Combustion of Wood Chips in a CFBC. Modeling and Validation

Adánez, Juan; Gayán, Pilar; Diego, Luis F. de; Garcı́a-Labiano, F.

doi:10.1021/ie020605z

Cited by 35 publications

(20 citation statements)

References 34 publications

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“…These models were developed to predict the fluid dynamics of large fluidized bed reactors. Actually, the vertical profile of solids predicted by the model described by Pallarés and Johnsson [356] showed good agreement with the experimental data for units as large as 226 MW circulating fluidized beds (CFB) and adequately predicted the combustion efficiency burning biomass in a 12 MW th CFB boiler [357]. Thus, the macroscopic models have a great potential to be used for the simulation, design and optimization of large fluidized-bed reactors in CLC systems.…”

Section: Fluid Dynamicsmentioning

confidence: 57%

Progress in Chemical-Looping Combustion and Reforming technologies

Adánez

Abad

Garcı́a-Labiano

et al. 2012

Progress in Energy and Combustion Science

1,999

1,614

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This work is a comprehensive review of the Chemical-Looping Combustion (CLC) and Chemical-Looping Reforming (CLR) processes reporting the main advances in these technologies up to 2010. These processes are based on the transfer of the oxygen from air to the fuel by means of a solid oxygen-carrier avoiding direct contact between fuel and air for different final purposes. CLC has arisen during last years as a very promising combustion technology for power plants and industrial applications with inherent CO 2 capture which avoids the energetic penalty present in other competing technologies.CLR uses the chemical looping cycles for H 2 production with additional advantages if CO 2 capture is also considered.The review compiles the main milestones reached during last years in the development of these technologies regarding the use of gaseous or solid fuels, the oxygen-carrier development, the continuous operation experience, and modelling at several scales. Up to 2010, more than 700 different materials based on Ni, Cu, Fe, Mn, Co, as well as other mixed oxides and low cost materials, have been compiled. Especial emphasis has been done in those oxygen-carriers tested under continuous operation in Chemical-Looping 2 prototypes. The total time of operational experience (≈ 3500 h) in different CLC units in the size range 0.3-120 kW th , has allowed to demonstrate the technology and to gain in maturity. To help in the design, optimization, and scale-up of the CLC process, modelling work is also reviewed. Different levels of modelling have been accomplished, including fundamentals of the gas-solid reactions in the oxygen-carriers, modelling of the air-and fuel-reactors, and integration of the CLC systems in the power plant. Considering the great advances reached up to date in a very short period of time, it can be said that CLC and CLR are very promising technologies within the framework of the CO 2 capture options.

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Section: Fluid Dynamicsmentioning

confidence: 57%

Progress in Chemical-Looping Combustion and Reforming technologies

Adánez

Abad

Garcı́a-Labiano

et al. 2012

Progress in Energy and Combustion Science

1,999

1,614

View full text Add to dashboard Cite

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“…Two kinds of particles were assumed: large non-elutriable particles which devolatilise uniformly in the bottom and splash regions and fine particles of elutriable size which can devolatilise along all the combustor. To determine the distribution of elutriable particles along the combustion chamber, age population balances of devolatilising particles were developed for biomass and coal [17]. It has to be pointed out that primary fragmentation of the biomass and coal particles has been included in the model.…”

Section: Devolatilisation Of Biomass/coalmentioning

confidence: 99%

“…Mass balances for the oxygen and the n different volatiles were developed for the different regions inside the riser [17]. In the bottom bed, a set of 2n+2 ordinary first-order differential equations was obtained for the bubble and emulsion phases.…”

Section: 3volatile Combustion the Following Chemical Reactions Wimentioning

confidence: 99%

“…As the oxygen concentration at each height depends on the char and volatile combustion, the mass balances for char, oxygen and volatiles were simultaneously solved [17]. The model predicts the oxygen, CO, methane, propane, ethylene, hydrogen and water vapour concentration profiles along the different regions of the riser.…”

Section: Shmentioning

confidence: 99%

“…Based on previous works on mathematical modelling of CFB coal combustion [15] and on biomass combustion [16,17], a mathematical model is developed here for the combustion of coal and biomass mixtures in circulating fluidised bed combustors. The model was validated with the experimental results found in tests carried out in two different CFBC pilot plants.…”

