Magnesium and Boron Combustion in Hot Steam Atmosphere

Abstract

ABSTRACT'lllis paper investigates t11e combustion of magnesium and boron powders in hot steam. A thermochemical analysis reveals theoretical results of such interactions. An experimental investigation demonstrates that stable exotllennic oxidation takes place, resulting in actual combustion at 1100 °c for magnesium atld 800 °c for boron. 'llle reaction generates large qUatltity of gaseous products consisting of ahnost pure hydrogen atld correspondiIlg to about 60 per cent of a complete chemical reaction.metals indicates the possibility of stable combustion in a steam atmosphere and the use of this heat for metal and steam preheating. It can be seen that from this point of view magnesium and especially boron are the metals of particular interest (Table 1 ).

Theoretical Performance Evaluation of a Marine Solid Propellant Water-Breathing Ramjet Propulsor

“…Second to beryllium is boron, which demonstrates a promising theoretical heat and gas (i.e., hydrogen) release. In practice, it is hard to obtain high combustion efficiency of boron (though Rosenband et al [10] have demonstrated combustion of boron in steam), and in addition boron is a relatively expensive ingredient. Hence, for practical applications, aluminum is commonly considered.…”

Combustion wave propagation in magnesium/water mixtures: Experiments and model

“…The transition from zone 2 to 3 is characterized by a sharp increase in the temperature gradient at T ∼ 710 K, which may be explained by ignition of Mg particles. Indeed, as determined by Rosenband et al (1998), Mg powder ignites in steam flow at ∼ 723 K. The reaction rate for burning particles is much higher than for those before ignition, and is usually limited by external diffusion of the oxidizer (Glassman, 1996). Thus, zone 2 is characterized by relatively slow, kinetic-controlled oxidation of Mg particles by water vapor, while in zone 3, rapid diffusion-controlled combustion of Mg particles occurs.…”

Kinetic Analysis and Modelling of Mg Powder Slow Combustion

“…With high energy densities, metal powders appear to be good candidates for low-carbon energy carriers, and got more attention these last years [3], [4]. Many aspects of metal combustion were investigated through the years, but large part of these work focused on high temperature systems with particles ignition [5]- [9]. Only few studies [10], [11] aimed to investigate the combustion of metal particles subjected to low heating rates, leading to an exclusively heterogeneous combustion, which could be named "slow combustion" (i.e.…”