As a new type of NO removal system, NO reduction in N_2-NO plasma was applied to solve the difficulties in the traditional methods, such as higher energy-consumption, larger equipment size and high cost, and so on. Us...As a new type of NO removal system, NO reduction in N_2-NO plasma was applied to solve the difficulties in the traditional methods, such as higher energy-consumption, larger equipment size and high cost, and so on. Using the experimental NO reduction system with single-pair electrode tip discharge structure, the NO reduction characteristics of N_2-NO system were revealed to guide the engineering practice; the results of NO reduction with single-pair electrode tip discharge plasma also have the same instructive meaning to the NO reduction with multi-pair electrode tip discharge plasma. The amount of both active N atom and NO removal rate increased with the distance l_g increasing between the two electrode tips and then dropped when the distance exceeded a certain value. The NO removal rate increased while the voltage between two electrode tips or the resident time of gas flow increased. The distance is a key geometrical variable factor that can determine the intensity of electric field between two electrode tips and the resident time of gas. In this paper, the effects of the dielectric features on NO reduction using dielectric-barrier discharge plasma system were also studied. The results of NO removal rate with different dielectrics such as Al_2O_3, CaO, MgO and glass showed that the electric field intensity is different with different dielectric, because it brings different energy to particles in discharge room and thus it causes different NO removal rate.展开更多
Conversion of methane by steam reforming was carried out by means of dielectric-barrier discharge.A systemic procedure was employed to determine the suitable experimental conditions.It was found that one of the plasma...Conversion of methane by steam reforming was carried out by means of dielectric-barrier discharge.A systemic procedure was employed to determine the suitable experimental conditions.It was found that one of the plasma generators can match the system best.A higher power input can always bring a higher conversion,but the selectivity to C2H6 decreased from 52.48% to 39.43% as the power increased from 20W to 49W.When discharge distance was 4mm,selectivities to almost all main products reached the max.The inner electrode made of stainless steel and the outer electrode with aluminum foil were one of the best options which can obviously enhance the conversion of methane.A larger flow rate always resulted in a lower conversion of methane.In the most time,19.93% steam promoted conversion of methane.展开更多
The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C2 hydrocarbons through plasma catalysis under the atmo...The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C2 hydrocarbons through plasma catalysis under the atmosphere pressure and room temperature. The influence of discharge frequency, structure of electrode, discharge voltage, number of electrode, ratio of H2/CH4, flow rate and catalyst on conversion of methane and selectivity of C2 hydrocarbons are investigated. At the same time, the reaction process is investigated. Higher conversion of methane and selectivity of C2 hydrocarbons are achieved and deposited carbons are eliminated by proper choice of parameters. The appropriate operation parameters in dielectric-barrier discharge plasma field are that the supply voltage is 20-40 kV (8.4-40 W), the frequency of power supply is 20 kHz, the structure of (b) electrode is suitable, and the flow of methane is 20-60 ml · min-1. The conversion of methane can reach 45%, the selectivity of C2 hydrocarbons is 76%, and the total selectivity of C2 hydrocarbons and C3 hydrocarbons is nearly 100%. The conversion of methane increases with the increase of voltage and decreases with the flow of methane increase; the selectivity of C2 hydrocarbons decreases with the increase of voltage and increases with the flow of methane increase. The selectivity of C2 hydrocarbons is improved with catalyst for conversion of natural gas to C2 hydrocarbons in plasma field. Methane molecule collision with radicals is mainly responsible for product formation.展开更多
