This article refers to the results of small-scale and commercial tests on high-temperature cracking of C4 fraction in FCC unit to increase the propylene yield. The bench tests revealed that the conversion rate of C4 f...This article refers to the results of small-scale and commercial tests on high-temperature cracking of C4 fraction in FCC unit to increase the propylene yield. The bench tests revealed that the conversion rate of C4 fraction during high-temperature cracking reached 37.38 % and propylene yield was equal to 15.60 % with the conversion rate of C4 olefins equating around 50%. The results of commercial application showed that adoption of the technology for high-temperature cracking of C4 fraction in FCC unit had led to an increase of propylene yield by 2.16 % with no remarkable changes in the yields and properties of other products.展开更多
In order to make more liquid products like gasoline, the oligomerition of a C4 feedstock taking placeon catalyst containing ZSM-5 was studied in a pressurized reactor. The products were C5- gas, liquid hydro-carbons a...In order to make more liquid products like gasoline, the oligomerition of a C4 feedstock taking placeon catalyst containing ZSM-5 was studied in a pressurized reactor. The products were C5- gas, liquid hydro-carbons and coke. During the reaction on the catalyst BO-1, when the WHSV was 0.71h-1 and total pressurewas 4.0MPa, the C5+ product yield reached a maximum at a temperature around 320℃. As oligomerizationreaction was the dominating one, there were minor C9 hydrocarbons in liquid products and the main productswere C7 and C8 olefins and n- C10 paraffins. When the temperature was higher than 286℃, a small amount of C9hydrocarbons was formed and more normal and isomeric paraffins other than olefins were formed in products.Gasoline yield increased linearly with a rising total pressure under the same operating conditions.展开更多
Geometry optimization of p-C_(6)H_(4)-connected cyclo[20]carbon(p-C_(6)H_(4)-C_(20))was carried out at M062X/6-311G(d,p)level,three kinds of bond orders(Mayer,Laplacian,and Wiberg),electron-hole distributions,localize...Geometry optimization of p-C_(6)H_(4)-connected cyclo[20]carbon(p-C_(6)H_(4)-C_(20))was carried out at M062X/6-311G(d,p)level,three kinds of bond orders(Mayer,Laplacian,and Wiberg),electron-hole distributions,localized orbital locators(LOL),and infrared(IR)spectrum were also performed at the same level.Based on TD-DFT M062X/6-311G(d,p)method,the first 20 excited states and ultraviolet(UV)spectra of p-C_(6)H_(4)-C_(20) were calculated.Calculation results of π-electron delocalization analyses prove thatπ-electron delocalization of p-C_(6)H_(4)-C_(20) is more likely to occur on shorter C-C bonds rather than longer C-C bonds,and inside/outside of the ring plane rather than above/below the ring plane.Two absorption peaks of p-C_(6)H_(4)-C_(20) locate at about 319 nm and 236 nm,respectively.展开更多
The goal of the present paper is to investigate an abstract system, called fractional differential variational inequality, which consists of a mixed variational inequality combined with a fractional evolution equation...The goal of the present paper is to investigate an abstract system, called fractional differential variational inequality, which consists of a mixed variational inequality combined with a fractional evolution equation in the framework of Banach spaces. Using discrete approximation approach, an existence theorem of solutions for the inequality is established under some suitable assumptions.展开更多
To improve the understanding of coupling effect between dynamic recrystallization(DRX)behaviors and flow behaviors of as-cast AlCu4 SiMg, a finite element(FE) simulation equipped with the models of DRX evolution was i...To improve the understanding of coupling effect between dynamic recrystallization(DRX)behaviors and flow behaviors of as-cast AlCu4 SiMg, a finite element(FE) simulation equipped with the models of DRX evolution was implemented. A series of isothermal compression tests were performed primarily on a Gleeble-3500 thermo-mechanical simulator in a temperature range of 648-748 K and a strain rate range of 0.01-10 s-1.According to the measured true stress-strain data,the strain hardening rate curves(dσ/dε versus σ) were plotted to identify the critical strains for DRX initiation(εc). By further derivation of the related material constants, the DRX volume fraction equation and the strain for 50% DRX(ε0.5) equation were solved. Accordingly, the aforementioned DRX equations were implanted into the FE model to conduct a series of simulations for the isothermal compression tests. The results show that during the evolution of DRX volume fraction at a fixed strain rate, the strain required for the same amount of DRX volume fraction increases with decreasing temperature. In contrast, at a fixed temperature, it increases with increasing strain rate. Ultimately, the DRX kinetics model of AlCu4 SiMg alloy and the consequence of the FE analysis were validated by microstructure observations.展开更多
