Fast co-pyrolysis of coal and biomass in a fluidized-bed reactor

Co-pyrolysis is one of the most promising options for the utilization of coal and biomass. Coal/biomass blends were prepared using Yilan subbituminous (YL) and corncob and the mass ratios of coal in mixtures varied between 0 and 100 %. Co-pyrolysis characteristics were investigated in a thermogravimetric analyzer from 303 to 973 K under the nitrogen flow of 100 mL min^?1. The co-pyrolysis residues were less than the sum simply added of the solid yields of individuals. With heating rate increased from 10 to 40 K min^?1, the residues decreased more severely compared to the expected under various blending ratios. For fast pyrolysis in fluidized-bed reactor, gas volumes and char yields of co-pyrolysis showed a significant linearity. But pyrolysis-oil yields were higher than the expected from the additive model when the YL blending ratios were less than 60 %. The co-pyrolysis evolved more H₂, CH₄, C₂ + C₃, and less CO than an additive pyrolysis process of individual fuel. The GC/MS results indicated that co-pyrolysis-oil contained more alcohols, ketones, aldehydes, or acids than that of individual fuel. All of that suggested the H/OH in volatiles produced from rapid pyrolysis of biomass transferred to the radicals of coal pyrolysis. The possible reaction mechanism also was provided in the paper.     

烟煤与生物质快速共热解产物特性分析

研究了烟煤(YL)分别与富含半纤维素的玉米芯(CB)和富含木质素的松木屑(SD)快速共热解产物产率和气体组成的变化规律。结果表明,烟煤与生物质共热解组分互相作用,造成共热解气、液、固相产率和气体组成的明显变化,且与生物质种类有关。相对于独立热解过程,玉米芯丰富的半纤维素造成热解水蒸气和CO₂浓度较高,且玉米芯中富含的K元素挥发迁移至煤焦表面,对热解半焦与水蒸气、CO₂的气化反应起到催化作用,反应生成的H₂和富氢组分易与热解生成的自由基结合,抑制自由基之间的缩聚反应,使得共热解气体和液体产率增加,而半焦产率减小。烟煤/松木屑共热解过程中,松木屑中富含的Ca元素在煤焦表面迁移,促进了松木屑热解液体在半焦表面裂解反应,生成CO₂、CO和富氢自由基等轻质组分,造成共热解半焦和液体产率降低而气体产率增加。热解产物半焦、焦油、水蒸气、CO₂之间的气化和裂解反应均产生富氢的次生组分,从而提高了共热解气体中CO和烃类气体产率,降低了H₂产率。     

原料对自由落下床中生物质与煤共热解行为的影响

在500～700℃和生物质混合比0～100％(质量分数)条件下,利用自由落下床反应器考察原料对生物质与煤共热解行为的影响.所用煤原料为大雁褐煤(DY)和铁法烟煤(TF),而生物质原料为农业废弃物秸秆(LS)和木材加工余料白松木屑(SD).结果表明,即使在自由落下床中停留时间短的条件下,生物质与煤共热解的协同效应仍然发生...     

Fast pyrolysis of rice straw,sugarcane bagasse and coconut shell in an induction-heating reactor

With the application of induction heating, a fast pyrolysis was used for producing valuable products from rice straw, sugarcane bagasse and coconut shell in an externally heated fixed-bed reactor. The effect of process parameters such as pyrolysis temperature, heating rate and holding time on the yields of pyrolysis products and their chemical compositions were investigated. The maximum yield of ca. 50% on the pyrolysis liquid product could be obtained at the proper process conditions. The chemical characterization by elemental (CHNO), calorific, Fourier transform infrared (FT-IR) spectroscopy and gas chromatography/mass spectrometry (GC–MS) showed that the pyrolysis liquid products contain large amounts of water (>65 wt.%), and fewer contents of oxygenated hydrocarbons composing of carbonyl groups, resulting in low pH and low heating values. The results were very similar to bio-oils obtained from other biomass materials. The residual solid (char or charcoal) was also characterized in the present study.     

