Numerical Study of Cylindrical Tropical Woods Pyrolysis Using Python Tool

In this paper, the thermal behavior of large pieces of wood pyrolysis has been modeled. Two mathematical models coupling heat transfer equations to chemical kinetics were used to predict the pyrolytic degradation of a 25 mm radius wood sample, assumed to be dry in the first model and wet in the second, when heated to 973.15 K. The reactions involved in the pyrolysis process are assumed to be endothermic. The diffusion of bounded water during the process is taken into account in the second model, where the heat transfer equation has been coupled to that of the diffusion of moisture. This model, although simple, provides more information on the drying and pyrolysis processes during the heating of wood, which is its originality. It can therefore be advantageously used to calculate the temperature distribution in a pyrolysis bed. The equations of the two models, discretized by an explicit finite difference method, were solved numerically by a program written in Python. The validation of both models against experimental work in the literature is satisfactory. The two models allow examination of the temperature profile in the radial direction of wood samples and highlighting of the effect of temperature on some thermal, physical and physicochemical characteristics.

Simulation of Wood Combustion in PATO Using a Detailed Pyrolysis Model Coupled to fireFoam

The numerical simulation of fire propagation requires capturing the coupling between wood pyrolysis, which leads to the production of various gaseous species, and the combustion of these species in the flame, which produces the energy that sustains the pyrolysis process. Experimental and numerical works of the fire community are targeted towards improving the description of the pyrolysis process to better predict the rate of production and the chemical nature of the pyrolysis gases. We know that wood pyrolysis leads to the production of a large variety of chemical species: water, methane, propane, carbon monoxide and dioxide, phenol, cresol, hydrogen, etc. With the idea of being able to capitalize on such developments to study more accurately the physics of fire propagation, we have developed a numerical framework that couples a detailed three-dimensional pyrolysis model and fireFoam. In this article, we illustrate the capability of the simulation tool by treating the combustion of a wood log. Wood is considered to be composed of three phases (cellulose, hemicellulose and lignin), each undergoing parallel degradation processes leading to the production of methane and hydrogen. We chose to simplify the gas mixture for this first proof of concept of the coupling of a multi-species pyrolysis process and a flame. In the flame, we consider two separate finite-rate combustion reactions for methane and hydrogen. The flame evolves during the simulation according to the concentration of the two gaseous species produced from the material. It appears that introducing different pyrolysis species impacts the temperature and behavior of the flame.

Obtaining a diesel fuel component from liquid products of oxidative pyrolysis of wood

Recycling and rational use of wood-processing industry waste is an urgent task for the economy and industry. On the basis of experimental studies on the oxidative pyrolysis of Siberian pine and Downy birch, a basic technological scheme for components of motor fuels obtaining is proposed. It is shown that the main components of liquid products of wood pyrolysis in water vapor are aromatic and saturated hydrocarbons, as well as oxygen-containing compounds that need to be hydrogenated.

Anti-Termites Properties of Liquid Smoke from Bintangur Wood

Wood and wood-based products are very vulnerable to termite attacks. One of the methods to control termite attacks is using chemical insecticide. However, the use of chemical insecticide is considered a negative effect on the environment. The aim of this research was to determine the anti-termite properties of liquid smoke against Coptotermes curvignathus Holmgren. The liquid smoke derived from bintangur wood pyrolysis at 370°C, 400°C, and 430°C was assessed as an anti-termite activity. Anti-termite activities against C. curvignathus were conducted by using liquid smoke with the concentration of 2%, 4%, 6%, and 8% (v/v). Simple linear regression was used to measure the effect of liquid smoke concentration against C. curvignathus. The results showed that the liquid smoke concentration of 6% and 8% at the three pyrolysis temperatures effectively controlled the subterranean termite's attack and resulted in 100% termites mortality. The chemical content of bintangur wood vinegar has contained phenol (1.23–1.65%) and acid (4.33–6.68%). Keywords: acid content, antitermitic activity, bintangur wood, phenol content, wood vinegar

Rheological Properties of Aged Crude Hard Wood Pyrolysis Oil

Upon storage of the pyrolysis oil, aging reactions may initiate phase separation and change of the rheological properties. These changes lead to unfavourable fuel characteristics in handling, transportation and applications. Efforts have been made for alleviation including methods on how to avoid these aging effects and development of equipment capable of handling aged pyrolysis liquids with unfavourable fuel characteristics. Therefore, the aim of this study was to explore the rheological properties of phase separated pyrolysis liquid fuel. Two batches of a well – stored poplar wood pyrolysis oils were used for the investigation; one batch was diluted with water to represent the oils undergoing severe phase separation (forced phase separation), and another batch was not diluted. Steady and dynamic rheological tests were conducted at various temperatures. Homogeneous (whole oil) and the bottom phases of pyrolysis oils were used. Results revealed that the whole oils of both diluted and undiluted oils exhibited low viscosity Newtonian behaviours at higher temperatures and high viscosity non-Newtonian behaviours at low temperatures. The bottom phases of both diluted and undiluted oils exhibited nonNewtonian behaviours with significant higher viscosity than the whole oils. The strain and frequency sweep dynamic tests showed existence of weak structures in the whole oils and strong network structures in the bottom phases. This study suggests that the handling, transportation and application of the pyrolysis oils undergoing phase separation are possible when the oils are treated with higher temperatures predominantly in turbulent state.

EFFECT OF ZEOLITE ON THE CATALYTIC CRACKING OF TAR YIELDS MAHOGANY WOOD PYROLYSIS

In this study, the effects of zeolite were observed to investigate the formation of a pyrolysis product, which is tar yield. Tar yields receive the most attention because of their potential as a bio-oil and chemical feedstocks. For this reason, efforts to increase tar yield were made, one of which was by adding zeolite to the pyrolysis process. The role of zeolite here was a pyrolysis catalyst. This research was conducted on a real pilot plant pyrolysis reactor which utilized mahogany wood as biomass feedstock with the addition of zeolite that was 0–50% of the total mass pyrolysis feedstock. The temperatures set in this pyrolysis were 250 °C, 500 °C, and 800 °C. The test results were measured in terms of the tar yield’s volume and mass. The chemical composition of tar yield was tested using a Gas Chromatograph Mass Spectrometry (GC-MS) to measure the percentage of its chemical constituent compounds. Then, the formation mechanism of tar compounds from pyrolysis was described by using HyperChem simulation. The results showed that an increase in zeolite catalyst percentage would generate more volume of tar yields. It was due to the breaking of biomass hydrocarbon chains, increasing the production of tar yields. Zeolite also affected the formation of hydrocarbon chains in tar yields where the chains became shorter as the percentage of zeolite catalyst rose. The mechanism of increasing tar product was due to the role of zeolite as a catalyst in the catalytic cracking process which is almost similar to acid-base reactions of Brønsted-Lowry and Lewis. This reaction took place when the pyrolysis yields moved through the pores of zeolite, breaking the long hydrocarbon chains into shorter ones which were dominated by alkenes, aromatic, and acidic compounds formation. In addition, acidic compounds represented by acetic acid function as a flammable matter possess the potential of becoming oil-fuel.