Co-precipitation continuous synthesis of the Ni-Rh-Ce0.75Zr0.25O2-δ catalyst in the membrane dispersion microreactor system for n-dodecane steam reforming to hydrogen

FUEL

卷:297

Article

Xue, Qiangqiang¹  Li, Zhengwen¹  Chen, Meng¹  Wang, Yujun¹  Yan, Binhang¹  Luo, Guangsheng¹ 

[1] Tsinghua Univ, Dept Chem Engn, State Key Lab Chem Engn, Beijing 100084, Peoples R China

关键词: Hydrogen energy;    Diesel steam reforming;    Ni-Rh;    Co-precipitation;    Membrane dispersion microreactor;    Continuous production;   

DOI  :  10.1016/j.fuel.2021.120785

来源: Elsevier

【 摘 要 】

Precipitation at the micro-scale to produce nanoparticles with small particle size and uniform dispersion is feasible. A membrane dispersion microreactor (MR) - matching spiral tube system was used to synthesize highly dispersed (MR)-Ni-Rh-Ce0.75Zr0.25O2-delta and (MR)-Ni- Ce0.75Zr0.25O2-delta catalysts with active metal particle sizes of 4.3 and 4.6 nm. Rapid nucleation of the catalyst precursor was achieved in the microreactor and ordered growth occurred in the spiral tube. Characterization by TEM, pulse CO chemisorption, and Raman spectroscopy prove that the catalysts synthesized in the microreactor system possess more oxygen vacancies and uniformly supported active metal than those in the stirred tank (S). The apparent activation energies of the catalysts for ndodecane steam reforming (SR) increase in the following order: (MR)-Ni-Rh-CZO (62 kJ/mol) < (S)-Ni-Rh-CZO (67 kJ/mol) < (MR)-Ni- CZO (77 kJ/mol) < (S)-Ni-CZO (84 kJ/mol). The initial hydrogen yields of (MR)-Ni-RhCZO and (S)-Ni-Rh-CZO are 88 and 59%, respectively, at T = 650 degrees C, WHSV = 12 h(-1), and S/C = 4. TPSR experiments indicated that (MR)-Ni-CZO mostly contributed to the cleavage of C-C and C-H bonds. The carbon deposition in the first 12 h of n-dodecane SR is only 2.4 mg/(g-cat.mol-H-2). For optimizing the continuous synthesis method, the initial hydrogen yield can be further improved to above 95% by increasing the mixing intensity, decreasing the ratio of the dispersed to continuous phase, and increasing the spiral tube length to synthesize better-dispersed catalysts.

【 授权许可】

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