石油化工过程中通常采用低温精馏法分离乙烷,以获得聚合级纯度的乙烯,该过程耗能巨大.而利用多孔材料的吸附分离来拆分两者,可极大地降低所需能耗和生产成本.目前,相关研究领域中已见报道的多孔材料虽能在实验室中较为高效地实现乙烷-...石油化工过程中通常采用低温精馏法分离乙烷,以获得聚合级纯度的乙烯,该过程耗能巨大.而利用多孔材料的吸附分离来拆分两者,可极大地降低所需能耗和生产成本.目前,相关研究领域中已见报道的多孔材料虽能在实验室中较为高效地实现乙烷-乙烯的分离,但它们多为乙烯选择性吸附剂.易被水、含硫杂质污染而失活,需要至少4个吸附-解吸循环才能实现乙烯纯度需求,吸附剂用量大等问题使之无法实用化.具有在混合物中优先捕获乙烷能力的多孔材料则可规避上述所有问题.文中在溶剂热条件下合成了一种具有低成本、较好稳定性的微孔材料[Co _(3)(HCOO)_(6)].实验研究显示,该材料在常温常压条件下具有优先吸附乙烷的能力,材料骨架对于乙烷的亲和力明显大于乙烯.IAST计算表明298 K 1 bar时,[Co_(3)(HCOO)_(6)]的乙烷/乙烯吸附选择比可以达到1.3,该材料能高效地实现乙烷/乙烯的吸附分离.展开更多
Boron nitride containing hydroxyl groups efficiently catalysed oxidative dehydrogenation of ethane to ethylene,offering rather high selectivity（95%） but only small amount of CO2 formation（0.4%） at a given ethane c...Boron nitride containing hydroxyl groups efficiently catalysed oxidative dehydrogenation of ethane to ethylene,offering rather high selectivity（95%） but only small amount of CO2 formation（0.4%） at a given ethane conversion of 11%.Even at high conversion level of 63%,the selectivity of ethylene retained at 80%,which is competitive with the energy-demanding industrialized steam cracking route.A long-term test for 200 h resulted in stable conversion and product selectivity,showing the excellent catalytic stability.Both experimental and computational studies have identified that the hydrogen abstraction of B-OH groups by molecular oxygen dynamically generated the active sites and triggered ethane dehydrogenation.展开更多
With increasing amount of unconventional natural gas,the production of ethane,propane and other low alkanes continues to increase.In our previous works,a partially decoupled process(PDP) was proposed for conversion of...With increasing amount of unconventional natural gas,the production of ethane,propane and other low alkanes continues to increase.In our previous works,a partially decoupled process(PDP) was proposed for conversion of ethane based on numerical simulations,which showed higher acetylene and ethylene selectivities than the original partial oxidation process.In the current work,the PDP of ethane for producing acetylene and ethylene was studied experimentally to verify the PDP concept.In the PDP of ethane,coke-oven gas or other cheap gas combusts with stoichiometric oxygen as heat carrier,and ethane is mixed with the heat carrier and undergoes pyrolysis at high temperatures.The jet-in-cross-flow(JICF) reactor was designed and manufactured to realize the PDP.A positioning device of 0.1 mm accuracy and a mass spectrometer were used to measure the spatial profiles of the species concentrations.The maximum combined yield(52.7%) of acetylene and ethylene was obtained even at the condition of heat loss,confirming that the PDP of ethane was advantageous over the partial oxidation process and at least comparable to the steam cracking process.展开更多
Owing to the importance of process intensification in the natural gas associated processes, the present contribution aims to investigate the production of an important natural gas downstream product in an improved sys...Owing to the importance of process intensification in the natural gas associated processes, the present contribution aims to investigate the production of an important natural gas downstream product in an improved system.Accordingly, a membrane-assisted reactor for the oxidative dehydrogenation of ethane is presented. The presented system includes a membrane for axial oxygen dosing into the reaction side. Such a strategy would lead to optimum oxygen distribution along the reactor length and prevention of hot spot formation as well. A feasibility study is conducted by developing a validated mathematical model composed of mass and energy balance equations. The effects of various operating variables are investigated by a rigorous sensitivity analysis.Then, by applying the genetic algorithm, a multi-objective optimization procedure is implemented to obtain the optimum operating condition. Considerable increase in the ethane conversion and ethylene yield are the advancements of membrane-assisted oxidative dehydrogenation reactor working under the optimum condition.More than 30% increase in the ethane conversion is obtained. Furthermore, the ethylene yield is enhanced up to 0.45.展开更多