Co/SiO2 and zirconium promoted Co/Zr/SiO2 catalysts were prepared using dielectric-barrier discharge （DBD） plasma instead of the conventional thermal calcination method. Fischer-Tropseh Synthesis （FTS） performance...Co/SiO2 and zirconium promoted Co/Zr/SiO2 catalysts were prepared using dielectric-barrier discharge （DBD） plasma instead of the conventional thermal calcination method. Fischer-Tropseh Synthesis （FTS） performances of the catalyst were evaluated in a fixed bed reactor. The results indicated that the catalyst treated by DBD plasma shows the higher FTS activity and yield of heavy hydrocarbons as compared with that treated by the conventional thermal calcination method. Increase in CO conversion was unnoticeable on the Co/SiO2 catalyst, but significant on the Co/Zr/SiO2 catalyst, both prepared by DBD plasma. On the other hand, heavy hydrocarbon selectivity and chain growth probability （a value） were enhanced on all the catalysts prepared by the DBD plasma. In order to study the effect of the DBD plasma treatment on the FTS performance, the catalysts were characterized by N2-physisorption, H2-temperature programed reduction （H2-TPR）, H2-temperature- programmed desorption （H2-TPD） and oxygen titration, transmission electron microscope （TEM） and X-ray diffraction （XRD）. It was proved that, compared with the traditional calcination method, DBD plasma not only could shorten the precursor decomposition time, but also could achieve better cobalt dispersion, smaller Co304 cluster size and more uniform cobalt distribution. However, cobalt reducibility was hindered to some extent in the Co/SiO2 catalyst prepared by DBD plasma, while the zirconium additive prevented significantly the decrease in cobalt reducibility and increased cobalt dispersion as well as the FTS performance.展开更多
A silica-supported cobalt catalyst was prepared by hydrogen dielectric-barrier dis- charge （H2-DBD） plasma. Compared to thermal hydrogen reduction, H2-DBD plasma treatment can not only fully decompose the cobalt pre...A silica-supported cobalt catalyst was prepared by hydrogen dielectric-barrier dis- charge （H2-DBD） plasma. Compared to thermal hydrogen reduction, H2-DBD plasma treatment can not only fully decompose the cobalt precursor but also partially reduce the cobalt oxides at lower temperature and with less time. The effect of the discharge atmosphere on the property of the plasma-prepared catalyst and the Fischer-Tropsch synthesis activity was studied. The re- sults indicate that H2-DBD plasma treatment is a promising alternative for preparing Co/SiO2 catalysts from the viewpoint of energy savings and efficiency.展开更多
In this investigation, a clean, atomic economic and direct synthesis of oxygenates (methanol, ethanol) form water and methane via dielectric-barrier discharge was developed at room temperature and under atmospheric pr...In this investigation, a clean, atomic economic and direct synthesis of oxygenates (methanol, ethanol) form water and methane via dielectric-barrier discharge was developed at room temperature and under atmospheric pressure. The effect of discharge voltage on this process was studied. The results showed that the conversion of water can be as high as 7%, the selectivity of methanol and ethanol can be as high as 100%.展开更多
Effects of cooling methods on stability and methane conversion rate using dielectric-barrier discharges （DBD） were systematically investigated in this article. The results showed that the methane conversion rate was...Effects of cooling methods on stability and methane conversion rate using dielectric-barrier discharges （DBD） were systematically investigated in this article. The results showed that the methane conversion rate was as high as 44.43% in a pure methane system at a flow rate of 100 mL·min^-1 and an input power of 234.2 W with air cooling. A dark greenish and soft film-like carbon was deposited on the outer surface of quartz tube when the outer electrode was watercooled, which decreased the methane conversion. With air cooling of inner electrode the selectivity of C2 hydrocarbons was higher than that with other cooling methods, while the C3 hydrocarbons had higher selectivity with flowing water cooling. Cooling the inner electrode could restrain the carbon deposition, but would decrease the methane conversion rate. The stability of both reaction and plasma operation can be improved through cooling the reactor. From thermodynamic analysis, it was found that the effective collisions frequency among the reactant molecules and free electrons （e^-） increased with temperature, which in turn led to a higher methane conversion rate and a change in the distribution of products.展开更多
Micro-combustion initiated by dielectric bar- tier discharge plasma has been applied for the removal of carbon template to prepare urchin-like ZnO particles. The combustion is operated at atmospheric pressure and low ...Micro-combustion initiated by dielectric bar- tier discharge plasma has been applied for the removal of carbon template to prepare urchin-like ZnO particles. The combustion is operated at atmospheric pressure and low gas temperature （less than 150 ℃）, and the template is fully decomposed and rapidly removed. The obtained urchin-like ZnO possesses two distinct morphologies： nanosheets and sub-micro rods. The unique morphologies form on ZnO hexagonal nuclei with the template effect of activated carbon.展开更多