Section: Introductionmentioning

confidence: 99%

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04/02018 Circulating fluidised bed co-combustion of coal and biomass

2004

Fuel and Energy Abstracts

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Circulating fluidised bed combustion (CFBC) is receiving wide research attention in view its potential as an economic and environmentally acceptable technology for burning low-grade coals, biomass and organic wastes, and thereby mixtures of them. Designs of the existing fluidised bed boilers for biomass combustion are mainly based on experience from coal combustion because the mechanism of combustion of biomass in fluidised beds is still not well understood. A good understanding of the combustion and pollutant formation processes and the modelling of the combustor can greatly avoid costly upsets of the plants.In this paper the performance of CFBC burning coal and biomass mixtures was analysed.Experimental results were obtained from the combustion of two kind of coals with a 2 forest residue (Pine bark) in two CFB pilot plants (0.1 and 0.3MW th ). The effect of the main operating conditions on carbon combustion efficiency was analysed. Moreover, a mathematical model to predict the behaviour of the co-combustion of coal and biomass wastes in CFB boilers has been developed and validated. The developed model can predict the different gas concentrations along the riser (O 2 , CO, CH 4 , etc.), and the carbon combustion efficiency. The experimental results of carbon combustion efficiencies were compared with those predicted by the model and a good correlation was found for all the conditions used.

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Overview and some issues related to co‐firing biomass and coal

et al. 2008

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Low heating values, variable chemical compositions, peculiar physical properties, high investment cost and insecurity of biomass feedstocks supply limit the applications of biomass for energy and other processes. Co-firing biomass and coal has potential for the development of biomass-to-energy capacity with significant economic, environmental, and social benefits. However, co-firing is not straightforward, and some questions need to be addressed due to the differences in chemical compositions and physical properties of biomass and coal. This paper highlights key issues related to co-firing, including reactor types, feeding, hydrodynamics, ash sintering, fouling, and corrosion, based on previous studies, as well as calculations and analysis. Direct co-firing is the most common option for biomass and coal co-firing currently, mostly due to relatively low investment needed to turn existing coal power plants into co-firing plants. For direct co-firing, the physical characteristics and chemical compositions of the fuel entering the combustors or gasifiers are critical to an optimum operation. Any biomass mixed with coal needs to have acceptable physical properties. More research is needed on co-firing biomass and coal, including work on: preparation, handling, storage, and feeding of biomass feedstocks (e.g. drying, torrefaction, pelletization); co-firing mechanisms; hydrodynamic analysis of co-firing combustors and gasifiers; boiler/gasifier capacity, slagging, fouling, corrosion, efficiency, reliability, fuel flexibility; lower emissions and gas cleaning; catalyst poisoning; investment and operating costs.Les applications de la biomasse pour les procédésénergétiques et d'autres procédés sont limités par les faibles pouvoirs calorifiques, des compositions chimiques variables, des propriétés physiques particulières, des coûts d'investissementélevés et l'insécurité quantà l'approvisionnement en biomasse comme matière première. La co-alimentation biomasse-charbon est potentiellement intéressante pour la transformation de la biomasse enénergie, avec des avantageséconomiques, environnementaux et sociaux significatifs. Toutefois, la co-alimentation n'est pas simple et certaines questions se posent du fait des différences dans les compositions chimiques et les propriétés physiques de la biomasse et du charbon. On souligne dans cet article les principaux aspects entrant dans la co-alimentation, notamment le type de réacteurs, l'alimentation, l'hydrodynamique, le frittage des cendres, l'encrassement et la corrosion, d'après desétudes antérieures ainsi que des calculs et analyses. La co-alimentation directe est l'option la plus commune pour la co-alimentation biomasse-charbon, principalement en raison de l'investissement relativement faible requis pour transformer les centralesélectriques alimentées au charbon actuelles en centrales hybrides. Pour la co-alimentation directe, les caractéristiques physiques et les compositions chimiques du fioul entrant dans les chambres de combustion et les gazéifieurs sont critiques pour un fo...

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Combustion of Wood Chips in a CFBC. Modeling and Validation

Cited by 35 publications

References 34 publications

Progress in Chemical-Looping Combustion and Reforming technologies

Progress in Chemical-Looping Combustion and Reforming technologies

04/02018 Circulating fluidised bed co-combustion of coal and biomass

Overview and some issues related to co‐firing biomass and coal

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