Showing papers on "Pyrolysis published in 2008"
TL;DR: Biochars, produced by pyrolysis of pine needles at different temperatures, were characterized by elemental analysis, BET-N2 surface areas and FTIR, and Sorption isotherms of naphthalene, nitrobenzene, and m-dinitrobenZene from water to the biochars were compared.
Abstract: The combined adsorption and partition effects of biochars with varying fractions of noncarbonized organic matter have not been clearly defined. Biochars, produced by pyrolysis of pine needles at different temperatures (100-700 degrees C, referred as P100-P700), were characterized by elemental analysis, BET-N2 surface areas and FTIR. Sorption isotherms of naphthalene, nitrobenzene, and m-dinitrobenzene from water to the biochars were compared. Sorption parameters (N and logKf) are linearly related to sorbent aromaticities, which increase with the pyrolytic temperature. Sorption mechanisms of biochars are evolved from partitioning-dominant at low pyrolytic temperatures to adsorption-dominant at higher pyrolytic temperatures. The quantitative contributions of adsorption and partition are determined by the relative carbonized and noncarbonized fractions and their surface and bulk properties. The partition of P100-P300 biochars originates from an amorphous aliphatic fraction, which is enhanced with a reduction of the substrate polarity; for P400-P600, the partition occurs with a condensed aromatic core that diminishes with a further reduction of the polarity. Simultaneously, the adsorption component exhibits a transition from a polarity-selective (P200-P400) to a porosity-selective (P500-P600) process, and displays no selectivity with P700 and AC in which the adsorptive saturation capacities are comparable to predicted values based on the monolayer surface coverage of molecule.
1,449 citations
TL;DR: In this article, a review of pyrolysis has been presented, where various types of pyrotechnics have been discussed in detail including slow, fast, flash and catalytic processes.
Abstract: Demand for energy and its resources, is increasing every day due to the rapid outgrowth of population and urbanization. As the major conventional energy resources like coal, petroleum and natural gas are at the verge of getting extinct, biomass can be considered as one of the promising environment friendly renewable energy options. Different thermo-chemical conversion processes that include combustion, gasification, liquefaction, hydrogenation and pyrolysis, have been used to convert the biomass into various energy products. Although pyrolysis is still under developing stage but during current energy scenario, pyrolysis has received special attention as it can convert biomass directly into solid, liquid and gaseous products by thermal decomposition of biomass in absence of oxygen. In this review article, the focus has been made on pyrolysis while other conventional processes have been discussed in brief. For having better insight, various types of pyrolysis processes have been discussed in detail including slow, fast, flash and catalytic pyrolysis processes. Besides biomass resources and constituents, the composition and uses of pyrolysis products have been discussed in detail. This review article aim to focus on various operational parameters, viz. temperature and particle size of biomass and product yields using various types of biomasses.
1,061 citations
TL;DR: In this paper, the authors evaluated the agronomic potential of biochar produced from poultry litter, peanut hulls, and pine chips produced at 400°C and 500°C with or without steam activation.
Abstract: The removal of crop residues for bio-energy production reduces the formation of soil organic carbon (SOC) and therefore can have negative impacts on soil fertility. Pyrolysis (thermoconversion of biomass under anaerobic conditions) generates liquid or gaseous fuels and a char (biochar) recalcitrant against decomposition. Biochar can be used to increase SOC and cycle nutrients back into agricultural fields. In this case, crop residues can be used as a potential energy source as well as to sequester carbon (C) and improve soil quality. To evaluate the agronomic potential of biochar, we analyzed biochar produced from poultry litter, peanut hulls, and pine chips produced at 400°C and 500°C with or without steam activation. The C content of the biochar ranged from 40% in the poultry litter (PL) biochar to 78% in the pine chip (PC) biochar. The total and Mehlich I extractable nutrient concentrations in the biochar were strongly influenced by feedstock. Feedstock nutrients (P, K, Ca, Mg) were concentrated in the biochar and were significantly higher in the biochars produced at 500°C. A large proportion of N was conserved in the biochar, ranging from 27.4% in the PL biochar to 89.6% in the PC biochar. The amount of N conserved was inversely proportional to the feedstock N concentration. The cation exchange capacity was significantly higher in biochar produced at lower temperature. The results indicate that, depending on feedstock, some biochars have potential to serve as nutrient sources as well as sequester C.
