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Hydrogen Production by Low-temperature Steam Reforming of Bio-oil over Ni/HZSM-5 Catalyst
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作者 仇松柏 宫璐 +3 位作者 刘璐 洪成贵 袁丽霞 李全新 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2011年第2期211-217,I0004,共8页
We investigated high catalytic activity of Ni/HZSM-5 catalysts synthesized by the impregnation method, which was successfully applied for low-temperature steam reforming of bio-oil. The influences of the catalyst comp... We investigated high catalytic activity of Ni/HZSM-5 catalysts synthesized by the impregnation method, which was successfully applied for low-temperature steam reforming of bio-oil. The influences of the catalyst composition, reforming temperature and the molar ratio of steam to carbon fed on the stream reforming process of bio-oil over the Ni/HZSM-5 catalysts were investigated in the reforming reactor. The promoting effects of current passing through the catalyst on the bio-oil reforming were also studied using the electrochemical catalytic reforming approach. By comparing Ni/HZSM-5 with commonly used Ni/Al2O3 catalysts, the Ni2O/ZSM catalyst with Ni-loading content of about 20% on the HZSM-5 support showed the highest catalytic activity. Even at 450 ℃, the hydrogen yield of about 90% with a near complete conversion of bio-oil was obtained using the Ni2O/ZSM catalyst. It was found that the performance of the bio-oil reforming was remarkably enhanced by the HZSM-5 supporter and the current through the catalyst. The features of the Ni/HZSM-5 catalysts were also investigated via X-ray diffraction, inductively coupled plasma and atomic emission spectroscopy, hydrogen temperature-programmed reduction, and Brunauer-Emmett-Teller methods. 展开更多
关键词 BIO-OIL HYDROGEN Steam reforming Ni/hzsm-5 catalyst
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响应面法优化Mn-Ce/HZSM-5催化氧化三氯乙烯 被引量:2
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作者 常甜 王宇 +2 位作者 赵作桐 胡锦超 沈振兴 《化工进展》 EI CAS CSCD 北大核心 2022年第11期5830-5842,共13页
三氯乙烯(TCE)是用途广泛的工业原料,其排放严重威胁着生态环境和人体健康。如何高效去除TCE成为亟待解决的关键问题。本文采用沉积-沉淀法制备了一系列不同Ce/Mn摩尔比的Mn-Ce/HZSM-5催化剂,用于催化去除TCE,并用响应面分析的方法探究... 三氯乙烯(TCE)是用途广泛的工业原料,其排放严重威胁着生态环境和人体健康。如何高效去除TCE成为亟待解决的关键问题。本文采用沉积-沉淀法制备了一系列不同Ce/Mn摩尔比的Mn-Ce/HZSM-5催化剂,用于催化去除TCE,并用响应面分析的方法探究不同因素对TCE催化氧化过程的影响。结果表明:Mn-Ce/HZSM-5催化剂对TCE有较好的催化活性,当Ce/Mn摩尔比为0.8时催化活性最高,主要归因于该催化剂较高的还原性和丰富的表面氧物种。另外,响应面分析结果表明:在Mn Ce_(0.8)/HZSM-5催化氧化TCE过程中,温度是影响TCE去除率和CO_(2)选择性的最关键因素,其次是流量和相对湿度(RH)。当气体流量为0.2L/min、温度为450℃、RH为16%时,最优TCE去除率为77.1%,CO_(2)选择性为70.0%,且Mn Ce_(0.8)/HZSM-5催化剂表现出较好的稳定性。研究结果为含氯挥发性有机物的去除提供了一种有效方法。 展开更多
关键词 mn-ce/hzsm-5催化剂 三氯乙烯 活性 响应面法 优化
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Preparation and Catalytic Application of Novel Water Tolerant Solid Acid Catalysts of Zirconium Sulfate/HZSM-5 被引量:11
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作者 JIANG Ya-jie JUAN Joon Ching +3 位作者 MENG Xiu-juan CAO Wei-liang YARMO Mohd Ambar ZHANG Jing-chang 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2007年第3期349-354,共6页
Esterification of acrylic acid(AA) to produce AA esters has widespread application in the chemical industry. A series of water tolerant solid acid catalysts was prepared, and characterized by XRD, nitrogen adsorptio... Esterification of acrylic acid(AA) to produce AA esters has widespread application in the chemical industry. A series of water tolerant solid acid catalysts was prepared, and characterized by XRD, nitrogen adsorption, TGA-DTA, XPS, and ammonia adsorption FTIR. The effects of Si/Al ratio, zirconium sulfate(ZS) loading on HZSM-5 and calcination temperature on the esterification were investigated. When 20% (mass fraction) ZS is loaded on HZSM-5, the conversion of AA reaches 100%. XRD analysis indicates that ZS is highly dispersed on HZSM-5 because no crystalline structure assigned to ZS is found. Catalytic activity and hydrophobicity of ZS supported on HZSM-5 are higher compared with those of parent ZS or HZSM-5. Results show that this kind of novel catalysts is an efficient water tolerant solid acid catalyst for esterification reactions. 展开更多
关键词 Solid acid catalyst Zirconium sulfate hzsm-5 Esterification reaction Water tolerant
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Effects of ZrO_2 on the Performance of CuO-ZnO-Al_2O_3/HZSM-5 Catalyst for Dimethyl Ether Synthesis from CO_2 Hydrogenation 被引量:13
