Influence of calcination temperature on the structure and catalytic reforming performance of Ni/CaO-Al2O3 catalyst
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摘要: 采用共沉淀法制备了一系列具有类水滑石结构前驱体的Ni/CaO-Al2O3复合催化剂,考察了制备过程中焙烧温度对复合催化剂结构及性能的影响。结果表明,焙烧温度可调控活性组分Ni与载体之间的相互作用力,进而调变复合催化剂的比表面积、活性组分Ni的颗粒粒径。当焙烧温度为700 ℃时,Ni与载体之间相互作用力适宜,复合催化剂具有最大的比表面积(21.42 m2/g)和最小的Ni颗粒粒径(19.51 nm);该复合催化剂在CO2吸附强化CH4/H2O重整制氢过程中可得到98.31%的H2浓度和94.87%的CH4转化率,循环10次后,H2浓度仍能保持在97.35%以上。这是因为大的比表面积为反应提供了更多的活性位点,利于CO2吸附过程的强化,而小的Ni颗粒粒径提高了复合催化剂的抗烧结能力。Abstract: Considering the tunable structure of hydrotalcite-like compounds, co-precipitation method was employed to synthesize Ni/CaO-Al2O3 composite catalysts. The influence of calcination temperature on the structure and catalytic reforming performance of Ni/CaO-Al2O3 catalyst investigated. The results showed that the specific surface area and Ni particle size of the as-synthesized composite catalysts were greatly affected by calcination temperature of the precursor derived from the variable interaction between the Ni and the support. When the calcination temperature was 700 ℃, the composite catalyst obtained a specific surface area of 21.42 m2/g and Ni particle size of 19.51 nm. The catalytic evaluation showed that the composite catalyst possessed a H2 concentration of 98.31% and a CH4 conversion of 94.87%, and H2 concentration exceeded 97.35% even after 10 cyclic runs. The high catalytic activity was ascribed to the higher specific surface area, which provided more active sites and enhanced CO2 sorption. The smaller Ni particle size improved the anti-sintering capacity of the composite catalyst, endowing the composite catalyst superior stability.
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表 1 不同焙烧温度复合催化剂的金属分散度与颗粒粒径
Table 1 Metal dispersion and particle size of the composite catalysts calcined at different temperature
Sample Metal surface area A/(m2·g-1) a Metal dispersion/%a CaO particle size d/nmb Ni particle size d/nmb Cat-700 11.95 1.79 36.89 19.51 Cat-750 9.72 1.46 38.03 24.42 Cat-800 7.13 1.07 40.12 28.81 Cat-850 5.92 0.98 39.49 33.73 a: calculated from H2-chemisorption; b: calculated from XRD results 表 2 不同焙烧温度复合催化剂的比表面积和孔结构
Table 2 BET specific surface area and pore structure of the composite catalysts calcined at different temperature
Sample BET specific surface area A/(m2·g-1) Total pore volume v/(cm3·g-1) Pore radius d/nm Cat-700 21.42 0.099 35.81 Cat-750 14.57 0.054 33.62 Cat-800 12.92 0.048 31.59 Cat-850 12.30 0.043 30.42 -
[1] BALASUBRAMANIAN B, ORTIZ A L, KAYTAKOGLU S, HARRISON D P. Hydrogen from methane in a single-step process[J]. Chem Eng Sci, 1999, 54(15):3543-3552. [2] SILVA J M, SORIA M A, MADEIRA L M. Thermodynamic analysis of glycerol steam reforming for hydrogen production with in situ hydrogen and carbon dioxide separation[J]. J Power Sources, 2015, 273:423-430. doi: 10.1016/j.jpowsour.2014.09.093 [3] ROMANO M C, CASSOTTI E N, CHIESA P, MEYER J, MASTIN J. Application of the sorption enhanced-steam reforming process in combined cycle-based power plants[J]. Energy Procedia, 2011, 4(4):1125-1132. https://core.ac.uk/download/pdf/82327775.pdf [4] LYSIKOV A, DEREVSCHIKOV V, OKUNEV A. Sorption-enhanced reforming of bioethanol in dual fixed bed reactor for continuous hydrogen production[J]. Int J Hydrogen Energy, 2015, 40(42):14436-14444. doi: 10.1016/j.ijhydene.2015.06.029 [5] XUE X, WU S. The microstructure and stability of a Ni-nano-CaO/Al2O3 reforming catalyst under carbonation-calcination cycling conditions[J]. Int J Hydrogen Energy, 2015, 40(16):5617-5623. doi: 10.1016/j.ijhydene.2015.02.032 [6] LI M. Thermodynamic analysis of adsorption enhanced reforming of ethanol[J]. Int J Hydrogen Energy, 2009, 34(23):9362-9372. doi: 10.1016/j.ijhydene.2009.09.054 [7] JING J Y, LI T Y, ZHANG X W, WANG S D, FENG J, TURMEL W A, LI W Y. Enhanced CO2 sorption performance of CaO/Ca3Al2O6 sorbents and its sintering-resistance mechanism[J]. Appl Energy, 2017, 199:225-233. doi: 10.1016/j.apenergy.2017.03.131 [8] JING J Y, ZHANG X W, WANG S D, LI T Y, LI W Y. Improving CO2 sorption performance of CaO/Ca3Al2O6 sorbents by thermally pretreated in CO2 atmosphere[J]. Energy Procedia, 2017, 142:3258-3263. doi: 10.1016/j.egypro.2017.12.500 [9] GARCIA-LARIO A L, AZNAR M, GRASA G S, MURILLO R. Evaluation of process variables on the performance of sorption enhanced methane reforming[J]. J Power Sources, 2015, 285:90-99. doi: 10.1016/j.jpowsour.2015.03.075 [10] CHEN Y, MAHECHABOTERO A, LIM C J, GRACE J R, ZHANG J, ZHAO Y, ZHENG C. Hydrogen production in a sorption-enhanced fluidized-bed membrane reactor:Operating parameter investigation[J]. Ind Eng Chem Res, 2014, 53(14):6230-6242. doi: 10.1021/ie500294k [11] RADFARNIA H R, ILIUTA M C. Hydrogen production by sorption-enhanced steam methane reforming process using CaO-Zr/Ni bifunctional sorbent-catalyst[J]. Chem Eng Process, 2014, 86:96-103. doi: 10.1016/j.cep.2014.10.014 [12] CHANBURANASIRI N, RIBEIRO A M, RODRIGUES A E, ARPORNWICHANOP A, LAOSIRIPOJANA N, PRASERTHDAM P, ASSABUMRUNGRAT S. Hydrogen production via sorption enhanced steam methane reforming process using Ni/CaO multifunctional catalyst[J]. Ind Eng Chem Res, 2011, 50(24):69-86. [13] RADFRNIA H R, ILIUTA M C. Development of Al-stabilized CaO-nickel hybrid sorbent-catalyst for sorption-enhanced steam methane reforming[J]. Chem Eng Sci, 2014, 109(16):212-219. [14] CESARIO M R, BARROS B S, COURSON C, MELO D M A, KIENNEMANN A. Catalytic performances of Ni-CaO-mayenite in CO2 sorption enhanced steam methane reforming[J]. Fuel Process Technol, 2015, 131:247-253. doi: 10.1016/j.fuproc.2014.11.028 [15] XU P, ZHOU Z, ZHAO C, CHENG Z. Ni/CaO-Al2O3 bifunctional catalysts for sorption-enhanced steam methane reforming[J]. AIChE J, 2015, 60(10):3547-3556. [16] PHROMPRASIT J, POWELL J, WONGSAKULPHASATCH S, KIATKITTIPONG W, BUMROONGSAKULSAWAT P, ASSABUMRUNGRAT S. Activity and stability performance of multifunctional catalyst (Ni/CaO and Ni/Ca12Al14O33-CaO) for bio-hydrogen production from sorption enhanced biogas steam reforming[J]. Int J Hydrogen Energy, 2016, 41(18):7318-7331. doi: 10.1016/j.ijhydene.2016.03.125 [17] WU K, JING J Y, LI W Y. Calcination temperature influence on the catalytic performance of Ni/CeO2-ZrO2 for low temperature steam reforming of methane[C]//31st Annual International Pittsburgh Coal Conference, 2014. Pittsburgh, PA, USA. [18] LI T Y, JING J Y, FENG J, LI W Y. Carbon dioxide capture over Al-doped CaO-based sorbents with enhanced reactive stability in cyclic operations[C]//2015 Internation Conference on Coal Science and Technology, 2015. Australia. [19] 荆洁颖, 王世东, 张学伟, 李清, 李文英. Ca/Al物质的量比对Ni/CaO-Al2O3结构及其催化重整性能的影响[J].燃料化学学报, 2017, 45(8):956-962. http://rlhxxb.sxicc.ac.cn/EN/article/downloadArticleFile.do?attachType=PDF&id=19072JING Jie-ying, WANG Shi-dong, ZHANG Xue-wei, LI Qing, LI Wen-ying. Influence of Ca/Al molar ratio on the structure and catalytic reforming performance of Ni/CaO-Al2O3 catalyst[J]. J Fuel Chem Technol, 2017, 45(8):956-962. http://rlhxxb.sxicc.ac.cn/EN/article/downloadArticleFile.do?attachType=PDF&id=19072 [20] WU C H, CHANG Y P, CHEN S Y, LIU D M, YU C T, PEN B L. Characterization and structure evolution of Ca-Al-CO3 hydrotalcite film for high temperature CO2 adsorption[J]. J Nanosci Nanotechnol, 2010, 10(7):4716-4720. doi: 10.1166/jnn.2010.1708 [21] CHANG P H, CHANG Y P, CHEN S Y, YY C T, CHYOU Y P. Ca-rich Ca-Al-oxide, high-temperature-stable sorbents prepared from hydrotalcite precursors:Synthesis, characterization, and CO2 capture capacity[J]. ChemSusChem, 2011, 4(12):1844-1851. doi: 10.1002/cssc.v4.12 [22] 张帆, 吴嵘, 吴素芳.水热沉淀法制NiO-CaO/Al2O3复合催化剂及其在ReSER制氢中的应用[J].高等化学工程学报, 2014, 28(5):985-991. http://www.doc88.com/p-7844755122573.htmlZHANG Fan, WU Rong, WU Su-fang. The preparation of a type of NiO-CaO sorption complex catalyst by hydrothermal precipitation method and its application in ReSER process[J]. J Chem Eng Chin Univ, 2014, 28(5):985-991. http://www.doc88.com/p-7844755122573.html