The discharge characteristics and temporal nonlinear behaviors of the atmospheric pressure coaxial electrode dielectric barrier discharges are studied by using a one-dimensional fluid model. It is shown that the disch...The discharge characteristics and temporal nonlinear behaviors of the atmospheric pressure coaxial electrode dielectric barrier discharges are studied by using a one-dimensional fluid model. It is shown that the discharge is always asymmetrical between the positive pulses and negative pulses. The gas gap severely affects this asymmetry. But it is hard to acquire a symmetrical discharge by changing the gas gap. This asymmetry is proportional to the asymmetric extent of electrode structure, namely the ratio of the outer electrode radius to the inner electrode radius. When this ratio is close to unity, a symmetrical discharge can be obtained. With the increase of frequency, the discharge can exhibit a series of nonlinear behaviors such as period-doubling bifurcation, secondary bifurcation and chaotic phenomena. In the period-doubling bifurcation sequence the period-n discharge becomes more and more unstable with the increase of n. The period-doubling bifurcation can also be obtained by altering the discharge gas gap. The mechanisms of two bifurcations are further studied.It is found that the residual quasineutral plasma from the previous discharges and corresponding electric field distribution can weaken the subsequent discharge, and leads to the occurrence of bifurcation.展开更多
The fabrication of a-C:H films from methane has been performed using dielectric-barrier discharges at atmospheric pressure. The effect of combined-feed gas, such as carbon dioxide, carbon monoxide or acetylene on the ...The fabrication of a-C:H films from methane has been performed using dielectric-barrier discharges at atmospheric pressure. The effect of combined-feed gas, such as carbon dioxide, carbon monoxide or acetylene on the formation of a-C:H films has been investigated. It has been demonstrated that the addition of carbon monoxide or acetylene into methane leads to a remarkable improvement in the fabrication of a-C:H films. The characterization of carbon film obtained has been conducted using FT-IR, Raman and SEM.展开更多
Co-based catalysts were prepared by using dielectric-barrier discharge （DBD） plasma as an alternative method to conventional thermal calcination. The characterization results of N2-physisorption, temperature program...Co-based catalysts were prepared by using dielectric-barrier discharge （DBD） plasma as an alternative method to conventional thermal calcination. The characterization results of N2-physisorption, temperature programmed reduction （TPR）, transmission electron microscope （TEM）, and X-ray diffraction （XRD） indicated that the catalysts prepared by DBD plasma had a higher specific surface area, lower reduction temperature, smaller particle size and higher cobalt dispersion as compared to calcined catalysts. The DBD plasma method can prevent the sintering and aggregation of active particles on the support due to the decreased treatment time （0.5 h） at lower temperature compared to the longer thermal calcination at higher temperature （at 500~C for 5 h）. As a result, the catalytic performance of the Fischer-Tropsch synthesis on DBD plasma treated Co/Si02 catalyst showed an enhanced activity, C5＋ selectivity and catalytic stability as compared to the conventional thermal calcined Co/SiO2 catalyst.展开更多
Hydrogen dielectric-barrier discharge (H<sub>2</sub>-DBD) plasma was successfully used to prepare carbon nanotubes (CNTs)-supported cobalt (Co) catalyst. The H<sub>2</sub>-DBD plasma treatment ...Hydrogen dielectric-barrier discharge (H<sub>2</sub>-DBD) plasma was successfully used to prepare carbon nanotubes (CNTs)-supported cobalt (Co) catalyst. The H<sub>2</sub>-DBD plasma treatment simultaneously decomposed and reduced the cobalt precursor at a lower temperature and in a shorter time than the conventional method (calcination and hydrogen reduction). It is considered that the H<sub>2</sub>-DBD plasma method can remarkably decrease the amount of energy input compared to traditional methods used to prepare the Co-based catalyst in Fischer-Tropsch synthesis (FTS). Results showed that the Co catalyst prepared by H<sub>2</sub>-DBD plasma had an equivalent catalytic performance for FTS as that prepared using the conventional method in calcination and hydrogen reduction, thereby determining that H<sub>2</sub>-DBD plasma was an effective alternative treatment for preparing the Co/CNTs catalyst for FTS. This technology will provide a new strategy for preparing catalysts in other catalysis processes.展开更多
