Parallels between slow pyrolysis of Estonian oil shale and forest biomass residues

Different types of forest residual biomass, including pine wood, pine bark and spruce needles, and Estonian Kukersite oil shale, were parallelly subjected to the slow pyrolysis in similar conditions. A Fischer assay, modeling industrial semi-coking retorts, was used. Both the yield and the composition of liquid, gaseous and solid products of pyrolysis were determined. FTIR-spectroscopic and chromatographic methods were used to study products group and individual composition. Common and specific features in biomass and oil shale semi-coking have been described. In comparison with oil shale, the biomass yielded less oil and more gas. Specifically large amounts of reaction water and carbon dioxide were obtained in biomass pyrolysis resulting in formation of significantly deoxygenated liquid and solid products. Bio-oils can be distinguished by the solubility in conventional solvents. Kukersite shale oil and the benzene-soluble fractions of different bio-oils were characterized by similar group composition.     

催化热解生物质制取富氢气体的研究

在实验室自制的固定床反应器上, 考察了秸秆和锯屑的热解行为, 研究了热解产物分布特别是富氢气体的体积分数和产率, 着重研究了（5种金属氧化物和2种碳酸盐催化剂）的催化效果。结果表明,温度从500 ℃提高到850 ℃, 秸秆和锯屑的热解气产率分别从29.0%提高到40.6%, 35.0％提高到46.5%, 而对应的富氢气体的体积分数分别从41.2％提高到48.2%, 40.6％提高到47.0%；在5种金属氧化物中，Cr2O3显示了最好的催化效果，在750 ℃时对应的热解气产率与不使用催化剂相比提高了10％，富氢气体的体积分数提高了13％；催化剂（CaCO3和Na2CO3）占生物质的质量分数对热解气和富氢气体产率有明显的影响，当质量分数从0增加到30％时， 热解气和富氢气体产率增加较明显，而后其值的增加可以忽略， 因此推荐使用的催化剂质量分数为30％。     

不同载体Ni基催化剂生物质热解气甲烷化反应性能

采用浸渍法制备了Ni金属负载在不同载体(SiO2、ZrO2、CeO2、Al2O3和Al2O3-CeO2)表面形成的催化剂,研究了水蒸气和载体对生物质热解气甲烷化反应性能的影响。结果表明,随着水蒸气量的增加CO转化率逐渐增大,而甲烷选择性呈现先增加后降低的变化趋势,当nw ater/ngas比值为0.26时达到最大。载体Al2O3相比SiO2、ZrO2和CeO2具有更大的比表面积和Ni金属分散度,促进了生物质热解气甲烷化反应活性和选择性。相比于Ni-Al2O3催化剂,Al2O3-CeO2复合载体具有更多的镍金属负载量活性金属分散度,以及最好的低温甲烷化反应性能。在300℃的低温条件下,Ni-Al2O3-CeO2催化剂的CO转化率达到97%,CH4增长率达到110%。     

Continuous high-temperature fluidized bed pyrolysis of coal in complex atmospheres: Product distribution and pyrolysis gas

This study is devoted to investigating the continuous coal pyrolysis in a laboratory fluidized bed reactor that fed coal and discharged char continuously at temperatures of 750–980 °C and in N₂-base atmospheres containing O₂, H₂, CO, CH₄ and CO₂ at varied contents. The results showed that the designed continuous pyrolysis test provided a clear understanding of the coal pyrolysis behavior in various complex atmospheres free of and with O₂. The effect of adding H₂, CO, CH₄ or CO₂ into the atmosphere on the tar yield was related to the O₂ content in the atmosphere. Without O₂ in the atmosphere, adding H₂ and CO₂ decreased the pyrolysis tar yield, but the tar yield was conversely higher with raising the CO and CH₄ contents in the atmosphere. In O₂-containing atmospheres, the influence from varying the atmospheric gas composition on the product distribution and pyrolysis gas composition was closely related to the oxidation or gasification reactions occurring to char, tar and the tested gas.     

