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褐煤热解分质清洁利用研究进展 被引量:5
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作者 马江 冯德林 王家祥 《煤炭加工与综合利用》 CAS 2017年第4期32-36,共5页
介绍了褐煤热解技术,对比研究了典型热解工艺,分析了褐煤热解的影响因素,探讨了分质产品的利用途径及现状,并对实现褐煤大规模高效利用应开展的研究工作进行了展望。
关键词 褐煤 热解分质 清洁利用 研究展望
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陕北低变质煤分质综合利用前景展望 被引量:36
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作者 尚建选 王立杰 甘建平 《煤炭转化》 CAS CSCD 北大核心 2011年第1期92-96,共5页
系统论述了煤炭分质利用技术的有关问题,以分质利用技术科学理念的提出及工艺路线分析为基础,结合我国陕北地区丰富的低变质煤炭和盐等资源优势,提出了煤炭分质利用-新型盐化工利用模式、煤炭分质利用-煤基替代石化产品模式和煤炭分质利... 系统论述了煤炭分质利用技术的有关问题,以分质利用技术科学理念的提出及工艺路线分析为基础,结合我国陕北地区丰富的低变质煤炭和盐等资源优势,提出了煤炭分质利用-新型盐化工利用模式、煤炭分质利用-煤基替代石化产品模式和煤炭分质利用-煤制天然气利用模式三种以煤炭分质利用技术为核心的陕北资源综合高效利用技术,并对其进行了技术及效益分析,对于指导我国低变质煤炭利用具有重要意义. 展开更多
关键词 热解 利用 节能减排
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Analysis and modeling of alumina dissolution based on heat and mass transfer 被引量:3
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作者 詹水清 李茂 +2 位作者 周孑民 杨建红 周益文 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第5期1648-1656,共9页
A comprehensive heat and mass transfer model of dissolution process of non-agglomerated and agglomerated alumina particles was established in an aluminum reduction cell. An appropriate finite difference method was use... A comprehensive heat and mass transfer model of dissolution process of non-agglomerated and agglomerated alumina particles was established in an aluminum reduction cell. An appropriate finite difference method was used to calculate the size dissolution rate, dissolution time and mass of alumina dissolved employing commercial software and custom algorithm based on the shrinking sphere assumption. The effects of some convection and thermal condition parameters on the dissolution process were studied. The calculated results show that the decrease of alumina content or the increase of alumina diffusion coefficient is beneficial for the increase of size dissolution rate and the decrease of dissolution time of non-agglomerated particles. The increase of bath superheat or alumina preheating temperature results in the increase of size dissolution rate and the decrease of dissolution time of agglomerated particles. The calculated dissolution curve of alumina(mass fraction of alumina dissolved) for a 300 k A aluminum reduction cell is in well accordance with the experimental results. The analysis shows that the dissolution process of alumina can be divided into two distinct stages: the fast dissolution stage of non-agglomerated particles and the slow dissolution stage of agglomerated particles, with the dissolution time in the order of 10 and 100 s, respectively. The agglomerated particles were identified to be the most important factor limiting the dissolution process. 展开更多
关键词 aluminum reduction cell alumina particles dissolution process heat and mass transfer finite difference method
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Thermogravimetric-Mass Spectrometric Study of the Pyrolysis Behavior of PVC 被引量:10
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作者 SUN Qing-lei SHI Xin-gang LIN Yun-liang ZHU He WANG Xiao CHENG Chuan-ge LIU Jian-hua 《Journal of China University of Mining and Technology》 EI 2007年第2期242-245,共4页
The pyrolysis characteristics of PVC were systematically investigated using a Netzschne TG thermo-balance coupled to a quadrupole mass spectrometer. The pyrolysis conditions were 0.1 MPa of Ar, a heating rate of 10 ℃... The pyrolysis characteristics of PVC were systematically investigated using a Netzschne TG thermo-balance coupled to a quadrupole mass spectrometer. The pyrolysis conditions were 0.1 MPa of Ar, a heating rate of 10 ℃/min and a final temperature of 1000℃. Both the thermogravimetric properties and the simultaneous evolution of gaseous products during pyrolysis were studied. The TG/DTG results showed that as the pyrolysis temperature increases the weight loss and weight loss rate of PVC increases. Near 412℃ the weight loss rate attained its peak value. At higher temperatures the rate of loss gradually decreases. The gases evolved during thermogravimetric analysis were analyzed by a mass spectrometer, monitoring the relative intensity of HC1, C6H6, light hydrocarbon and chlorine-containing gases The evolution curves showed that HC1, C6H6, light hydrocarbon and chlorine-containing gases all peak at about 416℃. This is consistent with the fact that the weight loss curves also peak at about 412℃. The extensive HCl evolution is consistent with the high chlorine content of PVC. The formation of these gases can be explained by considering these reactions: dehydrochlorination, intramolecular cyclization and the addition of HCl to unsaturated hydrocarbons. 展开更多
