The coal fly ash produced by gasification is estimated to be over 80 million ton per year in China by 2021.It has mainly been disposed as solid waste by landfill.There is lack of study focused on its utilization.In th...The coal fly ash produced by gasification is estimated to be over 80 million ton per year in China by 2021.It has mainly been disposed as solid waste by landfill.There is lack of study focused on its utilization.In this paper,the coal fly ash produced by gasification was at first analyzed and then applied to synthesize zeolite as an adsorbent.The effects of synthesis conditions on the cation exchange capacity(CEC)of zeolite were investigated.The results from X-ray diffraction and scanning electron microscope indicated that the crystallinity of the synthesized zeolite is the most important factor to affect the CEC.When the synthesized zeolite with the highest CEC(275.5 meq/100 g)was used for the adsorption of Cr(Ⅵ) from aqueous solution,the maximum adsorption capacity for Cr(Ⅵ) was found to be 17.924 mg/g.The effects of pH,contact time and initial concentration on the adsorption of Cr(Ⅵ) were also investigated.The adsorption kinetics and isotherms can be well described by the pseudo-secondorder model and Langmuir isotherm model,respectively.展开更多
Gasification or combustion of coal and biomass is the most important form of power generation today.However,the use of coal/biomass at high temperatures has an inherent problem related to the ash generated.The formati...Gasification or combustion of coal and biomass is the most important form of power generation today.However,the use of coal/biomass at high temperatures has an inherent problem related to the ash generated.The formation of ash leads to a problematic phenomenon called slagging.Slagging is the accumulation of molten ash on the walls of the furnace,gasifier,or boiler and is detrimental as it reduces the heat transfer rate,and the combustion/gasification rate of unburnt carbon,causes mechanical failure,high-temperature corrosion and on occasions,superheater explosions.To improve the gasifier/combustor facility,it is very important to understand the key ash properties,slag characteristics,viscosity and critical viscosity temperature.This paper reviews the content,compositions,and melting characteristics of ashes in differently ranked coal and biomass,and discusses the formation mechanism,characteristics,and structure of slag.In particular,this paper focuses on low-rank coal and biomass that have been receiving increased attention recently.Besides,it reviews the available methodologies and formulae for slag viscosity measurement/prediction and summarizes the current limitations and potential applications.Moreover,it discusses the slagging behavior of different ranks of coal and biomass by examining the applicability of the current viscosity measurement methods to these fuels,and the viscosity prediction models and factors that affect the slag viscosity.This review shows that the existing viscosity models and slagging indices can only satisfactorily predict the viscosity and slagging propensity of high-rank coals but cannot predict the slagging propensity and slag viscosity of low-rank coal,and especially biomass ashes,even if they are limited to a particular composition only.Thus,there is a critical need for the development of an index,or a model or even a measurement method,which can predict/measure the slagging propensity and slag viscosity correctly for all low-rank coal and biomass ashes.展开更多
Collaborations between China and Australia has always been crossed at almost all fields covering mathematics and physics,computer sciences and IT,chemistry,chemical engineering and materials,economics,business and man...Collaborations between China and Australia has always been crossed at almost all fields covering mathematics and physics,computer sciences and IT,chemistry,chemical engineering and materials,economics,business and management,mechanical,electrical and electronic engineering,social sciences and humanities,biomedical and health sciences,civil,environmental and agricultural engineering,etc.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(No.2017QNA25).
文摘The coal fly ash produced by gasification is estimated to be over 80 million ton per year in China by 2021.It has mainly been disposed as solid waste by landfill.There is lack of study focused on its utilization.In this paper,the coal fly ash produced by gasification was at first analyzed and then applied to synthesize zeolite as an adsorbent.The effects of synthesis conditions on the cation exchange capacity(CEC)of zeolite were investigated.The results from X-ray diffraction and scanning electron microscope indicated that the crystallinity of the synthesized zeolite is the most important factor to affect the CEC.When the synthesized zeolite with the highest CEC(275.5 meq/100 g)was used for the adsorption of Cr(Ⅵ) from aqueous solution,the maximum adsorption capacity for Cr(Ⅵ) was found to be 17.924 mg/g.The effects of pH,contact time and initial concentration on the adsorption of Cr(Ⅵ) were also investigated.The adsorption kinetics and isotherms can be well described by the pseudo-secondorder model and Langmuir isotherm model,respectively.
基金This work was financially supported by the Australian Research Council(ARC)under its Industrial Research Training Hub(IH170100009)scheme for the joint project between Monash University and Shanghai Boiler Works Co Ltd.Md Tanvir Alam would like to thank Monash University for his Ph.D Scholarship。
文摘Gasification or combustion of coal and biomass is the most important form of power generation today.However,the use of coal/biomass at high temperatures has an inherent problem related to the ash generated.The formation of ash leads to a problematic phenomenon called slagging.Slagging is the accumulation of molten ash on the walls of the furnace,gasifier,or boiler and is detrimental as it reduces the heat transfer rate,and the combustion/gasification rate of unburnt carbon,causes mechanical failure,high-temperature corrosion and on occasions,superheater explosions.To improve the gasifier/combustor facility,it is very important to understand the key ash properties,slag characteristics,viscosity and critical viscosity temperature.This paper reviews the content,compositions,and melting characteristics of ashes in differently ranked coal and biomass,and discusses the formation mechanism,characteristics,and structure of slag.In particular,this paper focuses on low-rank coal and biomass that have been receiving increased attention recently.Besides,it reviews the available methodologies and formulae for slag viscosity measurement/prediction and summarizes the current limitations and potential applications.Moreover,it discusses the slagging behavior of different ranks of coal and biomass by examining the applicability of the current viscosity measurement methods to these fuels,and the viscosity prediction models and factors that affect the slag viscosity.This review shows that the existing viscosity models and slagging indices can only satisfactorily predict the viscosity and slagging propensity of high-rank coals but cannot predict the slagging propensity and slag viscosity of low-rank coal,and especially biomass ashes,even if they are limited to a particular composition only.Thus,there is a critical need for the development of an index,or a model or even a measurement method,which can predict/measure the slagging propensity and slag viscosity correctly for all low-rank coal and biomass ashes.
文摘Collaborations between China and Australia has always been crossed at almost all fields covering mathematics and physics,computer sciences and IT,chemistry,chemical engineering and materials,economics,business and management,mechanical,electrical and electronic engineering,social sciences and humanities,biomedical and health sciences,civil,environmental and agricultural engineering,etc.
