t-ZrO_2/SAPO-34质量比对t-ZrO_2/SAPO-34复合催化剂物化性质及其甲醇制烯烃催化性能的影响
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摘要
采用介孔t-ZrO_2对微孔SAPO-34分子筛进行复合改性,利用水热包覆技术制备了t-ZrO_2/SAPO-34复合催化剂,研究了t-ZrO_2/SAPO-34质量比(m(t-ZrO_2)/m(SAPO-34))对复合催化剂物化性质和甲醇制烯烃(MTO)催化性能的影响。采用X射线衍射(XRD)、傅里叶红外光谱(FT-IR)、扫描电子显微镜(SEM)、程序升温脱附(NH_3-TPD)和N_2吸附-脱附(BET)等手段对不同复合催化剂的晶相组成、骨架结构、微观形貌、表面酸性及孔结构进行分析表征。结果表明,m(t-ZrO_2)/m(SAPO-34)对t-ZrO_2/SAPO-34复合催化剂的物化性质和催化性能影响较大。过高或过低m(t-ZrO_2)/m(SAPO-34)制得的复合催化剂中SAPO-34分子筛结晶度和骨架结构特征均有所减弱,分别呈现以介孔为主和以微孔为主的孔结构特征;当m(t-ZrO_2)/m(SAPO-34)为1/1时,制得的复合催化剂形成了包覆相结构和微-介孔层级结构(微孔比表面积113 m~2/g,介孔比表面积176 m~2/g,总比表面积289 m~2/g,总孔体积0.19cm~3/g),总酸量较大(0.344mmol/g);在常压、反应温度380℃、N_2流速20mL/min、进料空速2h~(-)的MTO反应条件下,复合催化剂表现出优越的催化性能、稳定性及反应寿命,甲醇转化率和低碳烯烃选择性分别达到100%和90.54%,催化寿命达到1130min,与单一SAPO-34分子筛相比,催化寿命延长了768min。
Microporous SAPO-34 molecular sieves were promoted by using mesoporous t-ZrO_2 to prepare t-ZrO_2/SAPO-34 composite catalysts.The effects of mass ratio of t-ZrO_2 to SAPO-34 on the physicochemical properties and catalytic performance of the composite catalyst fabricated via hydrothermal coating route in methanol-to-olefin(MTO)process were investigated.These catalysts were extensively characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),temperature programmed desorption(NH_3-TPD)and N_2 adsorption-desorption(BET)techniques,to investigate their crystalline phase,skeletal structure,morphology,surface acidity and pore structure,respectively.Results indicate that various mass ratios of t-ZrO_2 to SAPO-34 significantly impact on the physicochemical properties and catalytic performance of t-ZrO_2/SAPO-34 composite catalyst in MTO process.The crystallinity and skeleton characteristics of SAPO-34 molecular sieve in composite catalyst are significantly weakened when the mass ratio of t-ZrO_2 to SAPO-34 becomes higher or lower.As the mass ratio of 1/1,the uniformly continuous coating phase and hierarchical structure(microporous specific surface area of 113m~2/g,mesoporous specific surface area of 176m~2/g,total specific surface area of 289m~2/g,the total pore volume of 0.19cm~3/g)with total amount of acid of 0.344 mmol/g are successfully obtained in the composite catalyst,which exhibits excellent catalytic performances,stability and reaction life with methanol conversion of 100%,light olefins selectivity of 90.54%,and catalytic lifetime of 1130 min under the conditions of atmospheric pressure,reaction temperature of 380 ℃,nitrogen flow rate of 20 mL/min and feed speed of 2h~(-1).Compared with the single SAPO-34 molecular sieve,the catalytic lifetime of the t-ZrO_2/SAPO-34 composite catalyst is extended by 768 min.
