Pretreatment of biomass at regional depots could simplify supply logistics for the emerging biofuels industry. Ammonia Fiber Expansion (AFEX™) could be an appropriate pretreatment method for use at depots, if the process can be simplified. Here we investigate pretreatment of corn stover and wheat straw using a simple packed bed AFEX system that exploits the high porosity of biomass to facilitate ammonia transport.Results & discussion:
Steam stripping vertical packed beds allowed recovery of more than 90% residual ammonia as substantially dry vapor. AFEX-treated biomass gave enzyme hydrolysis yields equal to biomass treated in stirred batch reactors, and formed durable pellets.Conclusion:
Packed bed AFEX shows significant promise as a biomass pretreatment for use at distributed depots.