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作者 Yanqiao Zhao Jixiang Chen Jiyan Zhang 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2007年第4期389-392,共4页
A series of composite catalysts were prepared by the wet mixing method, and the mass ratio of CuO-ZnO-Al2O3-ZrO2 component to HZSM-5 zeolite (molar ratio of SiO2 to Al2O3 being 25) was 2:1. The CuO-ZnO-Al2O3-ZrO2 ... A series of composite catalysts were prepared by the wet mixing method, and the mass ratio of CuO-ZnO-Al2O3-ZrO2 component to HZSM-5 zeolite (molar ratio of SiO2 to Al2O3 being 25) was 2:1. The CuO-ZnO-Al2O3-ZrO2 (CuO/ZnO/Al2O3=3/6/1 by weight) component was prepared by a modified 'two-step' co-precipitation method. The effects of ZrO2 on the performance of CuO-ZnO-Al2O3/HZSMo5 catalyst for dimethyl ether synthesis from CO2 hydrogenation were investigated. It was found that ZrO2 improved the properties of CuO-ZnO-Al2O3/HZSM-5 as a structural promoter. 展开更多
关键词 CuO-ZnO-Al2O3/hzsm-5 catalyst CO2 hydrogenation dimethyl ether ZIRCONIA
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Effects of Calcination Temperature on the Acidity and Catalytic Performances of HZSM-5 Zeolite Catalysts for the Catalytic Cracking of n-Butane 被引量:4
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作者 Jiangyin Lu Zhen Zhao Chunming Xu Aijun Duan Pu Zhang 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2005年第4期213-220,共8页
The acidic modulations of a series of HZSM-5 catalysts were successfully made by calcination at different treatment temperatures, i.e. 500, 600, 650, 700 and 800 ℃, respectively. The results indicated that the total ... The acidic modulations of a series of HZSM-5 catalysts were successfully made by calcination at different treatment temperatures, i.e. 500, 600, 650, 700 and 800 ℃, respectively. The results indicated that the total acid amounts, their density and the amount of B-type acid of HZSM-5 catalysts rapidly decreased, while the amounts of L-type acid had almost no change and thus the ratio of L/B was obviously enhanced with the increase of calcination temperature (excluding 800 ℃). The catalytic performances of modified HZSM-5 catalysts for the cracking of n-butane were also investigated. The main properties of these catalysts were characterized by means of XRD, N2 adsorption at low temperature, NH3-TPD, FTIR of pyridine adsorption and BET surface area measurements. The results showed that HZSM-5 zeolite pretreated at 800 ℃ had very low catalytic activity for n-butane cracking. In the calcination temperature range of 500-700 ℃, the total selectivity to olefins, propylene and butene were increased with the increase of calcination temperature, while, the selectivity for arene decreased with the calcination temperature. The HZSM-5 zeolite calcined at 700 ℃ produced light olefins with high yield, at the reaction temperature of 650 ℃ the yields of total olefins and ethylene were 52.8% and 29.4%, respectively. Besides, the more important role is that high calcination temperature treatment improved the duration stability of HZSM-5 zeolites. The effect of calcination temperature on the physico-chemical properties and catalytic performance of HZSM-5 for cracking of n-butane was explored. It was found that the calcination temperature had large effects on the surface area, crystallinity and acid properties of HZSM-5 catalyst, which further affected the catalytic performance for n-butane cracking. 展开更多
关键词 hzsm-5 zeolite catalyst acidic modification calcination temperature N-BUTANE catalytic cracking OLEFIN
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Low-temperature activation of methane over rare earth metals promoted Zn/HZSM-5 zeolite catalysts in the presence of ethylene 被引量:4
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作者 Hengqiang Zhang Aiguo Kong Yongjie Ding Chengyong Dai Yongkui Shan 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第3期243-248,共6页
