On the basis of the results of simulation experiments, now we better understand the contribution of high carbon number hydrocarbons to diamondoid generation during thermal pyrolysis of crude oil and its sub-fractions(...On the basis of the results of simulation experiments, now we better understand the contribution of high carbon number hydrocarbons to diamondoid generation during thermal pyrolysis of crude oil and its sub-fractions(saturated, aromatic, resin, and asphalene fractions). However, little is known about the effect of volatile components in oil on diamondoid generation and diamondoid indices due to the lack of attention to these components in experiments. In this study, the effect of volatile components in oil on diamondoid generation and maturity indices was investigated by the pyrolysis simulation experiments on a normal crude oil from the HD23 well of the Tarim Basin and its residual oil after artificial volatilization, combined with quantitative analysis of diamondoids. The results indicate that the volatile components(≤n C12) in oil have an obvious contribution to the generation of adamantanes, which occurs mainly in the early stage of oil cracking(Easy Ro<1.0%), and influences the variations in maturity indices of adamantanes; but they have no obvious effect on the generation and maturity indices of diamantanes. Therefore, some secondary alterations e.g., migration, gas washing, and biodegradation, which may result in the loss of light hydrocarbons in oil under actual geological conditions, could affect the identification of adamantanes generated during the late-stage cracking of crude oil, and further influence the practical application of adamantane indices.展开更多
Techno-economic potentials of thermal and catalytic pyrolysis plants for the conversion of waste plastics to liquid fuels have been widely studied, but it is not obvious which of the two plants is more profitable, as ...Techno-economic potentials of thermal and catalytic pyrolysis plants for the conversion of waste plastics to liquid fuels have been widely studied, but it is not obvious which of the two plants is more profitable, as the existing studies used different assumptions and cost bases in their analyses, thereby making it difficult to compare the economic potentials of the two plants. In this study, industrial-scale thermal and catalytic waste plastics pyrolysis plants were designed and economically analyzed using ASPEN PLUS. Amorphous silica-alumina was considered the optimum catalyst, with 3:1 feed to catalyst ratio. Based on 20,000 tons/year of feed and 20% interest rate, the catalytic plant, having a net present value (NPV) of � million, was found to be economically less attractive than the thermal plant, having the NPV of �.4 million. On the contrary, sensitivity analyses of the two plants at a feed rate of 50,000 tons/year gave rise to a slightly higher NPV for the catalytic plant (� million) than the thermal plant having NPV of � million, thereby making the former more economically attractive for processing large amounts of waste plastics into liquid fuels. Consequently, as the catalytic plant showed a better scale economy and would produce higher quality liquid fuels than the thermal plant, it is recommended for commercialization in Nigeria.展开更多
An investigation of Fe-doping effect on SnO_(2) thin films was performed in this study using thermal spray pyrolysis(TSP) method.The surface morphology and structural,optical and electrical properties were studied by ...An investigation of Fe-doping effect on SnO_(2) thin films was performed in this study using thermal spray pyrolysis(TSP) method.The surface morphology and structural,optical and electrical properties were studied by field energy scanning electron microscope(FESEM),X-ray diffraction(XRD),ultraviolet-visible(UV-Vis) spectroscopy and four-point probe method.FES EM images demonstrate that the surface morphology of the as-deposited films varies when Fe-doping content varies.XRD studies reveal that crystallite size and preferential growth orientations of the films are dependent on Fe-doping concentrations.The grain size is found to decrease with the increase in Fe content.These studies also specify that the films have tetragonal rutile-type structure with mixed secondary phases.The texture coefficient value of(110) plane increases with the concomitant in-plane(220) decrease in higher doping concentrations.The resistivity and the optical absorbance are found to increase with Fe concentration.The direct optical band gap decreases from 3.94 to3.52 eV with increasing Fe content.展开更多
Novel acetylene terminated silazane compounds,with three types of substituent,were synthesized by the aminolysis of dichlorosilane with 3-aminophenylacetylene（3-APA）.Thermal property of the compounds is studied by t...Novel acetylene terminated silazane compounds,with three types of substituent,were synthesized by the aminolysis of dichlorosilane with 3-aminophenylacetylene（3-APA）.Thermal property of the compounds is studied by thermogravimetry analysis （TGA）.It shows that the acetylene terminated silazane has high temperature resistance.The char yield at 1000℃is 77.6,81.9 and 68.7 wt%for methyl,vinyl,and phenyl substituted silazane,respectively.The pyrolysis kinetics of the silazane is investigated by non-isothermal thermogravimetric measurement.The pyrolysis undergoes three stages,which is resolved by PEAKFTT.The kinetic parameters are calculated by the Kissinger method.The role of functionalities on the thermal resistance is discussed.The vinyl-silazane exhibits higher thermal stability because of higher cross-linking density.展开更多