Copper incorporated MCM-48 molecular sieve adsorbents with different Cu content have been hydrothermally synthesized. The samples have been characterized by various physicochemical methods, including X-ray diffraction...Copper incorporated MCM-48 molecular sieve adsorbents with different Cu content have been hydrothermally synthesized. The samples have been characterized by various physicochemical methods, including X-ray diffraction （XRD）, nitrogen adsorption （N2） and X-ray photoelectron spectroscopy （XPS）. The results reveal that Cu-MCM-48 with mass fraction of copper up to 10 % can still retain the uniform mesoporous framework of MCM-48. The copper in the framework of MCM-48 was easily auto-reduced to Cu（I） in N2 at high temperature, which did not alter the mesoporous structure of MCM-48. The adsorption equilibrium isotherms of ethylene and ethane on these molecular sieve adsorbents have been measured at 30℃. At 100 kPa, the adsorption capacities of ethylene on 5Cu-MCM-48 and 10Cu-MCM-48 are higher than those on MCM-48. The 10Cu-MCM-48 molecular sieve adsorbent has a higher selective adsorption ratio of ethylene to ethane, the separation factor is 3.8, and the amount of ethylene adsorbed is 11.1 ml·g ^-1.展开更多
Acetylene coupling with ethylene dichloride,which uses both coal and oil resources,is attractive for sustainable PVC manufacturing.Herein,highly active and stable carbon nitride‐based catalysts were developed by a no...Acetylene coupling with ethylene dichloride,which uses both coal and oil resources,is attractive for sustainable PVC manufacturing.Herein,highly active and stable carbon nitride‐based catalysts were developed by a novel pre‐oxidation‐pyrolysis process,affording unprecedented dehydrochlorination activity with good durability.The best‐performing system was further modified with different precious metals(Au,Pt,and Ru)to promote the hydrochlorination chemistry between the in‐situ formed hydrogen chloride and acetylene co‐feed.The presence of metal centers intensifies the hydrochlorination activity but weakens the dehydrochlorination ability due to competitive adsorption between the two reactants at the metal sites.Superior coupling performance was achieved over C_(3)N_(4)/AC and single‐atom Au/C_(3)N_(4)/AC catalysts in cascade reactors.Our results strongly suggest that dehydrochlorination is an essential step in the coupling reaction,and the activation of acetylene and ethylene dichloride molecules requires different active sites that should be engineered in future work.展开更多
The direct synthesis of C2 hydrocarbons （ethylene, acetylene and ethane） from methane is one of the most important task in C1 chemistry. Higher conversion of methane and selectivity to C2 hydrocarbons can be real-iz...The direct synthesis of C2 hydrocarbons （ethylene, acetylene and ethane） from methane is one of the most important task in C1 chemistry. Higher conversion of methane and selectivity to C2 hydrocarbons can be real-ized through plasma reaction. In order to explore the reaction process and mechanism, the possible reaction paths （1）—（4） were proposed on coupling reaction of methane through plasma and studied theoretically using semi-PM3 method [PM3 is parameterization method of modified neglect of diatomic overlap （MNDO）] including determining the transition state, calculating the activation energy and thermodynamic state functions and analyzing the bond or-der and intrinsic reaction coordinate. The reaction heat results indicate that the reactions （2） and （4） are exothermic, while reactions of （1） and （3） are endothermic. The activation energy results show that activation energy for reac-tions （1） and （2） was much lower than that of reaction paths （3） and （4）. Therefore, paths （1） and （2） is the favorable reaction path energetically. More interestingly by comparing the intrinsic reaction coordinated （IRC） of the reaction paths （1） and （2）, it is found that the variations of bond lengths in reaction path （1） has a crucial effect on the poten-tial energy, while in reaction path （2）, the adjustment of the system geometry also contributes to the whole potential energy of the system.展开更多
