Electrochemical Nitrogen Fixation for Distributed Fertilizer Production

Electrochemical Nitrogen Fixation for Distributed Fertilizer Production
Karthish Manthiram, Warren K. Lewis Career Development Professor, Department of Chemical Engineering

Period of performance: 

September 2017 to August 2019

Abstract: 

Low crop yields are a key contributor to malnourishment and poverty in Africa. Application of fertilizers is several times lower in Africa compared to other regions of the world, limiting the agricultural productivity of the soil. Although this could be solved by application of fertilizers, there do not exist robust, local markets for fertilizers in Africa. This is in part driven by the fact that farming in Africa is small-scale and scattered, and the costs of distribution are very high due to poor infrastructure; this situation is not compatible with the highly centralized production of ammonia for fertilizers via the Haber-Bosch process. The Haber-Bosch process needs to be conducted at large scales due to the high temperatures and pressures used, which are cost-prohibitive at smaller scales. This motivates the development of distributed methods of producing ammonia, which can be conducted locally using commonly available feedstocks.

We propose an electrochemical device, which can be driven using solar panels, to convert nitrogen from air and water to produce ammonia. Because the device requires only air, water, and sunlight, it can be deployed at remote locations. This electrochemical device will enable modular, small-scale operation at low temperatures (<100 oC) and pressures (1 bar). The produced ammonia can then be directly injected into soil or reacted with carbon dioxide to create urea, which can be easily handled by farmers for local use. Our research activities will initially involve the design of catalysts and electrochemical devices for efficient, low-cost synthesis of ammonia. We will then explore methods of delivering ammonia to soil and conduct a technoeconomic analysis of the developed process. Altogether, our proposed efforts will help to understand the viability of local, electrochemical generation of fertilizers to enable small communities of farmers to take control of their own soil health.