Methanol partial oxidation accompanied by heat recirculation in a Swiss-roll reactor

Hydrogen production with high efficiency is a crucial issue for prospective hydrogen economy and carbon emission reduction. Methanol partial oxidation triggered over an h-BN-Pt/Al₂O₃ catalyst from a cold start in a Swiss-roll reactor with heat recirculation are investigated experimentally. The effects of methanol flow rate (0.5 and 0.6 mL min⁻¹), O₂ concentration (21–35 vol%), and O₂-to-methanol (O₂/M) molar ratio (1.0–3.0) on the performance of methanol partial oxidation are examined. Heat exchange by transferring the excess enthalpy in the product gas to the feed gas is achieved in the reactor where the temperature of the feed gas before entering the catalyst bed can be promoted to around 100 °C. The experimental results indicate that a methanol flow rate of 0.5 mL min⁻¹ leads to more H₂ production compared to those obtained with a flow rate of 0.6 mL min⁻¹. In the conducted Swiss-roll reactor, oxygen supply plays an important role in accomplishing the partial oxidation, and the O₂/M ratio should be controlled beyond 1.0. By increasing the O₂ concentration, the H₂ concentration at O₂/M = 1.5 increases from 18.5 to 21.8%. However, the H₂ yield decreases, resulting from progressively dominant combustion mechanism. At a fixed gas hourly space velocity of 10,000 h⁻¹, the optimal O₂/M ratio for H₂ production is 2.5, for which the H₂ concentration and H₂ yield are 23.5% and 1.93 mol (mol methanol)⁻¹, respectively. The highest H₂ yield is close to the theoretical result. Overall, methanol partial oxidation along with heat recirculation in the Swiss-roll reactor can efficiently produce H₂, and the excess enthalpy recovery in the reactor can improve energy utilization.