Properties of Bio-oil from Fast Pyrolysis of Rice Husk

Physicochemical properties of bio-oil obtained from fast pyrolysis of rice husk were studied in the present work.Molecular distillation was used to separate the crude bio-oil into three fractions viz.light fraction,middle fraction and heavy fraction.Their chemical composition was analyzed by gas chromatograph and mass spectrometer（GC-MS）.The thermal behavior,including evaporation and decomposition,was investigated using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer（TG-FTIR）.The product distribution was significantly affected by contents of cellulose,hemicellulose and lignin.The bio-oil yield was 46.36%（by mass） and the yield of gaseous products was 27%（by mass）.The chemicals in the bio-oil included acids,aldehydes,ketones,alcohols,phenols,sugars,etc.The light fraction was mainly composed of acids and compounds with lower boiling point temperature,the middle and heavy fractions were consisted of phenols and levoglucosan.The thermal stability of the bio-oil was determined by the interactions and intersolubility of compounds.It was found that the thermal stability of bio-oil was better than the light fraction,but worse than the middle and heavy fractions.

In situ catalytic conversion of biomass fast pyrolysis vapors on HZSM–5

In situ catalytic conversion of biomass fast pyrolysis vapors was carried out on HZSM-5 with varying Si/Al ratios(ranging from 20 to 300) at 450 °C. The effects of Si/Al ratios of HZSM-5 zeolites on the distribution of biomass fast pyrolysis products and carbon deposits on catalysts were investigated. It was quite remarkable that after in situ catalytic conversion the amount of light phenols and hydrocarbons increased significantly while that of heavy phenols decreased a lot. Besides, the yield of cyclopentenones with relatively low oxygen content generally increased. It also indicated that as the Si/Al ratios of HZSM-5 increased, the amount of hydrocarbons and light phenols was found to drop greatly. The amount of carbon deposits was found to be around 8.5% with the exception of HZSM-5 with the Si/Al ratio of 300,which is much lower. Moreover, the carbon deposits yield dropped gradually with increasing Si/Al ratios of HZSM-5.Calcination of spent catalysts at 600 °C helped to restore the catalytic activity to a large extent despite a relatively lower efficiency of deoxygenation. Results indicated that HZSM-5 with relatively high acidity displayed great catalytic performance.

The effect of hydrothermal pretreatment on the structure and fast pyrolysis behaviors of Sheng Li lignite

The structure and composition of coal determine its fast pyrolysis characteristics,and the study of the relationship between them can play an important role in the efficient and clean utilization of coal.So,in this work,hydrothermal pretreatment was used to artificially change the structure and composition of Sheng Li(SL)lignite,which was used to investigate the influence of structural changes on pyrolysis.The physicochemical structure and composition of samples were characterized by X-ray diffraction,specific surface area and porosity analyzer,solid-state 13C nuclear magnetic resonance,Fourier transform infrared spectroscopy,and elemental analyzer.Pyrolysis experiments were carried out in a powderparticle fluidized bed reactor,and the distribution and composition of the pyrolysis products were analyzed.The gasification activity of char was investigated by thermogravimetric analysis with a CO_(2) atmosphere.The results show that hydrothermal pretreatment(HTP)can destroy the cross-linking structure of SL lignite,and affect its aromaticity,pore structure,functional group,and carbon structure to change the distribution and composition of pyrolysis products of SL lignite,especially the composition of tar.Finally,the structure–activity relationship between the structure,composition,and pyrolysis characteristics of coal was comprehensively studied.

