B_2O_3负载量对MoO_3/CeO_2-Al_2O_3耐硫甲烷化性能的影响
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摘要
考察B_2O_3负载量对于MoO_3/CeO_2-Al_2O_3催化剂对耐硫甲烷化活性的影响,利用BET、XRD、TEM、NH3-TPD等手段对催化剂进行了表征。结果表明,催化剂的耐硫甲烷化活性随B_2O_3负载量增加呈现先升高后降低的变化规律;当B_2O_3负载量为0.5%时,催化剂的耐硫甲烷化活性最高,CO转化率达到55%。结合表征分析,发现添加B_2O_3会影响催化剂载体的结构和表面酸度,从而影响活性组分的分散程度,进而影响MoO_3/CeO_2-Al_2O_3催化剂的耐硫甲烷化性能。催化剂的晶化程度太高或单位面积上的强酸量太多均不利于甲烷化反应;较好的活性组分分散度有利于催化剂甲烷化活性的提高。
Synthetic natural gas(SNG) production from coal is considered again due to rising prices for natural gas, the wish for less dependency from natural gas imports and the opportunity of reducing green house gases. The technical, economic and ecological feasibility of SNG with Mo-based catalysts showed water-gas shift and sulfur-resistant methanation has been studied. In this paper the impact of B_2O_3 loading on the MoO_3/CeO_2-Al_2O_3 catalysts for sulfur-resistant methanation was investigated. The catalysts were prepared by impregnation method and characterized by means of BET, XRD, TEM and NH3-TPD. The results showed that the sulfur-resistant methanation activity of Mo O3/CeO_2-Al_2O_3 catalysts were increased at first and then decreased as the increase of B_2O_3 loading. The catalyst adding 0.5% B_2O_3 showed the highest activity and the conversion of CO was 55%. The characterization results indicated that the addition of B_2O_3 had influences on the structure and surface acidity of catalysts and the dispersion of active components, which further impacted the activity of catalysts. Highcrystallization and enhancement of strong acid quantity were not beneficial to the sulfur-resistant methanation, while the high dispersion of active components was favorable to the improvement of the catalyst activity.
Synthetic natural gas(SNG) production from coal is considered again due to rising prices for natural gas, the wish for less dependency from natural gas imports and the opportunity of reducing green house gases. The technical, economic and ecological feasibility of SNG with Mo-based catalysts showed water-gas shift and sulfur-resistant methanation has been studied. In this paper the impact of B_2O_3 loading on the MoO_3/CeO_2-Al_2O_3 catalysts for sulfur-resistant methanation was investigated. The catalysts were prepared by impregnation method and characterized by means of BET, XRD, TEM and NH3-TPD. The results showed that the sulfur-resistant methanation activity of Mo O3/CeO_2-Al_2O_3 catalysts were increased at first and then decreased as the increase of B_2O_3 loading. The catalyst adding 0.5% B_2O_3 showed the highest activity and the conversion of CO was 55%. The characterization results indicated that the addition of B_2O_3 had influences on the structure and surface acidity of catalysts and the dispersion of active components, which further impacted the activity of catalysts. Highcrystallization and enhancement of strong acid quantity were not beneficial to the sulfur-resistant methanation, while the high dispersion of active components was favorable to the improvement of the catalyst activity.
引文
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[18]USMAN,KUBOTA T,HIROMITSU I,et al.Effect of boron addition on the surface structure of Co-Mo/Al2O3 catalysts[J].Journal of Catalysis,2007,247(1):78-85.
[19]MOHAMED L K,EI KADY F Y,SHABAN S A.The effect of boron on the activity of hydrotreating Co-Mo/Al2O3 catalyst[J].Energy Sources,Part A:Recovery,Utilization and Environmental Effects,2013,35(7):659-670.
[20]USMAN U,TAKAKI M,KUBOTA T,et al.Effect of boron addition on a Mo O3/Al2O3 catalyst:physico-chemical characterization[J].Applied Catalysis A:General,2005,286(1):148-154.
[21]SURESH R,PONNUSWAMY V,MARIAPPAN R.Effect of annealing temperature on the microstructural,optical and electrical properties of Ce O2 nanoparticles by chemical precipitation method[J].Applied Surface Science,2013,273(273):457-464.
[22]JIANG M,WANG B,YAO Y,et al.Effect of stepwise sulfidation on a Mo O3/Ce O2-Al2O3 catalyst for sulfur-resistant methanation[J].Applied Catalysis A:General,2014,469(2):89-97.
[2]KRAMER M,DUISBERG M,STOWE K,et al.Highly selective CO methanation catalysts for the purification of hydrogen-rich gas mixtures[J].Journal of Catalysis,2007,251(2):410-422.
[3]姚玉芹,刘思含,胡宗元,等.γ-Al2O3性质对钼基耐硫甲烷化催化剂活性的影响[J].石油化工,2014,43(7):754-758.YAO Y Q,LIU S H,HU Z Y,et al.Effects of alumina properties on the activity of Mo-based catalyst for sulfur-resistant methanation[J].Petrochemical Technology,2014,43(7):754-758.
