In this experiment, lignite was refined and processed through binderless briquette preparation process from low-rank coal and became briquette. Then, lignite and its briquette were pyrolysed as materials to compare th...In this experiment, lignite was refined and processed through binderless briquette preparation process from low-rank coal and became briquette. Then, lignite and its briquette were pyrolysed as materials to compare the nature of their pyrolysis. In this study, the experiment was carried out through a lab tube furnace, at a heating rate of 10 ~C/min, and the gas was analyzed and compared, which was collected at different temperatures. The results show that： in the pyrolysis temperature of 550-850 ℃, the semi-coke yield of briquette is 2%-6% higher than lignite, the tar yield of briquette is 2%-3% higher than lignite and the gas yield of briquette is 4%-9% less than lignite. The time required for complete release of the briquette is about 20 min less than lignite. The components in the pyrolysis gas of lignite and its briquette are the same, and their variation with the pyrolysis temperature is similar.展开更多
High-temperature pyrolysis technology can effectively solve the problem of municipal solid waste pollution.However,the pyrolysis gas contains a large amount of CO_(2),which would adversely affect the subsequent utiliz...High-temperature pyrolysis technology can effectively solve the problem of municipal solid waste pollution.However,the pyrolysis gas contains a large amount of CO_(2),which would adversely affect the subsequent utilization.To address this problem,a novel method of co-precipitation modification with Ca,Mg and Zr metals was proposed to improve the CO_(2)capture performance.X-ray diffraction(XRD)patterns and energy dispersive X-ray spectroscopy analysis showed that the two inert supports MgO and CaZrO_(3)were uniformly distributed in the modified calcium-based sorbents.In addition,the XRD results indicated that CaZrO_(3)was produced by the reaction of ZrO_(2)and CaO at high temperatures.The effects of doping ratios,adsorption temperature,calcination temperature,CO_(2)concentration and calcination atmosphere on the adsorption capacity and cycle stability of the modified calcium-based sorbent were studied.The modified calcium-based sorbent achieved the best CO_(2)capture performance when the doping ratio was 10:1:1 with carbonation at 700℃ under 20%CO_(2)/80%N_(2)atmosphere and calcination at 900℃ under100%N_(2)atmosphere.After ten cycles,the average carbonation conversion rate of Ca-10 sorbent was 72%.Finally,the modified calcium-based sorbents successfully reduced the CO_(2)concentration of the pyrolysis gas from 37%to 5%.展开更多
Nowadays,natural rubber(NR)is an indispensable material for industrial production and peoples’daily utilization.The root of Taraxacum kok-saghyz(TKS)contains a large amount of NR,which is potentially to be an alterna...Nowadays,natural rubber(NR)is an indispensable material for industrial production and peoples’daily utilization.The root of Taraxacum kok-saghyz(TKS)contains a large amount of NR,which is potentially to be an alternative rubber source of conventional Hevea brasiliensis(HB).In order to find a convenient,fast and green method for qualitative and quantitative analysis of NR in TKS,a pyrolysis gas chromatography-mass spectrometric(Py-GCMS)method was developed accordingly.The results indicated that the main products of TKS rubber after pyrolysis were isoprene and limonene,respectively,and the limit of detection(LOD)of TKS rubber was 2.603 mg/g.The ratios of NR mass fractions in TKSs by Py-GC-MS ranged from 1.20%±0.20%to 8.61%±0.28%.The developed method has been used for determination of actual TKS samples and can be further applied to the field test for rapid breeding and large-scale cultivation of TKS thereof.展开更多
When high-temperature steam is used as a medium to pyrolyze organic-rich shale,water steam not only acts as heat transfer but also participates in the chemical reaction of organic matter pyrolysis,thus affecting the g...When high-temperature steam is used as a medium to pyrolyze organic-rich shale,water steam not only acts as heat transfer but also participates in the chemical reaction of organic matter pyrolysis,thus affecting the generation law and release characteristics of gas products.In this study,based on a long-distance reaction system of organic-rich shale pyrolysis via steam injection,the effects of steam temperature and reaction distance on gas product composition are analyzed in depth and compared with other pyrolysis processes.The advantages of organic-rich shale pyrolysis via steam injection are then evaluated.The volume concentration of hydrogen in the gas product obtained via the steam injection pyrolysis of organic-rich shale