852 citations
TL;DR: In this paper, Van Soest's method was performed to extract lignin from different species of biomass, including fir and birch lignins, and the microstructure was studied by a Fourier transform infrared spectrometry.
786 citations
TL;DR: In this article, the main kinetic features of biomass pyrolysis, devolatilization, and the gas phase reactions of the released species are analyzed in a detailed manner.
Abstract: This paper analyzes the main kinetic features of biomass pyrolysis, devolatilization, and the gas phase reactions of the released species. Three complex steps are faced in sequence: the characterization of biomasses, the description of the release of the species, and finally, their chemical evolution in the gas phase. Biomass is characterized as a mixture of reference constituents: cellulose, hemicellulose, and lignin. This assumption is verified versus experimental data, mainly relating to thermal degradation of different biomasses. Devolatilization of biomasses is a complex process in which several chemical reactions take place in both the gas and the condensed phase alongside the mass and thermal resistances involved in the pyrolysis process. A novel characterization of the released species is applied in the proposed devolatilization models. The successive gas phase reactions of released species are included into an existing detailed kinetic scheme of pyrolysis and oxidation of hydrocarbon fuels. Compa...
636 citations
TL;DR: It is reported that gasoline-range aromatics can be produced from solid biomass feedstocks in a single reactor at short residence times (less than 2 min) and intermediate temperatures (400–600 8C) by a method the authors call catalytic fast pyrolysis.
Abstract: Owing to its low cost and large availability, lignocellulosic biomass is being studied worldwide as a feedstock for renewable liquid biofuels. Lignocellulosic biomass is not currently used as a liquid fuel because economical processes for its conversion have not yet been developed. Currently, there are several routes being studied to convert solid biomass into a liquid fuel which involve multiple steps thus greatly increasing the cost of biomass conversion. For example, ethanol production from lignocellulosic biomass involves multiple steps including pretreatment, enzymatic or acid hydrolysis, fermentation, and distillation. Dumesic and co-workers have demonstrated that diesel-range alkanes can be produced by aqueous-phase processing (APP) of aqueous carbohydrate solutions at low temperatures (100-300 8C). APP first requires that solid lignocellulosic biomass be converted into aqueous carbohydrates, which would require pretreatment and hydrolysis steps. At high temperatures (~800 8C), Dauenhauer et al. have shown that solid biomass can be reformed to produce synthesis gas through partial oxidation in an autothermal packed bed reactor over Rh catalysts. The ideal process for solid biomass conversion involves the production of liquid fuels from solid biomass in a single step at short residence times. Herein, we report that gasoline-range aromatics can be produced from solid biomass feedstocks in a single reactor at short residence times (less than 2 min) and intermediate temperatures (400–600 8C) by a method we call catalytic fast pyrolysis. Fast pyrolysis involves rapidly heating biomass (500 8Cs ) to intermediate temperatures (400–600 8C) followed by rapid cooling (vapor residence times 1–2 s). Fast pyrolysis produces a thermally unstable liquid product called bio-oil, which is an acidic combustible liquid containing more than 300 compounds. Bio-oils are not compatible with existing liquid transportation fuels including gasoline and diesel. To use bio-oil as a conventional liquid transportation fuel, it must be catalytically upgraded. As we show here, introduction of zeolite catalysts into the pyrolysis process can convert oxygenated compounds generated by pyrolysis of the biomass into gasolinerange aromatics. Catalytic fast pyrolysis first involves pyrolysis of solid biomass (e.g. cellulose) into volatile organics, gases, and solid coke. The organics then enter the zeolite catalyst where they are converted into aromatics, carbon monoxide, carbon dioxide, water, and coke. Inside the zeolite catalyst, the biomassderived species undergo a series of dehydration, decarbonylation, decarboxylation, isomerization, oligomerization, and dehydrogenation reactions that lead to aromatics, CO, CO2, and water. The challenge with selectively producing aromatics is to minimize the undesired formation of coke, which can be from homogeneous gas-phase thermal decomposition reactions or from heterogeneous reactions on the catalyst. The overall stoichiometry for the conversion of xylitol and glucose into toluene, CO, and H2O is shown in Equation (1) (76 and 24% carbon yields) and Equation (2) (63 and 36% carbon yields), respectively. Oxygen must be removed from the biomass-derived species as a combination of CO (or CO2) and H2O when aromatics are produced. The maximum theoretical yield of toluene from xylitol and glucose is 76 and 63%, respectively, when CO and H2O are produced as by-products.
