DSpace-CRIS

Now showing 1 - 3 of 3

Some of the metrics are blocked by your
consent settings
Comprehensive performance assessment of a continuous solar-driven biomass gasifier
(2018-12-15)
Chuayboon, Srirat
;
Abanades, Stéphane
;
Rodat, Sylvain
The experimental performance assessment of a continuous solar-driven biomass gasifier using real high-flux concentrated solar radiation as the source of process heat has been performed. A comprehensive parametric study considering different lignocellulosic biomass feedstocks (wood type), biomass feeding rates (0.6–2.7 g/min), steam/biomass molar ratios (1.6–2.8), carrier gas flow rates (2–3.3 Nl/min) and reaction temperatures (1100–1300 °C) was conducted for optimizing the syngas production capacity and evaluating the gasification performances. Different wood biomass feedstocks were continuously fed as particles and gasified with H<inf>2</inf>O for producing syngas, thus successfully demonstrating the reliability of the reactor that was operated compatibly with different particle sizes and shapes. A small excess of water with respect to stoichiometry was beneficial for biomass gasification regarding the increase of H<inf>2</inf> and CO and the decrease of CH<inf>4</inf>, CO<inf>2</inf> and C<inf>2</inf>H<inf>m</inf> production. An increase in the gas residence time resulted in the improvement of the syngas yields and quality. Significant enhancement of syngas yields and production rates through the rise of operating temperature was highlighted with activation energy in the range of 24–29 kJ/mol. Increasing biomass feeding rate improved the syngas yields and gasification rates, enabling efficient solar energy storage into syngas and enhancing the energy upgrade factor (U) above 1.20, the solar-to-fuel energy conversion efficiency (η<inf>solar-to-fuel</inf>) above 29% and the thermochemical reactor efficiency (η<inf>reactor</inf>) above 27%.
Some of the metrics are blocked by your
consent settings
Solar chemical looping gasification of biomass with the ZnO/Zn redox system for syngas and zinc production in a continuously-fed solar reactor
(2018-03-01)
Chuayboon, Srirat
;
Abanades, Stéphane
;
Rodat, Sylvain
The high-temperature solar-driven chemical looping gasification of lignocellulosic biomass with ZnO/Zn redox pair was investigated as a novel process producing both syngas and metallic zinc. A lab-scale solar reactor (1.5 kW) was operated for continuous combined biomass gasification and ZnO carbo-thermal reduction using solar energy as the source of high-temperature process heat. Experiments were performed at temperatures ranging from 1050 °C to 1300 °C with biomass/ZnO molar ratios from 0.5 to 1, using beech wood as a biomass feedstock. The objective of this study was to unveil the advantages and reliability of the combined process involving biomass pyro-gasification with solid ZnO as an oxidizing agent under continuous process operation for co-production of syngas and metallic Zn. The influence of temperature and reactant molar ratio on syngas production was highlighted and compared to the case of a pyrolysis process without any oxidant. Moreover, the chemical conversion of ZnO to Zn obtained by this endothermic step was also addressed, confirming pure Zn production with low recombination in the collected solid products. The evolved H<inf>2</inf> increased significantly, CO production also tended to increase slightly, while CO<inf>2</inf> and CH<inf>4</inf> decreased when increasing the temperature. The syngas yield of the combined gasification/carbo-thermal reduction (up to ∼8 mol<inf>syngas</inf>/mol<inf>biomass</inf> for a biomass/ZnO molar ratio of 0.75 at 1250 °C) was much higher in comparison with pyrolysis. The calorific value of the feedstock was solar up-graded through syngas and Zn production in the case of the biomass gasification using ZnO, whereas pyrolysis was not energetically efficient because of the energy content still remaining in the produced char. The optimal biomass/ZnO molar ratio was evidenced at 0.75 yielding maximum syngas production. The energy upgrade factor of the feedstock by the solar power input and the solar-to-fuel energy conversion efficiency were 1.17 and 19.8% respectively for a molar ratio of 0.75 at 1250 °C.
Some of the metrics are blocked by your
consent settings
Experimental analysis of continuous steam gasification of wood biomass for syngas production in a high-temperature particle-fed solar reactor
(2018-03-01)
Chuayboon, Srirat
;
Abanades, Stéphane
;
Rodat, Sylvain
Solar steam gasification of beech wood biomass has been performed in a novel high-temperature continuously-fed solar reactor for the thermochemical conversion of low-grade carbonaceous feedstock into transportable and storable gaseous fuels (syngas). The 1.5 kW<inf>th</inf> cavity-type solar reactor was operated in the temperature range of 1100–1300 °C. Large wood biomass particles (3–5 mm size) were continuously fed and gasified with the oxidizing agent to produce syngas, thus demonstrating the reactor suitability for large particle size processing. Operating parameters were varied in order to optimize the syngas production. The effect of steam flow-rate, carrier gas flow-rate, temperature, and biomass feeding rate on the syngas yield and reactor performances was experimentally investigated. The increase of steam flow-rate favored H<inf>2</inf>, CO<inf>2</inf> and CH<inf>4</inf> and reduced CO production. A noteworthy increase of the syngas yield with the temperature was highlighted, while the increase of carrier gas flow-rate was detrimental to the amount of syngas produced because of lowered gas residence time. The increase of biomass feeding rate (in the range of 0.8–1.8 g/min) showed noteworthy impact on the syngas composition without affecting the reactor performance, yielding high-quality syngas with a carbon conversion rate above 80%, while the total syngas yield was stable at about 70 mmol/g<inf>biomass</inf>.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results