关键词 PYROLYSIS PVC gas evolution TG-MS
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Comparative Study on the Pyrolysis Behaviors of Corn Stalk and Pine Sawdust Using TG-MS 被引量:1
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作者 赵云鹏 丁曼 +3 位作者 窦有权 樊星 王月伦 魏贤勇 《Transactions of Tianjin University》 EI CAS 2014年第2期91-96,共6页
The pyrolysis behaviors of corn stalk(CS) and pine sawdust(PS) were investigated with thermogravimetry-mass spectroscopy(TG-MS).The peak temperature of PS was higher and the main decomposition region shifted to higher... The pyrolysis behaviors of corn stalk(CS) and pine sawdust(PS) were investigated with thermogravimetry-mass spectroscopy(TG-MS).The peak temperature of PS was higher and the main decomposition region shifted to higher temperature compared with CS,which implied that the hemicellulose and cellulose of PS were more thermally stable than those of CS.However,the hemicellulose and cellulose of PS were more easily decomposed into gaseous products than those of CS during pyrolysis.The pyrolysis process of biomass can be described by a two-step independent first-order kinetic model.This fundamental study provides a basic insight into the biomass pyrolysis,which is beneficial for understanding the pyrolysis mechanism of biomass and developing an advanced thermal process for effective utilization of biomass. 展开更多
关键词 BIOMASS PYROLYSIS KINETICS TG-MS
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Formation and Characteristics of Acrylonitrile/Urea Inclusion Compound
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作者 邹均庭 王雨松 +2 位作者 庞文民 石磊 鲁非 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第2期198-202,I0004,共6页
The formation process and composition of the acrylonitrile/urea inclusion compounds (AN/UIC) with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry (DSC) and X-ra... The formation process and composition of the acrylonitrile/urea inclusion compounds (AN/UIC) with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). It is suggested that DSC can determine the guest/host ratio and the heat of decomposition. Meanwhile, the guest/host ratio and heat of decomposition are obtained, which are 1.17 and 5361.53 J/mol, respec- tively. It is suggested AN molecules included in urea canal lattice may be packed flat against each other. It is found that the formation of AN/UIC depends on the aging time. XRD results reveal that once AN molecules enter urea lattice, AN/UIC are formed, which possess the final structure. When AN molecules are sufficient, the length of AN molecular arrays in urea canals increases as aging time prolonging until urea tunnels are saturated by AN. 展开更多
关键词 ACRYLONITRILE Urea inclusion compound Molar ratio Heat of decomposition Formation process
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Simulation of alumina dissolution and temperature response under different feeding quantities in aluminum reduction cell 被引量:2
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作者 LI Si-yun LI Mao +2 位作者 HOU Wen-yuan LI He-song CHENG Ben-jun 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第8期2119-2128,共10页
In the feeding process of aluminum electrolytic, feeding quantity of alumina affects eventually dissolved quantity at the end of a feeding cycle. Based on the OpenFOAM platform, dissolution model coupled with heat and... In the feeding process of aluminum electrolytic, feeding quantity of alumina affects eventually dissolved quantity at the end of a feeding cycle. Based on the OpenFOAM platform, dissolution model coupled with heat and mass transfer was established. Applying the Rosin-Rammler function, alumina particle size distribution under different feeding quantities was obtained. The temperature response of electrolyte after feeding was included and calculated, and the dissolution processes of alumina with different feeding quantities (0.6, 0.8, 1.0, 1.2, 1.4, 1.6 kg) after feeding were simulated in 300 kA aluminum reduction