Carbon deposition during methanol to hydrocarbons leads to the quick deactivation of ZSM-5 catalyst and it is one of the major problems for this technology. Decreasing the crystal size or introducing mesopores into ZS...Carbon deposition during methanol to hydrocarbons leads to the quick deactivation of ZSM-5 catalyst and it is one of the major problems for this technology. Decreasing the crystal size or introducing mesopores into ZSM-5 zeolites can improve its diffusion property and decrease the coke formation. In this paper, nano-sized ZSM-5 zeolite with intercrystalline mesopores combining the mesoporous and nano sized structure was fabricated. For comparison, the mesoporous ZSM-5 and nano-sized ZSM-5 were also prepared. These catalyst samples were characterized by XRD, BET, NH3-TPD, TEM, Py-IR and TG techniques and used on the conversion of methanol to gasoline in a fixed-bed reactor at T=405 degrees C, WHSV =4.74 h(-1) and P=1.0 MPa. It was found that the external surface area of the nano-sized ZSM-5 zeolite with intercrystalline mesopores reached 104 m(2)/g, larger than that of mesoporous ZSM-5 (66 m(2)/g) and nano sized ZSM-5 (76 m(2)/g). Catalytic lifetime of the nano-sized ZSM-5 zeolite with intercrystalline mesopores was 93 h, which was only longer than that of mesoporous ZSM-5 (86 h), but shorter than that of nano sized ZSM-5 (104 h). Strong acidity promoted the coke formation and thus decreased the catalytic lifetime of the nano-sized ZSM-5 zeolite with intercrystalline mesopores though it presented large external surface that could improve the diffusion property. The special zeolite catalyst was further dealuminated to decrease the strong acidity. After this, its coke formation rate was slowed and catalytic lifetime was prolonged to 106 h because of the large external surface area and decreased weak acidity. This special structural zeolite is a potential catalyst for methanol to gasoline reaction. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
Methanol to gasoline reaction was investigated on two prepared ZSM-5 catalysts. The first one was a conventional catalyst denoted as ZSM-5(C) and the other was a hierarchical catalyst-ZSM-5(S) which was prepared b...Methanol to gasoline reaction was investigated on two prepared ZSM-5 catalysts. The first one was a conventional catalyst denoted as ZSM-5(C) and the other was a hierarchical catalyst-ZSM-5(S) which was prepared by incorporation of table sugar in catalyst gel during the synthesis procedure. The catalysts were characterized by FTIR, XRD, FE-SEM, N2 adsorption-desorption, NH3-TPD and TGA analytical technics. The proposed material showed pore modification as well as acidity moderating properties in ZSM-5 catalyst. The methanol to gasoline reaction was conducted in a fixed bed reactor with a WHSV of 1.5 h-1.Methanol conversions, gasoline yield and selectivity in production for the synthesized catalysts were determined by gas chromatography method. The sugar modified catalyst converted more methanol than the conventional one and an enhancement in catalyst’s life time was observed. The selectivity to aromatics and durene were reduced compared to the conventional catalyst, so the gasoline quality was also further improved. The coking rate of catalysts was calculated employing TGA method. A reduction in coking rate and an increase in coke capacity of the modified catalyst were observed.展开更多
The methanol-to-gasoline (MTG) process is an efficient way to produce liquidfuel. The academic basis of the coal-to-liquid process is described and two different synthesis processes are focused on: Fixed MTG process a...The methanol-to-gasoline (MTG) process is an efficient way to produce liquidfuel. The academic basis of the coal-to-liquid process is described and two different synthesis processes are focused on: Fixed MTG process and Fluid Bed MTG process. Then,the superiority of the Fluid Bed MTG Process is pointed out relative to the Fixed MTGProcess. In addition, the development of the coal-to-liquid technique in China is brieflysummarized.展开更多
ZSM-5 aggregates consisting of superfine and hierarchical nanocrystals(combined with micropores and intra-crystalline mesopores) with an average size of 30 nm were prepared through one-pot synthesis with the assistanc...ZSM-5 aggregates consisting of superfine and hierarchical nanocrystals(combined with micropores and intra-crystalline mesopores) with an average size of 30 nm were prepared through one-pot synthesis with the assistance of anionic polyacrylamide(APAM). The resultant zeolites(AHN-ZSM-5) were characterized by XRD, ICP-OES, SEM, TEM, BET, NH_3-TPD, Py-IR, and TG analyses and evaluated in the methanol to gasoline(MTG) reaction. Characterization results show that the hierarchical ZSM-5 aggregates possessed two kinds of mesopores, namely inter-and intra-crystalline mesopores. The amount of APAM considerably influenced the mesoporosity and textural properties of AHN-ZSM-5 zeolites. With the addition of APAM in the synthesis, the AHN-ZSM-5 zeolites exhibited large mesopore volume, large external surface area, and appropriate acidity. When applied in the MTG reaction, AHN-ZSM-5 demonstrated a catalytic lifetime that was 1.6 times longer than that of conventional ZSM-5 synthesized in the absence of APAM.展开更多