Microporous SAPO-34 molecular sieves were promoted by using mesoporous t-ZrO_2 to prepare t-ZrO_2/SAPO-34 composite catalysts.The effects of mass ratio of t-ZrO_2 to SAPO-34 on the physicochemical properties and catalytic performance of the composite catalyst fabricated via hydrothermal coating route in methanol-to-olefin(MTO)process were investigated.These catalysts were extensively characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),temperature programmed desorption(NH_3-TPD)and N_2 adsorption-desorption(BET)techniques,to investigate their crystalline phase,skeletal structure,morphology,surface acidity and pore structure,respectively.Results indicate that various mass ratios of t-ZrO_2 to SAPO-34 significantly impact on the physicochemical properties and catalytic performance of t-ZrO_2/SAPO-34 composite catalyst in MTO process.The crystallinity and skeleton characteristics of SAPO-34 molecular sieve in composite catalyst are significantly weakened when the mass ratio of t-ZrO_2 to SAPO-34 becomes higher or lower.As the mass ratio of 1/1,the uniformly continuous coating phase and hierarchical structure(microporous specific surface area of 113m~2/g,mesoporous specific surface area of 176m~2/g,total specific surface area of 289m~2/g,the total pore volume of 0.19cm~3/g)with total amount of acid of 0.344 mmol/g are successfully obtained in the composite catalyst,which exhibits excellent catalytic performances,stability and reaction life with methanol conversion of 100%,light olefins selectivity of 90.54%,and catalytic lifetime of 1130 min under the conditions of atmospheric pressure,reaction temperature of 380 ℃,nitrogen flow rate of 20 mL/min and feed speed of 2h~(-1).Compared with the single SAPO-34 molecular sieve,the catalytic lifetime of the t-ZrO_2/SAPO-34 composite catalyst is extended by 768 min.
引文
[1]WANG Y,JIAN G,PENG Z,et al.Preparation and application of Ba/ZSM-5 zeolite for reaction of methylvinyl ether and methanol[J].Catalysis Communications,2015,66(128):34-37.
[2]CHAE H J,SONG Y H,JEONG K E,et al.Physicochemical characteristics of ZSM-5/SAPO-34composite catalyst for MTO reaction[J].Journal of Physics&Chemistry of Solids,2010,71(4):600-603.
[3]JANG H G,MIN H K,LEE J K,et al.SAPO-34 and ZSM-5nanocrystals’size effects on their catalysis of methanol-to-olefin reactions[J].Applied Catalysis A:General,2012,437-438:120-130.
[4]何长青,刘中民,蔡光宇,等.双模板法控制SAPO-34分子筛的晶粒尺寸[J].分子催化,1994,8(3):207-212.(HE Changqing,LIU Zhongmin,CAI Guangyu,et al.Dual mode plate method controls the grain size of SAPO-34zeolite[J].Molecular Catalysis,1994,8(3):207-212.)
[5]YING L,YE M,CHENG Y W,et al.Characteristics of coke deposition over a SAPO-34 catalyst in the methanol-to-olefins reaction[J].Petroleum Science&Technology,2015,33(9):984-991.
[6]WANG C.Dual template-directed synthesis of SAPO-34 nanosheet assemblies with improved stability in the methanol to olefins reaction[J].J Mater Chem A,2015,3(10):5608-5616.
[7]SERRANO D P,ESCOLA J M,PIZARRO P.Synthesis strategies in the search for hierarchical zeolites[J].Chemical Society Reviews,2014,44(29):4004-4035.
[8]WANG F,SUN L,CHEN C,et al.Polyethyleneimine templated synthesis of hierarchical SAPO-34 zeolites with uniform mesopores[J].Rsc Advances,2014,4(86):46093-46096.
[9]LOPEZ-OROZCO S,INAYAT A,SCHWAB A,et al.Zeolitic materials with hierarchical porous structures[J].Advanced Materials,2015,23(22-23):2602-2615.
[10]ZHIBIN L,JOAQUIN M T,PATRICIA C,et al.Methanol to olefins:Activity and stability of nanosized SAPO-34molecular sieves and control of selectivity by silicon distribution[J].Physical Chemistry Chemical Physics,2013,15(35):14670-14680.
[11]ASKARI S,SEDIGHI Z,HALLADJ R.Rapid synthesis of SAPO-34nanocatalyst by dry gel conversion method templated with morphline:Investigating the effects of experimental parameters[J].Microporous&Mesoporous Materials,2014,197(10):229-236.