is the highest,which is more than 60%.The hydrogen content increases as the reaction distance is extended;however,the rate of increase changes gradually.Increasing the reaction distance from 800 to 4000 mm increases the hydrogen content from 34.91%to 69.68%and from 63.13%to 78.61%when the steam temperature is 500℃ and 555℃,respectively.However,the higher the heat injection temperature,the smaller the reaction distance required to form a high concentration hydrogen pyrolysis environment(hydrogen concentration>60%).When the steam pyrolysis temperature is increased from 500℃ to 555℃,the reaction distance required to form a high concentration of hydrogen is reduced from 3800 to 800 mm.Compared with the direct retorting process,the volume concentration of hydrogen obtained from high-temperature steam pyrolysis of organic-rich shale is 8.82 and 10.72 times that of the commonly used Fushun and Kivite furnaces,respectively.The pyrolysis of organic-rich shale via steam injection is a pyrolysis process in a hydrogen-rich environment.展开更多
The composition of biomass pyrolysis gas is complex,and the selective separation of its components is crucial for its further utilization.Metal-incorporated nitrogen-doped materials exhibit enormous potential,whereas ...The composition of biomass pyrolysis gas is complex,and the selective separation of its components is crucial for its further utilization.Metal-incorporated nitrogen-doped materials exhibit enormous potential,whereas the relevant adsorption mechanism is still unclear.Herein,16 metal-incorporated nitrogen-doped carbon materials were designed based on the density functional theory calculation,and the adsorption mechanism of pyrolysis gas components H2,CO,CO_(2),CH_(4),and C2H6 was explored.The results indicate that metal-incorporated nitrogen-doped carbon materials generally have better adsorption effects on CO and CO_(2)than on H_(2),CH_(4),and C_(2)H_(6).Transition metal Mo-and alkaline earth metal Mg-and Ca-incorporated nitrogen-doped carbon materials show the potential to separate CO and CO_(2).The mixed adsorption results of CO_(2)and CO further indicate that when the CO_(2)ratio is significantly higher than that of CO,the saturated adsorption of CO_(2)will precede that of CO.Overall,the three metal-incorporated nitrogen-doped carbon materials can selectively separate CO_(2),and the alkaline earth metal Mg-incorporated nitrogen-doped carbon material has the best performance.This study provides theoretical guidance for the design of carbon capture materials and lays the foundation for the efficient utilization of biomass pyrolysis gas.展开更多
The combination of pyrolysis high resolution gas chromatography and pat- tern recognition techniques is a powerful tool for the classification of traditional Chinese drug.A study has been completed on 55 Beimu samples...The combination of pyrolysis high resolution gas chromatography and pat- tern recognition techniques is a powerful tool for the classification of traditional Chinese drug.A study has been completed on 55 Beimu samples of five different geographic origins: Eastern China.Central China.South-western China,North-western China and North-eastern China.Principal component analysis and SIMCA are applied to effectively classifying the samples according to the origin of the plants.The chemical information contained in the high resolution gas chromatographic data is sufficient to characterize the geographic origin of sam- pies.展开更多
The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
Taraxacum kok-saghyz(TKS)is a plant native to the Tianshan valley on the border between China and Kazakhstan.TKS rubber is a good substitute for natural rubber.TKS's breeding work necessitates the need to screen h...Taraxacum kok-saghyz(TKS)is a plant native to the Tianshan valley on the border between China and Kazakhstan.TKS rubber is a good substitute for natural rubber.TKS's breeding work necessitates the need to screen high-yielding varieties,hence rapid determination of rubber content is essential for the screening.Conventional analytical methods cannot meet actual needs in terms of real-time testing and economic cost.Near-infrared spectroscopy analysis technology,which has developed rapidly in the field of industrial process analysis in recent years,is a green detection technology with obvious merits of fast measurement speed,low cost and no sample loss.This research aims to develop a portable non-destructive near-infrared spectroscopic detection scheme to evaluate the content of natural rubber in TKS fresh roots.Pyrolysis gas chromatography(Py-GC)was chosen as the reference method for the development of NIR prediction model.208 TKS fresh root samples were collected from the Inner Mongolia Autonomous Region of China.Near-infrared spectra were acquired for all samples.Randomly,two-thirds of them were selected as the calibration set,the remaining one-third as the validation set,and the partial least squares method was successfully established a good NIR prediction model for rubber content at 1080-1800 nm with a ratio of performance to deviation(RPD)of 5.54 and coefficient of determination(R^(2))of 0.95.This study showed that portable near-infrared spectroscopy could be used with ease for large-scale screening of TKS plants in farmland,and could greatly facilitate TKS germplasm preservation,high-yield cultivation,environment-friendly,high-efficiency and low-cost rubber extraction,and comprehensive advancement of the natural rubber industry thereof.