Experimental and predicted approaches for biomass gasification with enriched air–steam in a fluidised bed

Abstract

Thermo-chemical gasification of sawdust refuse-derived fuel was performed on a bench-scale fluidised bed gasifier with enriched air and steam as fluidising and oxidising agents. Dolomite as a natural mineral catalyst was used as bed material to reform tars and hydrocarbons. A series of experiments were carried out under typical operating conditions for gasification, as reported in the article. A modified equilibrium model, based on equilibrium constants, was developed to predict the gasification process. The sensitivity analysis of operating parameters, such as the fluidisation velocity, oxygen percentage of the enriched air and steam to biomass ratios on the produced gas composition, lower heating value, carbon conversion and cold gas efficiency was investigated. The results showed that the predicted syngas composition was in better agreement with the experimental data compared with the original equilibrium model. The higher fluidisation velocity enhanced gas-solid mixing, heat and mass transfers, and carbon fines elutriation, simultaneously. With the increase of oxygen percentage from 21% to 45%, the lower heating value of syngas increased from 5.52 MJ m(-3) to 7.75 MJ m(-3) and cold gas efficiency from 49.09% to 61.39%. The introduction of steam improved gas quality, but a higher steam to biomass ratio could decrease carbon conversion and gasification efficiency owing to a low steam temperature. The optimal value of steam to biomass ratio in this work was 1.0.

Understanding of the oxygen uncoupling characteristics of Cu Fe composite oxygen carriers for chemical-looping gasification

“…6~8). And the gasification conversion and gasification rates of biomass in O 2 -steam gasification atmosphere is high [25][26][27]. Fig.…”

“…Huynh et al studied the characteristics of O 2enriched air and steam biomass gasification process at 800 • C and concluded that this process favors the production of combustible gas components in the syngas [26]. Fu et al indicated that the biomass gasification could be completed below 800 • C when enriched air and steam were used as fluidizing and oxidizing agents [27].…”

Gasification of Pelletized Corn Residues with Oxygen Enriched Air and Steam

“…There was the competition for oxygen among different species present in the gasifier: H2, CO, CH4, char, tar, etc. It was likely that H2 and CO reacted with the additional oxygen since they were more reactive species ( Fu et al , 2014) . However, the oxidations released the heat and the temperature was increased with the amount of ER.…”

Oxygen-Enriched Gasification of Dried Sewage Sludge, Refuse-Derived Fuel, and Their Cogasification in a Laboratory-Scale Fluidized Bed

“…Gasification converts waste to a combustible gaseous mixture ("synthesis gas" or "syngas") of H 2 , CO, CO 2 , and CH 4 under a limited oxygen supply at a moderately high temperature. 12 To minimize the capital cost, and for simplicity and stability, air is most commonly used as the gasification agent. However, the dilution effect of nitrogen results in the production of a syngas with a low heating value (LHV) (about 4−6 MJ/Nm 3 ).…”

“…Gasification converts waste to a combustible gaseous mixture (“synthesis gas” or “syngas”) of H 2 , CO, CO 2 , and CH 4 under a limited oxygen supply at a moderately high temperature . To minimize the capital cost, and for simplicity and stability, air is most commonly used as the gasification agent.…”