At low temperature of 723 K, methane can be easily activated in the presence of ethylene in the feed, and converted to higher hydrocarbons (C2-C4) and aromatics (C6-C10), through its reaction over rare metals modi... At low temperature of 723 K, methane can be easily activated in the presence of ethylene in the feed, and converted to higher hydrocarbons (C2-C4) and aromatics (C6-C10), through its reaction over rare metals modified Zn/HZSM-5 zeolite catalysts without undesirable carbon oxides formation. Methane can get 37.3% conversion over the above catalysts under low temperature, and the catalysts show a longer lifetime than usual metal supported HZSM-5 zeolite catalysts without adding any rare earth metals. The effects of methane activation over various rare earth metal promoted Zn/HZSM-5 catalysts on the products and influences of several reaction conditions such as temperature, catalyst lifetime and molar ratio of CH4/C2H4 have been discussed. 展开更多
关键词 methane conversion hzsm-5 catalyst rare earth promoted
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Study on attrition of spherical-shaped Mo/HZSM-5 catalyst for methane dehydro-aromatization in a gas–solid fluidized bed 被引量:3
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作者 Xinzhuang Zhang Yunda Han +2 位作者 Dapeng Li Zhanguo Zhang Xiaoxun Ma 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第10期172-183,共12页
As a potential methane efficient conversion process,non-oxidative aromatization of methane in fluidized bed requires a catalyst with good attrition resistance,especially in the states of high temperature,longtime rapi... As a potential methane efficient conversion process,non-oxidative aromatization of methane in fluidized bed requires a catalyst with good attrition resistance,especially in the states of high temperature,longtime rapid movement and chemical reaction.Existing evaluation methods for attrition resistance,such as ASTM D5757 and Jet Cup test,are targeted for fresh catalysts at ambient temperature,which cannot well reflect the real process.In this study,spherical-shaped Mo/HZSM-5 catalyst prepared by dipping and spray drying was placed in a self-made apparatus for attrition testing,in which the catalyst attrition under different system temperatures,running time and process factors was investigated with percent mass loss(PML),particle size-mass distribution(PSMD)and scanning electron microscope(SEM).Carbon deposition on the catalyst before and after activation,aromatization and regeneration was analyzed by thermogravimetry(TG),and the attrited catalysts were evaluated for methane dehydro-aromatization(MDA).The results show that the surface abrasion and body breakage of catalyst particles occur continuously,with the increase of system temperature and running time,and make the PML rise gradually.The process factors of activation,aromatization and regeneration can cause the catalyst attrition and carbon deposits,which broaden the PSMD in varying degrees,and the carbon-substances on catalysts greatly improve their attrition resistance at high temperature.Catalyst attrition has a certain influence on its catalytic performance,and the main reasons point to particle breakage and fine powder escape. 展开更多
关键词 Attrition MO/hzsm-5 FLUIDIZED-BED catalyst activation Methane dehydro-aromatization
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Coking behaviors and kinetics on HZSM-5/SAPO-34 catalysts for conversion of ethanol to propylene 被引量:1
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作者 Ting Bai Xin Zhang +3 位作者 Feng Wang Wenting Qu Xiling Liu Chao Duan 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第3期545-552,共8页
The coke deposition on HZSM-5/SAPO-34 composite catalysts has been studied in the conversion of ethanol to propylene. The HZSM-5/SAPO-34 composite catalysts were synthesized by hydrothermal method(ZS-HS) and fully b... The coke deposition on HZSM-5/SAPO-34 composite catalysts has been studied in the conversion of ethanol to propylene. The HZSM-5/SAPO-34 composite catalysts were synthesized by hydrothermal method(ZS-HS) and fully blending(ZS-MM). The used catalysts were characterized by XRD, N;adsorption–desorption, TGA, TPO, elemental analysis, FTIR and XPS. The coking kinetics on both ZS-HS and ZS-MM has been investigated and their coking rate equations were obtained. The used ZS-MM catalyst had higher amount of coke and lower nC:nHthan the used ZS-HS. 90% of the coke was deposited in the micropores of ZS-HS, while almost 45% of the coke located in the micropores of ZS-MM. The coke deposited on ZS-HS catalyst was mainly graphite-like carbon species, whereas dehydrogenated coke species was the major on ZS-MM. The coking activation energy of ZS-MM was lower than that of ZS-HS, and the coking rate on ZS-MM was faster than on ZS-HS. In addition, the regeneration of ZS-MM catalyst showed that it had a good hydrothermal stability. The differences on coking behaviors on the two catalysts were due to their different acidic properties and textures. 展开更多
