Catalyst containing shape selective zeolite is used to investigate the catalytic cracking characteristics of palm oil and three types of hydrocarbon VGOs on a fixed fluidized bed(FFB) unit. The advantage of producing ...Catalyst containing shape selective zeolite is used to investigate the catalytic cracking characteristics of palm oil and three types of hydrocarbon VGOs on a fixed fluidized bed(FFB) unit. The advantage of producing light olefins and light aromatics by catalytic cracking of plant oil is discussed. Results indicate that the hydrocarbyl group of the plant oil molecule is quite readily crackable; the C_6—C_8 aromatics yield is well above and the light olefins yield is about the same with the hydrocarbon feeds, while the yields of low value products are lower; the hydrocarbyl group of the plant oil molecule has strong tendency of aromatization, and can enter the zeolite pores to selectively form C_6—C_8 aromatics; during catalytic cracking of plant oil and fatty acids, a portion of the oxygen is removed in the form of water through hydrogen transfer reaction, while olefins are prevented from being saturated, which can ensure proper yields of both low-carbon olefins and light aromatics.展开更多
Aromatization of light alkanes is a value-added process in both petrochemical and coal chemical industries.Here,single[Ga(OH)]^(2+)ion-exchanged mesoporous hollow-structured ZSM-5(Ga-MH-ZSM-5)material was prepared,and...Aromatization of light alkanes is a value-added process in both petrochemical and coal chemical industries.Here,single[Ga(OH)]^(2+)ion-exchanged mesoporous hollow-structured ZSM-5(Ga-MH-ZSM-5)material was prepared,and it shows unprecedented catalytic performance in light alkane aromatization,considering activity,product selectivity and catalytic stability.The average aromatics yields in ethane aromatization at 600℃and WHSV of 0.8 h^(-1) within 28 h and in propane aromatization at 580℃and WHSV of 1.1 h^(-1) within 20 h reach~18.4%and~70.8%with benzene,toluene and xylenes(BTX)accounting for~96%and~88%of aromatics,respectively.Ga-MH-ZSM-5-0.41 gave a TON for formation of aromatics(TON_(aromatics))from propane as high as 57479,whereas the reported catalysts maximally show a TON_(aromatics) of 5514.This also holds true for ethane aromatization;the TON_(aromatics) obtained on Ga-MH-ZSM-5-0.41 was³3845 in contrast to£392 on reported non-noble metal catalysts.The catalytic activity of Ga-MH-ZSM-5 highly depends on Ga species structures.[Ga(OH)]^(2+)ions are predominant species at Ga loading≤0.3 wt%,while more[Ga(OH)_(2)]^(+)and GaO_(x) oligomers are formed with increasing Ga content.Upon reduction with H_(2),[Ga(OH)]^(2+)and[Ga(OH)_(2)]^(+)are transformed into[GaH]^(2+)and[GaH_(2)]^(+)species,which show a propane dehydrogenation rate of 300 and 15 times of that of Brønsted acid sites respectively.The light alkanes are mainly dehydrogenated into light olefins on[GaH]^(2+)species,and then,oligomerized and cyclized into(alkyl)cycloalkanes on H^(+)sites,which is followed by possible ring expansion on H^(+)and sequential dehydrogenations into aromatics primarily on[GaH]^(2+).展开更多
Aromatic fractions of six light oils and two source rock samples from Panyu（番禺） lower uplift of Pearl River Mouth basin were analyzed using GC-MS（gas chromatography-mass spectrometric） technique.Thirteen aromati...Aromatic fractions of six light oils and two source rock samples from Panyu（番禺） lower uplift of Pearl River Mouth basin were analyzed using GC-MS（gas chromatography-mass spectrometric） technique.Thirteen aromatic series of hydrocarbons detected such as biphenyls,naphthalenes,phenanthrenes,dibenzothiophenes（more than two hundred aromatic hydrocarbon compounds） were used to analyze the origin and maturity of the light oils.This study indicates that the distribution of aromatic hydrocarbon compounds in the light oils of wells L1 and P1 differs from those of wells P2,P3 and P4.The light oil samples from wells L1 and P1 contain more dibenzofuran and fluorence hydrocarbons and less naphthalene hydrocarbons.The contents of fluorene,dibenzothiophene and dibenzofuran in the two groups of light oils also show their difference in sedimentary environment.Moreover,the diversity of the relative distributions of biphenyl and naphthalene is apparent between the two groups of light oils.As mentioned above,the origin of the light oils from wells L1 and P1 varies from that of wells P2,P3 and P4.According to the result of oil-source correlation,the light oils from wells P2,P3 and P4 mainly originated from the source rocks in the Enping（恩平） Formation.Accordingly,the light oils from wells L1 and P1 may have been derived from the lacustrine shales in the Wenchang（文昌） Formation or from the mixed source of the Wenchang Formation and the Enping Formation.Applying maturity parameters of methylnaphthalenes,methylphenanthrenes and methyldibenzothiophenes from the aromatic hydrocarbons to the study of the maturity of light oils from Panyu lower uplift indicates that the maturity has reached the high mature stage.展开更多