In order to optimize mass transportation and exchange,nature creates hierarchically porous networks which are composed of multi-level branches.Although bottom-up templating methods have succeeded in fabrication of the...In order to optimize mass transportation and exchange,nature creates hierarchically porous networks which are composed of multi-level branches.Although bottom-up templating methods have succeeded in fabrication of these kinds of hierarchically porous networks,the templates have to be assembled/packed in advance,therefore,driving the fabrication process too complex.In this report,we presented that the hierarchically porous networks could be fabricated through migration of templates,which was similar to formation of rive rs.During thermal pyrolysis of Prussian blue cages,the in situly generated iron oxides nanoparticles diffused and aggrega ted together to grow larger,and eventually moved outside from the porous carbons.The moving routes of the iron oxides became hierarchical channels in the obtained carbon cages.By using the porous carbon cages as electrode for Na-ion battery,a pseudocapacitor-type ion storage was investigated.展开更多
Research on the elastic responses of organic-rich shales during thermal evolution has predominantly focused on North American marine shales. However, the rock physics properties of lacustrine(continental) organic-rich...Research on the elastic responses of organic-rich shales during thermal evolution has predominantly focused on North American marine shales. However, the rock physics properties of lacustrine(continental) organic-rich shales with varying maturities, particularly under the unique geological conditions in China, have not yet been comprehensively explored. Therefore,characterizing the elastic properties of lacustrine organic-rich shales across various maturity stages is crucial for understanding their seismic rock physics responses and for enabling the identification of sweet spots in continental shale reservoirs using logging and seismic data, as well as facilitating geophysical monitoring of the in-situ conversion of oil shales. In this study,hydrous pyrolysis experiments were conducted on immature shales from the Chang 7 member of the Yanchang Formation in the Ordos Basin and the Jijuntun Formation in the Fushun Basin. Compressional and shear wave velocities, along with elastic anisotropy, were measured at various stages of thermal maturity to observe the evolution of the elastic properties. For the Chang7 shale(compacted shale), both P-and S-wave velocities perpendicular to the bedding decreased significantly during the oil and gas generation stages, with the S-wave velocity perpendicular to the bedding decreasing by over 40%. Meanwhile, the elastic anisotropy increased significantly, likely because of microcracks formed by hydrocarbon expulsion from the bedding-parallel organic matter. In contrast, the Jijuntun Formation shale(cemented shale) exhibited an increase in both P-and S-wave velocities during the oil generation stage. This trend could be attributed to early-stage cementation, which suppressed microcrack formation, while the increase in the elastic modulus of the organic matter became dominant. However, during the gas generation stage, both velocities decreased, while the anisotropy increased owing to the growth of organic pores and microcracks, which outweighed the structural support of the inorganic framework. These results identify the key elastic parameters that are sensitive to hydrocarbon generation in low-maturity lacustrine organic-rich shales and establish a rock physics basis for utilizing seismic and acoustic logging data to effectively monitor the in-situ conversion of oil shales.展开更多
Polyolefins,widely used for packaging,construction,and electronics,facilitate daily life but cause severe environmental pollution when discarded after usage.Chemical recycling of polyolefins has received widespread at...Polyolefins,widely used for packaging,construction,and electronics,facilitate daily life but cause severe environmental pollution when discarded after usage.Chemical recycling of polyolefins has received widespread attention for eliminating polyolefin pollution,as it is promising to convert polyolefin wastes to high-value chemicals(e.g.,fuels,light olefins,aromatic hydrocarbons).However,the chemical recycling of polyolefins typically involves high-viscosity,high-temperature and high-pressure,and its efficiency depends on the catalytic materials,reaction conditions,and more essentially,on the reactors which are overlooked in previous studies.Herein,this review first introduces the mechanisms and influencing factors of polyolefin waste upcycling,followed by a brief overview of in situ and ex situ processes.Emphatically,the review focuses on the various reactors used in polyolefin recycling(i.e.,batch/semi-batch reactor,fixed bed reactor,fluidized bed reactor,conical spouted bed reactor,screw reactor,molten metal bed reactor,vertical falling film reactor,rotary kiln reactor and microwave-assisted reactor)and their respective merits and demerits.Nevertheless,challenges remain in developing highly efficient reacting techniques to realize the practical application.In light of this,the review is concluded with recommendations and prospects to enlighten the future of polyolefin upcycling.展开更多
