(285e) Bioethanol from SWEET Sorghum: A Decentralized Production Approach

BIOETHANOL FROM SWEET SORGHUM: A DECENTRALIZED PRODUCTION APPROACH

Anuradha Mukherjee, Rob Whiteley, Josh Ramsey, and Danielle Bellmer

Oklahoma State University, Stillwater, OK

E-mail: anuradha.mukherjee@okstate.edu , rob.whiteley@okstate.edu, , josh.ramsey@okstate.edu, danielle.bellmer@okstate.edu

With growing emphasis on cellulosic and advanced biofuel production, sorghum crops are gaining popularity as potential bio feedstocks due to the high sugar content in stalks and their tolerance to dryer conditions. At Oklahoma State University (OSU) a small-scale sweet sorghum based decentralized model is being considered for bioethanol production. A demonstration prototype ethanol manufacturing facility has been built to highlight the feasibility of an on-farm sweet sorghum to ethanol process. Experiments conducted at the Alcohol Separation Unit (ASU), OSUâ??s bioethanol research and demonstration facility will help establish the feasibility of a small-scale on-farm ethanol model, and bring to attention any technical issues with the process. Some of these bioethanol production issues include finding cost and energy efficient downstream production processes, fouling of equipment in downstream processes for ethanol removal from fermented streams, and establishing troubleshooting experience for bioethanol production.
The ASU serves as both a research and demonstration prototype unit, first of its kind to study bioethanol production from fermented sweet sorghum liquid feedstock. This pilot plant has been built to establish a robust downstream separation strategy crucial for on-farm bioethanol production. The Alcohol Separation Unit has a two-column distillation set up for concentrating ethanol, with associated heat exchangers, pumps, and storage units. Each unit has been designed to work with the sweet sorghum liquid feedstock. This pilot plant was commissioned in Fall
2013. A total of 5000 gallons of sweet sorghum feed containing 5 wt% ethanol have been successfully processed at the pilot plant and 190 proof ethanol was produced in October 2013. The total mass balance closes at 92% and ethanol purities of 193.6 proof at 74oF with rectifier column conditions of 0.8 psig and 171oF were established during processing.
Research activity at the pilot plant will translate into recommendations for farmers in terms of construction, operation, maintenance, and economics. This presentation/article discusses in detail the design, set-up, and operation of the pilot-plant. Planned use for the pilot plant and recommendations for end users will also be discussed. Material and operational costs, energy balance, and economics of the sweet sorghum on-farm process are also included in the presentation.