Ag^+-exchanged resins are prepared and studied for ethylene/ethaneseparation by adsorption. On Ag^+-exchanged S9, at 25 deg. C and0.1013 Mpa, the equilibrium adsorbed amount for C_2H_4 is 0.992 mmol·g^-1, and The...Ag^+-exchanged resins are prepared and studied for ethylene/ethaneseparation by adsorption. On Ag^+-exchanged S9, at 25 deg. C and0.1013 Mpa, the equilibrium adsorbed amount for C_2H_4 is 0.992 mmol·g^-1, and The adsorption ratio for C_2H_4/C_2H_6 is 3.56. Theadsorption capacity can be restored almost completely at 25 deg. CAnd 75 deg. C, and the desorption residual amount is less than 0.01mmol·g^-1. For the adsorption consisting of physical Adsorption andπ-complexation with energy heterogeneity, the equilibrium data arecorrelated with Langmuir- Freundlich isotherm equation.展开更多
To investigate the possible use of waste products obtained after processing haddock, the present study prepared haddock bone calcium powder by NaOH and ethanol soaking （alkalinealeohol method） and prepared haddock b...To investigate the possible use of waste products obtained after processing haddock, the present study prepared haddock bone calcium powder by NaOH and ethanol soaking （alkalinealeohol method） and prepared haddock bone calcium tablets using the powder in combination with appropriate excipients. The biological efficacy of the haddock bone calcium tablets was investigated using Wistar rats as an experiment model. Results show that the optimal parameters for the alkalinealcohol method are： NaOH concentration 1 mol/L, immersion time 30 h; ethanol concentration 60%, immersion time 15 h. A mixture of 2% polyvinylpyrrolidone in ethanol was used as an excipient at a ratio of 1：2 to full-cream milk powder, without the use of a disintegrating agent. This process provided satisfactory tablets in terms of rigidity and taste. Animal studies showed that the haddock bone calcium tablets at a dose of 2 g·kg^-1·d^-1 or 5g·kg^-1·d^-1 significantly increased blood calcium and phosphorus levels and bone calcium content in rats. Therefore, these tablets could be used for calcium supplementation and prevent osteoporosis. Although the reasons of high absorption in the rats fed with haddock bone calcium tablets are unclear, it is suggested that there are some factors, such as treatment with method of alkaline-alcohol or the added milk, may play positive roles in increasing absorption ratio.展开更多
Nano-silver/polyvinylpyrrolidone(PVP)composite materials were successfully synthesized bi-insitu from silver nitrate solution with N-vinyl pyrrolidone (NVP) monomer,containing neither initiator nor reductant, in ultra...Nano-silver/polyvinylpyrrolidone(PVP)composite materials were successfully synthesized bi-insitu from silver nitrate solution with N-vinyl pyrrolidone (NVP) monomer,containing neither initiator nor reductant, in ultraviolet irradiation conditions.The resultant Ag/PVP nanocomposites were characterized by infrared spectroscopy (FT-IR), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD).TEM show that nano silver particles are homogeneously dispersed in PVP polymer matrix, and the mean size of spherical silver particles is about 5 nm.The spectroscopy of XPS and FTIR showed that there is an interaction between nano silver not only with carbonyl oxygen but also with the nitrogen group within the NVP molecule through the p-π conjugation effect in the nano-silver/PVP composites system.展开更多
文摘石油化工过程中通常采用低温精馏法分离乙烷,以获得聚合级纯度的乙烯,该过程耗能巨大.而利用多孔材料的吸附分离来拆分两者,可极大地降低所需能耗和生产成本.目前,相关研究领域中已见报道的多孔材料虽能在实验室中较为高效地实现乙烷-乙烯的分离,但它们多为乙烯选择性吸附剂.易被水、含硫杂质污染而失活,需要至少4个吸附-解吸循环才能实现乙烯纯度需求,吸附剂用量大等问题使之无法实用化.具有在混合物中优先捕获乙烷能力的多孔材料则可规避上述所有问题.文中在溶剂热条件下合成了一种具有低成本、较好稳定性的微孔材料[Co _(3)(HCOO)_(6)].实验研究显示,该材料在常温常压条件下具有优先吸附乙烷的能力,材料骨架对于乙烷的亲和力明显大于乙烯.IAST计算表明298 K 1 bar时,[Co_(3)(HCOO)_(6)]的乙烷/乙烯吸附选择比可以达到1.3,该材料能高效地实现乙烷/乙烯的吸附分离.
