Water and Energy Use in the Ethanol Industry

The biochemical conversion of grain and cellulosic feedstocks is both water and energy intensive. All ICM designed corn ethanol plants are zero process water discharge plants. Process water is recycled with or without treatment in UASB reactors, depending on the individual plant operation. The only water leaving an ICM designed plant is non-contact evaporative water and water contained in animal feed products. ICM’s cellulose technology is also designed to a zero process water discharge plant. In a typical cellulose conversion process, there is no co-product to absorb process water. This requires innovative approaches, including co-locating with another commercial plant and more complex water clean-up and recycle strategies.

ICM has also been a leader in dry mill energy use. Historically, ICM plants have used less energy per gallon of ethanol produced than other technology providers. To achieve ongoing improvements in energy efficiency, ICM has aggressively pursued the maximum use of the energy train within the plant. In corn ethanol plants the evaporator train has driven heat/energy requirements. For most cellulosic conversion plants the pretreatment unit operation becomes the high point of the energy train. In addition to maximizing process energy, ICM has also worked closely with equipment providers to identify opportunities to minimize energy consumption, and thus reduce the plant carbon footprint.