关键词 ETHANOL hzsm-5/SAPO-34 catalyst ACIDITY Coke Regeneration
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Catalytic kinetics of dimethyl ether one-step synthesis over CeO_2–CaO–Pd/HZSM-5 catalyst in sulfur-containing syngas process 被引量:1
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作者 Ruizhi Chu Wenxin Hou +4 位作者 Xianliang Meng Tingting Xu Zhenyong Miao Guoguang Wu Lei Bai 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第12期1735-1741,共7页
CeO_2–CaO–Pd/HZSM-5 catalyst was prepared for the dimethyl ether(DME) one-step synthesis in a continuous fixed-bed micro-reactor from the sulfur-containing syngas. The catalytic stability over hybrid catalyst of Ce... CeO_2–CaO–Pd/HZSM-5 catalyst was prepared for the dimethyl ether(DME) one-step synthesis in a continuous fixed-bed micro-reactor from the sulfur-containing syngas. The catalytic stability over hybrid catalyst of CeO_2–CaO–Pd/HZSM-5 was investigated to ensure that the kinetics experimental results were not significantly influenced by induction period and catalytic deactivation. A large number of kinetic data points(40 sets) were obtained over a range of temperature(240–300 °C), pressure(3–4 MPa), gas hourly space velocity(GHSV)(2000–3000 L·kg^(-1)·h^(-1)) and H_2/CO mole ratio(2–3). Kinetic model for the methanol synthesis reaction and the dehydration of methanol were obtained separately according to reaction mechanism and Langmuir–Hinshelwood mechanism. Regression parameters were investigated by the method combining the simplex method and Runge–Kutta method. The model calculations were in appropriate accordance with the experimental data. 展开更多
关键词 CeO_2–CaO –Pd/hzsm-5 catalyst DME One-step synthesis Catalytic kinetics Sulfur-containing syngas
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Effect of Binders on Aromatization Performance of HZSM-5 Catalyst
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作者 Chen Chunfang Yu Zhongwei +2 位作者 Ma Aizeng Wang Zijian Sun Yilan(SINOPEC Research Institute of Petroleum Processing,Beijing 100083) 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2011年第2期47-51,共5页
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 a... 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
关键词 hzsm-5 catalyst BINDER light hydrocarbon AROMATIZATION
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Study on the in situ desulfurization and viscosity reduction of heavy oil over MoO_(3)–ZrO_(2)/HZSM-5 catalyst
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作者 Rui-Qi Liu Li-Qiang Zhang +6 位作者 Hui-Da Pan Yi-Ya Wang Jin-Yu Li Xin-Wei Wang Zheng-Da Yang Xin-Lu Han Ri-Yi Lin 《Petroleum Science》 SCIE EI CAS CSCD 2023年第6期3887-3896,共10页
Heavy oil is characterized by high viscosity.High viscosity makes it challenging to recover and transport.HZSM-5,MoO_(3)/HZSM-5,ZrO_(2)/HZSM-5 and MoO_(3)–ZrO_(2)/HZSM-5 catalysts were developed to promote in situ de... Heavy oil is characterized by high viscosity.High viscosity makes it challenging to recover and transport.HZSM-5,MoO_(3)/HZSM-5,ZrO_(2)/HZSM-5 and MoO_(3)–ZrO_(2)/HZSM-5 catalysts were developed to promote in situ desulfurization and viscosity reduction of heavy oil.The physical and chemical properties of catalysts were characterized by XPS,XRD,TEM,NH3-TPD,etc.The effects of temperature,catalyst type and addition amount on viscosity and composition of heavy oil were evaluated.The results showed that the presence of MoO_(3)–ZrO_(2)/HZSM-5 nanoparticles during aquathermolysis could improve the oil quality by reducing the heavy fractions.It reduced viscosity by 82.56%after the reaction at 280℃ and catalyst addition of 1 wt%.The contents of resins and asphaltic in the oil samples were 5.69%lower than that in the crude oil.Sulfur content decreased from 1.45%to 1.03%.The concentration of H2S produced by the reaction was 2225 ppm.The contents of sulfur-containing functional groups sulfoxide and sulfone sulfur in the oil samples decreased by 19.92%after the catalytic reaction.The content of stable thiophene sulfur increased by 5.71%.This study provided a basis for understanding the mechanism of heavy oil desulfurization and viscosity reduction. 展开更多
