Characterization and prediction of biomass pyrolysis products (original) (raw)
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Experimental and Modelling Studies of Biomass Pyrolysis
Chinese Journal of Chemical Engineering, 2012
The analysis on the feedstock pyrolysis characteristic and the impacts of process parameters on pyrolysis outcomes can assist in the designing, operating and optimizing pyrolysis processes. This work aims to utilize both experimental and modelling approaches to perform the analysis on three biomass feedstocks wood sawdust, bamboo shred and Jatropha Curcas seed cake residue, and to provide insights for the design and operation of pyrolysis processes. For the experimental part, the study investigated the effect of heating rate, final pyrolysis temperature and sample size on pyrolysis using common thermal analysis techniques. For the modelling part, a transient mathematical model that integrates the feedstock characteristic from the experimental study was used to simulate the pyrolysis progress of selected biomass feedstock particles for reactor scenarios. The model composes of several sub-models that describe pyrolysis kinetic and heat flow, particle heat transfer, particle shrinking and reactor operation. With better understanding of the effects of process conditions and feedstock characteristics on pyrolysis through both experimental and modelling studies, this work discusses on the considerations of and interrelation between feedstock size, pyrolysis energy usage, processing time and product quality for the design and operation of pyrolysis processes.
Pyrolysis as a key process in biomass combustion and thermochemical conversion
Thermal Science, 2016
Biomass is a fuel with a highly volatile content and due to that, pyrolysis as a part of the combustion process, has a dominant role in the overall process development, as well as on final products and the process efficiency. It is of key importance to investigate the influence of the process parameters; as temperature, furnace/reactor environment, fuel properties, type, particle size, geometry, and the structure of the pyrolysis process has an influence regards the design of the combustion/pyrolysis equipment and the final products of the processes. This paper gives some results of the investigation?s related to this problem, mainly focussing on wooden biomass as the most important biomass type, as well as a comparison with relevant documented literature. Besides that, pyrolysis based technologies are one of the key directions in synthetic fuels production based on biomass. Biomass pyrolysis process parameters are crucial in reactor design as well as the quantity and quality of the...
Biofuel Research Journal
Modeling is regarded as a suitable tool to improve biomass pyrolysis in terms of efficiency, product yield, and controllability. However, it is crucial to develop advanced models to estimate products' yield and composition as functions of biomass type/characteristics and process conditions. Despite many developed models, most of them suffer from insufficient validation due to the complexity in determining the chemical compounds and their quantity. To this end, the present paper reviewed the modeling and verification of products derived from biomass pyrolysis. Besides, the possible solutions towards more accurate modeling of biomass pyrolysis were discussed. First of all, the paper commenced reviewing current models and validating methods of biomass pyrolysis. Afterward, the influences of biomass characteristics, particle size, and heat transfer on biomass pyrolysis, particle motion, reaction kinetics, product prediction, experimental validation, current gas sensors, and potentia...
Product Analysis and Thermodynamic Simulations from the Pyrolysis of Several Biomass Feedstocks
Energy & Fuels, 2007
The pyrolysis of southern pine, red oak, and sweet gum sawdust is reported. Pyrolysis experiments were conducted under either a helium or nitrogen atmosphere at ∼371-871°C, to determine the balance between liquid and gas products. Gas-and liquid-phase pyrolysis products were identified using gas chromatography (GC) and GC/mass spectrometry (MS). A total of 109 liquid and 40 gas compounds were identified. A total of 59 chemical compounds (35 liquids and 24 gaseous products) were quantitatively determined. The influence of the gas-phase residence time and biomass feed particle size were studied. The gas residence time determined the extent of secondary reactions. Very short residence times enhanced liquid production versus gas production. Particle sizes (d < 105 µm, 105 µm < d < 149 µm, 149 µm < d < 297 µm, and d > 297 µm) did not have a pronounced effect on either the yield or product distributions, indicating that heat-transfer limitations within the particles were negligible. The pyrolysis of pine, red oak, and sweet gum sawdust yielded similar product distributions. Simulations were conducted using the ASPEN/ SP software package based on Gibbs energy minimization. At high temperatures, dominant species were hydrogen and carbon monoxide, while at lower temperatures, methane, carbon dioxide, and water were the predominant species. Above 871°C, further increases in the temperature did not affect the product distribution. Lower gasification temperatures and higher steam/carbon ratios resulted in higher hydrogen and carbon monoxide production. Mohan, D.; Pittman, C. U.; Steele, P. Pyrolysis of wood/biomasss A critical review. Energy Fuels 2006, 20, 848-889. (2) Tsai, W. T.; Lee, M. K.; Chang, Y. M. Fast pyrolysis of rice straw, sugarcane bagasse and coconut shell in an induction-heating reactor. J. Anal. Appl. Pyrolysis 2006, 76, 230-237. (3) Guéhenneux, G.; Baussand, P.; Brothier, M.; Poletiko, C.; Boissonnet, G. Energy production from biomass pyrolysis: A new coefficient of pyrolytic valorization. Fuel 2005, 84, 733-739. (4) Huber, G. W.; Iborra, S.; Corma, A. Synthesis of transportation fuels from biomass: Chemistry, catalysts, and engineering. Chem. ReV. 2006, 106, 4044-4098. (5) Bridgwater, A. V. Renewable fuels and chemicals by thermal processing of biomass. Bridgwater, A. V.; Peacock, G. V. C. Fast pyrolysis process for biomass. Renewable Sustainable Energy ReV. 2000, 4, 1-73. (9) Butt, D. A. E. Formation of phenols from the low-temperature fast pyrolysis of Radiata pine (Pinus radiata). Part 1. Influence of molecular oxygen. J. Anal Appl. Pyrolysis 2006, 76, 38-47. (10) Piskorz, J.; Majerski, P.; Radlein, D.; Scott, D. S.; Bridgwater, A. V. Fast pyrolysis of sweet sorghum and sweet sorghum bagasse. J. Anal. Appl. Pyrolysis 1998, 46, 15-29.