The catalytic cracking of coal tar asphaltene(CTA)pyrolysis vapors was carried out over transition metalion modified zeolites to promote the generation of light aromatic hydrocarbons(L-ArHs)in a pyrolysisgas chromatog...The catalytic cracking of coal tar asphaltene(CTA)pyrolysis vapors was carried out over transition metalion modified zeolites to promote the generation of light aromatic hydrocarbons(L-ArHs)in a pyrolysisgas chromatography/mass spectrometry(Py-GC/MS)micro-reactor system.The effects of ultra stable Y(USY),Co/USY and Mo/USY on the selectivity and yield of L-ArHs products and the extent of deoxygenation(Edeoxygenation),lightweight(Elightweight)from CTA pyrolysis volatiles were investigated.Results showed that the yields of L-ArHs are mainly controlled by the acid sites and specific surface area of the catalysts,while the deoxygenation effect is determined by theirs pore size.The Eligltweight of CTA pyrolysis volatiles over USY is 9.65%,while the Edeoxygenation of CTA pyrolysis volatiles over Mo/USY reaches 20.85%.Additionally,the modified zeolites(Mo/USY and Co/USY)exhibit better performance than USY on L-ArHs production,owing to the synergistic effect of metal ions(Mo,Co)and acid sites of USY.Compared with the non-catalytic fast pyrolysis of CTA,the total yield of L-ArHs obtained over USY(4032 mg·kg^(-1)),Co/USY(4363 mg·kg^(-1))and Mo/USY(4953 mg·kg^(-1))were increased by 27.03%,38.19%and 54.78%,respectively.Furthermore,the possible catalytic conversion mechanism of transition metal ion(Co and Mo)modified zeolites was proposed based on the distribution of products and the characterizations of catalysts.展开更多
Background:Lesion to the retinal pigment epithelium(RPE)is a crucial event in age-related macular degeneration(AMD)development.Although the pathogenesis of this complex disease is poorly understood,sunlight exposure a...Background:Lesion to the retinal pigment epithelium(RPE)is a crucial event in age-related macular degeneration(AMD)development.Although the pathogenesis of this complex disease is poorly understood,sunlight exposure and smoking are major environmental risk factors associated with AMD.High-energy visible blue light(HEV;400-500 nm)is the most energetic and potentially harmful solar wavelengths reaching adults retina.On the other hand,RPE cells can be exposed to a large range of pollutants from cigarette smoke,with polycyclic aromatic hydrocarbons(PAH)being among the most toxic.Some PAH from cigarette smoke can absorb HEV light.This led us hypothesize that in RPE cells,the combination of PAH and HEV could synergize to exacerbate the stress caused by either factor alone.We thus investigate the combined effect of PAH and HEV light in RPE cells.Methods:Confluent RPE immortalized cells(ARPE19)were exposed to nanomolar concentrations of benzo[a]pyrene(BaP)or indeno[1,2,3-cd]pyrene(IcdP).While IcdP efficiently absorbs HEV wavelengths,BaP,the most studied PAH,does not significantly absorb HEV light and was used as a control.BaP or IcdP contaminated ARPE19 were then irradiated with increasing sub-lethal doses of HEV light(150-500 J/cm2)using a setup that mimics the light spectrum normally reaching the retina.Cytotoxicity,apoptosis and reactive oxygen species(ROS)generation were assessed in each condition.Results:In presence of low concentrations of IcdP,sub-lethal amounts of HEV light trigger,in a dose-dependent way,up to 70%of apoptotic cell death.Co-exposure to IcdP and HEV also leads to a synergistic ROS generation in ARPE19 cells,thus inducing oxidative stress.None of these effects were observed with BaP.Efficient inhibition of ROS production by specific antioxidants only decreases death by 20%in cells simultaneously exposed to both IcdP and HEV light.Conclusions:Low concentrations of IcdP synergize with HEV light to induce phototoxicity in ARPE19 cells.An increased oxidative stress results from the interaction between both agents and partially explains the enhanced HEV phototoxicity in IcdP contaminated ARPE19 cells.This suggests that another major mechanism is involved in the synergetic toxicity.For smokers,this synergy between HEV and PAH may accelerate RPE cells loss and contribute to their greater risk of developing AMD.展开更多