关键词 Heavy oil Hydrothermal cracking MoO_(3)-ZrO_(2)/hzsm-5 catalyst DESULFURIZATION Viscosity reduction
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Formation of Methane and Ethylene in Methanol Conversion over HZSM-5 Catalyst
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作者 Bo Qing XU Juan LIANG Su Qin ZHAO Guo Quan CHEN (Dalian Institute of Chemical Physics.Dalian 116023) 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第7期583-586,共4页
Primary formation of methane and secondary formation of ethylene in methanol conversion are evidenced by temperature-programmed-surface- reaction of adsorbed methanol on HZSM-5 catalyst.A reaction mechanism accounts f... Primary formation of methane and secondary formation of ethylene in methanol conversion are evidenced by temperature-programmed-surface- reaction of adsorbed methanol on HZSM-5 catalyst.A reaction mechanism accounts for the observed results is described. 展开更多
关键词 THAN Formation of Methane and Ethylene in Methanol Conversion over hzsm-5 catalyst OVER
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Direct synthesis of hydrogen peroxide over Pd nanoparticles embedded between HZSM-5 nanosheets layers 被引量:3
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作者 Guozhu Liu Hairui Liang +2 位作者 Yajie Tian Bofeng Zhang Li Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2020年第10期2577-2586,共10页
Direct synthesis of hydrogen peroxide(DSHP)was studied over Pd loaded on HZSM-5 nanosheets(Pd/ZN).Pd nanoparticles with average size of ca.4.3 nm were introduced into the adjacent nanosheet layers(thickness of ca.2.9 ... Direct synthesis of hydrogen peroxide(DSHP)was studied over Pd loaded on HZSM-5 nanosheets(Pd/ZN).Pd nanoparticles with average size of ca.4.3 nm were introduced into the adjacent nanosheet layers(thickness of ca.2.9 nm)by impregnation method.Pd/ZN with theoretical Si/Al molar ratio of 25 showed the highest selectivity for H2O2 among the prepared catalysts,together with highest formation rate of H2O2(38.0 mmol·(g cat)^-1·h^-1),1.9 times than that of Pd supported on conventional HZSM-5 zeolite(Pd/CZ-50).Better catalytic performance of nanosheet catalysts was attributed to the promoted Pd dispersion which promoted H2 dissociation,more BrΦnsted acid sites and stronger metal-support interaction which inhibited the dissociation of O-O bond in H2O2.The embedded structure sufficiently protected the Pd nanoparticles by space confinement which restrained the Pd leaching,leading to a better catalytic stability with 90%activity retained after 3 cycles,which was almost 3 times than that of Pd/CZ-50(30.4%activity retained). 展开更多
关键词 hzsm-5 nanosheets Palladium catalyst Silica/alumina molar ratio Metal-support interaction Direct synthesis of hydrogen peroxide
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Improved ethane conversion to ethylene and aromatics over a Zn/ZSM-5 and CaMnO^(3-δ) composite catalyst
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作者 Yan Zhang Xia Xu Heqing Jiang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第12期161-166,共6页
Ethane conversion to ethylene and aromatics over Zn/zeolite catalysts is a promising technology for efficient exploitation of light alkanes. However, the reaction faces two major hurdles including the limited ethane c... Ethane conversion to ethylene and aromatics over Zn/zeolite catalysts is a promising technology for efficient exploitation of light alkanes. However, the reaction faces two major hurdles including the limited ethane conversion due to thermodynamics and the drastic catalyst deactivation by kinetical coke accumulation. Here we present a route to improve ethane conversion using a composite catalyst, involving Zn/HZSM-5 for ethane dehydroaromatization and CaMnO3-δperovskite for in situ selective hydrogen oxidation. The in situ H2 consumption shifts ethane dehydrogenation equilibrium to the desired side and can obviously increase the yield of target product. Furthermore, it is found that the in situ generated H2 O through H2 combustion can significantly suppress the coke formation and consequently enhance the stability of the composite catalyst. After 400 min reaction, a product yield of 23% was retained over the composite catalyst, almost a threefold increase with respect to the Zn/HZSM-5 reference(8%). It is anticipated that this novel composite catalyst combined with an efficient reactor technology may improve the viability of ethane aromatization in utilization. 展开更多
