Papers by Keyword: Pyrolysis

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Authors: Nurhayati Abdullah, Aminu Aliyu Safana, Fauziah Sulaiman, Ibrahim Inuwa Abdullahi
Abstract: The fundamental objectives of this study is to analyzed and compare the physical and chemical properties of pyrolysis products (biochar and bio-oil) derived from two oil palm wastes. Empty fruit bunch (EFB) and mesocarp fibre (MF) were subjected to pyrolysis at a temperature of 400 °C for 2 hours holding time at 10 °C/min heating rate and with nitrogen flow rate of 2 L/min. The result obtained from raw material showed that MF contains a high quantity of hemicellulose and lignin which led to a high yield of bio-oil and biochar respectively, whereby, EFB contained a high content of cellulose. The high content of cellulose in EFB resulted in a high yield of gas compared to fibre. The higher heating value (HHV) of biochar and bio-oil were found to be 28.76 and 19.45 MJkg-1 for MF and, 24.33 and 19.98 MJkg-1 for EFB, respectively. Comparatively, the biochar obtained from MF material has high HHV than EFB material. However, all the biochars derived can be used for briquettes production as coal replacement in the future due to significantly high calorific value as compared to Malaysian sub-bituminous coal which has 24.6 MJkg-1. Furthermore, pyrolysis of any wastes encourages proper sanitation and lead to a healthy environment. It can also serve as a potential solution to the energy crisis in developing countries, Nigeria in particular if bio-oil can be improved to power electricity generation facilities in replacement to diesel.
Authors: Wei Cao, Wen Wei Zha, Wen Long Ni
Abstract: A novel and improved waste pyrolysis test system is developed by process design, pyrolysis host type design and the corresponding counterpart type design. It contains the design of waste pyrolysis pretreatment device, the sealing feeding device, the pyrolysis slag cooling device, the high temperature pyrolysis gas dust removal device and the pyrolysis gas desulfurization dust removal device. This study proposes a good testing model and a production validation on waste combustion under the oxygen-free and high-temperature condition. Thus it offers an effective technical support and guidance on improving the utilization of waste calorific value and preventing the generation of dioxin.
Authors: Hua Xiao Yan, Hui Zhao, Qi Liu, Yan Xiang Ai, Yan Zhang, Chang Long Wang, Shi Xue Zhou, Zuo Zhen Han
Abstract: The Suaeda salsa L. has been discovered to be a great potential as a new kind of renewable energy. The pyrolytic characteristics and kinetics of S. salsa were investigated at heating rates of 5, 10, 20, 30°C/min under nitrogen atmosphere respectively. The most probable mechanism function was deduced using Popescu method, which is a three-dimensional diffusion function (), and n=-2/3. Activation energy and pre-exponential factors were studied through the FWO, KAS and Popescu methods. The results showed that the activation energy increase as the pyrolysis process and three stages were observed in the TG-DTG curves of S.salsa. The results showed that S.salsa as a pyrolysis feedstock has a great potential and a good prospect in bio-oil production.
Authors: Chao Deng, Ying Li, Jin Hui Li, Hua Fen Li
Abstract: Polybrominated diphenyl ethers (PBDEs), especially pentaBDE and decaBDE have been extensively used as flame retardants in plastics of most electronic equipment. However, PBDE congeners have been found in the environment, in wildlife and in human body worldwide with evidences that they pose risks both to human health and to the entire ecosystem. China has become an important pentaBDE and decaBDE production country because of the increasing domestic demand due to rapid development of electronic industry in recent years. Although pentaBDE was phased out in 2004, decaBDE still remains in production and is used in electrical industry. Additionally, large amounts of plastics containing these pollutants from waste electrical and electronic equipment (WEEE) are generated in China each year and their disposal has been a vital environmental challenge. Machaniclal recycling, fedlock recycling and landfilling are three main means of disposal of WEEE plastics. This article reviews the production of PBDEs, the amounts of WEEE and the disposal of WEEE plastics worldwide, with a special focus on China. The state of the emission of PBDEs and highly toxic polybrominated dibenzo dioxins/furans in the process of disposal is summed up based on previous studies. This article recommends that mechanical recycling should be the main means of disposal of WEEE recycling with regards to the summaries, the current practices and the status in China.
