With extensive attention being paid to the potential environmental hazards of discarded face masks,catalytic pyrolysis technologies have been proposed to realize the valorization of wastes.However,recent catalyst sele...With extensive attention being paid to the potential environmental hazards of discarded face masks,catalytic pyrolysis technologies have been proposed to realize the valorization of wastes.However,recent catalyst selection and system design have focused solely on conversion efficiency,ignoring economic cost and potential life-cycle environmental damage.Here,we propose an economic-environmental hybrid pre-assessment method to help identify catalysts and reactors with less environmental impact and high economic returns among various routes to convert discarded face masks into carbon nanotubes(CNTs)and hydrogen.In catalyst selection,it was found that a widely known Fe-Ni catalyst exhibits higher catalytic activity than a cheaper Fe catalyst,potentially increasing the economic viability of the catalytic pyrolysis system by 38%-55%.The use of this catalyst also results in a carbon reduction of 4.12-10.20kilogram CO_(2) equivalent for 1 kilogram of discarded face masks,compared with the cheaper Fe catalyst.When the price of CNTs exceeds 1.49×10^(4) USD·t^(-1),microwave-assisted pyrolysis is the optimal choice due to its superior environmental performance(in terms of its life-cycle greenhouse gas reduction potential,eutrophication potential,and human toxicity)and economic benefits.In contrast,conventional heating pyrolysis may be a more economical option due to its good stability over 43 reaction regeneration cycles,as compared with a microwave-assisted pyrolysis catalyst with a higher conversion efficiency.This study connects foundational science with ecological economics to guide emerging technologies in their research stage toward technical efficiency,economic benefits,and environmental sustainability.展开更多
Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components,which can achieve the meaningful purpose of tra...Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components,which can achieve the meaningful purpose of transforming waste into high-value products.This study explored whether catalytic pyrolysis of digestate is feasible to prepare aromatic hydrocarbons by analyzing the thermogravimetric characteristics,pyrolysis characteristics,and catalytic pyrolysis characteristics of digestate.For digestate pyrolysis,an increase in temperature was found to elevate the CO,CH_4,and monocyclic aromatic hydrocarbon(benzene,toluene,and xylene;BTX)content,whereas it decreased the contents of phenols,acids,aldehydes,and other oxygenates.Furthermore,the catalytic pyrolysis process effectively inhibited the acids,phenols,and furans in the liquid,whereas the yield of BTX increased from 25.45%to 45.99%,and the selectivity of xylene was also increased from 10.32%to 28.72%after adding ZSM-5.ZSM-5 also inhibited the production of nitrogenous compounds.展开更多
Olive oil is an important food industry product in Mediterranean countries. Large quantities of OWR （olive waste residue） are generated during a two- or three-phase separation process. This represents a major pollut...Olive oil is an important food industry product in Mediterranean countries. Large quantities of OWR （olive waste residue） are generated during a two- or three-phase separation process. This represents a major pollution problem for the industry and oil farms. The OWR is a source of substances of high value and can be used as a low-cost renewable energy. This work studied the behaviour of OWRs during the thermal decomposition process. The experiments of the slow pyrolysis process of three different waste olive products as olive pomace, olive tree pruning and olive kernels were performed under a nitrogen atmosphere at different heating rates, using a thermogravimetric balance. The samples were heated to a maximum temperature of 1,023 K, with four different heating rates of 2, 5, 10, 15 K/min. A comparison of different isoconversional （Flynn-Wall-Ozawa）, not-isoconversional （Kissinger） model-free and model-fitting （Freeman-Carroll） methods to calculate the activation energy and pre-exponential factor is presented. In the Kissinger method the kinetic parameters were invariant for the whole pyrolysis process. While, in the case of Freeman-Carroll, it differs with change of the heating rate. The Flynn-Wall-Ozawa technique revealed the ＂not one-step＂ mechanism of reaction that occurs during the slow pyrolysis process. The kinetic data obtained in nitrogen atmosphere may provide more useful information for engineers for a better and complete description of the pyrolysis process and can be helpful to predict the kinetic model.展开更多
