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Methanol reforming is a key method of producing hydrogen, an eco-friendly energy source. A feasible validation has been performed using previous experimental data. Present numerical model, validated using previously published experimental data, facilitates a factor-by-factor study of methanol reforming performance characteristics. In particular, the effects of inlet temperature of reformed gas and heat source gas, gas hourly space velocity (GHSV), reformer length, and reformer diameter are numerically analyzed. The effect of each parameter on reforming performance was presented by analyzing the average temperature of the reformed gas for each location inside the reformer. In addition, the inlet temperature of the heat source gas was more dominant in reforming performance than that of the reformed gas through sensitivity analysis. Finally, the performance was explained in terms of residence time, and the relationship between CO selectivity and residence time was presented. • A Numerical simulation of a shell and tube methanol reformer was performed. • The effect of operating conditions (temperature, GHSV) on reforming performance was analyzed. • The effect of geometric shapes of the reformer on reforming performance was analyzed. • The reforming performance is more sensitive to the inlet temperature of heat source gas than that of the reformed gas. [ABSTRACT FROM AUTHOR]

A fuel cell air independent propulsion (AIP) system of underwater vehicle requires a hydrogen storage system. The methanol steam reforming system is a candidate of hydrogen storage which can produce hydrogen from chemical reaction. Different from reforming system for station fuel cell system, the methanol steam reformer (MSR) for underwater vehicle requires high-pressure operation. Since the longitudinal temperature uniformity is a core parameter of conversion efficiency of steam reforming system, this study is focused on computational analysis of phase change heat transfer through the annulus for methanol steam reforming reaction. The annulus MSR using phase change material was developed to improve the temperature uniformity. The simulation model is verified with safety and performance analysis code (SPACE). The performance parameters of MSR were flow arrangement, steam to carbon ratio (SCR), and gas hourly space velocity (GHSV). The results were analyzed in terms of the hydrogen yield, heat flux, liquid mass flow rate, and methanol conversion rate. The flow arrangement varied the methanol conversion rate to a minor extent of approximately 0.1% because wall temperature was maintained uniformly. In the case of SCR, the hydrogen yield at SCR 2.5 was 0.637 (dry basis), which was the highest yield rate. Also, if GHSV was increased, hydrogen yield decreased from 0.690 (dry basis) to 0.527 (dry basis). The heat transfer pattern was also analyzed and it was found that steam is interactively condensed along with the progress of the reforming reaction. • Methanol steam reforming reaction using the latent heat is analyzed numerically. • The two-phase flow model is validated with safety and performance analysis code. • Analyze the performance of the reformer using latent heat with various parameters. • Latent heat improves the temperature uniformity of endothermal reaction. [ABSTRACT FROM AUTHOR]