ExxonMobil starts new butyl rubber process

Abstract

Animal manure and crop residues are agricultural wastes rich in carbohydrates and nitrogen that represent a largely untapped reservoir of biomass. These farm wastes have great potential as feedstocks for the production of renewable biobased energy and chemical products. This chapter presents a novel integrated farm-based biorefining system for producing ethanol, methane, and algal biomass from a mixed feedstock of animal manure and corn stover. The system includes three unit operations for anaerobic digestion (AD), algae cultivation, and bioethanol production. The AD process produces methane and pretreats the biomass fiber for bioethanol production. The algae cultivation process treats the liquid AD effluent, further reducing the environmental impacts of excess nutrients in the agricultural residues and generating a protein-rich algal biomass. Finally, a bioethanol process utilizes the carbohydrates in the AD-treated fiber to produce ethanol. The integrated system uses the advantages of individual biological processes to synergistically improve the energy efficiency of lignocellulosic biofuel production, address the water usage of lignocellulosic biorefining, provide a solution to ­problems with feedstock logistics, and alleviate the environmental impacts of agricultural residues. This integrated biological process could eventually lead to reducing our reliance on fossil fuel, while simultaneously maximizing farmers’ interests and minimizing environmental impacts.