The main objective of this study was to establish optimal incineration conditions through the analysis of pollutant formation mechanisms involved in the combustion process of a retort incinerator. Calorific values of ...The main objective of this study was to establish optimal incineration conditions through the analysis of pollutant formation mechanisms involved in the combustion process of a retort incinerator. Calorific values of several types of municipal solid wastes were determined and related to specific incinerability indexes. The incinerability testing concerning this study was conducted on residues with an incinerability index （II） of 123. The samples were tested under different conditions： with and without chamber preheating, varying the percentage of inlet air （25, 50 and 75% of the system capacity）, measuring the temperatures of the primary and secondary chambers, and gauging the CO and NO stack emissions with an electrochemical cell. With comparative purposes in mind, samples with indexes ofI = 112, I = 123, I = 130 and I = 132 were also tested to assess the influence of the II on pollutant emissions.展开更多
Aged municipal solid wastes(MSW)excavated from landfills and dumpsites were characterized to analyze their fraction composition,moisture content,and lower heat value(LHV).The necessity and feasibility of recycling com...Aged municipal solid wastes(MSW)excavated from landfills and dumpsites were characterized to analyze their fraction composition,moisture content,and lower heat value(LHV).The necessity and feasibility of recycling combustibles from aged MSW to improve the incineration of fresh MSW were investigated.The results showed that combustibles in aged MSW were easily separated from other components and than LHV of the separated combustibles are higher than 11000 kJ/kg.The fresh MSW are of high moisture contents with average LHV below 6500 kJ/kg,making their stable combustion difficult to maintain in MSW incinerators.For both fresh MSW and aged MSW,plastics are the main contributor to their LHV.To improve incineration of fresh MSW that are characterized with low LHV,combustibles separated from aged MSW were made into refuse derived fuel(RDF)pellets and were then added to fresh MSW by 2%wt.–5%wt.LHV variation and air supply resistance change of the MSW layer on the incinerator grate caused by the addition of RDF was checked,and no significant changes were found.No obvious difference was observed for the‘burn-out time’between RDF pellets and fresh MSW either.RDF made from aged MSW combustibles is found to be a promising auxiliary fuel to improve the incineration of fresh MSW,and aged MSW from old landfill cells and dumpsites can be finally disposed of jointly with fresh MSW by recycling combustible from the former to be coincinerated with the latter in the incineration plants.展开更多
The municipal solid waste incineration fly ash (MSWI-FA) contains a large amount of heavy metals, and the process of iron ore sintering and treating fly ash needs to pay attention to the migration characteristics of h...The municipal solid waste incineration fly ash (MSWI-FA) contains a large amount of heavy metals, and the process of iron ore sintering and treating fly ash needs to pay attention to the migration characteristics of heavy metals. The impact of the application of MSWI-FA in the sintering process on the emission law of heavy metals in the collaborative treatment process was studied, and corresponding control technologies were proposed. The results showed that the direct addition of water washing fly ash (WM-FA) powder resulted in varying degrees of increase in heavy metal elements in the sinter. As the amount of WM-FA added increases, the content of heavy metal elements correspondingly increases, and an appropriate amount of WM-FA added is 0.5%–1.0%. The migration mechanism of heavy metals during the sintering treatment of WM-FA was clarified. Heavy metals are mainly removed through direct and indirect chlorination reactions, and Cu and Cr can react with SiO_(2) and Fe_(2)O_(3) in the sintered material to solidify in the sinter. Corresponding control techniques have been proposed to reduce the heavy metal elements in WM-FA through the pre-treatment of WM-FA. When the WM-FA was fed in the middle and lower layers of the sintered material, the high temperature of the lower layer was utilized to promote the removal of heavy metals. The Ni element content has decreased from 130 to 90 mg kg^(−1), and the Cd removal rate has increased by 23%. The removal rates of Cd and Cr elements increase by 2.4 and 5.5 times, respectively. There is no significant change in sintering indexes.展开更多
文摘The main objective of this study was to establish optimal incineration conditions through the analysis of pollutant formation mechanisms involved in the combustion process of a retort incinerator. Calorific values of several types of municipal solid wastes were determined and related to specific incinerability indexes. The incinerability testing concerning this study was conducted on residues with an incinerability index （II） of 123. The samples were tested under different conditions： with and without chamber preheating, varying the percentage of inlet air （25, 50 and 75% of the system capacity）, measuring the temperatures of the primary and secondary chambers, and gauging the CO and NO stack emissions with an electrochemical cell. With comparative purposes in mind, samples with indexes ofI = 112, I = 123, I = 130 and I = 132 were also tested to assess the influence of the II on pollutant emissions.