Methane coupling to produce C2 hydrocar-bons through a dielectric-barrier discharge(DBD)plasma reaction was studied in four DBD reactors.The effects of high voltage electrode position,different discharge gap,types of ...Methane coupling to produce C2 hydrocar-bons through a dielectric-barrier discharge(DBD)plasma reaction was studied in four DBD reactors.The effects of high voltage electrode position,different discharge gap,types of inner electrode,volume ratio of hydrogen to methane and air cooling method on the conversion of methane and distribution of products were investigated.Conversion of methane is obviously lower when a high voltage electrode acts as an outer electrode than when it acts as an inner electrode.The lifting of reaction temper-ature becomes slow due to cooling of outer electrode and the temperature can be controlled in the expected range of 60℃-150℃for ensuring better methane conversion and safe operation.The parameters of reactors have obvious effects on methane conversion,but it only slightly affects distribution of the products.The main products are ethyl-ene,ethane and propane.The selectivity of C2 hydrocar-bons can reach 74.50%when volume ratio of hydrogen to methane is 1.50.展开更多
The hydrogen fuel cell is a promising option as a future energy resource and the production of hydrogen is mainly depended on fossil fuels now.In this paper,methanol reforming to produce H2 through dielectric-barrier ...The hydrogen fuel cell is a promising option as a future energy resource and the production of hydrogen is mainly depended on fossil fuels now.In this paper,methanol reforming to produce H2 through dielectric-barrier discharge(DBD)plasma reaction was studied.Effects of the power supply parameters,reactor parameters and process conditions on conversion of methanol and distribution of products were investigated.The best reaction conditions were following:input power(45 W),material of inner electrode(stainless steel),discharge gap(3.40 mm),length of reaction zone(90.00 mm),dielectric thickness(1.25 mm),and methanol content(37.65%).The highest conversion of methanol and the yield of H2 were 82.38%and 27.43%,respectively.展开更多
In order to achieve the selective hydrogenation of biodiesel at room temperature and under normal pressure,we researched the upgrading of soybean biodiesel using a dielectric-barrier discharge(DBD)reaction system.Usin...In order to achieve the selective hydrogenation of biodiesel at room temperature and under normal pressure,we researched the upgrading of soybean biodiesel using a dielectric-barrier discharge(DBD)reaction system.Using Raney-Ni as the hydrogenation catalyst,the effects of the operating parameters on the hydrogenation depth and the selectivity of biodiesel were systematically analyzed.The results show that the polyunsaturated components in soybean methyl ester were reduced by 57.04%,and that the polyunsaturated components were hydrogenated to monounsaturated components with a selectivity of 77.75%.Based on the gas chromatography and mass spectrometry(GC-MS)test results,we established a kinetic model for biodiesel hydrogenation.A comparison of the calculated and experimental results shows that the hydrogenation of the biodiesel can be described by a quasi first-order reaction model.The calculated reaction rate constants indicate that under DBD plasma reaction conditions,the hydrogenation of biodiesel has high selectivity for the formation of monounsaturated components.展开更多
文摘As a new type of NO removal system, NO reduction in N_2-NO plasma was applied to solve the difficulties in the traditional methods, such as higher energy-consumption, larger equipment size and high cost, and so on. Using the experimental NO reduction system with single-pair electrode tip discharge structure, the NO reduction characteristics of N_2-NO system were revealed to guide the engineering practice; the results of NO reduction with single-pair electrode tip discharge plasma also have the same instructive meaning to the NO reduction with multi-pair electrode tip discharge plasma. The amount of both active N atom and NO removal rate increased with the distance l_g increasing between the two electrode tips and then dropped when the distance exceeded a certain value. The NO removal rate increased while the voltage between two electrode tips or the resident time of gas flow increased. The distance is a key geometrical variable factor that can determine the intensity of electric field between two electrode tips and the resident time of gas. In this paper, the effects of the dielectric features on NO reduction using dielectric-barrier discharge plasma system were also studied. The results of NO removal rate with different dielectrics such as Al_2O_3, CaO, MgO and glass showed that the electric field intensity is different with different dielectric, because it brings different energy to particles in discharge room and thus it causes different NO removal rate.
基金Supported by the National iqatural Science Foundation of China （20606023, 20490203）.