This work presents the synthesis of a new hole-buffering material TAZS and its successful application in polymer light-emitting diodes to enhance device performance. The TAZS is composed of aromatic 1,2,4-triazolylcor...This work presents the synthesis of a new hole-buffering material TAZS and its successful application in polymer light-emitting diodes to enhance device performance. The TAZS is composed of aromatic 1,2,4-triazolylcore linked with three trihydroxy tert-butyl terminals via azomethine linkages. The TAZS forms ashomogeneous film deposited by spin-coating process. The HOMO and LUMO levels of TAZS are -5.23 eV and -2.40 eV, respectively, as estimated from cyclic voltammogram. The current density results of hole-only and electron-only devices confirm strong hole-buffering capability of TAZS layer. Multilayer PLEDs with different thickness of TAZS (ITO/PEDOT: PSS/TAZS (x nm)/SY/ETL/LiF/Al) have been successfully fabricated, using spin-coating process to deposit hole-injecting PEDOT: PSS, TAZS, and emissive SY layers. The PLED with 16 nm TAZS reveals the optimal device performance, with maximum luminance and maximum current efficiency of 19,046 cd/m2 and 4.08 cd/A, respectively, surpassing those without TAZS as HBL (8484 cd/m2, 2.13 cd/A). The hole-buffering characteristic of TAZS contributes greatly to improved charges’ recombination ratio and enhanced emission efficiency.展开更多
Condensates and light oils are generally characterized by high maturity, low concentration of sterane and terpane biomarkers and low content of non-hydrocarbon fraction. As a result, some commonly-used sterane, terpan...Condensates and light oils are generally characterized by high maturity, low concentration of sterane and terpane biomarkers and low content of non-hydrocarbon fraction. As a result, some commonly-used sterane, terpane and carbazole migration parameters in conventional oil reservoirs may have a certain limitation in condensate and light oil reservoirs for their poor signal-noise ratios in the gas chromatography-mass spectrometry （GC-MS）. Naphthalene, phenanthrene and their methylated substituents, however, are present in significant concentrations in condensates and light oils. Taking the Fushan depression （in the Beibuwan Basin, Northern South China Sea） as an example, this paper attempts for the first time to use polycyclic aromatic hydrocarbon （PAH）-related parameters to trace migration directions and filling pathways for condensate and light oil reservoirs. The result shows that TMNr （i.e. 1, 3, 7-TMN/（1, 3, 7-TMN ＋ 1, 2, 5-TMN）, TMN： trimethylnaphthalene））, MPI-1 （i.e. 1.5×（2-MP ＋ 3-MP）/（P ＋ 1-MP ＋ 9-MP）, P： phenanthrene MP： methyiphenanthrene）, MN/DMN （∑methylnaphthalene/∑dimethylnaphthalene, %） and MN/TMN （∑nethylnaphthalene/∑trimethylna- phthalene, %） can be used to trace the filling pathways of condensate and light oil reservoirs. These parameters, together with geological consideration and other bulk oil properties （e.g. the gas to oil ratio and density）, suggest that the condensates and light oils in the Huachang oil and gas field are mainly sourced from the Bailian sag that is located to the northeast of the Huachang uplift in the Fushan depression.展开更多
The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated.Physicochemical properties of the catalysts,such as the specific surface area,pore volume and acid...The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated.Physicochemical properties of the catalysts,such as the specific surface area,pore volume and acidity,etc.,were characterized to correlate with their aromatization performance data.The results showed that the pore structure of Al2O3 could significantly affect the catalyst performance.As the accessible pore diameter of the catalyst increased from 8.0 nm to 9.0 nm,the light aromatics yield increased by 2.7 percentage points,while the operating time of the catalyst nearly doubled.In addition,catalysts prepared with SiO2 and aluminum phosphate was more active and stable than that prepared with Al2O3,of which the light aromatics yield enhanced 6---8 percentage points and the rtm length,or seivice eife run length nearly doubled.展开更多
基金financially supported by the SINOPEC Research and Development Project (Contact No. 115010)