Increasing global interest in methanoi fuel has led us to investigate the exhaust emissionsof its engine. Analysis of its inorganic and organic emissions. such as CO. NO_x and hydrocarbons(total HC) have been widely r...Increasing global interest in methanoi fuel has led us to investigate the exhaust emissionsof its engine. Analysis of its inorganic and organic emissions. such as CO. NO_x and hydrocarbons(total HC) have been widely reported. This paper presents an analysis of more than 20 kinds ofhydrocarbons in the emissions obtained from a spark-ignition Shanghai car running 85# gasoline anda comparison with emission from a Santana test car running M-100 methanol fuel. A set ofenrichment method has also been described. Test results show that at the current stage of methanolengine development the concentration of individual hydrocarbon including some poisonous substancesis lower than those of normal gasoline engine.展开更多
通过向合成ZSM-5分子筛的初始凝胶中加入Fenton试剂作为羟基自由基(·OH)引发剂,在90℃下合成了系列不同晶化时间的超细纳米ZSM-5分子筛(NZ5-Fx)。作为对比,采用传统模板法在170℃下晶化合成了纳米ZSM-5分子筛(NZ5-T)。采用XRD、SEM...通过向合成ZSM-5分子筛的初始凝胶中加入Fenton试剂作为羟基自由基(·OH)引发剂,在90℃下合成了系列不同晶化时间的超细纳米ZSM-5分子筛(NZ5-Fx)。作为对比,采用传统模板法在170℃下晶化合成了纳米ZSM-5分子筛(NZ5-T)。采用XRD、SEM、TEM、N_(2)物理吸附、^(29)Si MAS NMR、^(27)Al MAS NMR、EPR、NH_(3)-TPD和Py-IR等方法对分子筛进行了表征,并研究了·OH的引入对所合成的NZ5-Fx系列ZSM-5分子筛的物化性质及甲醇制汽油(MTG)催化反应性能的影响。结果表明,与样品NZ5-T相比,·OH促进下低温合成的NZ5-Fx系列ZSM-5分子筛具有更小的晶粒尺寸、更大的介孔孔容,位于孔道交叉处的骨架Al原子所占的比例更高,而且具有更加温和的酸性,在催化MTG反应中表现出更异优的催化性能。以纳米ZSM-5分子筛样品NZ5-F12d为MTG反应的催化剂,甲醇转化率为96.2%时,汽油的选择性高达66.5%。展开更多
基金the Science and Technology Foundation Platform Construction Project of Shanxi Province(No.2015091009)the National Science Foundation for Young Scientists of China(No.21606160)+1 种基金the Qualified Personnel Foundation of Taiyuan University of Technology(No.tyut-rc201454a)School Fund of Taiyuan University of Technology(Nos.1205-04020202 and 1205-04020102)
文摘Carbon deposition during methanol to hydrocarbons leads to the quick deactivation of ZSM-5 catalyst and it is one of the major problems for this technology. Decreasing the crystal size or introducing mesopores into ZSM-5 zeolites can improve its diffusion property and decrease the coke formation. In this paper, nano-sized ZSM-5 zeolite with intercrystalline mesopores combining the mesoporous and nano sized structure was fabricated. For comparison, the mesoporous ZSM-5 and nano-sized ZSM-5 were also prepared. These catalyst samples were characterized by XRD, BET, NH3-TPD, TEM, Py-IR and TG techniques and used on the conversion of methanol to gasoline in a fixed-bed reactor at T=405 degrees C, WHSV =4.74 h(-1) and P=1.0 MPa. It was found that the external surface area of the nano-sized ZSM-5 zeolite with intercrystalline mesopores reached 104 m(2)/g, larger than that of mesoporous ZSM-5 (66 m(2)/g) and nano sized ZSM-5 (76 m(2)/g). Catalytic lifetime of the nano-sized ZSM-5 zeolite with intercrystalline mesopores was 93 h, which was only longer than that of mesoporous ZSM-5 (86 h), but shorter than that of nano sized ZSM-5 (104 h). Strong acidity promoted the coke formation and thus decreased the catalytic lifetime of the nano-sized ZSM-5 zeolite with intercrystalline mesopores though it presented large external surface that could improve the diffusion property. The special zeolite catalyst was further dealuminated to decrease the strong acidity. After this, its coke formation rate was slowed and catalytic lifetime was prolonged to 106 h because of the large external surface area and decreased weak acidity. This special structural zeolite is a potential catalyst for methanol to gasoline reaction. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金the Petrochemical Research and Technology Company, Tehran, Iran for financial support of this research
文摘Methanol to gasoline reaction was investigated on two prepared ZSM-5 catalysts. The first one was a conventional catalyst denoted as ZSM-5(C) and the other was a hierarchical catalyst-ZSM-5(S) which was prepared by incorporation of table sugar in catalyst gel during the synthesis procedure. The catalysts were characterized by FTIR, XRD, FE-SEM, N2 adsorption-desorption, NH3-TPD and TGA analytical technics. The proposed material showed pore modification as well as acidity moderating properties in ZSM-5 catalyst. The methanol to gasoline reaction was conducted in a fixed bed reactor with a WHSV of 1.5 h-1.Methanol conversions, gasoline yield and selectivity in production for the synthesized catalysts were determined by gas chromatography method. The sugar modified catalyst converted more methanol than the conventional one and an enhancement in catalyst’s life time was observed. The selectivity to aromatics and durene were reduced compared to the conventional catalyst, so the gasoline quality was also further improved. The coking rate of catalysts was calculated employing TGA method. A reduction in coking rate and an increase in coke capacity of the modified catalyst were observed.