热裂解气相色谱法测定动物源性食品中敌百虫残留量

通过对热裂解气相色谱及气-质联用技术测定动物源性食品中敌百虫的探讨,建立了气相色谱进样口裂解产物的检测方法,并确定了气相色谱的主要分析条件(进样口280℃,DB-225毛细管色谱柱及FPD检测器)。样品前处理结合动物源性食品的特点,采用V(乙腈)∶V(水)=9∶1提取,乙酸锌水解除酯,并利用三氯化碳相转移的方式,建立了一套前处理方法。检测方法的回收率在80.7%~96.5%之间,RSD<5.5%,线性相关系数为0.9991,检出限为0.02mg/kg。该方法是按照我国关于兽药残留分析方法要求建立的,适合进出口及日常动物源性食品中敌百虫残留量的检测。     

Microwave pyrolysis of biomass

Because of the inherent moisture and large particle size of wood used in the Forest Products Industry, there has been regional interest in exploring the feasibility of processing wood, cellulose, and other such related materials using microwave dielectric-loss heating. A research project was undertaken in the late 1970’s to determine the important variables altering the rate of microwave-induced reactions of this polymeric material. The research presented dates from that period. Reaction proudcts were measured in detail and some optimization of the coupling of the microwave energy to the large particles was studied. Results and principal findings at the time of the study are presented in this paper as well as two papers by the author in the cited literature. Suggestions for future directions for this type of study are also presented.     

Fast pyrolysis of biomass

The development of viable fast pyrolysis processes for biomass and other carbonaceous feedstocks will offer significant advantages over conventional pyrolysis, flash pyrolysis and gasification processes with respect to product yield quality and flexibility. Fast pyrolysis is defined and related to other biomass thermochemical conversion processes in some detail. Brief references are made to corresponding coal, hydrocarbon and oil conversion research and development. Proposed mechanisms and chemical pathways are reviewed, potential products. product upgrading and product applications are identified. Fast pyrolysis research is reviewed on both the fundamental bench-scale level and the applied process development level.     

Determination of ergosterol as an indicator of fungal biomass in various samples using non-discriminating flash pyrolysis

Ergosterol is the major sterol constituent of most fungi. Since it is present in negligible amounts in higher plants, it can be used as a chemical marker for the presence of fungal contamination. A number of different ergosterol assays have been developed for the quantification of fungi in various samples. The paper presents the development of a new method for ergosterol detection based on the combination of non-discriminating flash pyrolysis with gas chromatography/mass spectrometry (Py-GC/MS). The design of the non-discriminating Py-GC/MS systems assures efficient transfer of high-molecular-weight pyrolysis products to the GC column for separation, followed by analyte detection by MS. The method was tested on different types of samples, including baker's yeast (Saccharomyces cerevisiae), moldy bread, indoor dust, and a leaf infected with powdery mildew. Ergosterol was detected in all these samples at levels ranging from approximately 4mg/g for the baker's yeast to approximately 6mug/g for household dust. The main benefits of non-discriminating pyrolysis over other techniques include elimination of the need for sample preparation, small sample size required and short analysis time.     

Introduction to pyrolysis of biomass

The pyrolytic properties of biomass are controlled by the chemical composition of its major components, namely cellulose, hemicelluloses and lignin and their minor components including extractives and inorganic materials. Pyrolysis of these materials proceeds through a series of complex, concurrent and consecutive reactions and provides a variety of products.Pyrolysis cellulose at lower temperatures below 300° C involves reduction in molecular weight, evolution of water, carbon dioxide and carbon monoxide and formation of char. On heating at higher temperature 300–500° C, the molecule is rapidly depolymerized to anhydroglucose units that further reacts to provide a XXXX pyrolyXXXXA: still higher temperatures, the anhydrosugar compounds undergo fussion, dehydration disproportionation and decarboxylation reaction to provide a mixture of low molecular weight gaseous and volatile produces. The composition of these produces and mechanism and kinetics of their production are reported.     