文摘Conversion of methane by steam reforming was carried out by means of dielectric-barrier discharge.A systemic procedure was employed to determine the suitable experimental conditions.It was found that one of the plasma generators can match the system best.A higher power input can always bring a higher conversion,but the selectivity to C2H6 decreased from 52.48% to 39.43% as the power increased from 20W to 49W.When discharge distance was 4mm,selectivities to almost all main products reached the max.The inner electrode made of stainless steel and the outer electrode with aluminum foil were one of the best options which can obviously enhance the conversion of methane.A larger flow rate always resulted in a lower conversion of methane.In the most time,19.93% steam promoted conversion of methane.
基金This work was supported by the Science and Technology Development from the SINOPEC (Grant No. X500005) the National Natural Science Foundation of China (Grant No. 29776037).
文摘The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C2 hydrocarbons through plasma catalysis under the atmosphere pressure and room temperature. The influence of discharge frequency, structure of electrode, discharge voltage, number of electrode, ratio of H2/CH4, flow rate and catalyst on conversion of methane and selectivity of C2 hydrocarbons are investigated. At the same time, the reaction process is investigated. Higher conversion of methane and selectivity of C2 hydrocarbons are achieved and deposited carbons are eliminated by proper choice of parameters. The appropriate operation parameters in dielectric-barrier discharge plasma field are that the supply voltage is 20-40 kV (8.4-40 W), the frequency of power supply is 20 kHz, the structure of (b) electrode is suitable, and the flow of methane is 20-60 ml · min-1. The conversion of methane can reach 45%, the selectivity of C2 hydrocarbons is 76%, and the total selectivity of C2 hydrocarbons and C3 hydrocarbons is nearly 100%. The conversion of methane increases with the increase of voltage and decreases with the flow of methane increase; the selectivity of C2 hydrocarbons decreases with the increase of voltage and increases with the flow of methane increase. The selectivity of C2 hydrocarbons is improved with catalyst for conversion of natural gas to C2 hydrocarbons in plasma field. Methane molecule collision with radicals is mainly responsible for product formation.
基金supported by the National Natural Science Foundation of China(No.21076151)
文摘Co/SiO2 and zirconium promoted Co/Zr/SiO2 catalysts were prepared using dielectric-barrier discharge （DBD） plasma instead of the conventional thermal calcination method. Fischer-Tropseh Synthesis （FTS） performances of the catalyst were evaluated in a fixed bed reactor. The results indicated that the catalyst treated by DBD plasma shows the higher FTS activity and yield of heavy hydrocarbons as compared with that treated by the conventional thermal calcination method. Increase in CO conversion was unnoticeable on the Co/SiO2 catalyst, but significant on the Co/Zr/SiO2 catalyst, both prepared by DBD plasma. On the other hand, heavy hydrocarbon selectivity and chain growth probability （a value） were enhanced on all the catalysts prepared by the DBD plasma. In order to study the effect of the DBD plasma treatment on the FTS performance, the catalysts were characterized by N2-physisorption, H2-temperature programed reduction （H2-TPR）, H2-temperature- programmed desorption （H2-TPD） and oxygen titration, transmission electron microscope （TEM） and X-ray diffraction （XRD）. It was proved that, compared with the traditional calcination method, DBD plasma not only could shorten the precursor decomposition time, but also could achieve better cobalt dispersion, smaller Co304 cluster size and more uniform cobalt distribution. However, cobalt reducibility was hindered to some extent in the Co/SiO2 catalyst prepared by DBD plasma, while the zirconium additive prevented significantly the decrease in cobalt reducibility and increased cobalt dispersion as well as the FTS performance.
基金supported by National Natural Science Foundation of China(No.21076151)
文摘A silica-supported cobalt catalyst was prepared by hydrogen dielectric-barrier dis- charge （H2-DBD） plasma. Compared to thermal hydrogen reduction, H2-DBD plasma treatment can not only fully decompose the cobalt precursor but also partially reduce the cobalt oxides at lower temperature and with less time. The effect of the discharge atmosphere on the property of the plasma-prepared catalyst and the Fischer-Tropsch synthesis activity was studied. The re- sults indicate that H2-DBD plasma treatment is a promising alternative for preparing Co/SiO2 catalysts from the viewpoint of energy savings and efficiency.
文摘In this investigation, a clean, atomic economic and direct synthesis of oxygenates (methanol, ethanol) form water and methane via dielectric-barrier discharge was developed at room temperature and under atmospheric pressure. The effect of discharge voltage on this process was studied. The results showed that the conversion of water can be as high as 7%, the selectivity of methanol and ethanol can be as high as 100%.
