Computational Modeling of the Combustion and Gasification Zones in a Downdraft Gasifier

Muilenburg, Marta; Shi, Yunye; Ratner, Albert

doi:10.1115/imece2011-64009

Cited by 10 publications

(11 citation statements)

References 11 publications

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“…Gasification could occur in any of the zones, but it was prevalent in the gasification zone due to the lack of an oxidizer (Muilenburg, 2011). In this sub-zone, due to the lack (or sub-stoichiometric presence) of oxygen, several reduction reactions occur at 800-1000 o C. The reaction that occurred in this sub-zone was mostly endothermic.…”

Section: Reduction Sub-zonementioning

confidence: 99%

Kinetic based simulation of fixed bed gasifier and performance study on syngas production from different biomass feed-stocks

Bilal¹,

Fanta²,

Satheesh³

2019

Eth J Sci & Technol

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Biomass is one of the most clean and renewable energy resources. In recent times, researchers have given more attention to biomass due to its zero emission of greenhouse gases such as carbon monoxide. In biomass utilization technologies, biomass gasification is an attractive mechanism for utilization of waste biomass generated from different agro-industries. Despite the application of fixed bed flow gasification on a large scale, the reaction rate in the hot conversion zone is almost unknown. However, knowledge regarding the rates of the gasification reaction at high temperature and high pressure is crucial for detailed design and optimization of these gasifiers. The study focused on the simulation of biomass (coffee bean and rice) husk gasification process based on the kinetics of the gasifier in order to investigate the produced syngas composition. The AspenPlus simulation was used to investigate the effect of operating parameters on the composition of the produced gas. Effect of different proportions of the simulation parameter includes gasification temperature, pressure, reactor volume, equivalence ratio and moisture on gas production and composition. Results of sensitivity analysis showed that an increase in temperature led to a rise in the production of H2 and CO gases. Whereas, an increase in moisture content of the biomass showed lower heating value of the produced gas. Based on the obtained result, the maximum lower heating value of syngas was obtained at the gasification temperature of 800 o C, steam to biomass ratio of 0.1, pressure of 1 bar, 0.05% of moisture content and 0.02 m 3 of reactor volume.

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Section: Reduction Sub-zonementioning

confidence: 99%

Kinetic based simulation of fixed bed gasifier and performance study on syngas production from different biomass feed-stocks

Bilal¹,

Fanta²,

Satheesh³

2019

Eth J Sci & Technol

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“…Fluidized Bed Gasifier (bubbling bed, circulating fluidized bed): Feedstock particles are fed from reactor side to a preheated granular (sand) bed, where the air or steam is fed through the bottom to fluidize biomass particles in the gasifier [11,16]as shown in Fig 4 [17].The upward drag force of gas thoroughly mixes the suspended solid particles inside the gasifier with the air, thereby increasing the solid fluid interactions compared to updraft or downdraft gasifiers. The major advantage of fluidized bed gasifiers is the uniform temperature profile in the gasification zone created by circulating fluid through fine granular material.…”

Section: Figure 3 -Updraft and Downdraft Gasifiersmentioning

confidence: 99%

Production of Syngas from Biomass Using a Downdraft Gasifier

Golpour¹,

Boravelli²,

Smith³

et al. 2017

IJERA

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The role of biomass in energy and fuel production as an alternative to fossil fuel is vitally important considering carbon dioxide production vs. secure energy. Sustainable, renewable and reliable resources of domestically produced biomass together with wind and solar energy are sensible options to support a small-scale power generation to meet local electricity demand plus provide heat for rural development. The present work focuses on: 1. Design, build and operate a vertical downdraft biomass gasifier with tar removal 2. Establishing the optimum operating methodology and parameters to maximize syngas production in biomass gasification through process testing. The one ton per day biomass gasification process unit designed in this work included a downdraft biomass thermochemical conversion gasifier, gas transportation line with tar removal and an enclosed combustion chamber. The reactor used internal heat transfer surfaces to enhance intra-bed heat and mass transfer inside the reactor. Three different woody biomass feedstock including pellets, picks and flakes were examined in this work. Specific results described in this paper include identifying and characterizing the key operating factors (i.e., temperature profile, feed stock carbon/hydrogen mass ratio, and air flow rate) required to optimize reactor yield. To achieve the maximum syngas production yield, experiments carried out using classical experimental design methodology.

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“…Computational Fluid Dynamics (CFD) modelling has previously been used to predict the behaviour of biomass gasification to optimize operating conditions of an existing gasifier [17][18][19][20][21][22][23][24][25][26][27][28][29]. In general, only a few aspects of the gasifier design have been investigated in any one study.…”

Section: Introductionmentioning

confidence: 99%

Optimisation of a throat downdraft gasifier for hydrogen production

Prasertcharoensuk

Hernandez²,

Bull

et al. 2018

Biomass and Bioenergy

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Gasification of coal is a well-known technology used to convert solid coal into gas (syngas). The implementation of gasification for waste and biomass still requires attention due to the difference in nature of biomass compared to coal. Although, modification to a gasifier is one of the main approaches to achieve high quality syngas production (high H2/CO ratio) and to eliminate tar formation, the effect of design of the gasifier has not been studied. Downdraft gasifiers are reported to produce relatively high quality syngas with low tar concentration compared to other designs. Therefore, in this study a 20 cm diameter throat downdraft gasifier was numerically optimised using Computational Fluid Dynamics modelling. The effect of throat diameter and the position of the air inlet nozzles above the throat on the properties of the gas and the temperature profile in the gasifier was systematically investigated and validated using experimental data. The throat diameter and the position of the air inlet nozzles had a significant effect on the properties of the gas and temperature profile. The modelling and experimental results agreed very well with less than 5% deviation. This confirms that the numerical approaches are valid and can be used in scaling up biomass gasification, reducing process development time from laboratory scales to pilot/industrial scales. The maximum concentration of H2 2 (31.2%mol) and highest H2/CO ratio (1.25) was found at a ratio of throat diameter to gasifier diameter of 0.40 and the position of the air inlet nozzles at 10 cm above the throat.

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Computational Modeling of the Combustion and Gasification Zones in a Downdraft Gasifier

Cited by 10 publications

References 11 publications

Kinetic based simulation of fixed bed gasifier and performance study on syngas production from different biomass feed-stocks

Kinetic based simulation of fixed bed gasifier and performance study on syngas production from different biomass feed-stocks

Production of Syngas from Biomass Using a Downdraft Gasifier

Optimisation of a throat downdraft gasifier for hydrogen production

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