The effect of size, shape and pyrolysis conditions on the thermal decomposition of wood particles and firebrands

Olszewski, Paweł; Chen, Yawei; Baum, Howard R.

doi:10.1016/j.ijheatmasstransfer.2016.11.051

Cited by 48 publications

(55 citation statements)

References 8 publications

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“…The presence of exothermic steps in the decomposition of charring polymeric solids was first observed and explained by Li and Stoliarov. 14 Atreya et al 30 found that wood particle pyrolysis consisted of an endothermic phase followed by an exothermic phase, which is consistent with the presented data.…”

Section: Resultssupporting

confidence: 91%

Development of a pyrolysis model for oriented strand board. Part I: Kinetics and thermodynamics of the thermal decomposition

Gong

Hong

Zhou

et al. 2021

Journal of Fire Sciences

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Oriented strand board is a widely used construction material responsible for a substantial portion of the fire load of many buildings. To accurately model the response of oriented strand board to fire, thermogravimetric analysis, differential scanning calorimetry, and microscale combustion calorimetry tests were carried out to construct a thermal decomposition model using a numerical solver, ThermaKin, and a hill climbing optimization algorithm. The model included a single-step water vaporization reaction and four consecutive reactions representing thermal decomposition of organic constituents of oriented strand board. The experiments and modeling revealed that the first two of the four reactions are endothermic, while the last two are exothermic. The net heat of decomposition was found to be near zero. The heat capacities of condensed-phase species and heats of combustion of evolved gases were also determined. The heats of combustion were found to vary over the course of decomposition—the trend captured by the model. Development of a complete pyrolysis model for this material will be a subject of Part II of this work.

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Section: Resultssupporting

confidence: 91%

Development of a pyrolysis model for oriented strand board. Part I: Kinetics and thermodynamics of the thermal decomposition

Gong

Hong

Zhou

et al. 2021

Journal of Fire Sciences

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“…The air-water vapour binary diffusion coefficient (DA/V), in function of the temperature and the pressure inside a particle, can be calculated with the equation proposed by Siau [84]: Where Dinert/i is the binary diffusion coefficient between an inert and an i th component, Σ is the sum of the atomic diffusion volumes (from Poling et al [102]) and Minert/i is the mean molecular mass ratio between an inert and an i th compound. The diffusion phenomena are omitted in certain publications related to modelling of pyrolysis of dry biomass [28,42,56,103]. Authors who modelled the pyrolysis of wet biomass have treated the diffusion coefficients as constant values (range from 10 -6 m 2 /s to 10 -5 m 2 /s) for all gas species in order not to overcomplicate the model [59,91,92,104].…”

Section: Gas Binary Diffusionmentioning

confidence: 99%

“…Where is the molar mass of the i th component in the mixture. Many authors use simplifications and implement the thermal conductivity of the gas mix as a constant value in the range from 0.025 W/(m K) to 0.026 W/(m K) [52,56,91,103].…”

Section: Thermal Conductivity: Gas Mixturementioning

confidence: 99%

Review on Modelling Approaches Based on Computational Fluid Dynamics for Biomass Pyrolysis Systems

Maziarka

Ronsse

Anca-Couce

2020

Biofuels and Biorefineries

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Modelling is a complex task combining elements of knowledge in the field of computer science, mathematics and natural sciences (fluid dynamics, mass and heat transfer, chemistry). In order to correctly model the process of biomass thermal degradation, in-depth knowledge of multi-scale unit processes is necessary. A biomass conversion model can be divided into three main submodels depending on the scale of the unit processes: the molecular model, single particle model and reactor model. Molecular models describe the chemical changes in the biomass constituents. Single-particle models correspond to the description of the biomass structure and its influence on the thermo-physical behaviour and the subsequent reactions of the compounds released during decomposition of a single biomass particle. The largest scale submodel and at the same time, the most difficult to describe is the reactor model, which describes the behaviour of a vast number of particles, the flow of the reactor gases as well as the interaction between them and the reactor. This chapter contains a basic explanation about which models are currently available and how they work from a practical point of view.

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“…In the formulation of the problems, the process of the influx of the products of thermal decomposition and chemical interaction of the solid products of pyrolysis of wood and water vapor into the boundary layer of the particle has been taken into account. As a result, a gas mixture is formed that is flammable when the critical temperatures and fuel concentrations are reached [44]. The time period from the beginning of the thermal effect on the particle to Fig.…”

Section: Mathematical Formulation Of the Problemmentioning

confidence: 99%

In vitro Effects of a Novel Silver-based Complex on Influenza Virus

Silnikov¹,

Plotnikov

2018

Journal of Pharmacology and Pharmacotherapeutics

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The results of the experimental and theoretical studies of the processes of the single particles ignition of the wood biomass of various forms (a cube, a cylinder and a sphere) have been presented. According to the results of the experimental studies, it has been established that the particles form can have a fairly significant effect on the characteristics and conditions of ignition. It has been shown that the wood particles in the form of a sphere are ignited much faster than cylindrical and cubic ones (ignition delay times are less by 56%). Such a tendency is maintained for particles sizes from 1 $ 10 À3 m to 3 $ 10 À3 m. According to the results of the experiments, the mathematical model for ignition of a particle of wet wood biomass has been formulated, taking into account the joint occurrence of the main processes of the thermal preparation (radiation-convective particle heating, evaporation of water, thermal decomposition of the organic part of the fuel, output, ignition and combustion of gaseous pyrolysis products, ignition of the char residue). The formulated system of the nonlinear differential equations in the partial derivatives with the corresponding boundary conditions describes the ignition process in a two-dimensional setting, taking into account the substantial nonuniformity of the temperature field of a wood particle in the induction period. We have taken into account that the evaporation process takes place in the front. Up to the present time, the mathematical models of such a degree of detailing of the physical processes occurring together when igniting wet wood have not been formulated. A comparative analysis of the ignition delay times (t ign) obtained theoretically and experimentally has showed their satisfactory correspondence. As a result of the numerical simulation, the temperature fields in the system "a fuel particle d hightemperature medium" have been obtained, illustrating the high gradients of the temperatures at the moment of ignition. It has been established that it is possible to ignite the water-saturated wood particles before they dry completely. It has been established that the ignition mode of wood particles is possible before they dry completely.

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The effect of size, shape and pyrolysis conditions on the thermal decomposition of wood particles and firebrands

Cited by 48 publications

References 8 publications

Development of a pyrolysis model for oriented strand board. Part I: Kinetics and thermodynamics of the thermal decomposition

Development of a pyrolysis model for oriented strand board. Part I: Kinetics and thermodynamics of the thermal decomposition

Review on Modelling Approaches Based on Computational Fluid Dynamics for Biomass Pyrolysis Systems

In vitro Effects of a Novel Silver-based Complex on Influenza Virus

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