基金National Natural Science Foundation of China(No.20606023)National Key Natural Science Foundation of China(No.20490203)
文摘Effects of cooling methods on stability and methane conversion rate using dielectric-barrier discharges （DBD） were systematically investigated in this article. The results showed that the methane conversion rate was as high as 44.43% in a pure methane system at a flow rate of 100 mL·min^-1 and an input power of 234.2 W with air cooling. A dark greenish and soft film-like carbon was deposited on the outer surface of quartz tube when the outer electrode was watercooled, which decreased the methane conversion. With air cooling of inner electrode the selectivity of C2 hydrocarbons was higher than that with other cooling methods, while the C3 hydrocarbons had higher selectivity with flowing water cooling. Cooling the inner electrode could restrain the carbon deposition, but would decrease the methane conversion rate. The stability of both reaction and plasma operation can be improved through cooling the reactor. From thermodynamic analysis, it was found that the effective collisions frequency among the reactant molecules and free electrons （e^-） increased with temperature, which in turn led to a higher methane conversion rate and a change in the distribution of products.
文摘Micro-combustion initiated by dielectric bar- tier discharge plasma has been applied for the removal of carbon template to prepare urchin-like ZnO particles. The combustion is operated at atmospheric pressure and low gas temperature （less than 150 ℃）, and the template is fully decomposed and rapidly removed. The obtained urchin-like ZnO possesses two distinct morphologies： nanosheets and sub-micro rods. The unique morphologies form on ZnO hexagonal nuclei with the template effect of activated carbon.
基金supported by the National Natural Science Foundation of China(Grant Nos.11447244 and 11405208)the Science Foundation of Hengyang Normal University,China(Grant No.14B41)the Hunan Provincial Applied Basic Research Base of Optoelectronic Information Technology,China(Grant No.GDXX010)
文摘The discharge characteristics and temporal nonlinear behaviors of the atmospheric pressure coaxial electrode dielectric barrier discharges are studied by using a one-dimensional fluid model. It is shown that the discharge is always asymmetrical between the positive pulses and negative pulses. The gas gap severely affects this asymmetry. But it is hard to acquire a symmetrical discharge by changing the gas gap. This asymmetry is proportional to the asymmetric extent of electrode structure, namely the ratio of the outer electrode radius to the inner electrode radius. When this ratio is close to unity, a symmetrical discharge can be obtained. With the increase of frequency, the discharge can exhibit a series of nonlinear behaviors such as period-doubling bifurcation, secondary bifurcation and chaotic phenomena. In the period-doubling bifurcation sequence the period-n discharge becomes more and more unstable with the increase of n. The period-doubling bifurcation can also be obtained by altering the discharge gas gap. The mechanisms of two bifurcations are further studied.It is found that the residual quasineutral plasma from the previous discharges and corresponding electric field distribution can weaken the subsequent discharge, and leads to the occurrence of bifurcation.
基金The project supported by the Key Foundation of Tianjin City Committee of Science Technology and ABB Corporate Research Ltd., Switzerland
文摘The fabrication of a-C:H films from methane has been performed using dielectric-barrier discharges at atmospheric pressure. The effect of combined-feed gas, such as carbon dioxide, carbon monoxide or acetylene on the formation of a-C:H films has been investigated. It has been demonstrated that the addition of carbon monoxide or acetylene into methane leads to a remarkable improvement in the fabrication of a-C:H films. The characterization of carbon film obtained has been conducted using FT-IR, Raman and SEM.
基金supported by National Natural Science Foundation of China (No.21076151)
文摘Co-based catalysts were prepared by using dielectric-barrier discharge （DBD） plasma as an alternative method to conventional thermal calcination. The characterization results of N2-physisorption, temperature programmed reduction （TPR）, transmission electron microscope （TEM）, and X-ray diffraction （XRD） indicated that the catalysts prepared by DBD plasma had a higher specific surface area, lower reduction temperature, smaller particle size and higher cobalt dispersion as compared to calcined catalysts. The DBD plasma method can prevent the sintering and aggregation of active particles on the support due to the decreased treatment time （0.5 h） at lower temperature compared to the longer thermal calcination at higher temperature （at 500~C for 5 h）. As a result, the catalytic performance of the Fischer-Tropsch synthesis on DBD plasma treated Co/Si02 catalyst showed an enhanced activity, C5＋ selectivity and catalytic stability as compared to the conventional thermal calcined Co/SiO2 catalyst.