The co-pyrolysis of flame retarded high impact polystyrene and polyolefins

The co-pyrolysis of brominated high impact polystyrene (Br-HIPS) with polyolefins using a fixed bed reactor has been investigated, in particular, the effect that different types of brominated aryl compounds and antimony trioxide have on the pyrolysis products. The pyrolysis products were analysed using FT-IR, GC–FID, GC–MS, and GC–ECD. Liquid chromatography was used to separate the oils/waxes so that a more detailed analysis of the aliphatic, aromatic, and polar fractions could be carried out. It was found that interaction occurs between Br-HIPS and polyolefins during co-pyrolysis and that the presence of antimony trioxide influences the pyrolysis mass balance. Analysis of the Br-HIPS + polyolefin co-pyrolysis products showed that the presence of polyolefins led to an increase in the concentration of alkyl and vinyl mono-substituted benzene rings in the pyrolysis oil/wax resulting from Br-HIPS pyrolysis. The presence of Br-HIPS also had an impact on the oil/wax products of polyolefin pyrolysis, particularly on the polyethylene oil/wax composition which converted from being a mixture of 1-alkenes and n-alkanes to mostly n-alkanes. Antimony trioxide had very little impact on the polyolefin wax/oil composition but it did suppress the formation of styrene and alpha-methyl styrene and increase the formation of ethylbenzene and cumene during the pyrolysis of the Br-HIPS.     

Copyrolysis of scrap tires with oily wastes

In this study, the conversion of hazardous wastes into liquid fuels was investigated. The pyrolysis of bilge water oil and oil sludge from ships, scrap tires and their blends was carried out at 400 and 500 °C in absence and presence of catalyst. A commercial fluid catalytic cracking catalyst and Red Mud were used as catalyst. Pyrolysis products were separated as gas, oil and char. The pyrolytic oils were characterized by using gas chromatography-mass selective detector (GC-MSD) and ¹H nuclear magnetic resonance (¹H-NMR). The effect of temperature and catalyst on the product distribution and the composition of oil from pyrolysis were investigated. Co-pyrolysis of scrap tire with oily wastes from ships produced oil that could be used as fuel, while its pyrolysis alone produced oil that could be used as a chemical feedstock. The results obtained in this study showed that co-pyrolysis of oily wastes with scrap tires could be an environmentally friendly way for the transformation of hazardous wastes into valuable products such as chemicals or fuels.     

Study of products yield of bagasse and sawdust via slow pyrolysis and iron-catalyze

In this paper, the via slow pyrolysis behavior of the bagasse and sawdust were studied at the different heating rates, the different iron-containing blend pyrolysis and the treatment temperature, the further understood for the pyrolysis of agricultural residues. The distribution of the products yield of the slow pyrolysis process, it is typically performed at temperature between 200 and 600 °C, the pyrolysis temperature increased, the bio-liquids and gas yields tended to increase, which at 400 °C was able to achieve maximum bio-liquids yields, the biochar yields tended to downward. For different heating rate, in the heating rate ranges for 80–100 W, the bio-liquids products yield curve increased from 44.5 wt% to 46.5 wt% for bagasse; the sawdust products yield increased from 41 wt% to 42.75 wt%. Iron-catalysts blend pyrolysis (0, 10, 25, 40 and 50 wt%), the bagasse bio-liquid yields respectively 56.25 wt% in the presence 50% iron-catalysts blend pyrolysis; the sawdust bio-liquid yields respectively 52.5 wt% in the presence 40% iron-catalysts blend. The pyrolysis process were calculated according to the kinetic mechanism were examined, the pyrolysis activation energy was between 6.55 and 7.49 kcal/mol for bagasse. Sawdust the pyrolysis activation energy was between 11.52 and 11.76 kcal/mol. Therefore, in this study a pyrolysis model of bagasse and sawdust thermal treatment may provide both agricultural and forestry transformation importance of resources.     

Utilization of camellia oleifera shell for production of valuable products by pyrolysis

Camellia oleifera shell is used as the feedstock to prepare the valuable products by pyrolysis using microwave heating at 400-800 °C. The yield of pyrolysis product is influenced by pyrolysis temperature, which indicates that high pyrolysis temperature promotes to generate bio-gas and restrains the production of biochar. However, pyrolysis temperature little influences the yield of bio-oil. The main compound of bio-oil is phenols, hydrocarbons, ketones, aldehydes and furans, respectively. While, bio-oil produced at 600 °C has as high as 78 % of phenols, which has potential application in chemical industries. The pyrolysis temperature has significantly influenced the composition and heating value of bio-gas. The maximum heating value of bio-gas is 12.44 MJ/Nm³, which is achieved at 600 °C. The physiochemical properties of biochar are also influenced by pyrolysis temperature. Biochar could be used as an adsorbent to adsorb Ag⁺ from aqueous solution, which is formed the value-added ABiochar composite by reduction. The adsorption and reduction process of Ag⁺ are investigated. While, ABiochar composite can be used as the catalyst for methylene blue degradation. ABiochar composite can be also used in the lithium ion battery cathode material for energy storage.     

