Catalyst-free ceramic-carbonate dual phase membrane reactor for hydrogen production from gasifier syngas

Ceramic-carbonate dual phase dense membranes are a new group of inorganic membranes with perm-selective to CO₂ at high temperatures. This paper reports a new catalyst-free tubular membrane reactor to shift CO from the hot gasifier syngas to H₂ and CO₂ with simultaneous separation of CO₂. The membrane reactor is based on a samarium-doped ceria (SDC)-carbonate dual phase membrane which removes CO₂ facilitating conversion of CO to H₂ at high temperatures. The results show that catalytic-free membrane reactor can convert CO to H₂ and CO₂ with removal of CO₂ at temperatures above 800 °C. At 900 °C, the membrane reactor gives CO₂ flux of 2.7×10⁻³ mol m⁻² s⁻¹, CO conversion and CO₂ recovery of 26.1%and 18.7%, respectively, much higher than the conventional fixed bed reactor under identical conditions. Temperature, steam to CO ratio, and syngas feed flow rate are key parameters to control the reaction performance. Increase of the feed pressure (reaction side) is an effective strategy to improve the reactor performance and CO₂ recovery. The membrane reactor shows high thermal and chemical stability under syngas WGS reaction environment. This work demonstrates potential of using catalyst-free SDC-carbonate dual phase membrane reactor for water gas shift reaction to convert CO to H₂ with CO₂ capture.