Acid activation of montmorillonite and its application for production of hydrogen via steam reforming of dimethyl ether
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摘要: 采用硝酸溶液在不同温度和时间下对钠基蒙脱土进行处理,制备了一系列酸活化蒙脱土(Acid-MMT),并以其为固体酸与商品化的Cu/ZnO/Al2O3物理混合组成双功能催化剂用于二甲醚水蒸气重整(SRD)反应。结果表明,与钠基蒙脱土相比,酸活化蒙脱土的结构、织构及酸性均发生了明显的变化,且变化的程度与酸处理条件密切相关。酸活化蒙脱土的结构和酸性明显影响双功能催化剂的SRD反应性能。其中,在80 ℃处理12 h的酸活化蒙脱土(Acid-MMT-80/12)与Cu/ZnO/Al2O3组成双功能催化剂表现出较好的SRD性能,在p = 0.1 MPa,t = 350 ℃,GHSV = 3000 h−1的反应条件下,二甲醚转化率和氢收率分别达到了97%和94%,且在反应10 h内基本保持不变,表现出了较好的稳定性。
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关键词:
- 二甲醚 /
- 水蒸气重整 /
- 制氢 /
- 酸活化蒙脱土 /
- Cu/ZnO/Al2O3
Abstract: A series of acid-activated montmorillonites (Acid-MMTs) were prepared via Na-montmorillonite treated with nitric acid solution at different treatment temperature and time. And the Acid-MMTs used as solid acid were physically mixed with commercial Cu/ZnO/Al2O3 to obtain bifunctional catalysts for steam reforming of dimethyl ether (SRD) reaction. The results showed that the structure, texture and acidity of Acid-MMTs were significantly changed compared with Na-MMT, which was dependent on the acid treatment conditions. The structure and acidity of Acid-MMTs obviously affected the SRD performance over bifunctional catalyst. The bifunctional catalyst composed of the Na-MMT activated in 20% nitric acid solution at 80 ℃ for 12 h (Acid-MMT-80/12) and Cu/ZnO/Al2O3 exhibited the best SRD performance, with the dimethyl ether conversion and H2 yield reaching 97% and 94% under the conditions of p =0.1 MPa, t =350 ℃, GHSV=3000 h−1, respectively, and DME conversion and H2 yield remained basically constant in 10 h, indicating that the catalyst had better stability.-
Key words:
- dimethyl ether /
- steam reforming /
- hydrogen production /
- acid-activated montmorillonite /
- Cu/ZnO/Al2O3
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图 4 Na-MMT(a),Acid-MMT-60/4(b),Acid-MMT-80/4(c),Acid-MMT-80/12(d),Acid-MMT-80/24(e),Acid-MMT-100/12(f)的孔径分布
Figure 4 Pore size distribution curves by BJH method using desorption branch data of Na-MMT (a), Acid-MMT-60/4 (b), Acid-MMT-80/4 (c), Acid-MMT-80/12 (d), Acid-MMT-80/24 (e), Acid-MMT-100/12 (f)
表 1 各样品的XRF分析
Table 1 Summary of the XRF results of different samples
Sample SiO2/% Al2O3/% Na2O/% MgO/% CaO/% Fe2O3/% Na-MMT 64.16 24.08 2.95 3.33 2.88 1.54 Acid-MMT-60/4 71.67 22.52 − 2.67 0.19 1.38 Acid-MMT-80/4 72.56 22.06 − 2.75 0.22 1.33 Acid-MMT-80/12 75.63 20.27 − 2.54 0.19 1.20 Acid-MMT-80/24 78.57 16.77 − 2.29 0.16 1.07 Acid-MMT-100/12 87.54 9.44 − 0.99 0.11 0.61 表 2 各样品的织构特征
Table 2 Summary of the textural properties of different samples
Sample BET surface area/(m2·g−1) Pore volume/(cm3·g−1) Average pore size/nm Na-MMT 12 0.07 24.9 Acid-MMT-60/4 139 0.17 4.9 Acid-MMT-80/4 183 0.24 5.2 Acid-MMT-80/12 282 0.51 7.3 Acid-MMT-80/24 262 0.71 10.8 Acid-MMT-100/12 250 0.84 13.4 -
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