Catalytic fast pyrolysis of Kraft lignin with HZSM-5 zeolite for producing aromatic hydrocarbons

Catalytic fast pyrolysis （CFP） of Kraft lignins with HZSM-5 zeolite for producing aromatics was investigated using analytical pyrolysis methods. Two Kraft lignins were fast pyrolyzed in the absence and presence of HZSM-5 in a Curie-point pyrolyzer. Without the catalyst, fast pyrolysis of lignin predominantly produced phenols and guaiacols that were derived from the subunits of lignin. However, the presence of HZSM-5 changed the product distribution dramatically. As the SiO2/ A1203 ratio of HZSM-5 decreased from 200 to 25 and the catalyst-to-lignin ratio increased from 1 to 20, the lignin- derived oxygenates progressively decreased to trace and the aromatics increased substantially. The aromatic yield increased considerably as the pyrolysis temperature increased from 500~C to 650~C, but then decreased with yet further increase of pyrolysis temperature. Under optimal reaction conditions, the aromatic yields were 2.0 wt.% and 5.2 wt.% for the two lignins that had effective hydrogen indexes of 0.08 and 0.35.

A review on ex situ catalytic fast pyrolysis of biomass

Catalytic fast pyrolysis （CFP） is deemed as the most promising way to convert biomass to transportation fuels or value added chemicals. Most works in literature so far have focused on the in situ CFP where the catalysts are packed or co-fed with the feedstock in the pyrolysis reactor. However, the ex situ CFP with catalysts separated from the pyrolyzer has attracted more and more attentions due to its unique advantages of individually optimizing the pyrolysis conditions and catalyst performances. This review compares the differences between the in situ and ex situ CFP operation, and summarizes the development and progress of ex situ CFP applications, including the rationale and performances of different catalysts, and the choices of suitable ex situ reactor systems. Due to the complex composition of bio-oil, no single approach was believed to be able to solve the problems completely among all those existing technologies. With the increased understanding of catalyst performances and reaction process, the recent trend toward an integration of biomass or bio-oil fractionation with subsequent thermo/biochemical conversion routes is also discussed.

Upgrading of biomass fast pyrolysis oil over a moving bed of coal char

Fast pyrolysis of sawdust(SD)and upgrading of the derived bio-oil*(water-free basis)over Shenmu bituminous coal char(SMC)were conducted in an integrated free fall pyrolyzer and moving bed upgrading reactor.The water soluble and heavy bio-oil*(THF soluble)yields decrease and the content of light bio-oil*(CH_(2)Cl_(2) soluble)increases significantly compared that without SMC despite the decrease of light bio-oil*yield.Chemical analyses of the light bio-oil*were performed using GC-MS and ^(1)H NMR techniques.The results show that during volatiles-char interaction,the SMC plays important roles in deoxygenation and denitrogenation.The role of SMC in the upgrading process was explored by BET,FT-IR and XRD characterization.The porous structure provides reaction active sites for the bio-oil upgrading.After volatiles-char interaction,the specific surface area of SMC decreases significantly and the carbon crystallite size increases.With increasing the char updating rate from 1 g/min to 4 g/min,the relatively fresh SMC surface leads to the increased active sites,the conversion of heavy bio-oil*is slightly promoted and the removal effects of heteroatoms(O,N)compounds in the light bio-oil*are enhanced.The changes in SMC specific surface area and microcrystalline size are weakened accordingly.

Catalytic hydrotreatment of alkaline lignin and its consequent influences on fast pyrolysis

The current state of lignin has been characterized by these three:(1)as one of the main components in lignocellulosic biomass with an abundant amount;(2)not be taken seriously but treated as a waste product;(3)underutilized due to a complex and stubborn structure.However,lignin can be a rich source for hydrocarbons and aromatic compounds when gives appropriate utilization.In this work,we have studied the hydrotreatment of alkaline lignin(AL)under relatively mild conditions and further investigated the characterization of hydrogenated lignin(HL),especially the behavior during fast pyrolysis.The recovery of the HL decreased with increasing reaction temperature from 60 wt.%to 41 wt.%in the range of 150-250℃.The hydrotreated products were analyzed using Elemental Analysis,FTIR(for HL)and GC-MS(for bio-oil).The HL samples were found to have a higher hydrogen/carbon atomic effective ratio(H/C_(eff) ratio)and a higher degree of saturation than AL.Compared to the internal structure of the lignin before and after hydrotreatment,the side chain groups were removed from AL during the process.After that,from the fast pyrolysis of HL,it was observed that more light hydrocarbons and aromatic compounds were formed than that of AL.Furthermore,fast pyrolysis in the hydrogen atmosphere revealed that more volatile fractions were released compared to the Helium atmosphere.The total olefins yield was increased for HL compared AL from 1.02 wt.%to 3.1 wt.%at 250℃for 7 hours.This study of HL is instructive to some extent for the industrial utilization of lignin.