共热解过程对褐煤焦和生物质焦氧化特性的影响

以锡盟褐煤和玉米秸秆为原料,利用固定床程序升温热解的方法制备了褐煤焦、生物质焦以及褐煤和生物质不同混合比例的共热解焦样,并进行了孔结构和化学结构的表征以及其灰成分分析。采用等温热重法在450 ℃下考察褐煤焦和生物质焦的混合样与其相同比例的共热解焦样的氧化活性,对比分析共热解过程对焦样反应活性的影响。实验结果表明,共热解过程中的二次反应对焦样结构有着明显的影响,进一步导致其反应活性下降。尤其是生物质添加量低于50%时,由于共热解过程生物质中大量挥发分的释放增强了其与半焦的二次反应,促使新生焦中部分小于五环的有机结构向更大的结构转化。但生物质添加量大于50%时,生物质焦的反应活性起主导作用,焦样中碱金属和碱土金属催化作用较明显,特别是钾的影响,使得共热解过程中挥发分与半焦的二次反应对其结构及反应性的影响减弱。     

Pyrolysis of waste tire on ZSM-5 zeolite with enhanced catalytic activities

Catalytic copyrolysis of waste tires over ZSM-5 zeolite with lubricant base oil (LBO) was undertaken at 430 °C under nitrogen atmosphere in a batch mode, and the pyrolysis oils were characterized using gas chromatography/mass spectroscopy (GC-MS). By combining with LBO, the ZSM-5 catalyzed pyrolysis system of tires has a sharply enhanced degradation rate. Compared to the pyrolysis without LBO, the liquid yield is increased from 33.6% to 48.0%, while the gas and the residue yields are decreased. In the pyrolysis oils, the content of heavy components is decreased and the content of light oils (n-C ≤ 12) is increased from 77.8%(without LBO) to 83.1%(with LBO); especially, the content of C₁₀ components has a sharp increase. Moreover, the liquid compositions are changed. Particularly, the percentage of limonene increased dramatically from 7.54% for thermal degradation to 13.58%. These results suggest that the enhanced catalytic effects on pyrolysis of tires in the catalytic systems are due to the improved interactions between tires and catalysts with the help of LBO. Therefore, it is possible to improve the process economics of scrap tires by catalytic copyrolysis with LBO, which can not only increase the pyrolysis rate remarkably but also produce high-value oil products.     

The co-pyrolysis of flame retarded high impact polystyrene and polyolefins

The co-pyrolysis of brominated high impact polystyrene (Br-HIPS) with polyolefins using a fixed bed reactor has been investigated, in particular, the effect that different types of brominated aryl compounds and antimony trioxide have on the pyrolysis products. The pyrolysis products were analysed using FT-IR, GC–FID, GC–MS, and GC–ECD. Liquid chromatography was used to separate the oils/waxes so that a more detailed analysis of the aliphatic, aromatic, and polar fractions could be carried out. It was found that interaction occurs between Br-HIPS and polyolefins during co-pyrolysis and that the presence of antimony trioxide influences the pyrolysis mass balance. Analysis of the Br-HIPS + polyolefin co-pyrolysis products showed that the presence of polyolefins led to an increase in the concentration of alkyl and vinyl mono-substituted benzene rings in the pyrolysis oil/wax resulting from Br-HIPS pyrolysis. The presence of Br-HIPS also had an impact on the oil/wax products of polyolefin pyrolysis, particularly on the polyethylene oil/wax composition which converted from being a mixture of 1-alkenes and n-alkanes to mostly n-alkanes. Antimony trioxide had very little impact on the polyolefin wax/oil composition but it did suppress the formation of styrene and alpha-methyl styrene and increase the formation of ethylbenzene and cumene during the pyrolysis of the Br-HIPS.     

