According to the Doehlert's matrix method, the adsorbent derived from sewage sludge was prepared through chemical activation under controlling the pyrolysis temperature and hold time. The characteristic parameters...According to the Doehlert's matrix method, the adsorbent derived from sewage sludge was prepared through chemical activation under controlling the pyrolysis temperature and hold time. The characteristic parameters including the total yield, adsorption of methylene blue, adsorption of iodine, BET surface area, micro-pore volume are 35%—49%, 16.5—38 mg/g, 285—362 mg/g, 185—359 m2/g, and 0.112—0.224 m3/g, respectively. According to the experimental data, the multi-linear regression method was adopted to fit the relations between the characteristic parameters and influential factors. At final, through optimization method, the optimal adsorbent is obtained when using 62 min as hold time and 1105K as pyrolysis temperature. Under the conditions, the adsorbent was produced and compared the characteristic parameters with model forecast value, the coherence is satisfied.展开更多
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
The Adansonia digitate L. known as Baobab is the only species present in West Africa and grows wild. All parts of the plant are used by humans. In Senegal, baobab pulp is widely consumed;it is used as raw material in ...The Adansonia digitate L. known as Baobab is the only species present in West Africa and grows wild. All parts of the plant are used by humans. In Senegal, baobab pulp is widely consumed;it is used as raw material in small and medium enterprises (SMEs) for making juices, concentrates, jams, powder. Drinks or juices from baobab are highly appreciated by consumers;however rapid fermentation can happen even after pasteurization that can shorten their shelf-life. A Doehlert experimental design was used to find a good scale of heat treatment ensuring a proper conservation of baobab juice. Results of the experimental design showed that a heat treatment of 80°C for 10 min gives a baobab juice with good sanitary quality that meets the international standards.展开更多
文摘According to the Doehlert's matrix method, the adsorbent derived from sewage sludge was prepared through chemical activation under controlling the pyrolysis temperature and hold time. The characteristic parameters including the total yield, adsorption of methylene blue, adsorption of iodine, BET surface area, micro-pore volume are 35%—49%, 16.5—38 mg/g, 285—362 mg/g, 185—359 m2/g, and 0.112—0.224 m3/g, respectively. According to the experimental data, the multi-linear regression method was adopted to fit the relations between the characteristic parameters and influential factors. At final, through optimization method, the optimal adsorbent is obtained when using 62 min as hold time and 1105K as pyrolysis temperature. Under the conditions, the adsorbent was produced and compared the characteristic parameters with model forecast value, the coherence is satisfied.
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The Adansonia digitate L. known as Baobab is the only species present in West Africa and grows wild. All parts of the plant are used by humans. In Senegal, baobab pulp is widely consumed;it is used as raw material in small and medium enterprises (SMEs) for making juices, concentrates, jams, powder. Drinks or juices from baobab are highly appreciated by consumers;however rapid fermentation can happen even after pasteurization that can shorten their shelf-life. A Doehlert experimental design was used to find a good scale of heat treatment ensuring a proper conservation of baobab juice. Results of the experimental design showed that a heat treatment of 80°C for 10 min gives a baobab juice with good sanitary quality that meets the international standards.