[12]AGHAEI E,HAGHIGHI M.Effect of crystallization time on properties and catalytic performance of nanostructured SAPO-34 molecular sieve synthesized at high temperatures for conversion of methanol to light olefins[J].Powder Technology,2015,269:358-370.
[13]HEYDEN H V,MINTOVA S,BEIN T.Nanosized SAPO-34 synthesized from colloidal solutions[J].Chemistry of Materials,2008,20(9):2956-2963.
[14]MIAO Y,PENG T,CHAN W,et al.A top-down approach to prepare silicoaluminophosphate molecular sieve nanocrystals with improved catalytic activity[J].Chemical Communications,2014,50(15):1845-1847.
[15]HAJIASHRAFI T,KHARAT A N,DAUTH A,et al.Preparation and characterization of lanthanide modified SAPO-34 nano catalysts and measurement of their activity for methanol to olefin conversion[J].Reaction Kinetics Mechanisms&Catalysis,2014,113(2):585-603.
[16]OBRZUT D L,ADEKKANATTU P M,THUNDIMADATHIL J,et al.Reducing methane formation in methanol to olefins reaction on metal impregnated SAPO-34 molecular sieve[J].Reaction Kinetics&Catalysis Letters,2003,80(1):113-121.
[17]WANG K,CAO G,KENNEDY G J,et al.Pore modification of H-SAPO-34 using dialkyl zinc:Structural characterization and reaction pathway[J].Journal of Physical Chemistry C,2011,115(38):18611-18617.
[18]XI D Y,SUN Q M,XU J,et al.In situ growth-etching approach to the preparation of hierarchically macroporous zeolites with high MTO catalytic activity and selectivity[J].Journal of Materials Chemistry A,2014,2(42):17994-18004.
[19]PAJAIE H S,TAGHIZADEH M.Optimization of nano-sized SAPO-34 synthesis in methanol-to-olefin reaction by response surface methodology[J].Journal of Industrial and Engineering Chemistry,2015,24:59-70.
[20]VARZANEH A Z,TOWFIGHI J,SAHEBDELFAR S.Carbon nanotube templated synthesis of metal containing hierarchical SAPO-34 catalysts:Impact of the preparation method and metal avidities in the MTOreaction[J].Microporous and Mesoporous Materials,2016,236:1-12.
[21]SCHMIDT F,PAASCH S,BRUNNER E,et al.Carbon templated SAPO-34 with improved adsorption kinetics and catalytic performance in the MTO-reaction[J].Microporous and Mesoporous Materials,2012,164(1):214-221.
[22]PAJAIE H S,TAGHIZADEH M.Optimization of nano-sized SAPO-34 synthesis in methanol-to-olefin reaction by response surface methodology[J].Journal of Industrial and Engineering Chemistry,2015,24:59-70.
[23]SALMASI M,FATEMI S,NAJAFABADI A T.Improvement of light olefins selectivity and catalyst lifetime in MTO reaction,using Ni and Mg-modified SAPO-34synthesized by combination of two templates[J].Journal of Industrial and Engineering Chemistry,2011,17(4):755-761.
[24]李婷,曹建新,刘飞.碘甲烷热裂解制低碳烯烃体系热力学分析[J].石油学报(石油加工),2015,31(3):712-719.(LI Ting,CAO Jianxin,LIU Fei.Thermodynamic analysis of low carbon olefin production by thermal cracking of methyl iodide[J].Acta Petrolei Sinica(Petroleum Processing Section),2015,31(3):712-719.)
[25]NIE R F,LEI H,PAN S Y,et al.Core-shell structured CuO-ZnO@H-ZSM-5 catalysts for COhydrogenation to dimethyl ether[J].Fuel,2012,96:419-425.
[26]张同旺,武雪峰,侯栓弟,等.催化剂积碳对甲醇制低碳烯烃效果的影响[J].石油学报(石油加工),2011,27(6):891-896.(ZHANG Tongwang,WU Xuefeng,HOU Shuandi,et al.The effect of coke deposition of catalyst on the reaction of methanol to olefins[J].Acta Petrolei Sinica(Petroleum Processing Section),2011,27(6):891-896.)