展开更多
An insightful understanding of the formation mechanism of process-inherent defects anddeformation is increasingly important for the property evaluation and structural design of ceramicmatrix composites (CMCs). For thi...An insightful understanding of the formation mechanism of process-inherent defects anddeformation is increasingly important for the property evaluation and structural design of ceramicmatrix composites (CMCs). For this purpose, a coupled thermal–diffusive–mechanical modelingapproach was proposed by considering three important phenomena that occur during the pyrolysisprocess for manufacturing CMCs: variations of the physical and mechanical properties of theconstituents, generation and diffusive of pyrolysis gas, and multiple thermal deformations. Thesynergistic effects of these three phenomena on the stress, damage development, microstructuralmorphology, and process deformation of SiC matrix composites were investigated using finiteelement simulations. This new approach was validated by comparing the simulation and experimentalresults. Significant volume shrinkage of the matrix during the polymer-to-ceramic transformationresulted in large tensile stresses and subsequent highly fragmented microstructure in CMCs. Thepyrolysis-gas-induced expansion on the matrix under a damage state may yield a positive processdeformation of CMCs at the macroscale, overcoming the effects of the volume shrinkage of the bulkmatrix at the microscale. The modeling approach is expected to guide high-quality manufacturing ofCMCs and comprehensive studies of structure–processing–property relationships.展开更多
The humic acid（HA） sample obtained from the alluvial soil was characterized by elemental composition, pyrolysis gas chromatography-mass spectrometry（Py-GC-MS） and solid-state 13C nuclear magnetic resonance （13C ...The humic acid（HA） sample obtained from the alluvial soil was characterized by elemental composition, pyrolysis gas chromatography-mass spectrometry（Py-GC-MS） and solid-state 13C nuclear magnetic resonance （13C NMR） spectroscopy. There is high fat content and a few nitrogen-containing functional groups in HA. Py-GC-MS demonstrates the characterization and structural identification of HA. One long list of identified pyrolysis products was proposed for the construction of conceptual model of HA. Solid-state 13C NMR data indicate there are higher values of alkyl-C, O-alkyl-C and aryl-C in HA. The elemental composition, structural carbon distribution and L3C NMR spectroscopy of simulated HA are consistent with those of experimental HA. HyperChem was used to simulate the three-dimensional molecular structure of the monomer, which was optimized by the molecular mechanics of the optimized potential for liquid simulations（OPLS） force field and molecular dynamics simulation to get the stable and balanced conformation. The deprotonation process study depicts that the degree of ionization of HA gets deeper, while the electronegativity of HA and the energy of van der Waals（vdW） increase. Moreover, the 3D structure of humic acid with -4 charges is the most stable. The deprotonation process is an endothermic process.展开更多
文摘In this experiment, lignite was refined and processed through binderless briquette preparation process from low-rank coal and became briquette. Then, lignite and its briquette were pyrolysed as materials to compare the nature of their pyrolysis. In this study, the experiment was carried out through a lab tube furnace, at a heating rate of 10 ~C/min, and the gas was analyzed and compared, which was collected at different temperatures. The results show that： in the pyrolysis temperature of 550-850 ℃, the semi-coke yield of briquette is 2%-6% higher than lignite, the tar yield of briquette is 2%-3% higher than lignite and the gas yield of briquette is 4%-9% less than lignite. The time required for complete release of the briquette is about 20 min less than lignite. The components in the pyrolysis gas of lignite and its briquette are the same, and their variation with the pyrolysis temperature is similar.
