In this study, composite briquettes were prepared using gravity dust and converter sludge as the main materials; these briquettes were subsequently reduced in a tube furnace at 1000-1300℃ for 5-30 min under a nitroge...In this study, composite briquettes were prepared using gravity dust and converter sludge as the main materials; these briquettes were subsequently reduced in a tube furnace at 1000-1300℃ for 5-30 min under a nitrogen atmosphere. The effects of reaction temperature, reaction time, and carbon content on the metallization and dezincification ratios of the composite briquettes were studied. The reduced com- posite briquettes were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy-dispersive spectroscopy （EDS）. The results show that the gravity dust and converter sludge are combined into the composite briquettes and a reasonable combination not only improves the performance of the composite briquettes, but also leads to the reduction with no or little reductant and flux. As the re- action temperature is increased and the reaction time is extended, the metallization and dezincification ratios of the composite briquettes in- crease gradually. When the composite briquettes are roasted at 1300℃ for 30 rain, the metallization ratio and dezineification ratio reaches 91.35% and 99.25%, respectively, indicating that most of the iron oxide is reduced and the zinc is almost completely removed. The carbon content is observed to exert a lesser effect on the reduction process; as the C/O molar ratio increases, the metallization and dezincification ra- tios first increase and then decrease.展开更多
Now one of the main cash crops in Côte d’Ivoire, the cashew tree feeds an entire industrial sector based on the processing of its fruit. This processing generates a large volume of waste, consisting of cashew nu...Now one of the main cash crops in Côte d’Ivoire, the cashew tree feeds an entire industrial sector based on the processing of its fruit. This processing generates a large volume of waste, consisting of cashew nutshells, the management of which poses environmental problems. With the aim of replacing charcoal and firewood with more environmentally friendly fuels, several studies are currently being carried out into the optimal use of cashew shells in fuel briquettes. To assess the environmental sustainability of these briquettes, this study calculates the environmental impacts associated with their life cycle, compares them with those of charcoal and firewood, and identifies the processes that contribute most to environmental pollution, with a view to improving them. Analysis of the results showed that cashew nutshell briquettes emit a range of pollutants over their life cycle that damage the environment and are responsible for the 7 impact categories considered: acidification, eutrophication, freshwater aquatic ecotoxicity, global warming, human toxicity, photochemical oxidation and terrestrial ecotoxicity potential. However, they are more environmentally friendly than charcoal and firewood for 5 impact categories: freshwater aquatic ecotoxicity, global warming, human toxicity, photochemical oxidation and terrestrial ecotoxicity potential. The 3 elementary processes, i.e. transport of biomass raw materials, production, and combustion of briquettes, emit pollutants that contribute most to the creation of environmental impact categories. The most relevant pollutants are nitrogen oxides (NOx), sulphur oxides (SOx) and particulate matter (PM).展开更多
Basic physicochemical properties of the dust from Laiwu Iron and Steel Co. Ltd. were studied. It is found that C, Zn, K, Na, etc. exist in the fabric filter dust, off gas （OG） sludge, fine ash in converter, and elec...Basic physicochemical properties of the dust from Laiwu Iron and Steel Co. Ltd. were studied. It is found that C, Zn, K, Na, etc. exist in the fabric filter dust, off gas （OG） sludge, fine ash in converter, and electrical field dust in sinter. Among these, OG sludge gives the finest particle, more than 90% of which is less than 2.51 mm. The dust can lead to a serious negative influence on the production of sintering and blast furnaces （BF） if it is recycled in sintering. The briquette and reduction experimental results showed that the qualified strength could be obtained in the case of 8wt% molasses or 4wt% QT-10 added as binders. Also, more than 75% of metallization ratio, more than 95% of dezincing ratio, as well as more than 80% of K and Na removal rates were achieved for the briquettes kept at 1250℃ for 15 min during the direct reduction process. SEM observation indicated that the rates of indirect reduction and carbonization became dominating when the bri-quettes were kept at 1250℃ for 6 min.展开更多