[27]TSUTOMU Y.Application of ZrO2as a catalyst and a catalyst support[J].Catalysis Today,1994,20(2):199-217.
[28]RAZAVIAN M,FATEMI S.Synthesis and application of ZSM-5/SAPO-34 and SAPO-34/ZSM-5 composite systems for propylene yield enhancement in propane dehydrogenation process[J].Microporous&Mesoporous Materials,2015,201:176-189.
[29]薛建伟,吴岚,吕志平,等.F-ZSM-5沸石的合成及对偏三甲苯-甲醇烷基化制均四甲苯的催化性能研究[J].燃料化学学报,2000,28(1):16-19.(XUE Jianwei,WU Lan,LZhiping,et al.Synthesis of F-ZSM-5zeolite and catalytic properties of four toluene for alkylation of partial toluene with methanol[J].Fuel Chemical,2000,28(1):16-19.)
[2]CHAE H J,SONG Y H,JEONG K E,et al.Physicochemical characteristics of ZSM-5/SAPO-34composite catalyst for MTO reaction[J].Journal of Physics&Chemistry of Solids,2010,71(4):600-603.
[3]JANG H G,MIN H K,LEE J K,et al.SAPO-34 and ZSM-5nanocrystals’size effects on their catalysis of methanol-to-olefin reactions[J].Applied Catalysis A:General,2012,437-438:120-130.
[4]何长青,刘中民,蔡光宇,等.双模板法控制SAPO-34分子筛的晶粒尺寸[J].分子催化,1994,8(3):207-212.(HE Changqing,LIU Zhongmin,CAI Guangyu,et al.Dual mode plate method controls the grain size of SAPO-34zeolite[J].Molecular Catalysis,1994,8(3):207-212.)
[5]YING L,YE M,CHENG Y W,et al.Characteristics of coke deposition over a SAPO-34 catalyst in the methanol-to-olefins reaction[J].Petroleum Science&Technology,2015,33(9):984-991.
[6]WANG C.Dual template-directed synthesis of SAPO-34 nanosheet assemblies with improved stability in the methanol to olefins reaction[J].J Mater Chem A,2015,3(10):5608-5616.
[7]SERRANO D P,ESCOLA J M,PIZARRO P.Synthesis strategies in the search for hierarchical zeolites[J].Chemical Society Reviews,2014,44(29):4004-4035.
[8]WANG F,SUN L,CHEN C,et al.Polyethyleneimine templated synthesis of hierarchical SAPO-34 zeolites with uniform mesopores[J].Rsc Advances,2014,4(86):46093-46096.
[9]LOPEZ-OROZCO S,INAYAT A,SCHWAB A,et al.Zeolitic materials with hierarchical porous structures[J].Advanced Materials,2015,23(22-23):2602-2615.
[10]ZHIBIN L,JOAQUIN M T,PATRICIA C,et al.Methanol to olefins:Activity and stability of nanosized SAPO-34molecular sieves and control of selectivity by silicon distribution[J].Physical Chemistry Chemical Physics,2013,15(35):14670-14680.
[11]ASKARI S,SEDIGHI Z,HALLADJ R.Rapid synthesis of SAPO-34nanocatalyst by dry gel conversion method templated with morphline:Investigating the effects of experimental parameters[J].Microporous&Mesoporous Materials,2014,197(10):229-236.
[12]AGHAEI E,HAGHIGHI M.Effect of crystallization time on properties and catalytic performance of nanostructured SAPO-34 molecular sieve synthesized at high temperatures for conversion of methanol to light olefins[J].Powder Technology,2015,269:358-370.
[13]HEYDEN H V,MINTOVA S,BEIN T.Nanosized SAPO-34 synthesized from colloidal solutions[J].Chemistry of Materials,2008,20(9):2956-2963.
[14]MIAO Y,PENG T,CHAN W,et al.A top-down approach to prepare silicoaluminophosphate molecular sieve nanocrystals with improved catalytic activity[J].Chemical Communications,2014,50(15):1845-1847.
[15]HAJIASHRAFI T,KHARAT A N,DAUTH A,et al.Preparation and characterization of lanthanide modified SAPO-34 nano catalysts and measurement of their activity for methanol to olefin conversion[J].Reaction Kinetics Mechanisms&Catalysis,2014,113(2):585-603.