基金the support given by the National Key Research and Development Program of China(2018YFC1901203)Natural Science Foundation of Guangdong Province,China(2021A1515010497)+1 种基金Guangzhou Science and Technology Innovation Development Special FundFundamental Research Funds for the Central Universities(2019MS017)。
文摘High-temperature pyrolysis technology can effectively solve the problem of municipal solid waste pollution.However,the pyrolysis gas contains a large amount of CO_(2),which would adversely affect the subsequent utilization.To address this problem,a novel method of co-precipitation modification with Ca,Mg and Zr metals was proposed to improve the CO_(2)capture performance.X-ray diffraction(XRD)patterns and energy dispersive X-ray spectroscopy analysis showed that the two inert supports MgO and CaZrO_(3)were uniformly distributed in the modified calcium-based sorbents.In addition,the XRD results indicated that CaZrO_(3)was produced by the reaction of ZrO_(2)and CaO at high temperatures.The effects of doping ratios,adsorption temperature,calcination temperature,CO_(2)concentration and calcination atmosphere on the adsorption capacity and cycle stability of the modified calcium-based sorbent were studied.The modified calcium-based sorbent achieved the best CO_(2)capture performance when the doping ratio was 10:1:1 with carbonation at 700℃ under 20%CO_(2)/80%N_(2)atmosphere and calcination at 900℃ under100%N_(2)atmosphere.After ten cycles,the average carbonation conversion rate of Ca-10 sorbent was 72%.Finally,the modified calcium-based sorbents successfully reduced the CO_(2)concentration of the pyrolysis gas from 37%to 5%.
基金This work was supported by the National Natural Science Foundation of China(No.51673012)National Key Research and Development Plan Fund(No.2017YFB0306901,2016YFF0203703-03)the Beijing Technology and Business University Youth Scholar Funds(No.PXM2019_014213_000007).
文摘Nowadays,natural rubber(NR)is an indispensable material for industrial production and peoples’daily utilization.The root of Taraxacum kok-saghyz(TKS)contains a large amount of NR,which is potentially to be an alternative rubber source of conventional Hevea brasiliensis(HB).In order to find a convenient,fast and green method for qualitative and quantitative analysis of NR in TKS,a pyrolysis gas chromatography-mass spectrometric(Py-GCMS)method was developed accordingly.The results indicated that the main products of TKS rubber after pyrolysis were isoprene and limonene,respectively,and the limit of detection(LOD)of TKS rubber was 2.603 mg/g.The ratios of NR mass fractions in TKSs by Py-GC-MS ranged from 1.20%±0.20%to 8.61%±0.28%.The developed method has been used for determination of actual TKS samples and can be further applied to the field test for rapid breeding and large-scale cultivation of TKS thereof.
基金Basic research program of Shanxi Province(20210302124136 and 20210302123177)National Key R&D Program of China(2019YFA0705501)+1 种基金Key R&D and promotion projects in Henan Province(212102310010)National Natural Science Foundation of China(52104144,U23B2088).