Polymer-derived ultra-high-temperature ceramic(UHTC)nanocomposites have attracted growing attention due to the increasing demands for advanced thermal structure components in aerospace.Herein,hafnium carbide(HfC)whisk...Polymer-derived ultra-high-temperature ceramic(UHTC)nanocomposites have attracted growing attention due to the increasing demands for advanced thermal structure components in aerospace.Herein,hafnium carbide(HfC)whiskers are successfully fabricated in carbon fiber preforms via the polymer-derived ceramic(PDC)method.A novel carbon nanotube(CNT)template growth mechanism combined with the PDC method is proposed in this work,which is different from the conventional vapor–liquid–solid(VLS)mechanism that is commonly used for polymer-derived nanostructured ceramics.The CNTs are synthesized and proved to be the templates for fabricating the HfC whiskers,which are generated by the released low-molecular-weight gas such as CO,CO_(2),and CH4 during the pyrolysis of a Hf-containing precursor.The formed products are composed of inner single crystal HfC whiskers that are measured to be several tens of micrometers in length and 100–200 nm in diameter and outer HfC/HfO_(2)particles.Our work not only proposes a new strategy to prepare the HfC whiskers,but also puts forward a new thinking of the efficient utilization of a UHTC polymer precursor.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41172115&41372138)the National Science&Technology Major Project of the Ministry of Science and Technology of China(Grant No.2011ZX05008-002-32)China Postdoctoral Science Foundation(Grant No.2014M561002)
文摘On the basis of the results of simulation experiments, now we better understand the contribution of high carbon number hydrocarbons to diamondoid generation during thermal pyrolysis of crude oil and its sub-fractions(saturated, aromatic, resin, and asphalene fractions). However, little is known about the effect of volatile components in oil on diamondoid generation and diamondoid indices due to the lack of attention to these components in experiments. In this study, the effect of volatile components in oil on diamondoid generation and maturity indices was investigated by the pyrolysis simulation experiments on a normal crude oil from the HD23 well of the Tarim Basin and its residual oil after artificial volatilization, combined with quantitative analysis of diamondoids. The results indicate that the volatile components(≤n C12) in oil have an obvious contribution to the generation of adamantanes, which occurs mainly in the early stage of oil cracking(Easy Ro<1.0%), and influences the variations in maturity indices of adamantanes; but they have no obvious effect on the generation and maturity indices of diamantanes. Therefore, some secondary alterations e.g., migration, gas washing, and biodegradation, which may result in the loss of light hydrocarbons in oil under actual geological conditions, could affect the identification of adamantanes generated during the late-stage cracking of crude oil, and further influence the practical application of adamantane indices.
文摘Techno-economic potentials of thermal and catalytic pyrolysis plants for the conversion of waste plastics to liquid fuels have been widely studied, but it is not obvious which of the two plants is more profitable, as the existing studies used different assumptions and cost bases in their analyses, thereby making it difficult to compare the economic potentials of the two plants. In this study, industrial-scale thermal and catalytic waste plastics pyrolysis plants were designed and economically analyzed using ASPEN PLUS. Amorphous silica-alumina was considered the optimum catalyst, with 3:1 feed to catalyst ratio. Based on 20,000 tons/year of feed and 20% interest rate, the catalytic plant, having a net present value (NPV) of � million, was found to be economically less attractive than the thermal plant, having the NPV of �.4 million. On the contrary, sensitivity analyses of the two plants at a feed rate of 50,000 tons/year gave rise to a slightly higher NPV for the catalytic plant (� million) than the thermal plant having NPV of � million, thereby making the former more economically attractive for processing large amounts of waste plastics into liquid fuels. Consequently, as the catalytic plant showed a better scale economy and would produce higher quality liquid fuels than the thermal plant, it is recommended for commercialization in Nigeria.