污泥与醋糟共热解特性及碱金属迁移规律

分别采用热重分析仪、真空固定床反应器和原子吸收光谱研究了污泥与醋糟共热解过程中反应动力学、产物分布和碱金属迁移行为,探究了协同效应及碱金属迁移规律。结果表明,两者共热解过程中存在明显协同效应;与理论计算相比,混合物分解所需的活化能下降了35.38%～29.49%,脱挥发指数比计算低3.5×10-8。协同效应导致气体产率增加,生物炭、液体产率降低;醋糟的存在加速了污泥的脱挥发分析出,提高了气体产物中合成气含量,加大了生物炭中大芳香环的裂解反应,使生物油中酚类和酯类物质含量明显增加;热解终止时,碱金属元素析出量达到79.19%～86.73%。     

Production of liquid fuels and chemicals from pyrolysis of Bangladeshi bicycle/rickshaw tire wastes

Tire wastes in the form of used bicycle/rickshaw tires available in Bangladesh were pyrolyzed in a fixed-bed fire-tube heating reactor under different pyrolysis conditions to determine the role of final temperature, sweeping gas flow rate and feed size on the product yields and liquid product composition. Final temperature range studied was between 375 and 575 °C and the highest liquid product yield was obtained at 475 °C. Liquid products obtained under the most suitable conditions were characterized by elemental analyses, FT-IR, ¹H NMR and GC–MS techniques. The results show that it is possible to obtain liquid products that are comparable to petroleum fuels and valuable chemical feedstock from bicycle/rickshaw tire wastes if the pyrolysis conditions are chosen accordingly.     

自由落下床中生物质与煤共热解的协同效应对焦油组成的影响

利用溶剂萃取-柱层析方法,将自由落下床中豆秸与大雁褐煤共热解以及单种原料热解的液体产品分为沥青烯、酚类、脂肪烃类、芳香烃类和极性物等组分。结果表明,共热解的沥青烯产率为11.4%,低于根据煤和生物质单独热解的质量加权平均计算值19.0%,且芳香性增大;与计算值相比,低分子量的酚类、甲基苯酚、二甲基苯酚及其衍生物的含量提高了5%;而且长侧链的脂肪烃含量减少。共热解焦油的芳香类组分中十氢萘的质量分数是43.37%,但其在单一原料热解焦油中并没有被检测到。热解油分析结果表明,自由落下床生物质与煤快速共热解过程中存在协同效应,其主要原因是,发生氢解和加氢反应。煤与生物质共热解有利于产生低分子量的化合物,改善油品的质量。     

Pyrolysis of Hailar lignite in an autogenerated steam agent

An in situ pyrolysis process of high moisture content lignite in an autogenerated steam agent was proposed. The aim is to utilize steam autogenerated from lignite moisture as a reactant to produce fuel gas and additional hydrogen. Thermogravimetric analysis revealed that mass loss and maximum mass loss rate increased with the rise of heating rates. The in situ pyrolysis process was performed in a screw kiln reactor to investigate the effects of moisture content and reactor temperature on product yields, gas compositions, and pyrolysis performance. The results demonstrated that inherent moisture in lignite had a significant influence on the product yield. The pyrolysis of L _R (raw lignite with a moisture content of 36.9 %, wet basis) at 900 °C exhibited higher dry yield of 33.67 mL g^?1 and H₂ content of 50.3 vol% than those from the pyrolysis of the predried lignite. It was also shown that increasing reaction temperature led to a rising dry gas yield and H₂ yield. The pyrolysis of L _R showed the maximum dry yield of 33.7 mL g^?1 and H₂ content of 53.2 vol% at 1,000 °C. The LHV of fuel gas ranged from 18.45 to 14.38 MJ Nm^?3 when the reactor temperature increased from 600 to 1,000 °C.     

Bio-oil production from Onopordum acanthium L. by slow pyrolysis

In this study, the usability of the plant thistle, Onopordum acanthium L., belonging to the family Asteraceae (Compositae), in liquid fuel production has been investigated. The experiments were performed in a fixed-bed Heinze pyrolysis reactor to investigate the effects of heating rate, pyrolysis temperature and sepiolite percentage on the pyrolysis product yields and chemical compositions. Experiments were carried out in a static atmosphere with a heating rate of 7 °C/min and 40 °C/min, pyrolysis temperature of 350, 400, 500, 550 and 700 °C and particle size of 0.6 < D_p < 0.85 mm. Catalyst experiments were conducted in a static atmosphere with a heating rate of 40 °C/min, pyrolysis temperature of 550 °C and particle size of 0.6 < D_p < 0.85 mm. Bio-oil yield increased from 18.5% to 27.3% with the presence of 10% of sepiolite catalyst at pyrolysis temperature of 550 °C, with a heating rate of 40 °C/min, and particle size of 0.6 < D_p < 0.85 mm. It means that the yield of bio-oil was increased at around 48.0% after the catalyst added. Chromatographic and spectroscopic studies on the bio-oil showed that the oil obtained from O. acanthium L. could be used as a renewable fuels and chemical feedstock.     

