Combustion and gasification of coals in fixed-beds

Hobbs, Michael L.; Radulovic, P. T.; Smoot, L.D.

doi:10.1016/0360-1285(93)90003-w

Cited by 168 publications

(94 citation statements)

References 134 publications

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“…Therefore, the produced gas is cleaner than the equivalent provided by the countercurrent model. The co-current version presents some limitations on controllability for large diameters or power output [9,10].This is mostly due to the formation of preferential channels in the fuel bed that prevent the tar rich stream moving from the pyrolysis region from meeting the hot core of the combustion region. Nevertheless, that problem is mitigated through the application of slow-rotating paddles to provide uniform distribution of particles in the bed [11].…”

Section: A Downdraft Gasificationmentioning

confidence: 99%

An Improved Method to Generate Electricity and Precipitated Silica from Rice Husk: Perspective Bangladesh

Bhuiyan¹,

Mojumdar²,

Hasan³

2011

IJESD

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Abstract-Electricity supply for rural areas, so long, has been a far cry in context of Bangladesh. Realizing this, many organizations along with Bangladesh government are trying to bring renewable energy in a competitive package to meet deficiency. But solar energy, mainly for its inefficiency and high cost, is not having much success in a broader aspect. SHSs are capable to maintain only household demand for 4-6 hours. But for the emergence of small enterprises and to boost the rural economy, energy security at countryside has indispensible role. This paper explores rice husk based biomass plant as an alternate energy source to meet the electricity demand of local enterprises, irrigation and rural households. Since the availability of rice husk is at stake, a mixture of biomass (rice husk & saw dust or rice husk & bamboo dust) instead of using only rice husk as fuel is also proposed for electricity generation. Ash generated from the husk is processed to produce silica and calcium carbonate through silica precipitation method. Demand and market analysis is also done to examine sales potential of products (electricity, silica and calcium carbonate).

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Section: A Downdraft Gasificationmentioning

confidence: 99%

An Improved Method to Generate Electricity and Precipitated Silica from Rice Husk: Perspective Bangladesh

Bhuiyan¹,

Mojumdar²,

Hasan³

2011

IJESD

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“…The moisture evaporation should be considered in two ways: boiling and diffusion below the boiling temperature. The reaction rate of char combustion is determined from the kinetic rate, diffusion rate and internal mass transport in the ash layer of the particle (8) . It can be expressed as Eq.…”

Section: Numerical Approachmentioning

confidence: 99%

“…From this factor and the combustion rate, the particle size and the internal porosity are determined. The changes in the particle size are described by well-known models: the shell progressive (SP) and ash segregation (AS) models (8) .…”

Section: Numerical Approachmentioning

confidence: 99%

Effect of Fuel Characteristics on the Thermal Processes in an Iron Ore Sintering Bed

Yang

Choi

2005

JSME international journal. Ser. B, Fluids and thermal engineer

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Coke in an iron ore sintering process is being replaced in part by powdered anthracite; less expensive fuel. In this study, influence of the different fuel characteristics on the thermal condition in the sintering bed has been investigated using a mathematical model. Numerical simulation along with experiments in a lab-scale sintering pot has been performed. The mathematical model is based on the assumption that the sintering bed can be treated as homogeneous medium, through which a reacting flow passes. Temperature distribution and flue gas composition are predicted for various kinds of solid fuel and various particle sizes of anthracite. The simulation results show that propagation of combustion zone is faster in the case of using coke than the case of using anthracite. Results also show that the reactivity of the anthracite can be improved by decreasing the size of fuel particles.

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“…The novel Lurgi fixed-bed gasifiers suffer from high tar yields in the product gases (Li X.T. et al, 2004), and the processing rates are slow compared with entrained-and fluidized-beds (Hobbs et al, 1993). Fluidized beds now find wide application in coal gasification (Li X.T.…”

Section: Introductionmentioning

confidence: 99%

Toward Low-Temperature Coal Gasification: Experimental and Numerical Studies of Thermochemical Coal Conversion Considering the Interactions between Volatiles and Char Particles

Zhang

Kudo

et al. 2017

KONA

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A novel triple-bed combined circulating fluidized-bed (TB-CFB) coal gasifier, consisting of a downer (pyrolyzer), a bubbling fluidized bed (gasifier), and a riser (combustor) was proposed for realizing low-temperature coal gasification. Several key thermochemical reactions were extracted from those expected in the downer unit: the reforming of refractory tar in both the gas phase and over the char surface, and the steam gasification of the nascent char. This review highlights our recent progress, both experimental and numerical, in studies of thermochemical coal conversion including the various reaction processes, by employing a drop-tube reactor that well approximates the reaction environment in a downer reactor. This discussion can be utilized in designing TBCFBs and optimizing their operation.

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Combustion and gasification of coals in fixed-beds

Cited by 168 publications

References 134 publications

An Improved Method to Generate Electricity and Precipitated Silica from Rice Husk: Perspective Bangladesh

An Improved Method to Generate Electricity and Precipitated Silica from Rice Husk: Perspective Bangladesh

Effect of Fuel Characteristics on the Thermal Processes in an Iron Ore Sintering Bed

Toward Low-Temperature Coal Gasification: Experimental and Numerical Studies of Thermochemical Coal Conversion Considering the Interactions between Volatiles and Char Particles

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