文摘An investigation of Fe-doping effect on SnO_(2) thin films was performed in this study using thermal spray pyrolysis(TSP) method.The surface morphology and structural,optical and electrical properties were studied by field energy scanning electron microscope(FESEM),X-ray diffraction(XRD),ultraviolet-visible(UV-Vis) spectroscopy and four-point probe method.FES EM images demonstrate that the surface morphology of the as-deposited films varies when Fe-doping content varies.XRD studies reveal that crystallite size and preferential growth orientations of the films are dependent on Fe-doping concentrations.The grain size is found to decrease with the increase in Fe content.These studies also specify that the films have tetragonal rutile-type structure with mixed secondary phases.The texture coefficient value of(110) plane increases with the concomitant in-plane(220) decrease in higher doping concentrations.The resistivity and the optical absorbance are found to increase with Fe concentration.The direct optical band gap decreases from 3.94 to3.52 eV with increasing Fe content.
文摘Novel acetylene terminated silazane compounds,with three types of substituent,were synthesized by the aminolysis of dichlorosilane with 3-aminophenylacetylene（3-APA）.Thermal property of the compounds is studied by thermogravimetry analysis （TGA）.It shows that the acetylene terminated silazane has high temperature resistance.The char yield at 1000℃is 77.6,81.9 and 68.7 wt%for methyl,vinyl,and phenyl substituted silazane,respectively.The pyrolysis kinetics of the silazane is investigated by non-isothermal thermogravimetric measurement.The pyrolysis undergoes three stages,which is resolved by PEAKFTT.The kinetic parameters are calculated by the Kissinger method.The role of functionalities on the thermal resistance is discussed.The vinyl-silazane exhibits higher thermal stability because of higher cross-linking density.
基金supported by the National Natural Science Foundation of China (No.21473059)
文摘In order to optimize mass transportation and exchange,nature creates hierarchically porous networks which are composed of multi-level branches.Although bottom-up templating methods have succeeded in fabrication of these kinds of hierarchically porous networks,the templates have to be assembled/packed in advance,therefore,driving the fabrication process too complex.In this report,we presented that the hierarchically porous networks could be fabricated through migration of templates,which was similar to formation of rive rs.During thermal pyrolysis of Prussian blue cages,the in situly generated iron oxides nanoparticles diffused and aggrega ted together to grow larger,and eventually moved outside from the porous carbons.The moving routes of the iron oxides became hierarchical channels in the obtained carbon cages.By using the porous carbon cages as electrode for Na-ion battery,a pseudocapacitor-type ion storage was investigated.
基金supported by the National Natural Science Foundation of China (Grant Nos. U23B20157 and 42174134)。
文摘Research on the elastic responses of organic-rich shales during thermal evolution has predominantly focused on North American marine shales. However, the rock physics properties of lacustrine(continental) organic-rich shales with varying maturities, particularly under the unique geological conditions in China, have not yet been comprehensively explored. Therefore,characterizing the elastic properties of lacustrine organic-rich shales across various maturity stages is crucial for understanding their seismic rock physics responses and for enabling the identification of sweet spots in continental shale reservoirs using logging and seismic data, as well as facilitating geophysical monitoring of the in-situ conversion of oil shales. In this study,hydrous pyrolysis experiments were conducted on immature shales from the Chang 7 member of the Yanchang Formation in the Ordos Basin and the Jijuntun Formation in the Fushun Basin. Compressional and shear wave velocities, along with elastic anisotropy, were measured at various stages of thermal maturity to observe the evolution of the elastic properties. For the Chang7 shale(compacted shale), both P-and S-wave velocities perpendicular to the bedding decreased significantly during the oil and gas generation stages, with the S-wave velocity perpendicular to the bedding decreasing by over 40%. Meanwhile, the elastic anisotropy increased significantly, likely because of microcracks formed by hydrocarbon expulsion from the bedding-parallel organic matter. In contrast, the Jijuntun Formation shale(cemented shale) exhibited an increase in both P-and S-wave velocities during the oil generation stage. This trend could be attributed to early-stage cementation, which suppressed microcrack formation, while the increase in the elastic modulus of the organic matter became dominant. However, during the gas generation stage, both velocities decreased, while the anisotropy increased owing to the growth of organic pores and microcracks, which outweighed the structural support of the inorganic framework. These results identify the key elastic parameters that are sensitive to hydrocarbon generation in low-maturity lacustrine organic-rich shales and establish a rock physics basis for utilizing seismic and acoustic logging data to effectively monitor the in-situ conversion of oil shales.