文摘When high-temperature steam is used as a medium to pyrolyze organic-rich shale,water steam not only acts as heat transfer but also participates in the chemical reaction of organic matter pyrolysis,thus affecting the generation law and release characteristics of gas products.In this study,based on a long-distance reaction system of organic-rich shale pyrolysis via steam injection,the effects of steam temperature and reaction distance on gas product composition are analyzed in depth and compared with other pyrolysis processes.The advantages of organic-rich shale pyrolysis via steam injection are then evaluated.The volume concentration of hydrogen in the gas product obtained via the steam injection pyrolysis of organic-rich shale is the highest,which is more than 60%.The hydrogen content increases as the reaction distance is extended;however,the rate of increase changes gradually.Increasing the reaction distance from 800 to 4000 mm increases the hydrogen content from 34.91%to 69.68%and from 63.13%to 78.61%when the steam temperature is 500℃ and 555℃,respectively.However,the higher the heat injection temperature,the smaller the reaction distance required to form a high concentration hydrogen pyrolysis environment(hydrogen concentration>60%).When the steam pyrolysis temperature is increased from 500℃ to 555℃,the reaction distance required to form a high concentration of hydrogen is reduced from 3800 to 800 mm.Compared with the direct retorting process,the volume concentration of hydrogen obtained from high-temperature steam pyrolysis of organic-rich shale is 8.82 and 10.72 times that of the commonly used Fushun and Kivite furnaces,respectively.The pyrolysis of organic-rich shale via steam injection is a pyrolysis process in a hydrogen-rich environment.
基金supported by the National Natural Science Foundation of China(Grant Nos.52106241,52276189 and 52006069)Fundamental Research Funds for the Central Universities(Grant Nos.2023JC009 and 2022YQ002).
文摘The composition of biomass pyrolysis gas is complex,and the selective separation of its components is crucial for its further utilization.Metal-incorporated nitrogen-doped materials exhibit enormous potential,whereas the relevant adsorption mechanism is still unclear.Herein,16 metal-incorporated nitrogen-doped carbon materials were designed based on the density functional theory calculation,and the adsorption mechanism of pyrolysis gas components H2,CO,CO_(2),CH_(4),and C2H6 was explored.The results indicate that metal-incorporated nitrogen-doped carbon materials generally have better adsorption effects on CO and CO_(2)than on H_(2),CH_(4),and C_(2)H_(6).Transition metal Mo-and alkaline earth metal Mg-and Ca-incorporated nitrogen-doped carbon materials show the potential to separate CO and CO_(2).The mixed adsorption results of CO_(2)and CO further indicate that when the CO_(2)ratio is significantly higher than that of CO,the saturated adsorption of CO_(2)will precede that of CO.Overall,the three metal-incorporated nitrogen-doped carbon materials can selectively separate CO_(2),and the alkaline earth metal Mg-incorporated nitrogen-doped carbon material has the best performance.This study provides theoretical guidance for the design of carbon capture materials and lays the foundation for the efficient utilization of biomass pyrolysis gas.
文摘The combination of pyrolysis high resolution gas chromatography and pat- tern recognition techniques is a powerful tool for the classification of traditional Chinese drug.A study has been completed on 55 Beimu samples of five different geographic origins: Eastern China.Central China.South-western China,North-western China and North-eastern China.Principal component analysis and SIMCA are applied to effectively classifying the samples according to the origin of the plants.The chemical information contained in the high resolution gas chromatographic data is sufficient to characterize the geographic origin of sam- pies.
