Green and Sustainable Chemical Looping Plasma Process for Ammonia and Hydrogen Production

Abstract

The overarching aim of this chapter is to propose a novel clean thermochemical process that harnesses thermal plasma technology to co-produce hydrogen and ammonia using a chemical looping process. The thermodynamic potential and feasibility of the process were demonstrated using a simulation of the system with aluminium and aluminium oxide as the oxygen and nitrogen carriers between the reactors. The effect of different operating parameters, such as feed ratio and temperature of the reactor, on the energetic performance of the process was investigated. Results showed that the nitridation and ammoniation reactors could operate at <1000 K, while the thermal plasma reactor could operate at much higher temperatures such as (> 6273 K) to reduce the alumina oxide to aluminium. The ratio of steam to aluminium nitride was identified as the key operating parameter for controlling the ammoniation reactor. Using a heat recovery unit, the extracted heat from the products was utilised to generate auxiliary steam for a combined cycle aiming at generating electricity for a thermal plasma reactor. It was demonstrated that the process can operate at an approximate self-sustaining factor ∼ 0.11, and an exergy partitioning fraction of up to 0.65. Integrating the process with solar photovoltaic showed a solar share of ∼32% without considering any battery storage units.