A pyrolysis/gas chromatographic method for the determination of hydrogen in solid samples

A method is described for the determination of hydrogen in solid samples. The sample is heated under vacuum after which the evolved gases are separated by gas chromatography with a helium ionization detector. The system is calibrated by injecting known amounts of hydrogen, as determined manometrically. The method, which is rapid and reliable, was checked for a variety of lunar soils; the limit of detection is about 10 ng of hydrogen.     

High-temperature gasification kinetics of biomass pyrolysis

The rate of gas formation from wood pyrolysis has been experimentally measured at temperatures from 300°C to 1000°C. The formation rate of specific product gases has been measured rather than the rate of solid weight loss. Even for very fine particles, the rate becomes heat transfer limited a: high temperatures. The product gases also approach thermodynamic equilibrium rapidly at high temperatures. The results are corrected using the experimental residence time distribution.     

Phosphorus catalysis in the pyrolysis behaviour of biomass

Phosphorus is a key plant nutrient and as such, is incorporated into growing biomass in small amounts. This paper examines the influence of phosphorus, present in either acid (H₃PO₄) or salt ((NH₄)₃PO₄) form, on the pyrolysis behaviour of both Miscanthus × giganteus, and its cell wall components, cellulose, hemicellulose (xylan) and lignin (Organosolv). Pyrolysis–gas chromatography–mass spectrometry (PY–GC–MS) is used to examine the pyrolysis products during thermal degradation, and thermogravimetric analysis (TGA) is used to examine the distribution of char and volatiles. Phosphorus salts are seen to catalyse the pyrolysis and modify the yields of products, resulting in a large increase in char yield for all samples, but particularly for cellulose and Miscanthus. The thermal degradation processes of cellulose, xylan and Miscanthus samples occur in one step and the main pyrolysis step is shifted to lower temperature in the presence of phosphorus. A small impact of phosphorus was observed in the case of lignin char yields and the types of pyrolysis decomposition products produced. Levoglucosan is a major component produced in fast pyrolysis of cellulose. Furfural and levoglucosenone become more dominant products upon P-impregnation pointing to new rearrangement and dehydration routes. The P-catalysed xylan decomposition route leads to a much simpler mixture of products, which are dominated by furfural, 3-methyl-2-cyclopenten-1-one and one other unconfirmed product, possibly 3,4-dihydro-2-methoxy-2H-pyran or 4-hydroxy-5,6-dihydro-(2H)-pyran-2-one. Phosphorus-catalysed lignin decomposition also leads to a modified mixture of tar components and desaspidinol as well as other higher molecular weight component become more dominant relative to the methoxyphenyl phenols, dimethoxy phenols and triethoxy benzene. Comparison of the results for Miscanthus lead to the conclusion that the understanding of the fast pyrolysis of biomass can, for the most part, be gained through the study of the individual cell wall components, provided consideration is given to the presence of catalytic components such as phosphorus.     

Inorganics distribution in bio oils and char produced by biomass fast pyrolysis: The key role of aerosols

Fast pyrolysis of biomass is a promising process for the preparation of bio-oil dedicated to energy production. Inorganic species originally present in biomass are known to induce problems such as bio-oil instability or deposits and fouling. However the mechanisms of inorganic species release during biomass pyrolysis into the raw bio-oils still remain unclear. The present work focuses on the determination of inorganic distribution in the products from wheat straw and beech wood fast pyrolysis performed in a fluidized bed. More specifically, the bio-oils are fractionated by using a series of condensers. The results show that more than 60 wt.% of the inorganic content of the overall bio-oil is contained in the aerosols. Several possible interpretations for this observation are discussed. It is likely that the inorganics are transported within the aerosols droplets and solid particles which are recovered in the bio-oils, either by mechano-chemical processes, or by entrainment of submicron intermediate liquid compound formed in the first steps of biomass fast pyrolysis.     