cell. The results show that with the increase of feeding quantity, accumulated mass fraction of dissolved alumina decreases, and the time required for the rapid dissolution stage extends. When the feeding quantity is 0.6 kg and 1.2 kg, it takes the shortest time for the electrolyte temperature dropping before rebounding back. With the increase of feeding quantity, the dissolution rate in the rapid dissolution stage increases at first and then decreases gradually. The most suitable feeding quantity is 1.2 kg. The fitting equation of alumina dissolution curve under different feeding quantities is obtained, which can be used to evaluate the alumina dissolution and guide the feeding quantity and feeding cycle. 展开更多
关键词 alumina dissolution heat and mass transfer particle size distribution temperature response NUMERICAL
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Effect of industrial microwave irradiation on the physicochemical properties and pyrolysis characteristics of lignite 被引量:5
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作者 Guoshun Zhou Qunxing Huang +3 位作者 Ben Yu Hui Tong Yong Chi Jianhua Yan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第5期1171-1178,共8页
The surface functional groups and pyrolysis characteristics of lignite irradiated by microwave were comparatively studied to evaluate the feasibility of using industrial 915 MHz for lignite drying. The drying kinetics... The surface functional groups and pyrolysis characteristics of lignite irradiated by microwave were comparatively studied to evaluate the feasibility of using industrial 915 MHz for lignite drying. The drying kinetics, micro structure, chemical functional groups, re-adsorption properties, and pyrolysis characteristics of the dried coal were respectively analyzed. Results indicated that for typical Chinese lignite studied in this paper, 915 MHz microwave drying was 7.8 times faster than that of the hot air drying. After industrial microwave drying, the sample possessed much higher total specific surface area and specific pore volume than that of air dried sample. The oxygen functional groups and re-adsorption ratio of microwave irradiated coal decreased, showing weakened hydrophilicity. Moreover, during the pyrolysis of the coal dried by hot air and microwave, the yield of tar largely increased from 1.3% to 8.5% and the gas production increased correspondingly. The composition of the tar was also furtherly analyzed, results indicated that Miscellaneous hydrocarbons(HCs) were the main component of the tar, and microwave irradiation can reduce the fraction of polycyclic aromatic hydrocarbons(PAHs) from 26.4% to 22.7%. 展开更多
关键词 LIGNITE Industrial microwave Physicochemical properties Pyrolysis characteristics
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Chaos Transfer in Fluidized Beds Accompanied with Biomass Pyrolysis 被引量:1
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作者 唐松涛 李定凯 +1 位作者 吕子安 沈幼庭 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第3期358-361,共4页
Experiments of biomass pyrolysis were carried out in a fluidized bed, and dynamic signals of pressure and temperature were recorded. Correlation dimension was employed to characterize the chaotic behavior of pressure ... Experiments of biomass pyrolysis were carried out in a fluidized bed, and dynamic signals of pressure and temperature were recorded. Correlation dimension was employed to characterize the chaotic behavior of pressure and temperature signals. Both pressure and temperature signals exhibit chaotic behavior, and the chaotic behavior of temperature signals is always weaker than that of pressure signals. Chaos transfer theory was advanced to explain the above phenomena. The discussion on the algorithm of the correlation dimension shows that the distance definition based on rhombic neighborhood is a better choice than the traditional one based on spherical neighborhood. The former provides a satisfactory result in a much shorter time. 展开更多
关键词 chaos transfer correlation dimension fluidized bed biomass pyrolysis
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Pyrolysis characteristics of rubber compositions in medical waste 被引量:3
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作者 邓娜 王维维 +3 位作者 陈广武 张彦 张于峰 马洪亭 《Journal of Central South University》 SCIE EI CAS 2013年第9期2466-2471,共6页
