Gasification of char from wood pellets and from wood chips: Textural properties and thermochemical conversion along a continuous fixed bed

Teixeira, Gabriel; Steene, Laurent Van de; Martin, E.; Gelix, Franck; Salvador, Sylvain

doi:10.1016/j.fuel.2012.05.039

Cited by 33 publications

(16 citation statements)

References 17 publications

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“…Concerning temperature T and partial pressure p j , low and high limits correspond to the operating conditions that can be used in a continuous char gasification reactor [14]. For the Boudouard reaction, steam gasification, and combustion, low limits were fixed at 1173 K, 1073 K and 973 K respectively.…”

Section: Statistical Methods For the Determination Of The Functionsmentioning

confidence: 99%

“…The upper limit was set at 6.5 mm based on the thickness distribution analysis found in [14]: 95% of the char particles were 0-6.5 mm thick.…”

Section: Statistical Methods For the Determination Of The Functionsmentioning

confidence: 99%

“…Initial porosity e 0 was determined from porosity measurement performed on WPC (0.80) and WCC (0.50) [14]. These values are taken as the upper and lower limits respectively.…”

Section: Statistical Methods For the Determination Of The Functionsmentioning

confidence: 99%

“…These results are satisfactory since WWC and WPC were both produced from maritime pine. Moreover the two initial chars were produced in the same pyrolysis operating conditions (temperature 750 K, residence time 1 h; flow rate 15 kg h À1 ) [14].…”

Section: Validation Of a Imentioning

confidence: 99%

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Prediction of the gasification kinetics of a single wood char particle from a limited set of parameters

Teixeira¹,

Steene²,

Ponthieux³

et al. 2014

Fuel

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. Prediction of the gasification kinetics of a single wood char particle from a limited set of parameters. Fuel, Elsevier, 2014, 123, pp.194-204 Three functions were built to calculate particle conversion rate of steam gasification, Boudouard reaction and combustion. Function determination includes the use of a validated particle model and a numerical experimental design. The functions take into account all phenomena controlling particle conversion rate of a char particle under a reactive atmosphere.The functions depend on a limited set of operating conditions -T, p i -and particle properties: e 0 , e p,0 and A i .The functions can be easily adapted to a new wood char by confronting 3-5 experimental results to the function. Keywords:Gasification Particle conversion rate Char particle Modeling a b s t r a c t Many biomass gasification models have been developed at reactor scale with the objectives of understanding the phenomena involved and optimizing the processes. Most of usual models consist in solving equations of heat, mass and momentum balance in a multiphase media. These equations call for source terms that provide production or consumption of heat and species by the reactions. The heat and mass source terms are directly derived from the particle conversion rate, dX/dt. This paper focuses on the determination of these source terms regarding the char gasification stage of the gasification process.We propose three simple functions to calculate wood particle conversion rate of steam gasification, Boudouard reaction and combustion. The determination of each function is based on a validated char gasification model at particle size and a numerical experimental design. The model of char particle gasification includes all the complexity of the transformation: intrinsic reaction kinetic and both internal and external heat/mass transfer limitations. The experimental design was used to define simulations to be carried out, and to establish a relevant correlation between the particle conversion rate and a limiting set of 5 influencing parameters. Two of them are representative of the operating conditions -temperature and partial pressure of the reactant gas, the three others corresponds to particle properties: porosity, thickness, and reactivity constant.The three functions were determined for the gasification of a wood chips char particle in a H 2 O/N 2 , CO 2 / N 2 , and O 2 /N 2 atmosphere respectively. And finally, considering wood pellet char, we showed that the functions could be adapted to this new char from only 3 to 5 experiments, showing a good correspondence between prediction functions and experimental results.

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Section: Statistical Methods For the Determination Of The Functionsmentioning

confidence: 99%

“…The upper limit was set at 6.5 mm based on the thickness distribution analysis found in [14]: 95% of the char particles were 0-6.5 mm thick.…”

Section: Statistical Methods For the Determination Of The Functionsmentioning

confidence: 99%

“…Initial porosity e 0 was determined from porosity measurement performed on WPC (0.80) and WCC (0.50) [14]. These values are taken as the upper and lower limits respectively.…”

Section: Statistical Methods For the Determination Of The Functionsmentioning

confidence: 99%

Section: Validation Of a Imentioning

confidence: 99%

See 2 more Smart Citations

Prediction of the gasification kinetics of a single wood char particle from a limited set of parameters

Teixeira¹,

Steene²,

Ponthieux³

et al. 2014

Fuel

Self Cite

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show abstract

“…The latter is the rate-determining step that controls the overall conversion process [15]. Gasification of biomass chars has been investigated in order to gain a better understanding of char reactivity, and kinetic models have been reported using steam and carbon dioxide as gasification agents [16][17][18][19][20]. In addition, several studies have been reported on the gasification of biomass char from different types of biomass, e.g., grapefruit skins [21], Japanese cedar [22], sunflower shells [23], beech wood [24], slash pine [25], and bagasse [26].…”

Section: Introductionmentioning

confidence: 99%

Kenaf as a Bioresource for Production of Hydrogen-rich Gas

Kojima

Kato²,

Yoon³

et al. 2014

Agrotechnol

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The two-step gasification of biomass via carbonization-step followed by steam gasification, which produces hydrogen-rich water gas without any byproducts, was achieved using a small laboratory system. Carbonization of kenaf from 600 to 1000°C produced suitable chars for further steam gasification, which generated clean hydrogenrich gases without any byproducts. On the other hand, carbonization of kenaf at 400°C yielded an insufficient char that still contained raw chemical components, and generated hydrocarbons and tar-like materials during gasification. Importantly, the wood gas generated during carbonization had a sufficient Higher Heating Value (HHV) to serve as the heating source for the gasification. A lower gasification temperature induced the water-gas shift reaction, which led to a change the hydrogen content in the water gas composition. Raising the gasification temperature increased the specific HHV and decreased the gas yield. In addition, at these gasification temperatures, the H 2 concentration in the water gases was greater than 58%, and the H 2 /CO ratio ranged from 1.8 to 3.0. On the other hand, increasing the steam supply rate decreased the specific HHV and CO yield and increased the H 2 and CO 2 yields. Therefore, the water-gas shift reaction played an important role under these conditions. On the basis of all of the above results, it was concluded that the water-gas reaction, C + H 2 O → CO + H 2 , leads to effective gasification of the kenaf char.

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Biomass Pyrolysis and Gasifier Designs

Amarasekara¹

2013

Handbook of Cellulosic Ethanol

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Gasification of char from wood pellets and from wood chips: Textural properties and thermochemical conversion along a continuous fixed bed

Cited by 33 publications

References 17 publications

Prediction of the gasification kinetics of a single wood char particle from a limited set of parameters

Prediction of the gasification kinetics of a single wood char particle from a limited set of parameters

Kenaf as a Bioresource for Production of Hydrogen-rich Gas

Biomass Pyrolysis and Gasifier Designs

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