基金supported by the National Natural Science Foundation of China(52076099,52306257,and 72293601)。
文摘With extensive attention being paid to the potential environmental hazards of discarded face masks,catalytic pyrolysis technologies have been proposed to realize the valorization of wastes.However,recent catalyst selection and system design have focused solely on conversion efficiency,ignoring economic cost and potential life-cycle environmental damage.Here,we propose an economic-environmental hybrid pre-assessment method to help identify catalysts and reactors with less environmental impact and high economic returns among various routes to convert discarded face masks into carbon nanotubes(CNTs)and hydrogen.In catalyst selection,it was found that a widely known Fe-Ni catalyst exhibits higher catalytic activity than a cheaper Fe catalyst,potentially increasing the economic viability of the catalytic pyrolysis system by 38%-55%.The use of this catalyst also results in a carbon reduction of 4.12-10.20kilogram CO_(2) equivalent for 1 kilogram of discarded face masks,compared with the cheaper Fe catalyst.When the price of CNTs exceeds 1.49×10^(4) USD·t^(-1),microwave-assisted pyrolysis is the optimal choice due to its superior environmental performance(in terms of its life-cycle greenhouse gas reduction potential,eutrophication potential,and human toxicity)and economic benefits.In contrast,conventional heating pyrolysis may be a more economical option due to its good stability over 43 reaction regeneration cycles,as compared with a microwave-assisted pyrolysis catalyst with a higher conversion efficiency.This study connects foundational science with ecological economics to guide emerging technologies in their research stage toward technical efficiency,economic benefits,and environmental sustainability.
基金partially funded by the GTCLC-NEG project,which received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement (101018756)the Brisk 2 European project (731101)for funding this project.The project acronym was B2PB-SIN2-1001,and the project title was“Optimization of catalytic pyrolysis of digestate and sewage sludge.”。
文摘Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components,which can achieve the meaningful purpose of transforming waste into high-value products.This study explored whether catalytic pyrolysis of digestate is feasible to prepare aromatic hydrocarbons by analyzing the thermogravimetric characteristics,pyrolysis characteristics,and catalytic pyrolysis characteristics of digestate.For digestate pyrolysis,an increase in temperature was found to elevate the CO,CH_4,and monocyclic aromatic hydrocarbon(benzene,toluene,and xylene;BTX)content,whereas it decreased the contents of phenols,acids,aldehydes,and other oxygenates.Furthermore,the catalytic pyrolysis process effectively inhibited the acids,phenols,and furans in the liquid,whereas the yield of BTX increased from 25.45%to 45.99%,and the selectivity of xylene was also increased from 10.32%to 28.72%after adding ZSM-5.ZSM-5 also inhibited the production of nitrogenous compounds.
文摘Olive oil is an important food industry product in Mediterranean countries. Large quantities of OWR （olive waste residue） are generated during a two- or three-phase separation process. This represents a major pollution problem for the industry and oil farms. The OWR is a source of substances of high value and can be used as a low-cost renewable energy. This work studied the behaviour of OWRs during the thermal decomposition process. The experiments of the slow pyrolysis process of three different waste olive products as olive pomace, olive tree pruning and olive kernels were performed under a nitrogen atmosphere at different heating rates, using a thermogravimetric balance. The samples were heated to a maximum temperature of 1,023 K, with four different heating rates of 2, 5, 10, 15 K/min. A comparison of different isoconversional （Flynn-Wall-Ozawa）, not-isoconversional （Kissinger） model-free and model-fitting （Freeman-Carroll） methods to calculate the activation energy and pre-exponential factor is presented. In the Kissinger method the kinetic parameters were invariant for the whole pyrolysis process. While, in the case of Freeman-Carroll, it differs with change of the heating rate. The Flynn-Wall-Ozawa technique revealed the ＂not one-step＂ mechanism of reaction that occurs during the slow pyrolysis process. The kinetic data obtained in nitrogen atmosphere may provide more useful information for engineers for a better and complete description of the pyrolysis process and can be helpful to predict the kinetic model.
