ABSTRACT
Ammonia fiber expansion (AFEX) treatment was first envisioned in the 1980s as an alternative to the ammoniation practices commonly performed on farms for the purpose of increasing nitrogen content and digestibility of forages for ruminants. Pellets produced from this pilot reactor have been proven to be equal to or superior to unpelletized AFEX treated biomass when subjected to enzymatic hydrolysis and subsequent fermentation to ethanol, with no further pretreatment or preprocessing required. Furthermore, these AFEX pellets can potentially be sold as a cattle feed, thereby opening up another market and incentivizing the development of a biomass market. AFEX treatment, then, can be considered a more extreme approach to this traditional ammoniation but the primary results— increased fiber digestibility and increased nitrogen content— are the same. AFEX pellets appear to meet the criteria needed for biomass logistics, handling, and storage. AFEX shows strong potential as a pre-processing operation within a depot setting.
