For a gasification process,the char-CO_(2)gasification is the controlling step worthwhile to be deeply investigated.The article chosen corn stalk(CS),poplar sawdust(PS)and bagasse residue(BR)as the typical waste speci...For a gasification process,the char-CO_(2)gasification is the controlling step worthwhile to be deeply investigated.The article chosen corn stalk(CS),poplar sawdust(PS)and bagasse residue(BR)as the typical waste species derived from agricultural,forestal and industrial sources.The char-CO_(2)gasification behavior,reaction kinetics and carbon structure were studied to reveal the intrinsic factors determining the reaction kinetics.Generally,the carbon conversion and maximum conversion rate were influenced by the feedstocks species and char preparation temperatures,as influenced by ash proportion,potassium content in ash and carbon structure of char.The char-CO_(2)reaction for CS was subject more to the catalytic effect of alkali compositions,while pore structure affected more the gasification reaction for PS char.The isoconversional kinetic analysis indicated that the gasification reaction became stable at carbon conversion of 0.5.Subsequently,sectionalized kinetic parameters were calculated for the initial gasification temperature to the temperature reaching 50%conversion.The result showed that high initial gasification temperature increased the char-CO_(2)gasification barrier to hardly start the reaction but accelerate the reaction rate.The carbon structure analyses further clarified that the reaction activation energy was highly related to the microcrystalline structure of carbon,while the reaction rate was more determined by carbon pore structure.展开更多
The steam gasification characteristics of poplar sawdust were investigated in a piston fed fixed-bed gasifier,reflecting the batch feeding process of fixed-bed gasifiers in industrial applications.The effects of opera...The steam gasification characteristics of poplar sawdust were investigated in a piston fed fixed-bed gasifier,reflecting the batch feeding process of fixed-bed gasifiers in industrial applications.The effects of operating conditions,including steam supply,the flow rate of inert gas,gasification temperature,and feeding rate,on gasification reactivity and performance were investigated online.The major gas product during pyrolysis was CO,followed by H2,CH4,and CO_(2),and the gasification was greatly facilitated by the injection of steam to generate H2.The gasification reactivity and performance were improved with increased steam supply and temperature.The maximum production rate of H_(2)by char gasification was tripled and doubled,respectively,with an increase in steam supply from 50 to 400 mL/min and a temperature rise from 800 to 900◦C,and the time required for complete gasification was also halved.Compared to pyrolysis,the volume fraction of H2 increased from 23%to 37%,and correspondingly,the H_(2)/CO ratio increased from 0.42 to 0.95.展开更多
基金supported by the national natural science foundation of China[grant number 52106231]the national key research and development program of China[grant number 2019YFC1906800].
文摘For a gasification process,the char-CO_(2)gasification is the controlling step worthwhile to be deeply investigated.The article chosen corn stalk(CS),poplar sawdust(PS)and bagasse residue(BR)as the typical waste species derived from agricultural,forestal and industrial sources.The char-CO_(2)gasification behavior,reaction kinetics and carbon structure were studied to reveal the intrinsic factors determining the reaction kinetics.Generally,the carbon conversion and maximum conversion rate were influenced by the feedstocks species and char preparation temperatures,as influenced by ash proportion,potassium content in ash and carbon structure of char.The char-CO_(2)reaction for CS was subject more to the catalytic effect of alkali compositions,while pore structure affected more the gasification reaction for PS char.The isoconversional kinetic analysis indicated that the gasification reaction became stable at carbon conversion of 0.5.Subsequently,sectionalized kinetic parameters were calculated for the initial gasification temperature to the temperature reaching 50%conversion.The result showed that high initial gasification temperature increased the char-CO_(2)gasification barrier to hardly start the reaction but accelerate the reaction rate.The carbon structure analyses further clarified that the reaction activation energy was highly related to the microcrystalline structure of carbon,while the reaction rate was more determined by carbon pore structure.
基金supported by the National Key Research and Development Program of China(No.2019YFC1906800).
文摘The steam gasification characteristics of poplar sawdust were investigated in a piston fed fixed-bed gasifier,reflecting the batch feeding process of fixed-bed gasifiers in industrial applications.The effects of operating conditions,including steam supply,the flow rate of inert gas,gasification temperature,and feeding rate,on gasification reactivity and performance were investigated online.The major gas product during pyrolysis was CO,followed by H2,CH4,and CO_(2),and the gasification was greatly facilitated by the injection of steam to generate H2.The gasification reactivity and performance were improved with increased steam supply and temperature.The maximum production rate of H_(2)by char gasification was tripled and doubled,respectively,with an increase in steam supply from 50 to 400 mL/min and a temperature rise from 800 to 900◦C,and the time required for complete gasification was also halved.Compared to pyrolysis,the volume fraction of H2 increased from 23%to 37%,and correspondingly,the H_(2)/CO ratio increased from 0.42 to 0.95.