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
基金supported by Beijing University of Chemical Technology-China-Japan Friendship Hospital Biomedical Translation Engineering Research Center Joint Project (RZ2020-02)the sponsorship provided by Beijing Linglong Dandelion Science&Technology Development Co.,Ltd.the financial support granted by the National Key Research and Development Program of China (2019YFF0302004)
文摘Taraxacum kok-saghyz(TKS)is a plant native to the Tianshan valley on the border between China and Kazakhstan.TKS rubber is a good substitute for natural rubber.TKS's breeding work necessitates the need to screen high-yielding varieties,hence rapid determination of rubber content is essential for the screening.Conventional analytical methods cannot meet actual needs in terms of real-time testing and economic cost.Near-infrared spectroscopy analysis technology,which has developed rapidly in the field of industrial process analysis in recent years,is a green detection technology with obvious merits of fast measurement speed,low cost and no sample loss.This research aims to develop a portable non-destructive near-infrared spectroscopic detection scheme to evaluate the content of natural rubber in TKS fresh roots.Pyrolysis gas chromatography(Py-GC)was chosen as the reference method for the development of NIR prediction model.208 TKS fresh root samples were collected from the Inner Mongolia Autonomous Region of China.Near-infrared spectra were acquired for all samples.Randomly,two-thirds of them were selected as the calibration set,the remaining one-third as the validation set,and the partial least squares method was successfully established a good NIR prediction model for rubber content at 1080-1800 nm with a ratio of performance to deviation(RPD)of 5.54 and coefficient of determination(R^(2))of 0.95.This study showed that portable near-infrared spectroscopy could be used with ease for large-scale screening of TKS plants in farmland,and could greatly facilitate TKS germplasm preservation,high-yield cultivation,environment-friendly,high-efficiency and low-cost rubber extraction,and comprehensive advancement of the natural rubber industry thereof.
基金The research is supported in part by the National Key R&D Program of China(No.2021YFF0501800)in part by the National Natural Science Foundation of China(Nos.12272174,12102179,and U22B6009)+1 种基金Natural Science Foundation of Jiangsu Province(No.BK20200409)the High Level Personnel Project of Jiangsu Province(No.JSSCBS20210618).
文摘An insightful understanding of the formation mechanism of process-inherent defects anddeformation is increasingly important for the property evaluation and structural design of ceramicmatrix composites (CMCs). For this purpose, a coupled thermal–diffusive–mechanical modelingapproach was proposed by considering three important phenomena that occur during the pyrolysisprocess for manufacturing CMCs: variations of the physical and mechanical properties of theconstituents, generation and diffusive of pyrolysis gas, and multiple thermal deformations. Thesynergistic effects of these three phenomena on the stress, damage development, microstructuralmorphology, and process deformation of SiC matrix composites were investigated using finiteelement simulations. This new approach was validated by comparing the simulation and experimentalresults. Significant volume shrinkage of the matrix during the polymer-to-ceramic transformationresulted in large tensile stresses and subsequent highly fragmented microstructure in CMCs. Thepyrolysis-gas-induced expansion on the matrix under a damage state may yield a positive processdeformation of CMCs at the macroscale, overcoming the effects of the volume shrinkage of the bulkmatrix at the microscale. The modeling approach is expected to guide high-quality manufacturing ofCMCs and comprehensive studies of structure–processing–property relationships.
基金the National Natural Science Foundation of China
文摘The humic acid（HA） sample obtained from the alluvial soil was characterized by elemental composition, pyrolysis gas chromatography-mass spectrometry（Py-GC-MS） and solid-state 13C nuclear magnetic resonance （13C NMR） spectroscopy. There is high fat content and a few nitrogen-containing functional groups in HA. Py-GC-MS demonstrates the characterization and structural identification of HA. One long list of identified pyrolysis products was proposed for the construction of conceptual model of HA. Solid-state 13C NMR data indicate there are higher values of alkyl-C, O-alkyl-C and aryl-C in HA. The elemental composition, structural carbon distribution and L3C NMR spectroscopy of simulated HA are consistent with those of experimental HA. HyperChem was used to simulate the three-dimensional molecular structure of the monomer, which was optimized by the molecular mechanics of the optimized potential for liquid simulations（OPLS） force field and molecular dynamics simulation to get the stable and balanced conformation. The deprotonation process study depicts that the degree of ionization of HA gets deeper, while the electronegativity of HA and the energy of van der Waals（vdW） increase. Moreover, the 3D structure of humic acid with -4 charges is the most stable. The deprotonation process is an endothermic process.