Marine dissolved organic matter （DOM） is one of the largest dynamic pools of organic carbon in the global carbon cycle, yet DOM is still chemically poorly characterized. To better understand the origin, composition,...Marine dissolved organic matter （DOM） is one of the largest dynamic pools of organic carbon in the global carbon cycle, yet DOM is still chemically poorly characterized. To better understand the origin, composition, and cycling of DOM in the China marginal sea, dissolved humic substances （DHS） were isolated from seawaters in two locations in the Southern Yellow Sea. The DHS were subdivided into fulvic acids （FAs）, humic acids （HAs） and the XAD-4 fractions. Complementary analytical approaches were used to characterize the isolated DHS samples including stable carbon isotopic composition, Fourier transform infrared spectroscopy （FTIR）, ~3C cross polarization magic angle spinning （CP/MAS） nuclear magnetic resonance （NMR）, and pyrolysis gas chromatography-mass spectrometry （Py-GC/MS）. The results demonstrated that both DHS samples encountered the influences from marine source, indicating that algal and microbial-derived materials are the predominant precursors for the studied samples. The three fractions of DHS showed different properties. FAs presented more aromatic features, whereas HAs contained more aliphatic lipids and proteinaceous materials. The XAD-4 fractions were enriched in 13C and contained more carbohydrates but less aromatic compounds. The lower molecular weight and higher heteroatom content and number of carboxyl groups for the XAD-4 fractions may give them considerable geochemical significance for aspects of trace metal species, bioavailability of pollutants, mineral weathering and water acidification in marine environments.展开更多
文摘This article refers to the results of small-scale and commercial tests on high-temperature cracking of C4 fraction in FCC unit to increase the propylene yield. The bench tests revealed that the conversion rate of C4 fraction during high-temperature cracking reached 37.38 % and propylene yield was equal to 15.60 % with the conversion rate of C4 olefins equating around 50%. The results of commercial application showed that adoption of the technology for high-temperature cracking of C4 fraction in FCC unit had led to an increase of propylene yield by 2.16 % with no remarkable changes in the yields and properties of other products.
文摘In order to make more liquid products like gasoline, the oligomerition of a C4 feedstock taking placeon catalyst containing ZSM-5 was studied in a pressurized reactor. The products were C5- gas, liquid hydro-carbons and coke. During the reaction on the catalyst BO-1, when the WHSV was 0.71h-1 and total pressurewas 4.0MPa, the C5+ product yield reached a maximum at a temperature around 320℃. As oligomerizationreaction was the dominating one, there were minor C9 hydrocarbons in liquid products and the main productswere C7 and C8 olefins and n- C10 paraffins. When the temperature was higher than 286℃, a small amount of C9hydrocarbons was formed and more normal and isomeric paraffins other than olefins were formed in products.Gasoline yield increased linearly with a rising total pressure under the same operating conditions.
文摘Geometry optimization of p-C_(6)H_(4)-connected cyclo[20]carbon(p-C_(6)H_(4)-C_(20))was carried out at M062X/6-311G(d,p)level,three kinds of bond orders(Mayer,Laplacian,and Wiberg),electron-hole distributions,localized orbital locators(LOL),and infrared(IR)spectrum were also performed at the same level.Based on TD-DFT M062X/6-311G(d,p)method,the first 20 excited states and ultraviolet(UV)spectra of p-C_(6)H_(4)-C_(20) were calculated.Calculation results of π-electron delocalization analyses prove thatπ-electron delocalization of p-C_(6)H_(4)-C_(20) is more likely to occur on shorter C-C bonds rather than longer C-C bonds,and inside/outside of the ring plane rather than above/below the ring plane.Two absorption peaks of p-C_(6)H_(4)-C_(20) locate at about 319 nm and 236 nm,respectively.