文摘Catalyst containing shape selective zeolite is used to investigate the catalytic cracking characteristics of palm oil and three types of hydrocarbon VGOs on a fixed fluidized bed(FFB) unit. The advantage of producing light olefins and light aromatics by catalytic cracking of plant oil is discussed. Results indicate that the hydrocarbyl group of the plant oil molecule is quite readily crackable; the C_6—C_8 aromatics yield is well above and the light olefins yield is about the same with the hydrocarbon feeds, while the yields of low value products are lower; the hydrocarbyl group of the plant oil molecule has strong tendency of aromatization, and can enter the zeolite pores to selectively form C_6—C_8 aromatics; during catalytic cracking of plant oil and fatty acids, a portion of the oxygen is removed in the form of water through hydrogen transfer reaction, while olefins are prevented from being saturated, which can ensure proper yields of both low-carbon olefins and light aromatics.
文摘Aromatization of light alkanes is a value-added process in both petrochemical and coal chemical industries.Here,single[Ga(OH)]^(2+)ion-exchanged mesoporous hollow-structured ZSM-5(Ga-MH-ZSM-5)material was prepared,and it shows unprecedented catalytic performance in light alkane aromatization,considering activity,product selectivity and catalytic stability.The average aromatics yields in ethane aromatization at 600℃and WHSV of 0.8 h^(-1) within 28 h and in propane aromatization at 580℃and WHSV of 1.1 h^(-1) within 20 h reach~18.4%and~70.8%with benzene,toluene and xylenes(BTX)accounting for~96%and~88%of aromatics,respectively.Ga-MH-ZSM-5-0.41 gave a TON for formation of aromatics(TON_(aromatics))from propane as high as 57479,whereas the reported catalysts maximally show a TON_(aromatics) of 5514.This also holds true for ethane aromatization;the TON_(aromatics) obtained on Ga-MH-ZSM-5-0.41 was³3845 in contrast to£392 on reported non-noble metal catalysts.The catalytic activity of Ga-MH-ZSM-5 highly depends on Ga species structures.[Ga(OH)]^(2+)ions are predominant species at Ga loading≤0.3 wt%,while more[Ga(OH)_(2)]^(+)and GaO_(x) oligomers are formed with increasing Ga content.Upon reduction with H_(2),[Ga(OH)]^(2+)and[Ga(OH)_(2)]^(+)are transformed into[GaH]^(2+)and[GaH_(2)]^(+)species,which show a propane dehydrogenation rate of 300 and 15 times of that of Brønsted acid sites respectively.The light alkanes are mainly dehydrogenated into light olefins on[GaH]^(2+)species,and then,oligomerized and cyclized into(alkyl)cycloalkanes on H^(+)sites,which is followed by possible ring expansion on H^(+)and sequential dehydrogenations into aromatics primarily on[GaH]^(2+).
基金supported by the National Natural Science Foundation of China (No. 40238060)the Key Laboratory of Tectonics and Petroleum Resources of the Ministry of Education of China (No. TPR-2009-07)
文摘Aromatic fractions of six light oils and two source rock samples from Panyu（番禺） lower uplift of Pearl River Mouth basin were analyzed using GC-MS（gas chromatography-mass spectrometric） technique.Thirteen aromatic series of hydrocarbons detected such as biphenyls,naphthalenes,phenanthrenes,dibenzothiophenes（more than two hundred aromatic hydrocarbon compounds） were used to analyze the origin and maturity of the light oils.This study indicates that the distribution of aromatic hydrocarbon compounds in the light oils of wells L1 and P1 differs from those of wells P2,P3 and P4.The light oil samples from wells L1 and P1 contain more dibenzofuran and fluorence hydrocarbons and less naphthalene hydrocarbons.The contents of fluorene,dibenzothiophene and dibenzofuran in the two groups of light oils also show their difference in sedimentary environment.Moreover,the diversity of the relative distributions of biphenyl and naphthalene is apparent between the two groups of light oils.As mentioned above,the origin of the light oils from wells L1 and P1 varies from that of wells P2,P3 and P4.According to the result of oil-source correlation,the light oils from wells P2,P3 and P4 mainly originated from the source rocks in the Enping（恩平） Formation.Accordingly,the light oils from wells L1 and P1 may have been derived from the lacustrine shales in the Wenchang（文昌） Formation or from the mixed source of the Wenchang Formation and the Enping Formation.Applying maturity parameters of methylnaphthalenes,methylphenanthrenes and methyldibenzothiophenes from the aromatic hydrocarbons to the study of the maturity of light oils from Panyu lower uplift indicates that the maturity has reached the high mature stage.
