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Bioethanol Distillation & Advanced
Learn about the bioethanol distillation process and discover the most reliable pumps for this challenging and exacting work at Burt Process Equipment.
Biofuels are the answer to today’s energy concerns. While Europe is currently the leader in biodiesel production and consumption, the U.S. leads the way in bioethanol. In bioethanol distillation, water in the ethanol must be removed. Pumping systems used in ethanol distillation have special requirements, such as high flow and high fiber capability, precise temperature control and reliability. All ethanol distillation equipment must be sanitary, reliable and easy to clean.
Before Distillation – The Dry Milling and Fermentation Process
There are two types of milling—dry milling (used for about 80 percent of U.S. corn ethanol) and wet milling. In dry milling, corn kernels are ground into flour, called “mash,” and then water is added to turn it into a slurry. Enzymes are used to hydrolyze the starch, turning it into simple sugars. The pH is adjusted with ammonia, which also acts as a nutrient for the yeast, which is added later in the process. To reduce bacteria levels, the mash is cooked at high temperatures, and it is then cooled in fermenters. The added yeast ferments sugars into ethanol and carbon dioxide. For 40-50 hours, this mash is agitated and kept cool, promoting yeast activity.
Ethanol Distillation Process and Water Removal
The mash is transferred to distillation columns so that the ethanol can be extracted. Regarding water/ethanol distillation, it is only possible to achieve 95-96 percent purity, due to the formation of low-boiling water and ethanol azeotrope. Further treatments are required to remove additional water, so that the ethanol can be combined with fossil fuels. See here for the ethanol distillation curve for EPA certification gasoline.
The Pumping Challenges for Ethanol Distillation
Because of the complex composition of this ethanol mash, with varying chemicals, viscosity and temperatures, bioethanol production equipment is subject to a lot of abuse, and that’s especially true of the pumps. Grundfos, a world leader in pumping technology and efficient solutions, manufacturers heavy duty pumps that are designed with a wide range of materials and specifications to meet the unique demands of the biofuel industry. These high performance, extremely reliable pumps are designed to protect against corrosion as well as explosion risk and cavitation, which are two primary concerns in ethanol distillation.
Grundfos’s ATEX-approved pumps are available in stainless steel to cope with the changes in liquid composition during distillation while ensuring continuous flow. The company also has pumps that can handle the liquid during the evaporation process, which ends with Dried Distillers Grain (DDG). Pumps designed to handle aggressive chemicals and alcohol include their NBG/NKG end-suction pumps and the CR multistage pump, which comes in stainless steel variants.
Other pumps for adding chemicals include SMART Digital (DDC, DDC and DDE) diaphragm dosing pumps (modular, simple design and with flow intelligence), motor-driven diaphragm dosing pumps (DMX), oscillating positive displacement pumps (DMH), precision dosing pumps (DDI) and large-volume dosing pumps (DME).
Grundfos pumps provide continuous operation, integration and control across the pump and factory systems, material variants and low NPSH pumps to reduce cavitation risk, pump approvals and certifications, CIP capability and service products that reduce downtime and optimize reliability. At Burt Process Equipment, we offer the complete line of high performance Grundfos pumps.