浆态床反应器中Cu-Co合金催化剂用于合成气制低碳醇的研究
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摘要
采用柠檬酸络合-等体积浸渍法将钙钛矿型复合氧化物LaCo0.7Cu0.3O3担载于SiO2表面,得到催化剂前驱体。利用X射线衍射(XRD)、N2吸附-脱附(BET)、程序升温还原(TPR)、透射电镜(TEM)等技术对催化剂进行表征。对还原后的催化剂,在加压浆态床反应器中测试了合成气制低碳醇的催化性能,并与固定床反应器中催化性能进行了对比。结果表明:还原后形成了La2O3修饰的SiO2负载Cu-Co合金颗粒(CuCo-Alloy/La2O3-SiO2)催化剂。浆态床反应器中,由于液体石蜡浆液的作用和对热点形成的抑制,C2+醇的选择性显著提高。在所考察的实验条件下,空速为900至1 500mL/(gcat·h)、压力3MPa、H2∶CO∶N2=8∶4∶1和温度为250℃时,总醇中C2+醇的选择性达到95%以上。
LaCo_(0.7)Cu_(0.3)O_(3 )was supported on SiO_2according to the incipient wetness impregnation method combined with citrate complexing method.The prepared catalyst precursors were characterized by XRD,BET,H_2-TPR and TEM.The catalytic performance for higher alcohols synthesis from syngas was conducted in a slurry reactor,which was compared with that in fixed-bed reactor.After reduction,the catalyst precursor favoured to form nanoparticles of Cu-Co alloy highly dispersed on SiO_2and modified with La_2O_3.In slurry reactor,the selectivity to C_(2+)OH was much higher,which may be attributed to the effect of liquid slurry of paraffin for suppressing the desorption of methanol and the formation of hot-spots.Under the experimental condition of 900to 1 500mL/(g_(cat)·h),3MPa,H_2∶CO∶N_2=8∶4∶1and 250℃,C_(2+)OH in the total alcohols was more than 95%in weight.
LaCo_(0.7)Cu_(0.3)O_(3 )was supported on SiO_2according to the incipient wetness impregnation method combined with citrate complexing method.The prepared catalyst precursors were characterized by XRD,BET,H_2-TPR and TEM.The catalytic performance for higher alcohols synthesis from syngas was conducted in a slurry reactor,which was compared with that in fixed-bed reactor.After reduction,the catalyst precursor favoured to form nanoparticles of Cu-Co alloy highly dispersed on SiO_2and modified with La_2O_3.In slurry reactor,the selectivity to C_(2+)OH was much higher,which may be attributed to the effect of liquid slurry of paraffin for suppressing the desorption of methanol and the formation of hot-spots.Under the experimental condition of 900to 1 500mL/(g_(cat)·h),3MPa,H_2∶CO∶N_2=8∶4∶1and 250℃,C_(2+)OH in the total alcohols was more than 95%in weight.
引文
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[3]WANG J,CHERNAVSKII P A,KHODAKOV A Y,et al.Structure and catalytic performance of aluminasupported copper-cobalt catalysts for carbon monoxide hydrogenation[J].Journal of Catalysis,2012,286(4):51-61.
[4]GUPTA M,SMITH M L,SPIVEY J J.Heterogeneous catalytic conversion of dry syngas to ethanol and higher alcohols on cu-based catalysts[J].Acs Catalysis,2011,1(6):641-656.
[5]LIU G,NIU T,PAN D,et al.Preparation of bimetal Cu-Co nanoparticles supported on meso-macroporous SiO2and their application to higher alcohols synthesis from syngas[J].Applied Catalysis A:General,2014,483:10-18.
[6]HONG Y,YANG Q,KANG N,et al.Cu-Co alloy nano-particles supported on SiO2and modified by La and y for ethanol synthesis from syngas[J].Chemistry Select,2017,2(25):7580-7589.
[7]SUN X,ROERTS G W.Synthesis of higher alcohols in a slurry reactor with cesium-promoted zinc chromite catalyst in decahydronaphthalene[J].Applied Catalysis A:General,2003,247(1):133-142.
[8]FANG Y Z,LIU Y,ZHANG L H.LaFeO3-supported nano Co-Cu catalysts for higher alcohol synthesis from syngas[J].Applied Catalysis A:General,2011,397(1/2):183-191.
[9]TIEN-THAO N,ALAMDARI H,KALIAGUINE S.Characterization and reactivity of nanoscale La(Co,Cu)O3perovskite catalyst precursors for Co hydrogenation[J].Journal of Solid State Chemistry,2008,181(8):2006-2019.
[10]LIU G,NIU T,CAO A,et al.The deactivation of Cu-Co alloy nanoparticles supported in ZrO2for higher alcohols synthesis from syngas[J].Fuel,2016,176:1-10.
[11]LEOFANTI G,PADOVAN M,TOZZOLA G,et al.Surface area and pore texture of catalysts[J].Catalysis Today,1998,90(4):207-219.
[12]WANG N,YU X,WANG Y,et al.A comparison study on methane dry reforming with carbon dioxide over lanio 3 perovskite catalysts supported on mesoporous sba-15,mcm-41and silica carrier[J].Catalysis Today,2013,212:98-107.
[13]TONIOLO F S,MAGALHAES R N S H,PEREZ CA C,et al.Structural investigation of lacoo 3and lacocuo 3perovskite-type oxides and the effect of Cu on coke deposition in the partial oxidation of methane[J].Applied Catalysis B Environmental,2012,s117/s118(3):156-166.
[14]TIEN-THAO N,ZAHEDI-NIAKI M H,ALAM-DARI H,et al.Conversion of syngas to higher alcohols over nanosized LaCO0.7Cu0.3O3perovskite precursors[J].Applied Catalysis A:General,2007,326(2):152-163.
[15]LISI L,BAGNASCO G,CIAMBELLI P,et al.Perovskite-type oxides.Ii.redox properties of LaMn1-xCuxO3and LaCO1-xCuxO3 and methane catalytic combustion[J].Journal of Solid State Chemistry,1999,146(1):176-183.
[16]LIU G,PAN D,NIU T,et al.Nanoparticles of Cu-Co alloy supported on high surface area LaFeO3-preparation and catalytic performance for higher alcohol synthesis from syngas[J].RSC Advances,2015,5(4):31637-31647.
[17]ROBERTS G W,MARQUEZ M A,MCCUTCHENM S.Alcohol synthesis in a high-temperature slurry reactor[J].Catalysis Today,1997,36(3):255-263.
[18]ZHANG X,LI Z,GUO Q,et al.Selective synthesis of mixed alcohols from syngas over catalyst Fe2O3/Al2O3in slurry reactor[J].Fuel Processing Technology,2010,91(4):379-382.
[19]TIEN-THAO N,ZAHEDI-NIAKI M H,ALAM-DARI H,et al.Effect of alkali additives over nanocrystalline Co-Cu-based perovskites as catalysts for higherv alcohol synthesis[J].Journal of Catalysis,2007,245(2):348-357.