文摘The methanol-to-gasoline (MTG) process is an efficient way to produce liquidfuel. The academic basis of the coal-to-liquid process is described and two different synthesis processes are focused on: Fixed MTG process and Fluid Bed MTG process. Then,the superiority of the Fluid Bed MTG Process is pointed out relative to the Fixed MTGProcess. In addition, the development of the coal-to-liquid technique in China is brieflysummarized.
基金supported by the National Natural Science Foundation of China (No. 21276183)
文摘ZSM-5 aggregates consisting of superfine and hierarchical nanocrystals(combined with micropores and intra-crystalline mesopores) with an average size of 30 nm were prepared through one-pot synthesis with the assistance of anionic polyacrylamide(APAM). The resultant zeolites(AHN-ZSM-5) were characterized by XRD, ICP-OES, SEM, TEM, BET, NH_3-TPD, Py-IR, and TG analyses and evaluated in the methanol to gasoline(MTG) reaction. Characterization results show that the hierarchical ZSM-5 aggregates possessed two kinds of mesopores, namely inter-and intra-crystalline mesopores. The amount of APAM considerably influenced the mesoporosity and textural properties of AHN-ZSM-5 zeolites. With the addition of APAM in the synthesis, the AHN-ZSM-5 zeolites exhibited large mesopore volume, large external surface area, and appropriate acidity. When applied in the MTG reaction, AHN-ZSM-5 demonstrated a catalytic lifetime that was 1.6 times longer than that of conventional ZSM-5 synthesized in the absence of APAM.
文摘Increasing global interest in methanoi fuel has led us to investigate the exhaust emissionsof its engine. Analysis of its inorganic and organic emissions. such as CO. NO_x and hydrocarbons(total HC) have been widely reported. This paper presents an analysis of more than 20 kinds ofhydrocarbons in the emissions obtained from a spark-ignition Shanghai car running 85# gasoline anda comparison with emission from a Santana test car running M-100 methanol fuel. A set ofenrichment method has also been described. Test results show that at the current stage of methanolengine development the concentration of individual hydrocarbon including some poisonous substancesis lower than those of normal gasoline engine.
文摘通过向合成ZSM-5分子筛的初始凝胶中加入Fenton试剂作为羟基自由基(·OH)引发剂,在90℃下合成了系列不同晶化时间的超细纳米ZSM-5分子筛(NZ5-Fx)。作为对比,采用传统模板法在170℃下晶化合成了纳米ZSM-5分子筛(NZ5-T)。采用XRD、SEM、TEM、N_(2)物理吸附、^(29)Si MAS NMR、^(27)Al MAS NMR、EPR、NH_(3)-TPD和Py-IR等方法对分子筛进行了表征,并研究了·OH的引入对所合成的NZ5-Fx系列ZSM-5分子筛的物化性质及甲醇制汽油(MTG)催化反应性能的影响。结果表明,与样品NZ5-T相比,·OH促进下低温合成的NZ5-Fx系列ZSM-5分子筛具有更小的晶粒尺寸、更大的介孔孔容,位于孔道交叉处的骨架Al原子所占的比例更高,而且具有更加温和的酸性,在催化MTG反应中表现出更异优的催化性能。以纳米ZSM-5分子筛样品NZ5-F12d为MTG反应的催化剂,甲醇转化率为96.2%时,汽油的选择性高达66.5%。