Authors: Samuel Bernard, Markus Weinmann, David Cornu, Philippe Miele
Abstract: Boron-modified polyvinylsilazanes have been studied for suitability as fiber precursor. A melt-tractable polymer displaying Si- and N-bonded methyl groups was successfully processed into green fibers ~18μm in diameter via a melt-spinning process. After the shaping process, the use of an ammonia curing atmosphere at 200°C allowed to increase the ceramic yield of the polymer, then avoid inter-fiber fusion during the further increase of the temperature. As-cured fibers were annealed in the temperature range 1000-1800°C in a nitrogen atmosphere to provide SiBCN ceramic fibers black colored, of flexible form and ~12μm in diameter in different crystallinity states going from totally amorphous below 1600°C to well-crystallized at 1800°C. The excellent strength retention after heat-treatment at 1600°C (1.3-1.5GPa) is clearly related to the high amorphous stability of fibers. Elemental compositions of such amorphous fibers showed a typical chemical formula of Si3.0B1.0C5.0N2.4. Between 1600°C and 1700°C, the fiber strength decreased to 0.9GPa then dropped to about one-quarter the original value at 1800°C while structural changes were evident by XRD analysis.
Authors: Yan Wang, Guan Yi Chen
Abstract: Bio-oil production from sewage sludge provides a potential sludge treatment alternative, which shows advantages in both sludge treatment and energy recovery. The related technologies to convert sludge into high quality fuel or synthesized bio-diesel have been widely studied recently. In this paper, major effective technologies of low temperature pyrolysis, direct thermochemical liquefaction, microwave pyrolysis and transesterification had been reviewed. Finally, the advantages and disadvantages of these methods are discussed in detail.
Authors: Yang Xie, Cang Su Xu, Dong Hua Fang, Qi Yuan Luo, Jian Ma
Abstract: Research and development in the fast pyrolysis of biomass has been absorbing substantial amounts of human and economic resources over the last two decades, resulting in notable advances in various areas including: characterization and upgrading of pyrolysis bio-oil; novel technologies capable of making use of the energy. This paper provides an updated review of its characteristics of biomass fast pyrolysis oil and a critical analysis of potential applications, such as diesel engines and turbine.
Authors: Xin Wang, Yan Li Wang, Yan Liu, Ke He Su, Qing Feng Zeng, Lai Fei Cheng, Li Tong Zhang
Abstract: The initial pathways in the CVD process of preparing silicon carbides with CH3SiCl3-H2 precursors was searched theoretically, which involves 21 well-defined transition states. The geometries of the species were optimized by employing the B3PW91/6-311G(d,p) method. The energy barriers and the reaction energies were evaluated with the accurate model chemistry method at G3(MP2) level after a non-dynamical electronic correlation detection. The heat capacities and entropies were obtained with statistical thermodynamics. The Gibbs free energies at 298.15 K and 1200 K for all the possible elementary reactions, including both direct decomposition and the radical attacking dissociations for MTS were reported. The energies at any temperature could be derived classically by using the analytical heat capacities. It was found that the free radical reactions have clearly kinetic ascendency to be the most efficient decomposition pathway.
Authors: Liang Jing Jing, Rui Li, Yu Yu Li
Abstract: Heat transfer in wood particle controls the process of the pyrolysis. This paper makes a 2-D transient heat transfer model in cylindrical to predict the thermal behavior of wood particle in the process of fast pyrolysis. Wood anisotropy and thermophysical properties are considered in this model, as well as the influence of heat reaction on temperature distribution in wood particle. Based on the calculation of transient temperature in wood particle, and analysis of the temperature distribution during the process of wood fast pyrolysis at different time, this paper preliminarily discusses the optimization of parameters in wood particle fast pyrolysis. Keywords: pyrolysis, heat transfer, particle, wood
Authors: Hang Zhang, Zuo Lun Wang, Jie Ding, Wen Sheng Linghu
Abstract: In this work the pyrolysis of waste printed circuit boards (PCBs) were investigated through TG technology and a quartz tube batch reactor, respectively. The TG analysis results showed that the total mass loss from 30-800 oC for PCB1 and PCB2 were 35.7% and 41.1%, respectively. With the increase of pyrolysis temperature in a batch reactor, gas yield of PCB2 increased, but increasing rate gradually decreased. The gas yield of PCB2 for pyrolysis time of 1min, 5min and 10min at 600 °C were 30.5%, 31.1% and 31.7%, respectively. It is suggested that the better pyrolysis temperature was at the range of 500-600 °C and the optimal pyrolysis time was 1min. The higher gas yield of PCB2 was obtained at air atmosphere than that at nitrogen atmosphere.
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