Green coal or bio-coal is coal produced with rich biodegradable materials, elaborated from agricultural and household residues with a high percentage of carbon. This green charcoal (fuel briquettes) is an alternative ...Green coal or bio-coal is coal produced with rich biodegradable materials, elaborated from agricultural and household residues with a high percentage of carbon. This green charcoal (fuel briquettes) is an alternative to charcoal. Well known for its contribution to greenhouse gas emissions, charcoal is one of the causes of tree felling. The valorization of waste by the manufacture of biofuels could be an alternative to the use of charcoal. The general objective of the present study is the valorization of nine biomasses from Togo as raw materials. Specifically, physico-chemical characteristics such as dehydration, acidity, and conductivity were determined. Information on the structure and composition of the biomass was found. These data on the nature of the biomass were found through the use of Fourier Transform Infrared (FTIR) and Thermogravimetry (TGA). The promising results inform on the nature of the analyzed samples and allow the selection of the best biomass which would give an important thermal conductivity for the manufacture of the briquettes, but also of the binders to be used according to the physico-chemical characteristics like the pH.展开更多
Indonesia is one of the largest coconut-producing countries in the world.The utilization of coconut shell waste into briquettes will increase the selling value and become a great export opportunity.However,the effect ...Indonesia is one of the largest coconut-producing countries in the world.The utilization of coconut shell waste into briquettes will increase the selling value and become a great export opportunity.However,the effect of adhesives on the quality of coconut shell charcoal briquettes made using screw extruder machine has not been widely studied.This study aims to determine the effect of adhesive type on the quality of coconut shell charcoal briquettes.The process of fabricating briquettes in this study included crushing,mixing,blending,pressing,and drying.In the mixing process,3 types of adhesives were used,namely tapioca flour(Briquette_1),cassava flour(Briquette_2),and modified cassava flour(Briquette_3)with a concentration of 5%of the weight of coconut shell charcoal powders.The quality of the resulting briquettes and commercial briquettes will be evaluated by moisture content,ash content,volatile matter,fixed carbon,calorific value,density,compressive,and drop test testing.The results of this research showed that the type of adhesive had a significant effect on the quality of the briquettes produced.Specimen Briquette_1 had better quality than commercial briquettes(Briquette_4)and other briquette specimens.The test results showed that Briquette_1 produced briquettes with better compressive strength and friability than the other specimens,at 6.95 N/mm^(2) and 4.44%,respectively.The moisture content,ash content,fixed carbon,and calorific value of Briquette_1 have met the requirements set by the Indonesian National Standard(SNI)number 01-6235-2000.Meanwhile,the volatile matter content and density of Briquette_1 are by the standards of Japan and the United States America(USA).展开更多
Briquette technology is an alternative green energy source to offset the increasing demand for charcoal and firewood to save the forests and the environment while creating employment for youth and women. Using the sco...Briquette technology is an alternative green energy source to offset the increasing demand for charcoal and firewood to save the forests and the environment while creating employment for youth and women. Using the scoping and realistic review techniques, a review study was conducted to establish the briquette technology’s existence, and its value chain, identify stakeholders and challenges along the value chain and explore the policies supporting the technology and potential employment opportunities for youth in the green energy sector. The review results indicated that the briquette technology value chain consists of sourcing raw materials, production process, distribution, and consumption as its components while transportation, storage or packaging, marketing, and training are its supporting services. In addition, it was found that stakeholders in the value chain are manufacturers, producers, and supporting service providers who differ based on their formalities, such as groups, companies, government organizations, Non-Governmental Organizations (NGOs), institutions, and enterprises. Furthermore, five challenges were identified that impair the briquette adoption. They include the technology, raw materials, and the quality of briquettes, promotion, and marketing. Also, the study found that there are limited policies that provide a conducive environment for briquette technology to flourish. The study concludes that briquette technology exists in Tanzania. However, it is not yet matured as compared to the developed countries, and the technology is not backstopped by existing policies. The study recommends the briquette technology as a viable employment opportunity, especially for youth and women;therefore, the formulated briquette value chain should be utilized for easy coordination of stakeholders and deployment of the technology. Also, there is a need to create awareness and innovative strategies for promoting and engaging more stakeholders in the technology through the policies that explicitly insist on adopt展开更多