关键词 Ethane aromatization Composite catalyst Zn/hzsm-5 CaMnO^(3-δ) Hydrogen consumption
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Hydrogenation of CO_(2) to p-xylene over ZnZrO_(x)/hollow tubular HZSM-5 tandem catalyst
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作者 Haifeng Tian Zhiyu Chen +3 位作者 Haowei Huang Fei Zha Yue Chang Hongshan Chen 《Journal of Energy Chemistry》 SCIE EI CAS 2024年第12期725-737,共13页
The conversion of CO_(2) into specific aromatics by modulating the morphology of zeolites is a promising strategy.HZSM-5 zeolite with hollow tubular morphology is reported.The morphology of zeolite was precisely contr... The conversion of CO_(2) into specific aromatics by modulating the morphology of zeolites is a promising strategy.HZSM-5 zeolite with hollow tubular morphology is reported.The morphology of zeolite was precisely controlled,and the acid sites on its outer surface were passivated by steam-assisted crystallization method,so that the zeolite exhibits higher aromatic selectivity than sheet HZSM-5 zeolite and greater p-xylene selectivity than chain HZSM-5 zeolite.The tandem catalyst was formed by combining hollow tubular HZSM-5 zeolites with ZnZrO_(x)metal oxides.The para-selectivity of p-xylene reached 76.2%at reaction temperature of 320℃,pressure of 3.0 MPa,and a flow rate of 2400 mL g^(-1)h^(-1)with an H_(2)/CO_(2) molar ratio of 3/1.Further research indicates that the high selectivity of p-xylene is due to the pore structure of hollow tubular HZSM-5 zeolite,which is conducive to the formation of p-xylene.Moreover,the passivation of the acid site located on the outer surface of zeolite effectively prevents the isomerization of p-xylene.The reaction mechanism of CO_(2) hydrogenation over the tandem catalyst was investigated using in-situ diffuse reflectance Fourier transform infrared spectroscopy and density functional theory.The results showed that the CO_(2) to p-xylene followed a methanol-mediated route over ZnZrO_(x)/hollow tubular HZSM-5 tandem catalysts.In addition,the catalyst showed no significant deactivation in the 100 h stability test.This present study provides an effective strategy for the design of catalysts aimed at selectively preparing aromatics through CO_(2)hydrogenation. 展开更多
关键词 Hollow tubular hzsm-5 zeolite Tandem catalyst CO_(2)hydrogenation P-xylene Reaction mechanism
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Plastic upgrading via catalytic pyrolysis with combined metal-modified gallium-based HZSM-5 and MCM-41
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作者 Huaping Lin Likai Zhu +3 位作者 Ye Liu Vasilevich Sergey Vladimirovich Bilainu Oboirien Yefeng Zhou 《Frontiers of Chemical Science and Engineering》 SCIE EI 2024年第11期179-191,共13页
Currently,the conversion of waste plastics into high-value products via catalytic pyrolysis enables the advancement of plastics’open-loop recycling.However,enhancing selectivity remains a critical challenge.This stud... Currently,the conversion of waste plastics into high-value products via catalytic pyrolysis enables the advancement of plastics’open-loop recycling.However,enhancing selectivity remains a critical challenge.This study introduces a novel approach to catalytic pyrolysis,utilizing a combination of MCM-41 and modified gallium-based HZSM-5 catalysts,to achieve exceptional selectivity for aromatic liquid-phase products from linear low-density polyethylene.Firstly,to enhance the probability of dehydroaromatization optimization,the type and proportion of metal active sites within the HZSM-5 catalyst are fine-tuned,which would establish equilibrium with acid sites,resulting in a remarkable 15.72%increase in the selectivity of aromatic hydrocarbons.Secondly,to enhance the accessibility of volatiles to active sites,mesoporous MCM-41 with cracking capabilities