http://www.ciriaf.it/ft/File/Pubblicazioni/pdf/1571.pdf

Thermogravimetric analysis and kinetic study of poplar wood pyrolysis

Plant biomass are woody and non-wood materials (e.g., oil palm, bamboo, rattan, bagasse, and kenaf) and are abundant and renewable resource. Unfortunately, the heavy reliance on this resource is a threat to forest ecosystems and a recipe for accelerated land resource degradation. Due to the increasing scarcity of wood resources, many rural communities have shifted to utilization of crop residues for many different applications. The non-wood biomass is readily available, environmental friendly, and technologically suitable, and therefore, an excellent raw material for the future. The non-wood materials like bamboo, rattan, oil palm, and bagasse have superior properties and durability, which can be further prolonged by the modifi cation treatment. The modifi cation treatments increase the performance of the non-wood and could make it suitable for applications in many fi elds ranging from construction industry to automotive industry. This chapter deals with the properties improvement techniques of the selected non-wood biomasses and evaluates its applications for various purposes. The new developments dealing with the improvement of non-wood properties have also been presented in the chapter. The performance of non-wood biomass materials has been compared to the wood-based materials. Recent studies pertaining to the above topics have also been cited. Finally, the advanced applications of the improved non-wood biomasses have been highlighted.

Biomass and bioenergy

Reaction mechanisms and multi-scale modelling of lignocellulosic biomass pyrolysis

Research interest in the conversion of lignocellulosic biomass into energy and fuels through the pyrolysis process has increased significantly in the last decade as the necessity for a renewable source of carbon has become more evident. For optimal design of pyrolysis reactors, an understanding of the pyrolysis kinetics of lignocellulosic biomass is of fundamental importance. The distributed activation energy model (DAEM) has been usually used to describe the pyrolysis kinetics of lignocellulosic biomass. In this review, we start with the derivation of the DAEM. After an overview of the activation energy distribution and frequency factor in the DAEM, we focus on the numerical calculation and parameter estimation methods of the DAEM. Finally, this review summarizes recent results published in the literature for the application of the DAEM to the pyrolysis kinetics of lignocellulosic biomass.

An overview of distributed activation energy model and its application in the pyrolysis of lignocellulosic biomass

Kinetic parameters of red pepper waste as biomass to solid biofuel.

Pyrolysis of a wood chips mixture and main wood compounds such as hemicellulose, cellulose and lignin was investigated by thermogravimetry. The investigation was carried out in inert nitrogen atmosphere with temperatures ranging from 20°C to 900°C for four heating rates: 2 K min−1, 5 K min−1, 10 K min−1, and 15 K min−1. Hemicellulose, cellulose, and lignin were used as the main compounds of biomass. TGA and DTG temperature dependencies were evaluated. Decomposition processes proceed in three main stages: water evaporation, and active and passive pyrolysis. The decomposition of hemicellulose and cellulose takes place in the temperature range of 200–380°C and 250–380°C, while lignin decomposition seems to be ranging from 180°C up to 900°C. The isoconversional method was used to determine kinetic parameters such as activation energy and pre-exponential factor mainly in the stage of active pyrolysis and partially in the passive stage. It was found that, at the end of the decomposition process, the value of activation energy decreases. Reaction order does not have a significant influence on the process because of the high value of the pre-exponential factor. Obtained kinetic parameters were used to calculate simulated decompositions at different heating rates. Experimental data compared with the simulation ones were in good accordance at all heating rates. From the pyrolysis of hemicellulose, cellulose, and lignin it is clear that the decomposition process of wood is dependent on the composition and concentration of the main compounds.

http://kchbi.chtf.stuba.sk/cevoze/doc/Kinetic%20study%20of%20wood%20chips%20decomposition%20by%20TGA.pdf