Thermogravimetric study of rubber compositions (operating glove and catheter) in medical waste was carried out using the thermogravimetric analyser (TGA),at the heating rate of 20 ℃/min in a stream of N2.The resu... Thermogravimetric study of rubber compositions (operating glove and catheter) in medical waste was carried out using the thermogravimetric analyser (TGA),at the heating rate of 20 ℃/min in a stream of N2.The results indicate that the decomposition process of operating glove appears an obvious mass loss stage at 250-485 ℃,while catheter has two obvious stages at 240-510 ℃ and 655-800 ℃,respectively; both samples present endothermic pyrolysis reaction; the decomposition of operating glove and the first mass loss stage of catheter are in agreement with natural rubber pyrolysis; the second mass loss stage of catheter corresponds to CaCO3 decomposition.Based on the experimental results,a novel two-step four-reaction model was established to simulate the whole continuous processes,which could more satisfactorily describe and predict the pyrolysis processes of rubber compositions,being more mechanistic and conveniently serving for the engineering. 展开更多
关键词 medical waste RUBBER operating glove CATHETER PYROLYSIS MODEL
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Upgrading of Yi'an gas coal by low temperature pyrolysis under different atmospheres 被引量:4
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作者 Wei Xiaomei Zhou Min +2 位作者 Zhang Chun Lei Jiali Song Liqiang 《Mining Science and Technology》 EI CAS 2011年第3期401-405,共5页
The quality of Yi'an gas coal before and after low temperature upgrading under either a N2 or H2 atmosphere was examined by thermogravimetric and infrared analyses. The effect of upgrading on the prepared coke qualit... The quality of Yi'an gas coal before and after low temperature upgrading under either a N2 or H2 atmosphere was examined by thermogravimetric and infrared analyses. The effect of upgrading on the prepared coke quality was analyzed. The results show that the carboxyl and phenolic hydroxyls in the coal molecular structure are removed after upgrading by low temperature pyrolysis under either N2 or Hz atmospheres. This improves coal caking properties to a certain extent. The upgrading effect under a Hz atmosphere is remarkably better than the effect observed after upgrading under N2. Compared to coke obtained from raw coal, the compressiveand micro-strength of the cokes obtained from upgraded coal are greatly improved. The effect on coke reactivity with CO2 is not significant. The best upgrading temperature for Yi'an gas coal under either a N2 or H2 atmosphere is 250 or 275 ℃ respectively. 展开更多
关键词 Yi'an gas coal Atmosphere Upgrading Coke quality
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Analysis of Pyrolysates for Polysulphoneamide Fiber by Py-GC/MS
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作者 钱和生 林丹丽 《Journal of Donghua University(English Edition)》 EI CAS 2006年第2期63-67,共5页
Pyrolysis of polysulphoneamide fiber has been investigated using pyrolysis gas chromatography-mass spectroscopy at the different temperatures from 420℃ to 750℃. Its compositions of pyrolysates have been analyzed. At... Pyrolysis of polysulphoneamide fiber has been investigated using pyrolysis gas chromatography-mass spectroscopy at the different temperatures from 420℃ to 750℃. Its compositions of pyrolysates have been analyzed. At 420℃,pyrolysis of molecular chain could not completdy take place, 12 compounds of pyrolysis have only been identified. When the temperature increases, the compositions of pyrolysate increase sharply. Several compounds, especially sulfur dioxide, benzene, aniline, benzoic acid, 1,4-benzene dicaronitrile, N-phenyl-acetamide, diphenylamine, benzc[g] isoquinoline, N-phenyl-benzamide, hi-( 4-cyanophenyl )benzamide, could be formed. The degradation mechanisms which are determined by structure and amount of the thermal decomposition products are described. During pyrolysis, for polysulphoneamide, polymeric chain scissions take place as a successive removal of the monomer units from the polymeric chain. The chain scissions are followed by secondary reactions, which lead to a variety of compounds. Additional reactions can also take place during pyrolysis. 展开更多
关键词 polysulphoneamide fiber PYROLYSIS gas chromatography mass spectroscopy.