534 citations
TL;DR: The authors investigated four reference fuels and three low lignin Lolium Festuca grasses which were subjected to pyrolysis to produce pyroolysis oils, and found that the mineral matter had the dominate effect on pyropolylysis in compared to lignins content, in terms of pyroplysis yields for organics, char and gases.
499 citations
TL;DR: In this article, the authors present a review of the production and utilisation of liquids from the thermal processing of biomass and related materials to substitute for synthetic phenol and formaldehyde in phenol formaldehyde resins.
Abstract: This review covers the production and utilisation of liquids from the thermal processing of biomass and related materials to substitute for synthetic phenol and formaldehyde in phenol formaldehyde resins. These resins are primarily employed in the manufacture of wood panels such as plywood, MDF, particle-board and OSB. The most important thermal conversion methods for this purpose are fast pyrolysis and vacuum pyrolysis, pressure liquefaction and phenolysis. Many feedstocks have been tested for their suitability as sources of phenolics including hard and softwoods, bark and residual lignins. Resins have been prepared utilising either the whole liquid product, or a phenolics enriched fraction obtained after fractional condensation or further processing, such as solvent extraction. None of the phenolics production and fractionation techniques covered in this review are believed to allow substitution of 100% of the phenol content of the resin without impacting its effectiveness compared to commercial formulations based on petroleum derived phenol. This survey shows that considerable progress has been made towards reaching the goal of a price competitive renewable resin, but that further research is required to meet the twin challenges of low renewable resin cost and satisfactory quality requirements. Particular areas of concern are wood panel press times, variability of renewable resin properties, odour, lack of reactive sites compared to phenol and potential for increased emissions of volatile organic compounds.
485 citations
TL;DR: In this article, bagasse pith has been used as a raw material for the preparation of different activated carbons for the removal of reactive orange (RO) dye from aqueous solutions and batch adsorption experiments were performed as a function of initial dye concentration, contact time, adsorbent dose and pH.
445 citations
TL;DR: In this article, a continuous auger was used to produce bio-oil at 450 °C by fast pyrolysis in a continuously auger reactor, using four feed stocks: pine wood, pine bark, oak wood, and oak bark.
Abstract: Bio-oil was produced at 450 °C by fast pyrolysis in a continuous auger reactor. Four feed stocks were used: pine wood, pine bark, oak wood, and oak bark. After extensive characterization of the whole bio-oils and their pyrolytic lignin-rich ethyl acetate fractions by gas chromatography/mass spectrometry (GC/MS), gel permeation chromatography (GPC), calorific values, viscosity dependences on shear rates and temperatures, elemental analyses, 1H and 13C NMR spectroscopy, water analyses, and ash content, these bio-oils were shown to be comparable to bio-oils produced by fast pyrolysis in fluidized bed and vacuum pyrolysis processes. This finding suggests that portable auger reactors might be used to produce bio-oil at locations in forests to generate bio-oil on-site for transport of the less bulky bio-oil (versus raw biomass) to biorefineries or power generation units. The pyrolysis reported herein had lower heat transfer rates than those achieved in fluidized bed reactors, suggesting significant further impr...
445 citations
TL;DR: In this article, the pyrolysis of biomass from pine wood was carried out in a fluidized bed reactor at 450°C and different structures of acidic zeolite catalysts were used as bed material in the reactor.