基金financially supported by the National Natural Science Foundation of China(No.U1260202)the National Basic Research Priorities Program of China(No.2012CB720401)the State Key Laboratory of Solid Waste Reuse for Building Materials
文摘In this study, composite briquettes were prepared using gravity dust and converter sludge as the main materials; these briquettes were subsequently reduced in a tube furnace at 1000-1300℃ for 5-30 min under a nitrogen atmosphere. The effects of reaction temperature, reaction time, and carbon content on the metallization and dezincification ratios of the composite briquettes were studied. The reduced com- posite briquettes were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy-dispersive spectroscopy （EDS）. The results show that the gravity dust and converter sludge are combined into the composite briquettes and a reasonable combination not only improves the performance of the composite briquettes, but also leads to the reduction with no or little reductant and flux. As the re- action temperature is increased and the reaction time is extended, the metallization and dezincification ratios of the composite briquettes in- crease gradually. When the composite briquettes are roasted at 1300℃ for 30 rain, the metallization ratio and dezineification ratio reaches 91.35% and 99.25%, respectively, indicating that most of the iron oxide is reduced and the zinc is almost completely removed. The carbon content is observed to exert a lesser effect on the reduction process; as the C/O molar ratio increases, the metallization and dezincification ra- tios first increase and then decrease.
文摘Now one of the main cash crops in Côte d’Ivoire, the cashew tree feeds an entire industrial sector based on the processing of its fruit. This processing generates a large volume of waste, consisting of cashew nutshells, the management of which poses environmental problems. With the aim of replacing charcoal and firewood with more environmentally friendly fuels, several studies are currently being carried out into the optimal use of cashew shells in fuel briquettes. To assess the environmental sustainability of these briquettes, this study calculates the environmental impacts associated with their life cycle, compares them with those of charcoal and firewood, and identifies the processes that contribute most to environmental pollution, with a view to improving them. Analysis of the results showed that cashew nutshell briquettes emit a range of pollutants over their life cycle that damage the environment and are responsible for the 7 impact categories considered: acidification, eutrophication, freshwater aquatic ecotoxicity, global warming, human toxicity, photochemical oxidation and terrestrial ecotoxicity potential. However, they are more environmentally friendly than charcoal and firewood for 5 impact categories: freshwater aquatic ecotoxicity, global warming, human toxicity, photochemical oxidation and terrestrial ecotoxicity potential. The 3 elementary processes, i.e. transport of biomass raw materials, production, and combustion of briquettes, emit pollutants that contribute most to the creation of environmental impact categories. The most relevant pollutants are nitrogen oxides (NOx), sulphur oxides (SOx) and particulate matter (PM).
文摘Basic physicochemical properties of the dust from Laiwu Iron and Steel Co. Ltd. were studied. It is found that C, Zn, K, Na, etc. exist in the fabric filter dust, off gas （OG） sludge, fine ash in converter, and electrical field dust in sinter. Among these, OG sludge gives the finest particle, more than 90% of which is less than 2.51 mm. The dust can lead to a serious negative influence on the production of sintering and blast furnaces （BF） if it is recycled in sintering. The briquette and reduction experimental results showed that the qualified strength could be obtained in the case of 8wt% molasses or 4wt% QT-10 added as binders. Also, more than 75% of metallization ratio, more than 95% of dezincing ratio, as well as more than 80% of K and Na removal rates were achieved for the briquettes kept at 1250℃ for 15 min during the direct reduction process. SEM observation indicated that the rates of indirect reduction and carbonization became dominating when the bri-quettes were kept at 1250℃ for 6 min.