基于TG-FTIR的生物质催化热解试验研究

运用热重－傅里叶红外光谱联用技术(TG-FTIR),以麦秸为研究对象,探讨催化与非催化条件下生物质的热解挥发分析出特性,分析研究热解温度、催化剂种类对生物质热解主要析出产物的影响。通过热重TG和DTG曲线,获得了相关热解特性参数及动力学参数。结果表明,添加NiO和CaO存在两个失重峰,并促进麦秸热解反应进行,降低表观活化能,其中NiO对提高热解析出产率作用更显著。通过红外光谱对热解产物实时测量的分析表明,CO与CO2的析出与失重峰基本一致,而CH4的析出滞后于前两者。添加NiO和CaO有利于减少热解产物中的CO2的浓度,促进挥发分产物CO、CH4的生成。其中CaO更有利于生物质在温度800℃以下的热解性能改善,而NiO在800℃以上具有更好的催化作用。     

升温速率对生物质热解的影响

稻壳、稻秆及麦秆是中国主要的农业废弃物,如何综合、有效地利用这些农业废弃物进行资源化研究显得十分必要。热解是热化学转化中最为基本的过程,是气化、液化及燃烧过程的初始和伴生反应,对热解的分析有助于热化学转化过程控制及高效转化工艺的开发。目前,国内外对生物质及其组分的热解已有大量的研究,但对中国主要的农业废弃物稻壳、稻秆及麦秆的研究较少。本研究利用热重和红外联用技术深入研究了升温速率对三种典型生物质热解气体产物的影响,并对生物质的热解动力学及热解气体产物的析出规律进行实时在线分析。     

Chemometric detection of thermally degraded samples in the analysis of drugs of abuse with gas chromatography-Fourier-transform infrared spectroscopy

We present a chemometric procedure for the identification of the reference standard chromatographic peak in cases where the GC-FTIR analysis of commercial standards results in the appearance of more than one peak in the GC chromatogram. The procedure has been designed for phenethylamines, which represent the class with the largest number of individual molecules on the illicit drug market, and which are abused for their stimulant and/or hallucinogenic effects. The similarity between their vapor-phase FTIR spectra was modeled using principal component analysis (PCA), and class identity was assigned on the basis of soft independent modeling of class analogy (SIMCA). Additional peaks could be assigned to impurities in the standards, but most often they were artifacts formed during the GC-FTIR analysis of thermolabile or chemically unstable compounds. The latter case is illustrated by the identification of the reference standard chromatographic peak and FTIR spectrum of the potent psychotropic amphetamine derivative N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB), and by the elucidation of the chemical changes that occur in the molecule of MBDB due to thermal degradation.     

Comparison of contact and radiant ablative pyrolysis of biomass

Ablation characterizes the phenomena occurring when a solid, submitted to a high external heat flux density, gives rise to solids, liquids and/or gases that can be rapidly and continuously eliminated. Ablation can be exploited for carrying out the fast pyrolysis of materials such as biomass. This paper describes and compares, on a fundamental point of view, two methods of biomass ablative pyrolysis. In the first one, biomass is pressed against a hot surface (contact ablative pyrolysis). In the second one, biomass intercepts a concentrated radiation (radiant ablative pyrolysis). The comparison is made on the basis of the values of ablation thickness and velocity (derived from experiments and modelling), and of product fractions and compositions. The results can be very different in spite of the fact that biomass may be subjected to similar heat flux densities in both cases. The paper shows the advantages, drawbacks and complementarities of each technology.     

Gasification and catalytic conversion of biomass by flash pyrolysis

The influence of the water content, the gasification atmosphere and the action of inorganic catalysts on biomass pyrolysis is discussed. The pyrolysis conditions are characterized by a heating rate of a wood sample of 250–300°C/s and a residence time of the gas in the hot zone of the reactor of less than 1 s. Volumes, carbon contents, weights and energy balances at different temperatures (600–1000°C) are tabulated. The total volume of pyrolysis gas and the yields increase with increasing temperature and water content. This increase is especially due to the production of hydrogen. A large part of the gasified hydrogen comes from water. Water that has not been driven off from green wood is more gasifiable than water that is re-added or from the atmosphere. Three types of catalysts were tested: alumina, aluminosilicate material and nickel-supported catalyst. The results show that it is possible to control the distribution of gas species by controlling the water content of the biomass and selecting the catalyst on which the wood is pyrolysed. A nickel catalyst on mordenite seems to be very efficient in directing pyrolysis gas production towards synthesis gas.