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Development and Test of an Experimental Apparatus to Study Thermal-Choking in Ideal Gases and Self-decomposition in Superheated N2O
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作者 Patrick Lemieux Alberto Fara +1 位作者 Pablo Sanchez William Murray 《Journal of Energy and Power Engineering》 2015年第1期25-39,共15页
N2O represents a popular oxidizer for hybrid rocket motors for a variety of reasons, including safety, ease of access and self-pressurization. It is often used as a saturated two-phase fluid in these applications to t... N2O represents a popular oxidizer for hybrid rocket motors for a variety of reasons, including safety, ease of access and self-pressurization. It is often used as a saturated two-phase fluid in these applications to take advantage of self-pressurization. Recent interest in using this oxidizer in regeneratively cooled engines requires a detailed heat transfer process analysis to the coolant, in order to quantify performance. Since the injection of N2O typically takes place in the two-phase region, our study focuses on heat transfer rates in this region, and extends the region to include superheated vapor. This analysis is critical for these cooling applications, because the exothermic decomposition nature of N2O also means that unchecked heating in the superheated region may result in a runaway reaction in the cooling passages. Furthermore, provided that sufficient heat transfer rates are available, N2O is expected to accelerate in the cooling passages due to Rayleigh flow effects much like those of a calorically perfect gas. The proximity of superheated N2O to its saturated vapor curve, at the conditions studied here, makes the suitability of a perfect gas model questionable, but that benchmarks is still useful. This paper presents the development of an experimental apparatus (a "Rayleigh tube"), specifically designed to study this problem, and test the analytical methods developed to model it. Since we focus on the development of the apparatus, the data presented were uses primarily calorically perfect gas surrogates, but the goal is to apply the apparatus and method to N2O. The design and construction of the Rayleigh tube is presented, along with preliminary results with perfect gases. Finally, we present preliminary results on heated N2O flow. Using a simple model for predicted dry-out point, we investigate where superheating may be expected to occur. We present estimates of critical heating and compare them to the heat required to achieve self-decomposition. 展开更多
关键词 Self-decomposition N2O Rayleigh apparatus
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Prediction of pyrolysis kinetic parameters from biomass constituents based on simplex-lattice mixture design 被引量:1
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作者 Panusit Sungsuk Sasiporn Chayaporn +3 位作者 Sasithorn Sunphorka Prapan Kuchonthara Pornpote Piumsomboon Benjapon Chalermsinsuwan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第4期535-542,共8页
The aim of this study is to determine the effect of the main chemical components ofbiomass: cellulose, hemicel- lulose and lignin, on chemical kinetics ofbiomass pyrolysis. The experiments were designed based on a si... The aim of this study is to determine the effect of the main chemical components ofbiomass: cellulose, hemicel- lulose and lignin, on chemical kinetics ofbiomass pyrolysis. The experiments were designed based on a simplex- lattice mixture design. The pyrolysis was observed by using a thermogravimetric analyzer. The curves obtained from the employed analytical method fit the experimental data (R2 〉 0.9). This indicated that this method has the potential to determine the kinetic parameters such as the activation energy (E~), frequency factor (A) and re- action order (n) for each point of the experimental design. The results obtained from the simplex-lattice mixture design indicated that cellulose had a significant effect on Ea and A, and the interaction between cellulose and lignin had an important effect on the reaction order, n. The proposed models were then proved to be useful for predicting pyrolysis behavior in real biomass and so could be used as a simple approximation for predicting the overall trend of chemical reaction kinetics. 展开更多
关键词 BiomassPyrolysisSimplex-lattice mixture designKineticsModeling
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Pyrolysis of Polytrimethylene Terephthalate(PTT) Fiber by Pyrolysis Gas Chromatography-Mass Spectroscopy
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作者 钱和生 《Journal of Donghua University(English Edition)》 EI CAS 2007年第5期604-609,共6页