Correlation between solubility parameters and recovery of phenolic compounds from fast pyrolysis bio-oil by diesel extraction

Fast pyrolysis bio-oils(fpBO)were extracted with two alternative commercial transportation fuels,hydrocarbon diesel and bio-diesel.The extraction of fpBO with commercial diesel fuel provided a yield of 4.3 wt%,but the yield increased significantly to 26.6 wt%when bio-diesel was the extractant.The molecular weight of fpBO before and after extraction were consistent with the loss of a more soluble,low molecular weight fraction from the crude fpBO.The relative energy difference(RED),based on the Hansen solubility parameter(HSP),is used to examine the extraction efficiency of specific compounds in the two different‘solvents’.Differences in the RED values could be used to rationalize differences in the partitioning of common fpBO phenolics.

Renewable p-Xylene Production by Co-catalytic Pyrolysis of Cellulose and Methanol

This work developed a one-step process for renewable p-xylene production by co-catalytic fast pyrolysis (co-CFP) of cellulose and methanol over the different metal oxides modified ZSM5 catalysts. It has been proven that La2O3-modified ZSM5(80) catalyst was an effective one for the production of biobased p-xylene. The selectivity and yield of p-xylene strongly depended on the acidity of the catalysts, reaction temperature, and methanol content. The highest p-xylene yield of 14.5 C-mol% with a p-xylene/xylenes ratio of 86.8% was obtained by the co-CFP of cellulose with 33wt% methanol over 20%La2O3-ZSM5(80) catalyst. The deactivation of the catalysts during the catalytic pyrolysis process was investigated in detail.The reaction pathway for the formation of p-xylene from cellulose was proposed based on the analysis of products and the characterization of catalysts.

Pyrolysis technologies for biochar production in waste management:a review

Pyrolysis is a thermal conversion process in the absence of air to derive energy components from the residues.Renewable-energy technologies will play a major role in addressing future challenges related to environmental safety and energy security.One of the many easily available renewable energy sources is biomass-an organic material that is thought to be carbon-neutral.Pyrolysis technology is a thermochemical process that can be used to produce useful products from biomass,such as biochar,bio-oil and combustible pyrolysis gases.The structure and relative product yield are impacted by the pyrolysis method employed.This article evaluates different approaches for biomass pyrolysis.Fast,slow and advanced pyrolysis methods using various pyrolyser reactors have been studied in the literature and are provided to increase the variety and use of these methods in upcoming studies and research.Slow pyrolysis can lead to increased ecological well-being,as it increases the amount of biochar produced using auger and rotary-kiln reactors.Rapid pyrolysis,mainly in fluidized-bed reactors with bubbling and rotating circulation,can be used to obtain bio-oil.Advanced pyrolysis methods offer a good probability of yielding great prosperity for specific applications.The selection of a pyrolysis process is based on the required output in terms of solid,liquid and gaseous fuels,and the parameter plays a crucial role in the pyrolysis performance.

Semi-Interpenetrating Novolac-Epoxy Thermoset Polymer Networks Derived from Plant Biomass

Bio-based phenol-formaldehyde polymer (BioNovolac) was developed by reacting molar excess of bio-oil/phenolwith formaldehyde in acidic medium. Glycidyl 3,5-diglycidoxybenzoate (GDGB), was prepared by directglycidylation of α-resorcylic acid (RA), a naturally occurring phenolic monomer. GDGB was crosslinked in thepresence of BioNovolac by anionic polymerization. Fourier transform infrared spectroscopy (FTIR) confirmedthe formation of semi-interpenetrating polymer networks. The glass transition temperature and moduli of biobasedcrosslinked systems were observed to increase with increasing GDGB content. Active chain density andmass retention measured by dynamic mechanical analysis (DMA) and Soxhlet extraction, respectively, indicated ahigh crosslink density of the cured networks. Scanning electron microscopy (SEM) images depicted thehomogeneity of the bulk phase. The preparation of bio-based epoxy-novolac thermoset network resulted inreduced consumption of petroleum-based chemicals.

