蒙脱土基HZSM-5的制备及其在二甲醚水蒸气重整制氢中的应用

HZSM-5 synthesized by montmorillonite and its application for production of hydrogen via steam reforming of dimethyl ether

  • 摘要: 以亚熔岩活化蒙脱土为原料,采用传统水热法、晶种导向法、蒸汽辅助晶化法和气溶胶晶化法制备了具有不同织构和酸性的HZSM-5,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,并考察其二甲醚水蒸气重整(SRD)反应性能。通过XRD、FT-IR、SEM、N2低温吸附-脱附和NH3-TPD对样品进行表征。结果表明,合成方法影响了HZSM-5的晶体尺寸、织构及酸性等,进而影响了以其为固体酸的双功能催化剂的SRD性能。传统水热法合成的TH-HZSM-5因其具有适宜的酸量以及相对大的表面积、孔容和孔径,以其为固体酸与Cu/ZnO/Al2O3以质量比为1∶1组成的双功能催化剂表现出较好的SRD反应性能,在压力为0.1 MPa、温度为300 ℃、空速为5000 mL/(g·h)的反应条件下,二甲醚初始转化率和氢气收率分别达到了100%和91%。

     

    Abstract: HZSM-5 with different texture and acidity was prepared using sub-molten salt activated montmorillonite as raw material by traditional hydrothermal method, seed-directed method, steam-assisted crystallization method and aerosol crystallization method. And the HZSM-5 used as solid acid was physically mixed with commercial Cu/ZnO/Al2O3 to obtain bifunctional catalysts for steam reforming of dimethyl ether (SRD) reaction. The samples were systematically characterized by XRD, FT-IR, SEM, N2 adsorption-desorption at low temperature, and NH3-TPD techniques. The results showed that the crystal size, textural and acidity properties of HZSM-5 could be effectively regulated by the synthesis method, and then affecting the SRD performance of the corresponding bifunctional catalyst. TH-HZSM-5 synthesized by the traditional hydrothermal method exhibited suitable acid content and relatively large surface area, pore volume and pore size, and thus bifunctional catalyst composed of TH-HZSM-5 as solid acid and Cu/ZnO/Al2O3 with a mass ratio of 1∶1 showed better SRD reaction performance, and the dimethyl ether conversion and H2 yield reached 100% and 91% under the conditions of reaction temperature 300 ℃, pressure 0.1 MPa, space velocity 5000 mL/(g·h), respectively.

     

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