Kinetic study of wood chips decomposition by TGA

This work deals with pyrolysis decomposition of wood chips and the main components of wood by thermogravimetric analysis (TGA). Experiments were carried out in the inert atmosphere of nitrogen. The pyrolysis temperature range was varied linearly from 20 °C to 900 °C with the heating rate equal to 5 K min–1 to detect all the changes without overlapping. Samples of cellulose, hemicellulose and lignin were used as main components of wood. Thermogravimetric (TG) and differential thermogravimetric (DTG) curves were obtained from experimental data. These records were compared with those obtained by mathematical modeling. The distribution activation energy model (DAEM) was used for mathematical description of experimental data and the prediction of kinetic parameters. According to the DAEM approach, every possible decomposition reaction with various values of activation energies is in progress at each time and temperature. Preexponential factors, mean activation energy and variance were obtained as kinetic parameters. This model is able to describe the integral decomposition curve of biomass, however, a problem occurs when describing the differential curve of biomass thermal decomposition. In general, this model does not accurately describe the decomposition of materials, which are a mixture of several compounds.

/pdf/calculation-of-kinetic-parameters-of-the-thermal-2pfcylemoi.pdf

Calculation of Kinetic Parameters of the Thermal Decomposition of Wood by Distributed Activation Energy Model (DAEM)

Influence of particle size and kinetic parameters on tire pyrolysis

Activated sewage sludge samples obtained from two different waste water treatment plants were investigated by thermogravimetric analysis. Due to a very high content of water in the sludge samples, these had to be dried at 160°C in an electrical oven in order to remove all adsorbed water. To ensure pyrolysis conditions, nitrogen atmosphere was applied. The pyrolysis decomposition process was carried out in the temperature range from ambient temperature to 900°C at three different heating rates: 2 K min−1, 5 K min−1, 10 K min−1. TGA and DTG curves of the decomposition processes were obtained. Temperature of onset decomposition, final temperature of decomposition, maximum decomposition rate, and decomposition temperature were determined by thermogravimetric analysis for both sludge samples used. The main decomposition process takes place at temperatures in the range from 230°C to 500°C. Above this temperature, there are only small changes in the mass loss which are often attributed to the decomposition of carbonates present in the sewage sludge samples. To determine the apparent kinetic parameters such as the activation energy and the preexponential factor, the so called Friedman isoconversional method was used. Because of the requirements of this method, initial and final parts of the decomposition process, where crossings of the decomposition lines occurred, were cut off. Obtained dependencies of the apparent activation energies and preexponential factors as a function of conversion were used backwards to calculate the modeled decomposition process of sewage sludge and the experimental data were in good accordance with the data obtained by simulation.

Kinetic study of pyrolysis of waste water treatment plant sludge

The present work deals with thermo-catalytic decomposition of pyrolytic oil from the scrap tire pyrolysis process. Such oil can be used as a model tar in an experimental study of tar removal from pyrolysis or gasification process gas. Several experiments under different conditions were carried out in order to determine conditions of the gasification and pyrolysis processes. Influence of the oil to steam ratio, temperature, and of the presence of dolomite catalyst was studied. Addition of water steam has positive effect on the hydrogen content in the outgoing process gas as well as on the conversion of the injected oil. The catalytic gasification experiment in a quasi steady state produced process gas with the composition: 61 mole % of H2, 6.4 mole % of CO, and 11.7 mole % of CH4. At temperatures lower than 800°C, the amount of process gas decreased resulting also in a decrease of the oil conversion. A comparison of gasification experiments using fresh calcined dolomite with experiments proceeding with regenerated dolomite was done under the same conditions. There was a decrease in the process gas volumetric flow when regenerated catalyst was used.

Lukáš Gašparovič

Papers

Kinetic study of wood chips decomposition by TGA

Calculation of Kinetic Parameters of the Thermal Decomposition of Wood by Distributed Activation Energy Model (DAEM)

Influence of particle size and kinetic parameters on tire pyrolysis

Kinetic study of pyrolysis of waste water treatment plant sludge

Catalytic gasification of pyrolytic oil from tire pyrolysis process