基金received funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement(823731-CONMECH)supported by the National Science Center of Poland under Maestro Project(UMO-2012/06/A/ST1/00262)+3 种基金National Science Center of Poland under Preludium Project(2017/25/N/ST1/00611)supported by the International Project co-financed by the Ministry of Science and Higher Education of Republic of Poland(3792/GGPJ/H2020/2017/0)Qinzhou University Project(2018KYQD06)National Natural Sciences Foundation of Guangxi(2018JJA110006)
文摘The goal of the present paper is to investigate an abstract system, called fractional differential variational inequality, which consists of a mixed variational inequality combined with a fractional evolution equation in the framework of Banach spaces. Using discrete approximation approach, an existence theorem of solutions for the inequality is established under some suitable assumptions.
基金Project(cstc2016jcyjA0335)supported by Chongqing Foundation and Frontier Research,ChinaProject(P2017-020)supported by Open Fund Project of State Key Laboratory of Materials Processing and Die&Mould Technology,China
文摘To improve the understanding of coupling effect between dynamic recrystallization(DRX)behaviors and flow behaviors of as-cast AlCu4 SiMg, a finite element(FE) simulation equipped with the models of DRX evolution was implemented. A series of isothermal compression tests were performed primarily on a Gleeble-3500 thermo-mechanical simulator in a temperature range of 648-748 K and a strain rate range of 0.01-10 s-1.According to the measured true stress-strain data,the strain hardening rate curves(dσ/dε versus σ) were plotted to identify the critical strains for DRX initiation(εc). By further derivation of the related material constants, the DRX volume fraction equation and the strain for 50% DRX(ε0.5) equation were solved. Accordingly, the aforementioned DRX equations were implanted into the FE model to conduct a series of simulations for the isothermal compression tests. The results show that during the evolution of DRX volume fraction at a fixed strain rate, the strain required for the same amount of DRX volume fraction increases with decreasing temperature. In contrast, at a fixed temperature, it increases with increasing strain rate. Ultimately, the DRX kinetics model of AlCu4 SiMg alloy and the consequence of the FE analysis were validated by microstructure observations.
基金Supported by the National Natural Science Foundation of China(No.41403108)the West Light Foundation of the Chinese Academy of Sciences(No.Y412011004)the Natural Science Foundation of Qinghai Province(No.2014-ZJ-937Q)
文摘Marine dissolved organic matter （DOM） is one of the largest dynamic pools of organic carbon in the global carbon cycle, yet DOM is still chemically poorly characterized. To better understand the origin, composition, and cycling of DOM in the China marginal sea, dissolved humic substances （DHS） were isolated from seawaters in two locations in the Southern Yellow Sea. The DHS were subdivided into fulvic acids （FAs）, humic acids （HAs） and the XAD-4 fractions. Complementary analytical approaches were used to characterize the isolated DHS samples including stable carbon isotopic composition, Fourier transform infrared spectroscopy （FTIR）, ~3C cross polarization magic angle spinning （CP/MAS） nuclear magnetic resonance （NMR）, and pyrolysis gas chromatography-mass spectrometry （Py-GC/MS）. The results demonstrated that both DHS samples encountered the influences from marine source, indicating that algal and microbial-derived materials are the predominant precursors for the studied samples. The three fractions of DHS showed different properties. FAs presented more aromatic features, whereas HAs contained more aliphatic lipids and proteinaceous materials. The XAD-4 fractions were enriched in 13C and contained more carbohydrates but less aromatic compounds. The lower molecular weight and higher heteroatom content and number of carboxyl groups for the XAD-4 fractions may give them considerable geochemical significance for aspects of trace metal species, bioavailability of pollutants, mineral weathering and water acidification in marine environments.
