As part of efforts to reduce anthropogenic CO_(2) emissions by the steelmaking industry,this study investigated the direct reduction of industrially produced hematite pellets with H_(2) using the Doehlert experimental...As part of efforts to reduce anthropogenic CO_(2) emissions by the steelmaking industry,this study investigated the direct reduction of industrially produced hematite pellets with H_(2) using the Doehlert experimental design to evaluate the effect of pellet diameter(10.5-16.5 mm),porosity(0.36-0.44),and temperature(600-1200℃).A strong interactive effect between temperature and pellet size was observed,indicating that these variables cannot be considered independently.The increase in temperature and decrease in pellet size considerably favor the reduction rate,while porosity did not show a relevant effect.The change in pellet size during the reduction was negligible,except at elevated temperatures due to crack formation.A considerable decrease in mechanical strength at high temperatures suggests a maximum process operating temperature of 900℃.Good predictive capacity was achieved using the modified grain model to simulate the three consecutive non-catalytic gas-solid reactions,considering different pellet sizes and porosities,changes during the reaction from 800 to 900℃.However,for other temperatures,different mechanisms of structural modifications must be considered in the modeling.These results represent significant contributions to the development of ore pellets for CO_(2)-free steelmaking technology.展开更多
西班牙研究者M.A.Lopez-Manchado和M.Arroyo在聚烯烃热塑性弹性体(TPOs)研究中应用多赫勒均匀网法(an uniform net of Doehlert)。这种TPOs是一种以共混物PP/(乙烯-辛烯共聚物)为基质、用PET短纤维补强的三元复合物。多赫勒均匀网法是...西班牙研究者M.A.Lopez-Manchado和M.Arroyo在聚烯烃热塑性弹性体(TPOs)研究中应用多赫勒均匀网法(an uniform net of Doehlert)。这种TPOs是一种以共混物PP/(乙烯-辛烯共聚物)为基质、用PET短纤维补强的三元复合物。多赫勒均匀网法是一种国内未见应用的试验设计方法。他们应用多赫勒均匀网法设计试验方案,求得复合物的拉伸模量等4项力学性能与组分变量PP和PET纤维用量之间关系的响应方程式。笔者从研究者的论文提取一个二变量的多赫勒均匀网法在TPOs研究中应用的案例,并说明和评议多赫勒均匀网法和试验设计的全过程;特别是利用原著提供的基本试验数据进行逐步回归分析,讨论应用回归方程式应注意的几个基本问题和指出原著响应方程式存在的问题。展开更多
基金Institute of Technological Research–IPT,Fundcao de AmparoàPesquisa do Estado de Sao PauloBrazil[Process 2019/05840-3]+1 种基金Conselho Nacional de Desenvolvimento Científico e TecnológicoBrazil[Process 167470/2018-3]。
文摘As part of efforts to reduce anthropogenic CO_(2) emissions by the steelmaking industry,this study investigated the direct reduction of industrially produced hematite pellets with H_(2) using the Doehlert experimental design to evaluate the effect of pellet diameter(10.5-16.5 mm),porosity(0.36-0.44),and temperature(600-1200℃).A strong interactive effect between temperature and pellet size was observed,indicating that these variables cannot be considered independently.The increase in temperature and decrease in pellet size considerably favor the reduction rate,while porosity did not show a relevant effect.The change in pellet size during the reduction was negligible,except at elevated temperatures due to crack formation.A considerable decrease in mechanical strength at high temperatures suggests a maximum process operating temperature of 900℃.Good predictive capacity was achieved using the modified grain model to simulate the three consecutive non-catalytic gas-solid reactions,considering different pellet sizes and porosities,changes during the reaction from 800 to 900℃.However,for other temperatures,different mechanisms of structural modifications must be considered in the modeling.These results represent significant contributions to the development of ore pellets for CO_(2)-free steelmaking technology.
文摘西班牙研究者M.A.Lopez-Manchado和M.Arroyo在聚烯烃热塑性弹性体(TPOs)研究中应用多赫勒均匀网法(an uniform net of Doehlert)。这种TPOs是一种以共混物PP/(乙烯-辛烯共聚物)为基质、用PET短纤维补强的三元复合物。多赫勒均匀网法是一种国内未见应用的试验设计方法。他们应用多赫勒均匀网法设计试验方案,求得复合物的拉伸模量等4项力学性能与组分变量PP和PET纤维用量之间关系的响应方程式。笔者从研究者的论文提取一个二变量的多赫勒均匀网法在TPOs研究中应用的案例,并说明和评议多赫勒均匀网法和试验设计的全过程;特别是利用原著提供的基本试验数据进行逐步回归分析,讨论应用回归方程式应注意的几个基本问题和指出原著响应方程式存在的问题。
