Hydrogen production for fuel cell application via thermo-chemical technique: An analytical evaluation

Fuel cells are considered as the promising candidates for next-generation energy systems for which supplying the required hydrogen is the most important issue. Because of resource scarcity and environmental pollution associated with hydrocarbon reforming, magnesium-water combustion can be applied as an eco-friendly alternative method for hydrogen generation. This study aims to investigate magnesium combustion as a heat and hydrogen source. By proposing an asymptotic model of flame structure, the combustion of single magnesium particle is examined in which the model consists of internal and external zones and a thin reaction layer. Then, the governing equations including mass, energy, and mass fractions of species and their appropriate boundary conditions are derived and solved analytically. Afterwards, with the aid of Taylor approximation, the explicit formulas are extracted for flame location and temperature and magnesium evaporation rate. Subsequently, the effects of various parameters on combustion characteristics and hydrogen production are scrutinized. Eventually, by employing the examined model for single particle, the discrete method is applied to analyze the magnesium dust cloud combustion. The results indicate that the hydrogen production rate is higher than 10(-3) kg/s for the condition of d = 10 mu m, P =1 atm, Le =1 with dust concentration greater than 250 mg/liter.

Automated summary

The study investigates magnesium combustion as an eco-friendly alternative method for hydrogen generation, analyzing the combustion process and deriving explicit formulas for flame location, temperature, and magnesium evaporation rate with the aid of a proposed asymptotic model of flame structure. It also examines the effects of various parameters on combustion characteristics and hydrogen production. The results suggest a hydrogen production rate higher than 10(-3) kg/s under specific conditions.