[4]GAO J,LIU Q,GU F,et al.Recent advances in methanation catalysts for the production of synthetic natural gas[J].RSC Advances,2015,5(29):22759-22776.
[5]王光永,徐绍平.煤制替代/合成天然气技术的研究进展[J].石油化工,2016,45(1):1-9.WANG G Y,XU S P.Technological progresses in substitute/synthetic natural gas from coal[J].Petrochemical Technology,2016,45(1):1-9.
[6]路霞,陈世恒,王万丽,等.CO甲烷化Ni基催化剂的研究进展[J],石油化工,2010,39(3):340-345.LU X,CHEN S H,WANG W L,et al.Progress in Ni-based catalysts for CO methanation[J].Petrochemical Technology,2010,39(3):340-345.
[7]孟凡会,常慧蓉,李忠.Ni-Mn/Al2O3催化剂在浆态床中CO甲烷化催化性能[J].化工学报,2014,65(8):2997-3003.MENG F H,CHANG H R,LI Z.Catalytic performance of Ni-Mn/Al2O3 catalyst for CO methanation in slurry-bed reactor[J].CIESC Journal,2014,65(8):2997-3003.
[8]CZEKAJ I,STRUIS R,WAMBACH J,et al.Sulphur poisoning of Ni catalysts used in the SNG production from biomass:computational studies[J].Catalysis Today,2011,176(1):429-432.
[9]YUAN C,NAN Y,WANG X,et al.The Si O2 supported bimetallic Ni–Ru particles:a good sulfur-tolerant catalyst for methanation reaction[J].Chemical Engineering Journal,2015,260(260):1-10.
[10]王玮涵,李振花,王保伟,等.耐硫甲烷化反应的研究进展[J].化工学报,2015,66(9):3357-3366.WANG W H,LI Z H,WANG B W,et al.Recent advances in sulfur-resistant methanation[J].CIESC Journal,2015,66(9):3357-3366.
[11]WANG B,SHANG Y,DING G,et al.Effect of the ceria-alumina composite support on the Mo-based catalyst’s sulfur-resistant activity for the synthetic natural gas process[J].Reaction Kinetics,Mechanisms and Catalysis,2012,106(2):495-506.
[12]王保伟,尚玉光,丁国忠,等.铈铝复合载体对钼基催化剂耐硫甲烷化催化性能的研究[J].燃料化学学报,2012,40(11):1390-1396.WANG B W,SHANG Y G,DING G Z,et al.Ceria-alumina composite support on the sulfur-resistant methanation activity of Mo-based catalyst[J].Journal of Fuel Chemistry and Technology,2012,40(11):1390-1396.
[13]JIANG M,WANG B,LV J,et al.Effect of sulfidation temperature on the catalytic activity of Mo O3/Ce O2-Al2O3 toward sulfur-resistant methanation[J].Applied Catalysis A:General,2013,466:224-232.
[14]JIANG M,WANG B,YAO Y,et al.A comparative study of Ce O2-Al2O3 support prepared with different methods and its application on Mo O3/Ce O2-Al2O3 catalyst for sulfur-resistant methanation[J].Applied Surface Science,2013,285(1):267-277.
[15]JIANG M,WANG B,YAO Y,et al.The role of the distribution of Ce species on Mo O3/Ce O2-Al2O3 catalysts in sulfur-resistant methanation[J].Catalysis Communications,2013,35(35):32-35.
[16]FRANCK D,RIGOLE M,MICHEL G A,et al.Characterization of boria-alumina mixed oxides prepared by a sol-gel method(1):NMR characterization of the xerogels[J].Chemistry of Materials,2005,17(9):2369-2377.
[17]CHAN K,LEE J J,BAE J S,et al.Hydrodesulfurization of DBT,4-MDBT,and 4,6-DMDBT on fluorinated Co Mo S/Al2O3 catalysts[J].Applied Catalysis A:General,2000,200(1):233-242.
[18]USMAN,KUBOTA T,HIROMITSU I,et al.Effect of boron addition on the surface structure of Co-Mo/Al2O3 catalysts[J].Journal of Catalysis,2007,247(1):78-85.
[19]MOHAMED L K,EI KADY F Y,SHABAN S A.The effect of boron on the activity of hydrotreating Co-Mo/Al2O3 catalyst[J].Energy Sources,Part A:Recovery,Utilization and Environmental Effects,2013,35(7):659-670.
[20]USMAN U,TAKAKI M,KUBOTA T,et al.Effect of boron addition on a Mo O3/Al2O3 catalyst:physico-chemical characterization[J].Applied Catalysis A:General,2005,286(1):148-154.
[21]SURESH R,PONNUSWAMY V,MARIAPPAN R.Effect of annealing temperature on the microstructural,optical and electrical properties of Ce O2 nanoparticles by chemical precipitation method[J].Applied Surface Science,2013,273(273):457-464.
[22]JIANG M,WANG B,YAO Y,et al.Effect of stepwise sulfidation on a Mo O3/Ce O2-Al2O3 catalyst for sulfur-resistant methanation[J].Applied Catalysis A:General,2014,469(2):89-97.