TL;DR: In this paper, a carbon composite catalyst was developed for oxygen reduction in PEM fuel cells through high-temperature pyrolysis of Co-Fe-N chelate complex, followed by the chemical post-treatment.
TL;DR: In this article, the effect of pyrolysis temperature and activation hold time on textural and chemical surface properties of raw date stones and carbon materials produced are studied, as expected, the percentage yield decreases with increase of activation temperature and hold time.
TL;DR: In this article, the effects of pyrolysis temperature (350−600 °C), and biomass particle size (100−600 μm), on the yields and composition of bio-oil, gas, and char are reported.
Abstract: This paper presents an investigation of the production of crude bio-oil, char, and pyrolytic gases from the fast pyrolysis of mallee woody biomass in Australia. The feedstock was ground, sieved to several narrow particle size ranges, and dried prior to pyrolysis in a novel laboratory-scale fluidized-bed reactor. The effects of pyrolysis temperature (350−600 °C), and biomass particle size (100−600 μm), on the yields and composition of bio-oil, gas, and char are reported. In agreement with previous reports, the pyrolysis temperature has an important impact on the yield and composition of bio-oil, char, and gases. Biomass particle size has a significant effect on the water content of bio-oil. It is interesting to note that the temperature for maximum bio-oil yield, between 450 and 475 °C, resulted in an oil with the highest content of oligomers and, consequently, with the highest viscosity. Such observations suggest that the conventional viewpoint of pyrolyzing biomass at temperatures over 400 °C to maximize...
TL;DR: In this article, the chemical composition of bio-oil is compared with what is known about the compositions of these feedstocks, including switchgrass and alfalfa, by using GC-MS and HPLC.
Abstract: Bio-oils from the fast pyrolysis of switchgrass forage and two sets of alfalfa stems (from two stages of development—bud and full flower stages) have been analyzed by wet-chemical methods, GC-MS, and HPLC. The chemical composition of bio-oil is important because it may give insights into its quality, stability, or suitability for downstream upgrading. Pyrolysis experiments were conducted at 500 °C under a nitrogen atmosphere in 2.5 kg/h fluidized bed reactor. A total of 62 chemical species were positively identified in the liquids. Of the identified compounds, 27 have been quantified. The chemical compositions of the bio-oils are compared with what is known about the compositions of these feedstocks. While the compositions of the bio-oil from the two alfalfa stems were similar, there were numerous differences in the compositions of the alfalfa and switchgrass bio-oils. Noted are the higher levels of nitrogen, water, and aromatic hydrocarbons in bio-oils produced from alfalfa stems than from switchgrass an...
TL;DR: The homogeneous conditions and conditions for inhibiting char formation by phenol were elucidated and it was found that mixtures of phenol and lignin become homogeneous at 400-600 degrees C and high water densities of 428-683 kg/m3, corresponding to maximum pressures of 93 MPa.
TL;DR: In this article, a liquefaction process was proposed to depolymerize natural biopolymer lignin into a liquid bio-oil with a very low oxygen content, suitable as a blending component to be combined with conventional fossil fuels for motor fuel applications.
Abstract: This paper reports a novel liquefaction process that is capable of depolymerizing the natural biopolymer lignin into a liquid bio-oil with a very low oxygen content, suitable as a blending component to be combined with conventional fossil fuels for motor fuel applications. During the conversion, both depolymerization and removal of oxygen by formation of water occur in a single step. Formic acid serves as both the hydrogen donor and reaction medium in the pyrolysis/solvolysis process. Using an alcohol as cosolvent can improve the liquid yields and H/C ratios. Very little coke (5%) is produced. The liquids produced comprise two easily separable phases, where the lighter organic phase consists mainly of low molecular weight alkylphenols and C8−C10 aliphatics. The process is developed to be combined with ethanol production from lignocellulosic carbohydrates in a biorefinery concept aimed at converting all fractions of the wood into renewably sourced liquid fuels.