油浆高温快速裂解过程的气固相产物研究

采用高频炉快速热解装置研究油浆的高温快速热解特性,考察了热解温度、氮气流量对气固相产物的组成和产率的影响。温度是影响气相产物产率的关键因素,气相产物主要为甲烷、氢气和乙烯,升高温度可提高甲烷和氢气的产率,而乙烯产率受高温下二次反应的影响在800℃到达最大值后逐渐降低,乙烷、丙烯产率较小且受二次反应的影响在700℃到达最大值后逐渐降低,温度高于800℃时会有少量乙炔生成且升温可提高乙炔产率。增加氮气流量可降低甲烷、氢气分压,缩短乙烯、丙烯等在高温区的停留时间,从而增加气相产物的产率。积炭产率随热解温度升高迅速增加,氮气流量的增加能够削弱二次反应从而降低积炭产率。     

Essential Quality Attributes of Tangible Bio‐Oils from Catalytic Pyrolysis of Lignocellulosic Biomass

This review covers the characteristics of pyrolysis and catalytic pyrolysis bio‐oils by focusing on the fundamental factors that determine bio‐oil upgradability. The abundant works on the subject of bio‐oil production from lignocellulosic biomass were studied to establish the essential attributes of the bio‐oils for assessment of the oil stability and upgradability. Bio‐oils from catalytic pyrolysis processes relating to catalysts of different compositions and structures are discussed. A general relationship between the higher heating value and the oxygen content in the catalytic pyrolysis oils exists, but this relationship does not apply to the thermal pyrolysis oil. Reporting bio‐oil yield is meaningful only when the oxygen content of the oil is measured because the pyrolytic oil stability is mainly determined by the oxygen content. Isoenergy plot that associates bio‐oil yield with oxygen content is presented and discussed.     

High-temperature pyrolysis of poly(vinyl chloride): Gas chromatographic-mass spectrometric analysis of the pyrolysis products from PVC resin and plastisols

A pyrolysis–gas chromatographic–mass spectrometric technique for analyzing the pyrolysis products from polymers in an inert atmosphere is described. Initial studies encompassing the pyrolysis of poly(vinyl chloride) homopolymer and a series of PVC plastisols (based on o-phthalate esters) have provided a complete qualitative and semi-quantitative analysis of the pyrolysis products from these materials. PVC resin yields a series of aliphatic and aromatic hydrocarbons when pyrolyzed at 600°C; the amount of aromatic products is greater than the amount of aliphatic products. Benzene is the major organic degradation product. A typical PVC plastisol [PVC/o-dioctyl phthalate (100/60)] yields, upon pyrolysis, products that are characteristic of both the PVC matrix and the phthalate plasticizer. The pyrolysis products from the plasticizer dilute those from the PVC portion of the plastisol and are, in turn, the major degradation products. There are no degradation products resulting from an interaction of the PVC with the plastisol. The pyrograms resulting from pyrolysis of the various plastisols of PVC can be used for purposes of “fingerprinting.” Identification of the major peaks in a typical plastisol pyrogram provides information leading to a precise identification of the plasticizer. The pyrolysis data from this study were related to a special case of flammability and toxicity.     

Modeling the evolution of volatile species during tobacco pyrolysis

A great need exists for comprehensive biomass-pyrolysis models that could predict yields and evolution patterns of selected volatile products as a function of feedstock characteristics and process conditions. Low heating rate data obtained from a thermogravimetric analyzer (TGA), coupled with Fourier transform infrared analysis of evolving products (TG-FTIR), were used to perform kinetic analysis of tobacco pyrolysis. The results were utilized to create input to a biomass-pyrolysis model based on first-order kinetic expressions with a Gaussian distribution of activation energies. Pyrolysis simulations were carried out for high heating rate conditions, and predicted product yields were compared with literature data.