is introduced.The doping ratio of MCM-41 is meticulously controlled to facilitate the diffusion of cracked volatiles to the active centers of modified gallium-based HZSM-5,enabling efficient reforming reactions.Experimental findings demonstrate that MCM-41 significantly enhances the dehydroaromatization activity of the modified gallium-based HZSM-5 catalyst.Under the influence of MCM-41:Zr_(2)Ga_(3)/HZSM-5=1:2 catalyst,the selectivity for aromatic hydrocarbons reaches an impressive 93.11%,with a notable 60.01%selectivity for benzene,toluene,ethylbenzene,and xylene.Lastly,this study proposes a plausible pathway for the generation of high-value aromatic hydrocarbons using the combined catalyst. 展开更多
关键词 polyethylene pyrolysis aromatic hydrocarbons bimetal catalyst hzsm-5 MCM-41
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Catalyst activity comparison of alcohols over zeolites
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作者 Karthikeyan K. Ramasamy Yong Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2013年第1期65-71,共7页
Alcohol transformation to transportation fuel-range hydrocarbon over HZSM-5 (SIO2/A1203 = 30) catalyst was studied at 360 C and 300 psig. Product distributions and catalyst life were compared between methanol, ethan... Alcohol transformation to transportation fuel-range hydrocarbon over HZSM-5 (SIO2/A1203 = 30) catalyst was studied at 360 C and 300 psig. Product distributions and catalyst life were compared between methanol, ethanol, 1-propanol and 1-butanol as a feed. The catalyst life for 1-propanol and l-butanol was more than double compared with that for methanol and ethanol. For all the alcohols studied, the product distributions (classified to paraffin, olefin, naphthene, aromatic and naphthalene compounds) varied with time on stream (TOS). At 24 h TOS, liquid product from 1-propanol and 1-butanol transformation primarily contains higher olefin compounds. The alcohol transformation process to higher hydrocarbon involves a complex set of reaction pathways such as dehydration, oligomerization, dehydrocyclization and hydrogenation. Compared with ethylene generated from methanol and ethanol, oligomerization of propylene and butylene has a lower activation energy and can readily take place on weaker acidic sites. On the other hand, dehydrocyclization of the oligomerized products of propylene and butylene to form the cyclic compounds requires the sites with stronger acid strength. Combination of the above mentioned reasons are the primary reasons for olefin rich product generated in the later stage of the time on stream and for the extended catalyst life time for 1-propanol and 1-butanol compared with methanol and ethanol conversion over HZSM-5. 展开更多
关键词 ZEOLITE hzsm-5 alcohol conversion catalyst activity hydrocarbons
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Development of catalysts for direct non-oxidative methane aromatization
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作者 Yuji Ogawa Yuebing Xu +2 位作者 Zhanguo Zhang Hongtao Ma Yo Yamamoto 《Resources Chemicals and Materials》 2022年第1期80-92,共13页
Direct catalytic conversion of methane to benzene at non-oxidative condition is considered as one of key reac-tions for constitution of sustainable carbon-cycling processes,since either biomethane or CO_(2)-based synt... Direct catalytic conversion of methane to benzene at non-oxidative condition is considered as one of key reac-tions for constitution of sustainable carbon-cycling processes,since either biomethane or CO_(2)-based synthetic methane can serve as its feed source.While this concern may motivate many researchers over the world to make their continuous effort to gain deep insight into the catalytic mechanism of this catalysis system and the essential cause of the catalyst deactivation,successful development of a catalyst with high performance,enhanced coking resistance and long-term operating stability will be the key to its industrial application.Here in this review pa-per,we demonstrate the high catalytic activity and stability of our two shaped Mo/HZSM-5 catalysts developed respectively for fixed-bed and fluidized-bed operations at severe reaction conditions.Thermodynamically,a pos-sibly high aromatization temperature is required to attain a desired high benzene formation