HiGee Stripper-Membrane System for Decentralized Bioethanol Recovery and Purification

Economic production of bioethanol from lignocellulosic feedstock is one of the important solutions to the rising environmental concerns and depleting crude-oil reserves. However, feedstock available for bulk production of bioethanol is spread over a wide horizon and is of low-energy density, and bioethanol produced in the fermentor is dilute (∼5 wt %), which significantly increases the energy required for and cost of bioethanol production. To address these issues, the present article introduces a process-intensified technology, namely, HiGee (short for high gravity) stripper combined with a membrane (HSM) process for concentrating bioethanol. The performance of HSM is compared with one of the best energy-efficient process for bioethanol purification in the literature. Design, optimization, and technoeconomic evaluation of both the processes are performed, and the HSM process is found to be compact, require lower capital and operating costs, and have a high turndown ratio over the conventional process. The size benefit of the HSM process is essential for transporting bioethanol separation units using commercial motor vehicles for decentralized and portable bioethanol recovery and purification.