In an attempt to aid in the demilitarization and disposal of propellant from end of life cycle military munition items, a methodology is presented in which the nitrogen content in the propellant is conserved and assimilated into algae cultivations in order to produce hydrocarbon fuels. The process includes an alkaline hydrolysis reaction to break down the nitrocellulose main ingredient into a caustic solution of nitrates and nitrites followed by pH neutralization and algal assimilation for ethanologenisis. While hydrolysis processes have long been employed for the demilitarization of pure nitrocellulose, little research has been applied to formulated, final product propellants.  The addition of stabilizers and alternative explosives as well as a compacted grain configuration complicate the solubility, reaction kinetics and products as compared to the hydrolysis of pure nitrocellulose and optimization of nitrogen release into solution was not previously studied. Assimilation of the resulting nitrogen rich hydrolysate into selected cyanobacteria capable of producing biofuels requires designated algae strains contain the transport genes to uptake both nitrate and nitrite in a solution that is not toxic to the algae. In this work alkaline hydrolysis was optimized using a statistical design of experiments to maximize nitrogen content. The resulting hydrolysate was neutralized, analyzed and then used as the sole nitrogen nutrient source for algae cultivation. Results from indoor and outdoor algal cultures indicate ethanol production within 20% of control cultures using commercial grade nitrates.

Conservation of nitrogen in military propellant for ethanol production by algae

255th National Meeting (2018)

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