基金financed by the projects of the National Natural Science Foundation of China(21776229,21908180,22078266)the National Key Research&Development Program of China(2018YFB0604603)the Key Research and Development Program of Shaanxi(2020ZDLGY11-02,2018ZDXM-GY-167)。
文摘The catalytic cracking of coal tar asphaltene(CTA)pyrolysis vapors was carried out over transition metalion modified zeolites to promote the generation of light aromatic hydrocarbons(L-ArHs)in a pyrolysisgas chromatography/mass spectrometry(Py-GC/MS)micro-reactor system.The effects of ultra stable Y(USY),Co/USY and Mo/USY on the selectivity and yield of L-ArHs products and the extent of deoxygenation(Edeoxygenation),lightweight(Elightweight)from CTA pyrolysis volatiles were investigated.Results showed that the yields of L-ArHs are mainly controlled by the acid sites and specific surface area of the catalysts,while the deoxygenation effect is determined by theirs pore size.The Eligltweight of CTA pyrolysis volatiles over USY is 9.65%,while the Edeoxygenation of CTA pyrolysis volatiles over Mo/USY reaches 20.85%.Additionally,the modified zeolites(Mo/USY and Co/USY)exhibit better performance than USY on L-ArHs production,owing to the synergistic effect of metal ions(Mo,Co)and acid sites of USY.Compared with the non-catalytic fast pyrolysis of CTA,the total yield of L-ArHs obtained over USY(4032 mg·kg^(-1)),Co/USY(4363 mg·kg^(-1))and Mo/USY(4953 mg·kg^(-1))were increased by 27.03%,38.19%and 54.78%,respectively.Furthermore,the possible catalytic conversion mechanism of transition metal ion(Co and Mo)modified zeolites was proposed based on the distribution of products and the characterizations of catalysts.
文摘Background:Lesion to the retinal pigment epithelium(RPE)is a crucial event in age-related macular degeneration(AMD)development.Although the pathogenesis of this complex disease is poorly understood,sunlight exposure and smoking are major environmental risk factors associated with AMD.High-energy visible blue light(HEV;400-500 nm)is the most energetic and potentially harmful solar wavelengths reaching adults retina.On the other hand,RPE cells can be exposed to a large range of pollutants from cigarette smoke,with polycyclic aromatic hydrocarbons(PAH)being among the most toxic.Some PAH from cigarette smoke can absorb HEV light.This led us hypothesize that in RPE cells,the combination of PAH and HEV could synergize to exacerbate the stress caused by either factor alone.We thus investigate the combined effect of PAH and HEV light in RPE cells.Methods:Confluent RPE immortalized cells(ARPE19)were exposed to nanomolar concentrations of benzo[a]pyrene(BaP)or indeno[1,2,3-cd]pyrene(IcdP).While IcdP efficiently absorbs HEV wavelengths,BaP,the most studied PAH,does not significantly absorb HEV light and was used as a control.BaP or IcdP contaminated ARPE19 were then irradiated with increasing sub-lethal doses of HEV light(150-500 J/cm2)using a setup that mimics the light spectrum normally reaching the retina.Cytotoxicity,apoptosis and reactive oxygen species(ROS)generation were assessed in each condition.Results:In presence of low concentrations of IcdP,sub-lethal amounts of HEV light trigger,in a dose-dependent way,up to 70%of apoptotic cell death.Co-exposure to IcdP and HEV also leads to a synergistic ROS generation in ARPE19 cells,thus inducing oxidative stress.None of these effects were observed with BaP.Efficient inhibition of ROS production by specific antioxidants only decreases death by 20%in cells simultaneously exposed to both IcdP and HEV light.Conclusions:Low concentrations of IcdP synergize with HEV light to induce phototoxicity in ARPE19 cells.An increased oxidative stress results from the interaction between both agents and partially explains the enhanced HEV phototoxicity in IcdP contaminated ARPE19 cells.This suggests that another major mechanism is involved in the synergetic toxicity.For smokers,this synergy between HEV and PAH may accelerate RPE cells loss and contribute to their greater risk of developing AMD.
