Evaluation of Reduced Kinetics in Simulation of Gasified Biomass Gas Combustion

Zhang, Xiaoxiang; Munjat, Nur Farizan; Jayasuriya, Jeevan; Fakhrai, Reza; Fransson, Torsten

doi:10.1115/gt2013-95565

Cited by 2 publications

(2 citation statements)

References 28 publications

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“…The combustion of such gas mixtures showed a reduction of NOx emissions during the combustion of CO and H 2 with air [30]. Furthermore, this gas mixture was recently investigated as an alternative fuel for reciprocating engines and gas turbines in the context of heat and/or electricity generation or co-generation processes [31,32]. The Computations Fluid Dynamics (CFD), which is low cost compared to experimental tests, has become a crucial tool for understanding the combustion process of the gas mixture and for controlling the emission levels.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study of Turbulent Combustion of a Lignocellulosic Gas Mixture in an Updraft Fixed Bed Reactor

et al. 2022

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Lignocellulosic biomass is an established source of energy with various applications. Yet, its diversity renders the proper combustion of its thermochemical degradation vapors challenging. In this work, the combustion of syngas obtained from biomass thermochemical conversion was numerically investigated to limit pollutant emission. The Computational Fluid Dynamics (CFD) simulation was performed using the open-source OpenFOAM. The reactor was considered in an axisymmetric configuration. The gas mixture resulting from the pyro-gasification devolatilization was composed of seven species: CO, CO2, H2O, N2, O2, light, and heavy hydrocarbon, represented by methane (CH4) and benzene (C6H6), respectively. The evolutions of mass, momentum, energy, and species’ concentrations were tracked. The flow was modeled using the RANS formulation. For the chemistry, reduced kinetic schemes of three and four steps were tested. Moreover, the Eddy Dissipation Concept (EDC) model was used to account for the turbulence–chemistry interaction. The numerical prediction enabled us to describe the temperature and the species. Results show that all transported variables were closely dependent on the mass flow rate of the inflow gas, the primary and the secondary air injections. Finally, from a process perspective, the importance of the secondary air inlet to limit pollutants emissions can be concluded.

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Section: Introductionmentioning

confidence: 99%

A Numerical Study of Turbulent Combustion of a Lignocellulosic Gas Mixture in an Updraft Fixed Bed Reactor

et al. 2022

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“…On the other hand, the laminar flame speed (high-temperature chemistry) for the WD-2 is around 10% lower than that for the DRM-19 [115,122]. Since the flames are prone to showing more stabilities with a shorter ignition delay and a higher burning velocity, while the WD-2 (with a shorter ignition delay but also a lower flame speed) shows larger flame oscillations (shown in Figure 2.12 (b)), as compared to the DRM-19, therefore, it can be indicated that the flame speed is a primary factor in determining the above-discussed oscillating flame behaviours.…”

Section: Reaction Mechanismsmentioning

confidence: 86%

Micro/mesoscale combustion based portable power generating system

Kang¹

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Micro/mesoscale combustion-driven power generation is a promising alternative to replace traditional batteries for powering small scale electronics owing to its much higher energy densities. However, the considerable heat losses from the combustor walls due to the dramatically increased surface-tovolume ratio, as well as the short flow residence time at small scales pose a technical challenge in stabilising the flame inside the micro/mesoscale combustor. On the other hand, the significantly enhanced flame-wall thermal coupling at small scales can also lead to some unique flame characteristics.Recently, solid state power conversion of the heat released in the micro/mesoscale combustor such as thermoelectric (TE) and thermophotovoltaic (TPV) has been favoured over traditional power conversion methods such as micro-turbines. This is due to the excessive mechanical and viscous losses that rotating machinery suffers from upon miniaturisation.One of the main aims of this thesis is to perform numerical simulations to investigate the fundamental aspects of micro/mesoscale combustion, such as micro-flame behaviours of propagation and stabilisation, the conditions under which flame dynamics occur and the choices that suppress them. A set of modelling techniques that gives guidelines and practices for performing the time-accurate micro/mesoscale combustion simulations has been developed through investigation. Knowledge on standard and well-accepted numerical methods in literature are collected in a cohesive document. The less well-established modelling choices have been thoroughly evaluated and discussed.Using the developed numerical models, the effects of hydrogen and carbon monoxide addition on premixed methane/air flame dynamics is investigated. Results show that the flame instabilities which exist in pure methane/air flames could be effectively suppressed via a small amount of additives. Deep understanding of the underlying physics and chemistry has been gained. The effects of wall temperature profiles on the simulated micro-flame behaviours are also studied. The role of the combustion heat release and the gas-solid heat transfer in determining the micro-flame propagation speed is identified.Experimental works are also carried out, towards a full system demonstration for micro-power generation. The focus is placed on the "wall thermal engineering" on the improvement of the combustor performance and power output. The thermally-orthotropic pyrolytic graphite for the combustor wall material is explored. Compared to an isotropic material of stainless steel, a widened flame stability limit with pyrolytic graphite is demonstrated. Moreover, a uniform and moderate temperature distribution over the combustor surface is achieved, which is favourable for thermoelectric power conversion applications. Meanwhile, a novel, compact mesoscale thermophotovoltaic power generating system using a combination of porous media combustion and a simple band-pass filtering method is developed. The use of the porous media effectively enh...

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Evaluation of Reduced Kinetics in Simulation of Gasified Biomass Gas Combustion

Abstract: It is essentially important to use appropriate chemical kinetic models in the simulation process of gas turbine combustion.

Cited by 2 publications

References 28 publications

A Numerical Study of Turbulent Combustion of a Lignocellulosic Gas Mixture in an Updraft Fixed Bed Reactor

A Numerical Study of Turbulent Combustion of a Lignocellulosic Gas Mixture in an Updraft Fixed Bed Reactor

Micro/mesoscale combustion based portable power generating system

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