基金supported by the National Natural Science Foundation of China (21225312, U1462120, 21473206)Cheung Kong Scholars Programme of China (T2015036)~~
文摘Boron nitride containing hydroxyl groups efficiently catalysed oxidative dehydrogenation of ethane to ethylene,offering rather high selectivity（95%） but only small amount of CO2 formation（0.4%） at a given ethane conversion of 11%.Even at high conversion level of 63%,the selectivity of ethylene retained at 80%,which is competitive with the energy-demanding industrialized steam cracking route.A long-term test for 200 h resulted in stable conversion and product selectivity,showing the excellent catalytic stability.Both experimental and computational studies have identified that the hydrogen abstraction of B-OH groups by molecular oxygen dynamically generated the active sites and triggered ethane dehydrogenation.
文摘With increasing amount of unconventional natural gas,the production of ethane,propane and other low alkanes continues to increase.In our previous works,a partially decoupled process(PDP) was proposed for conversion of ethane based on numerical simulations,which showed higher acetylene and ethylene selectivities than the original partial oxidation process.In the current work,the PDP of ethane for producing acetylene and ethylene was studied experimentally to verify the PDP concept.In the PDP of ethane,coke-oven gas or other cheap gas combusts with stoichiometric oxygen as heat carrier,and ethane is mixed with the heat carrier and undergoes pyrolysis at high temperatures.The jet-in-cross-flow(JICF) reactor was designed and manufactured to realize the PDP.A positioning device of 0.1 mm accuracy and a mass spectrometer were used to measure the spatial profiles of the species concentrations.The maximum combined yield(52.7%) of acetylene and ethylene was obtained even at the condition of heat loss,confirming that the PDP of ethane was advantageous over the partial oxidation process and at least comparable to the steam cracking process.
文摘Owing to the importance of process intensification in the natural gas associated processes, the present contribution aims to investigate the production of an important natural gas downstream product in an improved system.Accordingly, a membrane-assisted reactor for the oxidative dehydrogenation of ethane is presented. The presented system includes a membrane for axial oxygen dosing into the reaction side. Such a strategy would lead to optimum oxygen distribution along the reactor length and prevention of hot spot formation as well. A feasibility study is conducted by developing a validated mathematical model composed of mass and energy balance equations. The effects of various operating variables are investigated by a rigorous sensitivity analysis.Then, by applying the genetic algorithm, a multi-objective optimization procedure is implemented to obtain the optimum operating condition. Considerable increase in the ethane conversion and ethylene yield are the advancements of membrane-assisted oxidative dehydrogenation reactor working under the optimum condition.More than 30% increase in the ethane conversion is obtained. Furthermore, the ethylene yield is enhanced up to 0.45.
基金Supported by the National Natural Science Foundation of China （20276029） and the Specialized Research Fund for the Doctoral Program of Higher Education of China （20040291005）.
文摘Copper incorporated MCM-48 molecular sieve adsorbents with different Cu content have been hydrothermally synthesized. The samples have been characterized by various physicochemical methods, including X-ray diffraction （XRD）, nitrogen adsorption （N2） and X-ray photoelectron spectroscopy （XPS）. The results reveal that Cu-MCM-48 with mass fraction of copper up to 10 % can still retain the uniform mesoporous framework of MCM-48. The copper in the framework of MCM-48 was easily auto-reduced to Cu（I） in N2 at high temperature, which did not alter the mesoporous structure of MCM-48. The adsorption equilibrium isotherms of ethylene and ethane on these molecular sieve adsorbents have been measured at 30℃. At 100 kPa, the adsorption capacities of ethylene on 5Cu-MCM-48 and 10Cu-MCM-48 are higher than those on MCM-48. The 10Cu-MCM-48 molecular sieve adsorbent has a higher selective adsorption ratio of ethylene to ethane, the separation factor is 3.8, and the amount of ethylene adsorbed is 11.1 ml·g ^-1.
文摘Acetylene coupling with ethylene dichloride,which uses both coal and oil resources,is attractive for sustainable PVC manufacturing.Herein,highly active and stable carbon nitride‐based catalysts were developed by a novel pre‐oxidation‐pyrolysis process,affording unprecedented dehydrochlorination activity with good durability.The best‐performing system was further modified with different precious metals(Au,Pt,and Ru)to promote the hydrochlorination chemistry between the in‐situ formed hydrogen chloride and acetylene co‐feed.The presence of metal centers intensifies the hydrochlorination activity but weakens the dehydrochlorination ability due to competitive adsorption between the two reactants at the metal sites.Superior coupling performance was achieved over C_(3)N_(4)/AC and single‐atom Au/C_(3)N_(4)/AC catalysts in cascade reactors.Our results strongly suggest that dehydrochlorination is an essential step in the coupling reaction,and the activation of acetylene and ethylene dichloride molecules requires different active sites that should be engineered in future work.