Py-GC/MS study of lignin pyrolysis and effect of catalysts on product distribution

Fast pyrolysis is one of the most promising methods to convert lignin into fuels and chemicals.In the present study,pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS)was used to evaluate vapor phase product distribution of lignin fast pyrolysis.During the non-catalytic pyrolysis process,lignin was pyrolyzed at 400℃,500℃ and 600℃ respectively,finding that the highest yield of aromatic hydrocarbons was obtained at 600℃.Catalytic pyrolysis experiments were also conducted to investigate the effects of catalyst pore structure and acidity on the product distributions.Five different catalysts(HZSM-5,MCM-41,TiO_(2),ZrO_(2) and Mg(Al)O)were applied to lignin catalytic pyrolysis,and the catalytic performance was estimated by analyzing the pyrolytic products.The catalysts were characterized by using X-ray diffraction(XRD),BET,and NH3(CO_(2))temperature programmed desorption.Based on these characterizations,discussion was carried out to explain the formation of the produc distributions.Among the five catalysts,HZSM-5 exhibited the best performance on the formation of aromatic hydrocarbons.

Enhanced anaerobic digestion of corn stover by thermo-chemical pretreatment

In order to solve the problem of lignocellulose degraded speedily and efficiently in anaerobic digestion,the thermo-chemical pretreatment was applied to enhance biogas production from corn stover.Corn stover was thermo-chemical pretreated with a fluidized bed pyrolysis reactor at 180℃,200℃ and 220℃,respectively.Lignin degradations during pretreatment were 15.07%,32.57% and 33.31%,respectively.The Scanning Electron Microscope(SEM)images and Fourier Transform Infrared Spectroscopy(FTIR)spectra confirm that the thermo-chemical pretreatment can change the structure of corn stover and make lignin content decrease.The thermo-chemical pretreated corn stover was digested using a 2-L fermentation reactor.Experimental results showed thermo-chemical pretreatment could improve biodegradability and enhance biogas production.The highest total biogas production was 23319 mL for 20 d which was 10.0% higher than that of the untreated corn stover.

Life cycle assessment of biofuel production from microalgae cultivated in anaerobic digested wastewater

The whole process of biofuel production from Desmodesmus sp.EJ 8-10 cultivated in anaerobic digested wastewater(ADW)under the optimal temperature was evaluated by using the method of Life Cycle Assessment(LCA).The energy efficiency and environment emissions were under considerable for the corresponding parametric study.The functional unit was 1 kg microalgae.It was concluded that the harvest stage was responsible for the main energy consumption during the microalgal whole pyrolysis process.The energy conversion efficiency of the whole process was larger than 1,which indicated that the process was profitable.The environmental impact of the whole process was 1165.67 mPET2000,among which the primary impact on the environment was eutrophication that accounts for 57.36%,followed by photochemical ozone synthesis(22.56%),acidification(17.36%);and global warming(2.73%),respectively.

Research on combustion characteristics of bio-oil from sewage sludge

Combustion characteristics of bio-oil from sewage sludge were investigated using thermogravimetry(TG)andFourierTransform InfraredSpectroscopy(FT-IR)techniques.The combustion process could be divided into two weight loss stages.Light compounds volatilized and were oxidized in the first stage and the heterogeneous combustion between oxygen and heavy compounds happened in the second stage,which were confirmed by FT-IR technique.Most weight loss occurred in the first stage.The effect of heating rate was also studied and higher heatingrates were foundto facilitate the combustion process.The kinetic parameters of the two stages were calculated and the change of activation energy indicated higher heating rates benefited combustion.