基金Supported by the National Natural Science Foundation of China (No.21506154)the program for New Century Excellent Talents in University of Ministry of Education of China (NCET-06-0239)
文摘Hydrogen dielectric-barrier discharge (H<sub>2</sub>-DBD) plasma was successfully used to prepare carbon nanotubes (CNTs)-supported cobalt (Co) catalyst. The H<sub>2</sub>-DBD plasma treatment simultaneously decomposed and reduced the cobalt precursor at a lower temperature and in a shorter time than the conventional method (calcination and hydrogen reduction). It is considered that the H<sub>2</sub>-DBD plasma method can remarkably decrease the amount of energy input compared to traditional methods used to prepare the Co-based catalyst in Fischer-Tropsch synthesis (FTS). Results showed that the Co catalyst prepared by H<sub>2</sub>-DBD plasma had an equivalent catalytic performance for FTS as that prepared using the conventional method in calcination and hydrogen reduction, thereby determining that H<sub>2</sub>-DBD plasma was an effective alternative treatment for preparing the Co/CNTs catalyst for FTS. This technology will provide a new strategy for preparing catalysts in other catalysis processes.
基金supported by the National Natural Science Foundation of China(Grant No.20606023)the National Key Natural Science Foundation of China(No.20490203).
文摘Methane coupling to produce C2 hydrocar-bons through a dielectric-barrier discharge(DBD)plasma reaction was studied in four DBD reactors.The effects of high voltage electrode position,different discharge gap,types of inner electrode,volume ratio of hydrogen to methane and air cooling method on the conversion of methane and distribution of products were investigated.Conversion of methane is obviously lower when a high voltage electrode acts as an outer electrode than when it acts as an inner electrode.The lifting of reaction temper-ature becomes slow due to cooling of outer electrode and the temperature can be controlled in the expected range of 60℃-150℃for ensuring better methane conversion and safe operation.The parameters of reactors have obvious effects on methane conversion,but it only slightly affects distribution of the products.The main products are ethyl-ene,ethane and propane.The selectivity of C2 hydrocar-bons can reach 74.50%when volume ratio of hydrogen to methane is 1.50.
基金supported by the National Natural Science Foundation of China(Grant No.20606023).
文摘The hydrogen fuel cell is a promising option as a future energy resource and the production of hydrogen is mainly depended on fossil fuels now.In this paper,methanol reforming to produce H2 through dielectric-barrier discharge(DBD)plasma reaction was studied.Effects of the power supply parameters,reactor parameters and process conditions on conversion of methanol and distribution of products were investigated.The best reaction conditions were following:input power(45 W),material of inner electrode(stainless steel),discharge gap(3.40 mm),length of reaction zone(90.00 mm),dielectric thickness(1.25 mm),and methanol content(37.65%).The highest conversion of methanol and the yield of H2 were 82.38%and 27.43%,respectively.
基金supported by National Natural Science Foundation of China(No.51761145011)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Jiangsu University Senior Talent Fund Project(No.12811020026)。
文摘In order to achieve the selective hydrogenation of biodiesel at room temperature and under normal pressure,we researched the upgrading of soybean biodiesel using a dielectric-barrier discharge(DBD)reaction system.Using Raney-Ni as the hydrogenation catalyst,the effects of the operating parameters on the hydrogenation depth and the selectivity of biodiesel were systematically analyzed.The results show that the polyunsaturated components in soybean methyl ester were reduced by 57.04%,and that the polyunsaturated components were hydrogenated to monounsaturated components with a selectivity of 77.75%.Based on the gas chromatography and mass spectrometry(GC-MS)test results,we established a kinetic model for biodiesel hydrogenation.A comparison of the calculated and experimental results shows that the hydrogenation of the biodiesel can be described by a quasi first-order reaction model.The calculated reaction rate constants indicate that under DBD plasma reaction conditions,the hydrogenation of biodiesel has high selectivity for the formation of monounsaturated components.