基金the Asian Regional Research Program on Environmental Technology“Sustainable Solid Waste Landfill Management in Asia”funded from Sweden International Development Agency(Sida)and key project in China National Sciences&Technology Pillar Program during the Eleventh Five Year Plan period(Grant No.2008BAC46B06).
文摘Aged municipal solid wastes(MSW)excavated from landfills and dumpsites were characterized to analyze their fraction composition,moisture content,and lower heat value(LHV).The necessity and feasibility of recycling combustibles from aged MSW to improve the incineration of fresh MSW were investigated.The results showed that combustibles in aged MSW were easily separated from other components and than LHV of the separated combustibles are higher than 11000 kJ/kg.The fresh MSW are of high moisture contents with average LHV below 6500 kJ/kg,making their stable combustion difficult to maintain in MSW incinerators.For both fresh MSW and aged MSW,plastics are the main contributor to their LHV.To improve incineration of fresh MSW that are characterized with low LHV,combustibles separated from aged MSW were made into refuse derived fuel(RDF)pellets and were then added to fresh MSW by 2%wt.–5%wt.LHV variation and air supply resistance change of the MSW layer on the incinerator grate caused by the addition of RDF was checked,and no significant changes were found.No obvious difference was observed for the‘burn-out time’between RDF pellets and fresh MSW either.RDF made from aged MSW combustibles is found to be a promising auxiliary fuel to improve the incineration of fresh MSW,and aged MSW from old landfill cells and dumpsites can be finally disposed of jointly with fresh MSW by recycling combustible from the former to be coincinerated with the latter in the incineration plants.
基金supported by the National Natural Science Foundation of China(No.52274344)the Science and Technology Innovation Program of Hunan Province(2023RC3042)Provincial Natural Science Foundation of Hunan(Nos.2022JJ30723 and 2023JJ20068).
文摘The municipal solid waste incineration fly ash (MSWI-FA) contains a large amount of heavy metals, and the process of iron ore sintering and treating fly ash needs to pay attention to the migration characteristics of heavy metals. The impact of the application of MSWI-FA in the sintering process on the emission law of heavy metals in the collaborative treatment process was studied, and corresponding control technologies were proposed. The results showed that the direct addition of water washing fly ash (WM-FA) powder resulted in varying degrees of increase in heavy metal elements in the sinter. As the amount of WM-FA added increases, the content of heavy metal elements correspondingly increases, and an appropriate amount of WM-FA added is 0.5%–1.0%. The migration mechanism of heavy metals during the sintering treatment of WM-FA was clarified. Heavy metals are mainly removed through direct and indirect chlorination reactions, and Cu and Cr can react with SiO_(2) and Fe_(2)O_(3) in the sintered material to solidify in the sinter. Corresponding control techniques have been proposed to reduce the heavy metal elements in WM-FA through the pre-treatment of WM-FA. When the WM-FA was fed in the middle and lower layers of the sintered material, the high temperature of the lower layer was utilized to promote the removal of heavy metals. The Ni element content has decreased from 130 to 90 mg kg^(−1), and the Cd removal rate has increased by 23%. The removal rates of Cd and Cr elements increase by 2.4 and 5.5 times, respectively. There is no significant change in sintering indexes.
