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Performance of a nickel-alumina catalytic layer for simultaneous production and purification of hydrogen in a tubular membrane reactor

Amanipour, M ; Sharif University of Technology | 2016

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  1. Type of Document: Article
  2. DOI: 10.1039/c6ra12870j
  3. Publisher: Royal Society of Chemistry , 2016
  4. Abstract:
  5. A catalytic membrane reactor was synthesized by coating a 4-5 micron thick Ni/γ-Al2O3 layer on top of a hydrogen selective SiO2/Al2O3 composite membrane using a sol-gel method. Mercury intrusion and BET analysis indicated a uniform size distribution with an average pore size of 285 nm and average surface area of 279 m2 g-1. Single-component permeation tests were carried out for H2, CH4 and CO2 in the temperature range of 650-800 °C and the results showed the same permeance and selectivity values for hydrogen as the composite membrane without a catalytic layer. Performance of the catalytic membrane was evaluated by using as a membrane reactor for the methane steam reforming reaction with a C:H molar ratio of 1:3 at a gas hourly space velocity (GHSV) of 100 000 h-1 and 3 bar. CH4 conversion increased from 52% to 91% with increasing reaction temperature from 600 °C to 750 °C, which is well above the equilibrium curve at the reaction conditions, but slightly lower than the membrane reactor with a packed nickel catalytic bed because of its higher surface area compared to the catalytic layer. Hydrothermal stability of the catalytic membrane reactor was evaluated in a reforming reaction at 650 °C. Hydrogen permeance dropped by only 45% from 5.0 × 10-7 mol m-2 s-1 Pa-1 to 2.7 × 10-7 mol m-2 s-1 Pa-1 after exposure to a humid atmosphere for 48 h, which means no major morphological changes in the catalytic membrane's structure
  6. Keywords:
  7. Alumina ; Bioreactors ; Carbon dioxide ; Catalytic reforming ; Composite membranes ; Mercury (metal) ; Nickel ; Pore size ; Purification ; Sol-gel process ; Sol-gels ; Steam reforming ; Catalytic Membrane ; Catalytic membrane reactors ; Equilibrium curves ; Gas hourly space velocities ; Hydrothermal stabilities ; Morphological changes ; Reaction conditions ; Reaction temperature ; Membranes
  8. Source: RSC Advances ; Volume 6, Issue 79 , 2016 , Pages 75686-75692 ; 20462069 (ISSN)
  9. URL: http://pubs.rsc.org/en/Content/ArticleLanding/2016/RA/C6RA12870J#!divAbstract