文摘This work presents the synthesis of a new hole-buffering material TAZS and its successful application in polymer light-emitting diodes to enhance device performance. The TAZS is composed of aromatic 1,2,4-triazolylcore linked with three trihydroxy tert-butyl terminals via azomethine linkages. The TAZS forms ashomogeneous film deposited by spin-coating process. The HOMO and LUMO levels of TAZS are -5.23 eV and -2.40 eV, respectively, as estimated from cyclic voltammogram. The current density results of hole-only and electron-only devices confirm strong hole-buffering capability of TAZS layer. Multilayer PLEDs with different thickness of TAZS (ITO/PEDOT: PSS/TAZS (x nm)/SY/ETL/LiF/Al) have been successfully fabricated, using spin-coating process to deposit hole-injecting PEDOT: PSS, TAZS, and emissive SY layers. The PLED with 16 nm TAZS reveals the optimal device performance, with maximum luminance and maximum current efficiency of 19,046 cd/m2 and 4.08 cd/A, respectively, surpassing those without TAZS as HBL (8484 cd/m2, 2.13 cd/A). The hole-buffering characteristic of TAZS contributes greatly to improved charges’ recombination ratio and enhanced emission efficiency.
基金supported by the Natural Science Foundation of China(Grant No.40972089),CNPC Innovation Fund(Grant No.07E1001)the State Key Laboratory of the Petroleum Resources and Prospecting(Grant No.PRPDX2008-01)
文摘Condensates and light oils are generally characterized by high maturity, low concentration of sterane and terpane biomarkers and low content of non-hydrocarbon fraction. As a result, some commonly-used sterane, terpane and carbazole migration parameters in conventional oil reservoirs may have a certain limitation in condensate and light oil reservoirs for their poor signal-noise ratios in the gas chromatography-mass spectrometry （GC-MS）. Naphthalene, phenanthrene and their methylated substituents, however, are present in significant concentrations in condensates and light oils. Taking the Fushan depression （in the Beibuwan Basin, Northern South China Sea） as an example, this paper attempts for the first time to use polycyclic aromatic hydrocarbon （PAH）-related parameters to trace migration directions and filling pathways for condensate and light oil reservoirs. The result shows that TMNr （i.e. 1, 3, 7-TMN/（1, 3, 7-TMN ＋ 1, 2, 5-TMN）, TMN： trimethylnaphthalene））, MPI-1 （i.e. 1.5×（2-MP ＋ 3-MP）/（P ＋ 1-MP ＋ 9-MP）, P： phenanthrene MP： methyiphenanthrene）, MN/DMN （∑methylnaphthalene/∑dimethylnaphthalene, %） and MN/TMN （∑nethylnaphthalene/∑trimethylna- phthalene, %） can be used to trace the filling pathways of condensate and light oil reservoirs. These parameters, together with geological consideration and other bulk oil properties （e.g. the gas to oil ratio and density）, suggest that the condensates and light oils in the Huachang oil and gas field are mainly sourced from the Bailian sag that is located to the northeast of the Huachang uplift in the Fushan depression.
文摘The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated.Physicochemical properties of the catalysts,such as the specific surface area,pore volume and acidity,etc.,were characterized to correlate with their aromatization performance data.The results showed that the pore structure of Al2O3 could significantly affect the catalyst performance.As the accessible pore diameter of the catalyst increased from 8.0 nm to 9.0 nm,the light aromatics yield increased by 2.7 percentage points,while the operating time of the catalyst nearly doubled.In addition,catalysts prepared with SiO2 and aluminum phosphate was more active and stable than that prepared with Al2O3,of which the light aromatics yield enhanced 6---8 percentage points and the rtm length,or seivice eife run length nearly doubled.
