The characteristics of biomass oxygen gasification with a higher equivalence ratio (0.31–0.40) in a pilot scale (50 kg/h) downdraft fixed bed gasification system were studied using pine wood block and corn stalk briquette as feedstocks. Experiments were carried out to investigate the influence of the higher equivalence ratio on the gasification performance. The gas composition was analyzed by gas chromatography. Upon increasing the equivalence ratio from 0.31 to 0.40, the reaction temperature, gas yield, and carbon conversion efficiency increased, while the lower heating value and tar and dust contents of syngas decreased. The gas yield and carbon conversion efficiency of corn stalk briquette gasification were lower than those of pine wood block gasification by about 3.0% and 5.0% at each equivalence ratio. The higher equivalence ratio strengthened the gasification and improved the gas yield as well as carbon conversion but lowered the lower heating value of the syngas. Too high equivalence ratio (>0.40) would result in excess gasification and more combustible components being burnt out. Too low equivalence ratio (<0.31) would lead to incomplete gasification and more tar residue. The optimal equivalence ratios were 0.37 and 0.33 for corn stalk briquette and pine wood block, respectively. The results of this study will help to improve our understanding of syngas production with low tar and medium heating values by biomass oxygen gasification.
The effects of catechol on the change of cetyltrimethylammonium bromide (CTAB) micelles in aqueous solutions have been studied by Ultramicroelectrode (UME) cyclic voltammetry and Time-Resolved Fluorescence Quenching (TRFQ). It has been shown that the diffusion coefficient decreases and the micelle aggregation number increases with the addition of catechol. This indicates that catechol has influence on the size or shape of CTAB micelles. In order to analyze the change of the micelles, other micelle parameters like the effective radius (a), surface area of micelle (S), area of single CTAB molecule (A) and packing parameter (P) were calculated. The values of P which is relative to the shape of the micelles are consistent with the change of the diffusion coefficient. All the results show that catechol can accelerate the increase of the aggregate size and sphere-to-rod morphology change of CTAB micelles even with lower concentration of CTAB. This is because that hydrophobic force makes catechol insert into CTAB micelles between CTAB molecules, which leads to the increase of the radius of curvature. The increase of aggregate size and the sphere-to-rod morphology change are also promoted as a result.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.