Modeling of heterogeneous chemical reactions caused in pyrolysis of biomass particles
Advanced Powder Technology, 2007
Pyrolysis of woody biomass was studied experimentally with the aim of investigating heat transfer and heterogeneous chemical reactions. In rapid pyrolysis, two different pyrolysis rates were obtained, with different reactions taking place depending on the temperature (a process producing gas and a process producing tar + water). However, the temperature at the transit stage between the two steps for gas differs from the temperature for tar + water. The fact means that there are two processes for gas generation. The experimental results obtained for slow pyrolysis showed that the average temperature in the biomass layer increased slowly as compared with the change in the set temperature. This tendency does not vary over a mean particle size range of 1.1 < D p,50 (mean particle size) < 11 mm. Numerical simulation of heat transfer in a tubular reactor, without considering chemical enthalpy, was carried out. Comparison of the calculated results with the experimental heat flow rates in the biomass layer revealed two endothermic regions and two exothermic regions. The flow rate of gas generated in the reaction showed two peaks at the exothermic regions. Thus, it was concluded that heat transfer by pyrolysis consists of many processes. Furthermore, we propose a new mechanism representing the heterogeneous chemical reactions involved in pyrolysis, which is divided into four processes: (i) evaporation of water, (ii) decomposition of cellulose, (iii) decomposition of generated tar and (iv) decomposition of lignin.
Pyrolysis behaviors of various biomasses
Polymer Degradation and Stability, 2014
Thermal behavior of different types of biomass, namely forestry e Eucalyptus globulus sawdust, Norway spruce (Picea abies) thermo mechanical pulp; agricultural e energy grass, Brassica rapa, and by-products e pine cones, grape seeds, was evaluated by thermogravimetry and by analytical pyrolysis. The liquid products from pyrolysis were analyzed by gas chromatography coupled with mass selective detector, Fourier transform infrared spectroscopy and by nuclear magnetic resonance spectroscopy. The elemental analysis and the calorific values of the pyrolysis residues were investigated. It has been established that the pyrolysis products consisted mainly of carboxylic acids, ketones, furans, phenols, guaiacols, catechols, and their derivatives, resulting from the degradation of the main structural components of biomass. The distribution of compounds in oils was strongly depended on biomass source, differences in the pyrolysis behavior among the biomass samples being found.
Thermal analysis of biomass and corresponding pyrolysis products
Fuel, 1996
Biomass samples were submitted to thermoanalytical investigation to evaluate their thermal behaviour in both oxidizing and inert atmospheres. The trend of the t.g.a, and d.t.g, curves in air or He were evaluated to obtain information on reactivity of the samples and some correlations with their analytical characteristics. In particular, evaluation of lignin content was found to be useful to predict biomass thermal behaviour and the quality of pyrolysis products obtained. As the standard determination of lignin content is complicated, an alternative method using thermogravimetry was also used. A simple laboratory apparatus was used to obtain the pyrolysis products of the biomass samples, allowing a small amount of oil to be collected for thermogravimetric evaluation of its quality. The quality of biomass-derived oil depended on the lignin content of the starting material. Comparison of the thermogravimetric curve of the bio-oil with the corresponding curve of a bio-oil sample produced in an industrial plant showed that the oils obtained in the laboratory apparatus were considerably lighter and therefore better suited for use as fuel.
Pyrolysis and Combustion Characteristics of Biomass and Waste-Derived Feedstock
Industrial & Engineering Chemistry Research, 2006
The trend for material and energy recovery from wastes along with the need to reduce greenhouse gases has led to an increased interest in the thermal exploitation of biomass and/or wastes. In this work, the pyrolysis and combustion behavior of 10 biomass and waste materials was investigated in a nonisothermal thermogravimetric analyzer (TA Q600) at ambient pressure and 150-250-µm particle size. The effect of the heating rate (5, 20, 50, and 100°C/min) was also considered. The independent parallel first-order reaction model was elaborated for the kinetic analysis of the pyrolysis results. The thermal degradation of the biomass/ waste samples was modeled assuming three or four parallel reactions. At increased heating rates, enhanced pyrolysis rates were achieved. As a result, a slight decrease in total weight loss was observed, accompanied by a systematic increase in pyrolysis starting temperature and an almost linear increase in maximum pyrolysis rate from 5% to 90%/min. Increased combustion reactivity was found for olive kernel and willow, followed by forest residue. The catalytic effect of mineral matter on char oxidation was pronounced in the MBM (meat and bone meal) sample, leading to a reaction rate decrease and shifting the DTG curve to lower temperatures between 300 and 400°C.
Pyrolysis products from different biomasses
Applied Energy, 2001
The purpose of this study was to evaluate the amounts of various pyrolysis products (gases, water, tar and charcoal) from three biomasses (wood, coconut shell and straw) and to suggest a kinetic equation for the thermal cracking of tar at temperatures varying from 400 to 900 C. From the results, a comparative analysis is done for the biomasses, and a kinetic model of thermal cracking of tar is proposed for a residence time ranging from zero to 4s . This can be applied to the purification of gasification gases used as a feed gas to a combustion engine, and so contributes to the design of gasifiers. #