文摘Green coal or bio-coal is coal produced with rich biodegradable materials, elaborated from agricultural and household residues with a high percentage of carbon. This green charcoal (fuel briquettes) is an alternative to charcoal. Well known for its contribution to greenhouse gas emissions, charcoal is one of the causes of tree felling. The valorization of waste by the manufacture of biofuels could be an alternative to the use of charcoal. The general objective of the present study is the valorization of nine biomasses from Togo as raw materials. Specifically, physico-chemical characteristics such as dehydration, acidity, and conductivity were determined. Information on the structure and composition of the biomass was found. These data on the nature of the biomass were found through the use of Fourier Transform Infrared (FTIR) and Thermogravimetry (TGA). The promising results inform on the nature of the analyzed samples and allow the selection of the best biomass which would give an important thermal conductivity for the manufacture of the briquettes, but also of the binders to be used according to the physico-chemical characteristics like the pH.
文摘Indonesia is one of the largest coconut-producing countries in the world.The utilization of coconut shell waste into briquettes will increase the selling value and become a great export opportunity.However,the effect of adhesives on the quality of coconut shell charcoal briquettes made using screw extruder machine has not been widely studied.This study aims to determine the effect of adhesive type on the quality of coconut shell charcoal briquettes.The process of fabricating briquettes in this study included crushing,mixing,blending,pressing,and drying.In the mixing process,3 types of adhesives were used,namely tapioca flour(Briquette_1),cassava flour(Briquette_2),and modified cassava flour(Briquette_3)with a concentration of 5%of the weight of coconut shell charcoal powders.The quality of the resulting briquettes and commercial briquettes will be evaluated by moisture content,ash content,volatile matter,fixed carbon,calorific value,density,compressive,and drop test testing.The results of this research showed that the type of adhesive had a significant effect on the quality of the briquettes produced.Specimen Briquette_1 had better quality than commercial briquettes(Briquette_4)and other briquette specimens.The test results showed that Briquette_1 produced briquettes with better compressive strength and friability than the other specimens,at 6.95 N/mm^(2) and 4.44%,respectively.The moisture content,ash content,fixed carbon,and calorific value of Briquette_1 have met the requirements set by the Indonesian National Standard(SNI)number 01-6235-2000.Meanwhile,the volatile matter content and density of Briquette_1 are by the standards of Japan and the United States America(USA).
文摘Briquette technology is an alternative green energy source to offset the increasing demand for charcoal and firewood to save the forests and the environment while creating employment for youth and women. Using the scoping and realistic review techniques, a review study was conducted to establish the briquette technology’s existence, and its value chain, identify stakeholders and challenges along the value chain and explore the policies supporting the technology and potential employment opportunities for youth in the green energy sector. The review results indicated that the briquette technology value chain consists of sourcing raw materials, production process, distribution, and consumption as its components while transportation, storage or packaging, marketing, and training are its supporting services. In addition, it was found that stakeholders in the value chain are manufacturers, producers, and supporting service providers who differ based on their formalities, such as groups, companies, government organizations, Non-Governmental Organizations (NGOs), institutions, and enterprises. Furthermore, five challenges were identified that impair the briquette adoption. They include the technology, raw materials, and the quality of briquettes, promotion, and marketing. Also, the study found that there are limited policies that provide a conducive environment for briquette technology to flourish. The study concludes that briquette technology exists in Tanzania. However, it is not yet matured as compared to the developed countries, and the technology is not backstopped by existing policies. The study recommends the briquette technology as a viable employment opportunity, especially for youth and women;therefore, the formulated briquette value chain should be utilized for easy coordination of stakeholders and deployment of the technology. Also, there is a need to create awareness and innovative strategies for promoting and engaging more stakeholders in the technology through the policies that explicitly insist on adopt