Pyrolysis of polytrimethylene terephthalate(PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of th... Pyrolysis of polytrimethylene terephthalate(PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of the temperature on its composition of pyrolysates.At 400℃,pyrolysis of molecular chain could occur,only 13 pyrolysates could be identified.The trimethylene moieties bound to the macromolecular core by ester bonds are cleaved at around 400℃.At 550℃-750℃,pyrolysis of molecular chain could completely take place,46 pyrolysates could be found.As the temperature increases,the compositions of pyrolysate are distinctly increased.Several compounds,especially benzoic acid,monopropenyl-p-phthalate,2-propenyl benzoate,di-2-propenyl ester,1,4-benzenedicarboxylic acid,benzene,1,5-hexadiene,biphenyl and 1,3-propanediol dibenzoate could be formed.The thermal degradation mechanism,which is determined by structure and amount of the thermal decomposition products,are described.During pyrolysis of polytrimethylene terephthalate,polymeric chain scissions take place a peeling reaction as a successive removal of the dimer units from the polymeric chain.The chain scissions are followed by the elimination reaction,linkage action and secondary reactions,which bring about a variety fragment. 展开更多
关键词 polytrimethylene terephthalate fiber PYROLYSIS thermal degradation gas chromatography mass spectroscopy
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Distributed Bio-Hydrogen Refueling Stations 被引量:1
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作者 Peter J. Schubert 《Journal of Earth Science and Engineering》 2016年第4期183-190,共8页
Hydrogen fuel cell cars are now available for lease and for sale. Renewable hydrogen fuel can be produced from water via electrolysis, or from biomass via gasification. Electrolysis is power-hungry with high demand fr... Hydrogen fuel cell cars are now available for lease and for sale. Renewable hydrogen fuel can be produced from water via electrolysis, or from biomass via gasification. Electrolysis is power-hungry with high demand from solar or wind power. Gasification, however, can be energy self-sufficient using a recently-patented thermochemical conversion technology known as I-HPG (indirectly-heated pyrolytic gasification). I-HPG produces a tar-free syngas from non-food woody biomass. This means the balance of plant can be small, so the overall system is economical at modest sizes. This makes it possible to produce renewable hydrogen from local agricultural residues; sufficient to create distributed refueling stations wherever there is feedstock. This work describes the specifics of a novel bio-hydrogen refueling station whereby the syngas produced has much of the hydrogen extracted with the remainder powering a generator to provide the electric power to the I-HPG system. Thus the system runs continuously. When paired with another new technology, moderate-pressure storage of hydrogen in porous silicon, there is the potential to also power the refueling operation. Such systems can be operated independently. It is even possible to design an energy self-sufficient farm where all electric power, heat, and hydrogen fuel is produced from the non-food residues of agricultural operations. No water is required, and the carbon footprint is negative, or at least neutral. 展开更多
关键词 BIOMASS HYDROGEN distributed generation fuel cell vehicle
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Structural evolution of chars from biomass components pyrolysis in a xenon lamp radiation reactor
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作者 Haizhou Lin Shurong Wang +3 位作者 Li Zhang Bin Ru Jinsong Zhou Zhongyang Luo 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第2期232-237,共6页
The structural evolution of the chars from pyrolysis of biomass components (cellulose, hemicellulose and lignin) in a xenon lamp radiation reactor was investigated. The elemental composition analysis showed that the... The structural evolution of the chars from pyrolysis of biomass components (cellulose, hemicellulose and lignin) in a xenon lamp radiation reactor was investigated. The elemental composition analysis showed that the C content increased at the expense of H and O contents during the chars formation. The values of AH/C/ZSO/c for the formation of cellulose and hemicellulose chars were close to 2, indicating that dehydration was the dominant reaction. Meanwhile, the value was more than 3 for lignin char formation, suggesting that the occurrence of demethoxylation was prevalent. FTIR and XRD analyses further disclosed that the cellulose pyrolysis needed to break down the stable crystal structure prior to the severe depolymerization. As for hemicellulose and lignin pyrolysis, the weak branches and linkages decomposed firstly, followed by the major decomposition. After the devolatilization at the main pyrolysis stage, the three components encountered a slow carbonization process to form condensed aromatic chars. The SEM results showed that the three components underwent different devolatilization behaviors, which induced various surface mornhologies of the chars. 展开更多
关键词 Biomass componentsPyrolysisCharStructural characterization
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Asymptotic Solution for Coupled Heat and Mass Transfer During the Solidification of High Water Content Materials
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作者 齐德瑄 何凯 +1 位作者 杜如虚 张义同 《Transactions of Tianjin University》 EI CAS 2010年第4期239-243,共5页