基金Supported by the National Natural Science Foundation of China (No.20606023).
文摘The direct synthesis of C2 hydrocarbons （ethylene, acetylene and ethane） from methane is one of the most important task in C1 chemistry. Higher conversion of methane and selectivity to C2 hydrocarbons can be real-ized through plasma reaction. In order to explore the reaction process and mechanism, the possible reaction paths （1）—（4） were proposed on coupling reaction of methane through plasma and studied theoretically using semi-PM3 method [PM3 is parameterization method of modified neglect of diatomic overlap （MNDO）] including determining the transition state, calculating the activation energy and thermodynamic state functions and analyzing the bond or-der and intrinsic reaction coordinate. The reaction heat results indicate that the reactions （2） and （4） are exothermic, while reactions of （1） and （3） are endothermic. The activation energy results show that activation energy for reac-tions （1） and （2） was much lower than that of reaction paths （3） and （4）. Therefore, paths （1） and （2） is the favorable reaction path energetically. More interestingly by comparing the intrinsic reaction coordinated （IRC） of the reaction paths （1） and （2）, it is found that the variations of bond lengths in reaction path （1） has a crucial effect on the poten-tial energy, while in reaction path （2）, the adjustment of the system geometry also contributes to the whole potential energy of the system.
基金Supported by the Scientific Reserch Foundation for Returned Overseas Chinese Scholars, Ministry of Education, P. R. China.
文摘Ag^+-exchanged resins are prepared and studied for ethylene/ethaneseparation by adsorption. On Ag^+-exchanged S9, at 25 deg. C and0.1013 Mpa, the equilibrium adsorbed amount for C_2H_4 is 0.992 mmol·g^-1, and The adsorption ratio for C_2H_4/C_2H_6 is 3.56. Theadsorption capacity can be restored almost completely at 25 deg. CAnd 75 deg. C, and the desorption residual amount is less than 0.01mmol·g^-1. For the adsorption consisting of physical Adsorption andπ-complexation with energy heterogeneity, the equilibrium data arecorrelated with Langmuir- Freundlich isotherm equation.
基金Supported by the Major Technology Project of Zhejiang Province (No. 2007C12013)
文摘To investigate the possible use of waste products obtained after processing haddock, the present study prepared haddock bone calcium powder by NaOH and ethanol soaking （alkalinealeohol method） and prepared haddock bone calcium tablets using the powder in combination with appropriate excipients. The biological efficacy of the haddock bone calcium tablets was investigated using Wistar rats as an experiment model. Results show that the optimal parameters for the alkalinealcohol method are： NaOH concentration 1 mol/L, immersion time 30 h; ethanol concentration 60%, immersion time 15 h. A mixture of 2% polyvinylpyrrolidone in ethanol was used as an excipient at a ratio of 1：2 to full-cream milk powder, without the use of a disintegrating agent. This process provided satisfactory tablets in terms of rigidity and taste. Animal studies showed that the haddock bone calcium tablets at a dose of 2 g·kg^-1·d^-1 or 5g·kg^-1·d^-1 significantly increased blood calcium and phosphorus levels and bone calcium content in rats. Therefore, these tablets could be used for calcium supplementation and prevent osteoporosis. Although the reasons of high absorption in the rats fed with haddock bone calcium tablets are unclear, it is suggested that there are some factors, such as treatment with method of alkaline-alcohol or the added milk, may play positive roles in increasing absorption ratio.
文摘Nano-silver/polyvinylpyrrolidone(PVP)composite materials were successfully synthesized bi-insitu from silver nitrate solution with N-vinyl pyrrolidone (NVP) monomer,containing neither initiator nor reductant, in ultraviolet irradiation conditions.The resultant Ag/PVP nanocomposites were characterized by infrared spectroscopy (FT-IR), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD).TEM show that nano silver particles are homogeneously dispersed in PVP polymer matrix, and the mean size of spherical silver particles is about 5 nm.The spectroscopy of XPS and FTIR showed that there is an interaction between nano silver not only with carbonyl oxygen but also with the nitrogen group within the NVP molecule through the p-π conjugation effect in the nano-silver/PVP composites system.