[16]OBRZUT D L,ADEKKANATTU P M,THUNDIMADATHIL J,et al.Reducing methane formation in methanol to olefins reaction on metal impregnated SAPO-34 molecular sieve[J].Reaction Kinetics&Catalysis Letters,2003,80(1):113-121.
[17]WANG K,CAO G,KENNEDY G J,et al.Pore modification of H-SAPO-34 using dialkyl zinc:Structural characterization and reaction pathway[J].Journal of Physical Chemistry C,2011,115(38):18611-18617.
[18]XI D Y,SUN Q M,XU J,et al.In situ growth-etching approach to the preparation of hierarchically macroporous zeolites with high MTO catalytic activity and selectivity[J].Journal of Materials Chemistry A,2014,2(42):17994-18004.
[19]PAJAIE H S,TAGHIZADEH M.Optimization of nano-sized SAPO-34 synthesis in methanol-to-olefin reaction by response surface methodology[J].Journal of Industrial and Engineering Chemistry,2015,24:59-70.
[20]VARZANEH A Z,TOWFIGHI J,SAHEBDELFAR S.Carbon nanotube templated synthesis of metal containing hierarchical SAPO-34 catalysts:Impact of the preparation method and metal avidities in the MTOreaction[J].Microporous and Mesoporous Materials,2016,236:1-12.
[21]SCHMIDT F,PAASCH S,BRUNNER E,et al.Carbon templated SAPO-34 with improved adsorption kinetics and catalytic performance in the MTO-reaction[J].Microporous and Mesoporous Materials,2012,164(1):214-221.
[22]PAJAIE H S,TAGHIZADEH M.Optimization of nano-sized SAPO-34 synthesis in methanol-to-olefin reaction by response surface methodology[J].Journal of Industrial and Engineering Chemistry,2015,24:59-70.
[23]SALMASI M,FATEMI S,NAJAFABADI A T.Improvement of light olefins selectivity and catalyst lifetime in MTO reaction,using Ni and Mg-modified SAPO-34synthesized by combination of two templates[J].Journal of Industrial and Engineering Chemistry,2011,17(4):755-761.
[24]李婷,曹建新,刘飞.碘甲烷热裂解制低碳烯烃体系热力学分析[J].石油学报(石油加工),2015,31(3):712-719.(LI Ting,CAO Jianxin,LIU Fei.Thermodynamic analysis of low carbon olefin production by thermal cracking of methyl iodide[J].Acta Petrolei Sinica(Petroleum Processing Section),2015,31(3):712-719.)
[25]NIE R F,LEI H,PAN S Y,et al.Core-shell structured CuO-ZnO@H-ZSM-5 catalysts for COhydrogenation to dimethyl ether[J].Fuel,2012,96:419-425.
[26]张同旺,武雪峰,侯栓弟,等.催化剂积碳对甲醇制低碳烯烃效果的影响[J].石油学报(石油加工),2011,27(6):891-896.(ZHANG Tongwang,WU Xuefeng,HOU Shuandi,et al.The effect of coke deposition of catalyst on the reaction of methanol to olefins[J].Acta Petrolei Sinica(Petroleum Processing Section),2011,27(6):891-896.)
[27]TSUTOMU Y.Application of ZrO2as a catalyst and a catalyst support[J].Catalysis Today,1994,20(2):199-217.
[28]RAZAVIAN M,FATEMI S.Synthesis and application of ZSM-5/SAPO-34 and SAPO-34/ZSM-5 composite systems for propylene yield enhancement in propane dehydrogenation process[J].Microporous&Mesoporous Materials,2015,201:176-189.
[29]薛建伟,吴岚,吕志平,等.F-ZSM-5沸石的合成及对偏三甲苯-甲醇烷基化制均四甲苯的催化性能研究[J].燃料化学学报,2000,28(1):16-19.(XUE Jianwei,WU Lan,LZhiping,et al.Synthesis of F-ZSM-5zeolite and catalytic properties of four toluene for alkylation of partial toluene with methanol[J].Fuel Chemical,2000,28(1):16-19.)
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