This paper focuses on obtaining an asymptotic solution for coupled heat and mass transfer problem during the solidification of high water content materials. It is found that a complicated function involved in governin... This paper focuses on obtaining an asymptotic solution for coupled heat and mass transfer problem during the solidification of high water content materials. It is found that a complicated function involved in governing equations can be approached by Taylor polynomials unlimitedly, which leads to the simplification of governing equations. The unknown functions involved in governing equations can then be approximated by Chebyshev polynomials. The coefficients of Chebyshev polynomials are determined and an asymptotic solution is obtained. With the asymptotic solution, the dehydration and freezing fronts of materials are evaluated easily, and are consistent with numerical results obtained by using an explicit finite difference method. 展开更多
关键词 heat transfer mass transfer SOLIDIFICATION asymptotic analysis
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Experimental Investigation of Pyrolysis Process of Woody Biomass Mixture 被引量:3
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作者 Tijana R.Kosanic Mirjana B.Ceranic +3 位作者 Slavko N.Duric Vojin R.Grkovic Milan M.Milotic Sasa D.Brankov 《Journal of Thermal Science》 SCIE EI CAS CSCD 2014年第3期290-296,共7页
This paper describes an experimental investigation of pyrolysis of woody biomass mixture. The mixture consists of oak, beech, fir, cherry, walnut and linden wood chips with equal mass fractions. During the experiment,... This paper describes an experimental investigation of pyrolysis of woody biomass mixture. The mixture consists of oak, beech, fir, cherry, walnut and linden wood chips with equal mass fractions. During the experiment, the sample mass inside the reactor was 10 g with a particle diameter of 5-10 mm. The sample in the reactor was heated in the temperature range of 24-650℃. Average sample heating rates in the reactor were 21, 30 and 54 ℃/min. The sample mass before, during and after pyrolysis was determined using a digital scale. Experimental results of the sample mass change indicate that the highest yield of pyrolytic gas was achieved at the temperature slightly above 650℃ and ranged from 77 to 85%, while char yield ranged from 15 to 23%. Heating rate has sig- nificant influence on the pyrolytic gas and char yields. It was determined that higher pyrolysis temperatures and heating rates induce higher yields of pyrolytic gas, while the char mass reduces. Condensation of pyrolytic gas at the end of the pyrolysis process at 650℃ produced 2.4-2.72 g of liquid phase. The results obtained represent a starting basis for determining material and heat balance of pyrolysis process as well as woody biomass pyrolysis equipment. 展开更多
关键词 PYROLYSIS woody biomass mixture pyrolysis temperature gas yield
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Decomposition of Different Litter Fractions in a Subtropical Bamboo Ecosystem as Affected by Experimental Nitrogen Deposition 被引量:13
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作者 TU Li-Hua HU Hong-Ling +5 位作者 HU Ting-Xing ZHANG Jian LIU Li LI Ren-Hong DAI Hong-Zhong LUO Shou-Hua 《Pedosphere》 SCIE CAS CSCD 2011年第6期685-695,共11页
As an important component of the global carbon (C) budget, litter decomposition in terrestrial ecosystems is greatly affected by the increasing nitrogen (N) deposition observed globally. We hypothesized that diffe... As an important component of the global carbon (C) budget, litter decomposition in terrestrial ecosystems is greatly affected by the increasing nitrogen (N) deposition observed globally. We hypothesized that different litter fractions derived from a single tree species may respond to N deposition differently depending on the quality of the litter substrate. To test the hypothesis, a two-year field experiment was conducted using the litterbag method in a Pleioblastus amarus plantation in the rainy region of Southwest China. Four N treatment levels were applied: control (no N added), low-N (50 kg N ha-1 year-1), medium-N (150 kg N ha-a year-1), and high-N (300 kg N ha-1 year-l). We observed different patterns of mass loss for the three P. amarus litter fractions (leaves, sheaths, and twigs) of varying substrate quality in the control plots. There were two decomposition stages with different decay rates (fast rate in early stages and slow rate in the later stages) for leaves and sheaths, while we did not observe a slower phase for the decay of twigs during the 2-year study period. The annual decomposition rate (k) of twigs was significantly lower than that of leaves or sheaths. Addition of N slowed the decomposition of leaves and twigs in the later stages of decomposition by inhibiting the decay of lignin and cellulose, while addition of N did not affect the mass loss of sheaths during the study period. In the decomposition of all three litter fractions, experimental N deposition reduced the net N accumulation in the early stages and also decreased the net N release in the later stages. The results of this study suggest that litter substrate quality may be an important factor affecting litter decomposition in a bamboo ecosystem affected by N deposition. 展开更多
关键词 decomposition rate litter substrate N dynamics plant biomass Pleioblastus amarus
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