Biomass gasification for ammonia production

109 million tonnes of ammonia is produced globally each year, 85% of this is synthesised from combining H2, produced from steam reforming of natural gas, and nitrogen separated from air. The process is very energy intensive and releases 208 million tonnes of CO2. Production of ammonia from renewable resources, such as biomass, could substantially reduce this. One option is to gasify biomass to produce a hydrogen rich syngas for ammonia production. This paper reviews currently available gasification technologies to assess the viability of ammonia production using this method, and identifies those most suitable for further analysis. The gasifier selection is based on the following criteria: syngas composition, efficiency, operating conditions, scale and biomass track record. Potential process schemes are presented with preliminary mass/energy and greenhouse gas balances to estimate the potential value of developing such a system. Critical issues are identified in the overall system, from biomass cultivation to ammonia production. These issues need to be evaluated further via economic and life cycle assessment techniques.