TL;DR: A review of the experimental and modeling study status of plasma-assisted pyrolysis is presented in this article with experimental validations to provide the current status of the study and to provide an overview of the current state of the research.
Abstract: Biomass pyrolysis is a process by which a biomass feedstock is thermally degraded in the absence of air/oxygen. It is used for the production of solid (charcoal), liquid ( tar and other organics) and gaseous products. These products are of interest as they are possible alternate sources of energy. The study of pyrolysis is gaining increasing importance, as it is not only an independent process, it is also a first step in the gasification or combustion process, and has many advantages over other renewable and conventional energy sources. Studies have been conducted on pyrolysis of biomass and other substances by several researchers. The actual reaction scheme of pyrolysis of biomass is extremely complex because of the formation of over a hundred intermediate products. Mode ling of pyrolysis includes chemical kinetics model, heat transfer model and mass transfer model. Various kinetic models, heat and mass transfer models reported in the literature and our previous study are reported in the present review with experimental validations to provide the current status of the study. Plasma pyrolysis provides high temperature and high energy for reaction as the reaction sample is rapidly heated up to a high temperature. This review also covers the experimental and modeling study status of plasma-assisted pyrolysis. (c) 2008 Society of Chemical Industry and John Wiley a Sons, Ltd
TL;DR: In this article, three structural parameters that influenced the catalytic site density on the carbon support were identified: (i) the average particle diameter of the pristine carbon black, dparticle, available from BET area measurements; (ii) the amount of disordered phase which is proportional to WD, the width at half maximum of the D peak in the Raman spectrum of pristine carbon; and (iii) the mean size of the graphene layers characterizing the graphitic crystallites in the carbon black La.
TL;DR: In this paper, a rhizome was catalytically pyrolysed at 500 °C using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) in order to investigate the effect of catalysts on bio-oil properties.
TL;DR: In this paper, the effects of methanol addition on some properties of the bio-oil were also investigated and the results indicate that the rice husk biooil is a valuable liquid fuel but with some undesired properties.
TL;DR: In this article, pyrolysis of sawdust and its three components (cellulose, hemicellulose and lignin) were performed in a thermogravimetric analyzer under syngas and hydrogen.
TL;DR: In this article, the authors obtained the very proper kinetic parameters (the distribution curve of activation energy, f(E), and the activation energy dependent frequency factor, k0(E)) of biomass pyrolysis by utilizing the distributed activation energy model (DAEM) proposed by Miura and Maki.
TL;DR: This low-cost local plant, which was pyrolyzed and treated chemically with a 50% zinc chloride solution, to remove methylene blue and iodine may also prove useful for the removal of large organic molecules as well as potential inorganic contaminants.
TL;DR: In this paper, pyrolyzed porphyrins were investigated for oxygen reduction electrocatalysis, and steady state polarization curves were obtained using gas diffusion type electrodes in 0.5 m sulfuric acid and membrane electrode assembly (MEA) configurations under working PEM fuel cell conditions.
TL;DR: In this paper, two modified carbons were prepared by concurrently passing N 2 during pyrolysis of impregnated precursor with 50% H 3 PO 4 at 500°C, and post-heat treatment at 800°C for one carbon.
TL;DR: In this paper, eight inorganic additives were investigated in terms of their catalytic effects on the pyrolysis of pine wood sawdust was carried out by microwave heating at ca. 470°C under dynamic nitrogen atmosphere.
TL;DR: In this paper, the catalytic gasification of char from co-pyrolysis of coal and wheat straw was studied, which revealed higher gasification reactivity than that of coal, especially at high level of carbon conversion.
TL;DR: In this article, the authors investigated the fast pyrolysis of washed and unwashed empty fruit bunches (EFB), a waste of the palm oil industry, and found that the maximum ash content of washed feedstock that still yields homogenous liquids is less than about 3 mf
TL;DR: From the experimental results of specific surface area, zeta potential, and Cu2+ adsorption, the applications of solid residues in the water and wastewater treatment could be expected and might imply that microwave-induced pyrolysis of biomass waste has the potential to produce the H2-rich fuel gas.