchs shown that the heating voltage and the stirring speed under certain conditions,m raw materials: mCH3 OH = 1:12,sulfuric acid 2.5%（based on raw materials never dry weight）,10 mins under time,liquefaction conversion increases as the temperature ncreases during 120-220 ℃.The maximum liquefaction conversion is 91.10%,87.55% and 65.15% of bamboo,poplar,masson pine liquefaction reaction respectively when the reaction temperature is 220 ℃.The maximum yield of methyl glucoside of bamboo and poplar liquefaction reaction are 87.83% and 57.75% respectively at 200 ℃,and masson pine’s is 40.85% at 220 ℃.The yield of phenolics of bamboo,poplar,masson pine liquefaction reaction were 45.43%,36.06%,25.14% at 220 ℃ respectively.The relationship of between liquefaction products and the dissolution of componentsof lignocellulosic biomass is studied: According to the classification for liquefaction products,it can get water-soluble substances,can get various phenolics,too.The yields ofmethyl glucoside of bamboo and poplar are increasing at 120-200 ℃,The decompositionof cellulose and hemicellulose are increasing as the temperatures is increasing.Methyl glucoside is unstable at 200 ℃ and 220 ℃.So,decomposition of hemicellulose and cellulose are at lower temperature,lignin’s decomposition temperatures happens at higher temperature.The yields of liquied products of masson pine are increasing at 120-220 ℃,the results indicates that the dissolution of components of masson pine at highest temperature.The law of dissolution of liquefied wood fiber structure is studied,it can provide basis for obtaining higher purity intermediate: The analysis for liquefaction residue by SEM and XRD shows that the relative crystallinity of residue is higher than raw materials,the reason is that the amorphous region of hemicellulose,cellulose and lignin are decomposed.The SEM test of resude of bamboo and poplar shows that raw material has completely turned into very small particles at 220 ℃,the 002 peak of residue of bamboo is disappearred at 220 ℃,and relative crystallinity of poplar liquefied residue decreased 12.86% compared with the raw material at 220 ℃.Pine masson liquefaction process is different from bomass and poplar,its fiber structure is more solid,its liquefaction are happened at higher temperature,the relative crystallinity liquefaction residue higher 24.11% than raw materials at 220 ℃.（b）The thermal instability of liquefied intermediate（methyl glycoside）are researched.The conditions are methanol as solvent,acid as catalyst,the five carbon decomposes at 140 ℃,and the main products are β-methoxy-2-furan ethanol and furfural.The stability of the methyl glucoside will reduce as temperatures continuing to rise and the extension of reaction time,and the species of products increased.Six carbon indican is decomposed initial is 180 ℃,the main product of levulinic acid methyl ester and 5-HMF.