(180h) Improving Green Ammonia Production and Storage Using Absorbents

Ammonia is a key component in fertilizer required for global food production as well as a variety of specialty chemicals including electrolytes for batteries, food additives, analytical reagents, and is an ideal energy vector for a carbon-free economy. The availability of renewable resources like wind energy coupled with its co-location in areas with high fertilizer demand, give rise to the possible synthesis of green ammonia at small scale close to the end user. There is a growing interest in this method of ammonia synthesis as excess renewable energy can be stored as ammonia and converted back into electricity or hydrogen fuel during periods of high-power demand. Through our pilot scale process, we have demonstrated that ammonia can be made using air, water, and wind energy but this product is however more expensive than one based on fossil-fuels. One way of reducing this cost is by replacing the traditional ammonia separation by condensation with reactive absorption using metal halides. Although this method of ammonia separation is more efficient, these pure absorbent materials are unstable and show decreasing capacity with prolonged usage. Here, we discuss efforts to synthesize stable absorbent materials with improved mass and heat transfer compared to pure metal halides. These innovative materials possess better thermal properties and exhibit higher capacity for ammonia than previously used materials; making them ideal candidates not only for ammonia separation, but also for medium-to-long-term safe ammonia storage and transportation to support a green circular economy.