基金The authors are thankful for the financial support of the National Natural Science Foundation(Grant Nos.22293061,22208292)Zhejiang Provincial Natural Science Foundation(Grant Nos.LD24E030003)+2 种基金the State Key Laboratory of Chemical Engineering(Grant Nos.SKL-ChE-23D02,SKL-ChE-23T04)the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(Grant No 2022SZ-TD003)the Research Funds of Institute of Zhejiang University-Quzhou(Grant Nos.IZQ2021RCZX002,IZQ2021RCZX003,IZQ2021KJ2011 and IZQ2022RCZX201).
文摘Polyolefins,widely used for packaging,construction,and electronics,facilitate daily life but cause severe environmental pollution when discarded after usage.Chemical recycling of polyolefins has received widespread attention for eliminating polyolefin pollution,as it is promising to convert polyolefin wastes to high-value chemicals(e.g.,fuels,light olefins,aromatic hydrocarbons).However,the chemical recycling of polyolefins typically involves high-viscosity,high-temperature and high-pressure,and its efficiency depends on the catalytic materials,reaction conditions,and more essentially,on the reactors which are overlooked in previous studies.Herein,this review first introduces the mechanisms and influencing factors of polyolefin waste upcycling,followed by a brief overview of in situ and ex situ processes.Emphatically,the review focuses on the various reactors used in polyolefin recycling(i.e.,batch/semi-batch reactor,fixed bed reactor,fluidized bed reactor,conical spouted bed reactor,screw reactor,molten metal bed reactor,vertical falling film reactor,rotary kiln reactor and microwave-assisted reactor)and their respective merits and demerits.Nevertheless,challenges remain in developing highly efficient reacting techniques to realize the practical application.In light of this,the review is concluded with recommendations and prospects to enlighten the future of polyolefin upcycling.
基金supported by the National Natural Science Foundation of China(Grant Nos.52293373,52130205,and 52061135102)the National Key R&D Program of China(Grant No.2021YFA0715803).Also,we would like to thank ND Basic Research Funds of Northwestern Polytechnical University(Grant No.G2022WD)and China Scholarship Program,2020(Grant No.202006290179).
文摘Polymer-derived ultra-high-temperature ceramic(UHTC)nanocomposites have attracted growing attention due to the increasing demands for advanced thermal structure components in aerospace.Herein,hafnium carbide(HfC)whiskers are successfully fabricated in carbon fiber preforms via the polymer-derived ceramic(PDC)method.A novel carbon nanotube(CNT)template growth mechanism combined with the PDC method is proposed in this work,which is different from the conventional vapor–liquid–solid(VLS)mechanism that is commonly used for polymer-derived nanostructured ceramics.The CNTs are synthesized and proved to be the templates for fabricating the HfC whiskers,which are generated by the released low-molecular-weight gas such as CO,CO_(2),and CH4 during the pyrolysis of a Hf-containing precursor.The formed products are composed of inner single crystal HfC whiskers that are measured to be several tens of micrometers in length and 100–200 nm in diameter and outer HfC/HfO_(2)particles.Our work not only proposes a new strategy to prepare the HfC whiskers,but also puts forward a new thinking of the efficient utilization of a UHTC polymer precursor.