rate,but adopting such a temperature will certainly accelerate coke formation and catalyst deactivation.Therefore,the focus of the catalyst development was laid on finding various effective ways of suppressing coke accumulation and catalyst deactivation at practically required severe reaction conditions,and much effort was made to attain the purpose.As a result,a highly active and selective pelleted Mo/HZSM-5 catalyst has been successfully developed and was stably run in a fixed-bed reactor under cyclic regeneration operation mode over 1000 h.In parallel a binder-free,fluidizable Mo/HZSM-5 catalyst with certain mechanical strength has also been developed and successfully tested in a dual circulating fluidized-bed reactor system to provide a stable benzene yield of about 12%at 1073 K and 3000 ml/g/h space velocity. 展开更多
关键词 Methane dehydroaromatization Methane to benzene(MTB)Mo/hzsm-5 catalyst development Fixed-bed reactor Fluidized-bed reactor
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Effect of Phosphoric Acid on HZSM-5 Catalysts for Prins Condensation to Isoprene from Isobutylene and Formaldehyde 被引量:1
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作者 YU Xue ZHANG Yuewei +4 位作者 LIU Bing MA Huiyong WANG Yan BAO Qiang WANG Zhenlu 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2018年第3期485-489,共5页
A series of HZSM-5 zeolites modified with different amounts of phosphoric acid(P/HZSM-5) was prepared. The physicochemical features of the P/HZSM-5 catalysts were characterized via X-ray diffraction(XRD), N2 adsor... A series of HZSM-5 zeolites modified with different amounts of phosphoric acid(P/HZSM-5) was prepared. The physicochemical features of the P/HZSM-5 catalysts were characterized via X-ray diffraction(XRD), N2 adsorption-desorption, NH3-temperatttre programmed desorption(NH3-TPD) and Fourier tranform infrared(FTIR) spectra of the adsorbed pyridine, and the performances of the catalysts for Prins condensation to isoprene from isobutylene and formaldehyde were investigated. The maximum isobutene conversion and isoprene selectivity were 10.3% and 94.6% on the HZSM-5 catalyst with a Si/A1 molar ratio of 600 using 5%(mass fraction) phosphoric acid. The phosphoric acid modification not only modulated the amount of acidic sites but also regulated the acid type. An appropriate amount of weak Lewis and Bronsted acid sites served as the active sites for the condensation of isobutene with formaldehyde, and the strong acid sites could cause side reactions and coke deposition. 展开更多
关键词 ISOBUTYLENE ISOPRENE FORMALDEHYDE hzsm-5 catalyst Phosphoric acid modification
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Two-step fast microwave-assisted pyrolysis of biomass for bio-oil production using microwave absorbent and HZSM-5 catalyst 被引量:3
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作者 Bo Zhang Zhaoping Zhong +2 位作者 Qinglong Xie Shiyu Liu Roger Ruan 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2016年第7期240-247,共8页
A novel technology of two-step fast microwave-assisted pyrolysis(f MAP) of corn stover for bio-oil production was investigated in the presence of microwave absorbent(Si C) and HZSM-5catalyst. Effects of f MAP temp... A novel technology of two-step fast microwave-assisted pyrolysis(f MAP) of corn stover for bio-oil production was investigated in the presence of microwave absorbent(Si C) and HZSM-5catalyst. Effects of f MAP temperature and catalyst-to-biomass ratio on bio-oil yield and chemical components were examined. The results showed that this technology, employing microwave, microwave absorbent and HZSM-5 catalyst, was effective and promising for biomass fast pyrolysis. The f MAP temperature of 500°C was considered the optimum condition for maximum yield and best quality of bio-oil. Besides, the bio-oil yield decreased linearly and the chemical components in bio-oil were improved sequentially with the increase of catalyst-to-biomass ratio from 1:100 to 1:20. The elemental compositions of bio-char were also determined. Additionally, compared to one-step f MAP process, two-step f MAP could promote the bio-oil quality with a smaller catalyst-to-biomass ratio. 展开更多
关键词 Two-step Microwave Pyrolysis hzsm-5 zeolite catalyst Catalytic upgrading
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