Bioethanol production

Bioethanol is blended into transport fuel to reduce its overall carbon footprint, and is produced by fermenting biological feedstock materials such as sugarcane and corn. Other starch crops include wheat, barley, rice and tapioca, while cellulosic fibres from crop and wood residues, dedicated energy crops, and industrial waste can also be used. Alfa Laval delivers leading bioethanol production technology for use throughout the process, increasing uptime and yield while saving energy & space.

Alfa Laval is helping to support producers in their drive to make bioethanol production more profitable and sustainable, enabling them to:

Get the most out of every processing step with components that help maximize yield, uptime, and product quality, while minimizing energy consumption
Achieve optimal separation performance, reliability and energy efficiency by using industry-leading decanters to remove spent grains
Boost efficiency through heat recovery by high-performance heat exchangers, as a close-temperature approach optimizes uptime and means a rapid ROI
Access innovative technologies primed for use at every process phase whatever the feedstock, from sugarcane and corn to other starch crops and waste

Process steps

Pre-treatment section

Alfa Laval WideGap plate heat exchangers, with their extra-wide spacing between plates, have been specifically developed to efficiently handle streams with a high degree of fibre and solids. That means they are the ideal solution when water slurries with milled grains and cellulose are heated during liquefaction, and for the saccharification steps and cooling phase before fermentation.

For cellulosic-based ethanol plants, where fibres are very long and abundant, Alfa Laval spiral heat exchangers are an excellent alternative.

For wheat-based plants, Alfa Laval’s gluten separation systems and separators provide a reliable way to extract additional value from the process. 

Fermentation 

Alfa Laval gasketed heat exchanger solutions keep the fermentation temperature at optimum levels, even when the cooling water is just a few degrees colder than the fermenter temperature.

Meanwhile, Alfa Laval’s tank cleaning equipment ensures rapid, reliable cleaning of the fermenter, improving both yields and reliability. 

For sugar- and molasses-based ethanol plants, Alfa Laval disc stack separators can efficiently separate and recycle yeast from the beer after fermentation to further increase the ethanol yield.

Distillation/dehydration 

Alfa Laval has developed purpose-built reboilers and condensers that are well-suited for the distillation section of the bioethanol production process. The low weight and compactness of the AlfaCond condenser, for example, is valuable when placed at the top of the distillation tower, making installation easier and cheaper.

The efficiency of Alfa Laval reboilers makes it possible to work with small temperature differences that optimize energy efficiency still further by offering the possibility to use lower-quality heat sources. 

When it comes to pressure swing dehydration, where fatigue may become a problem, then Alfa Laval’s flexible gasketed plate heat exchangers are the most durable equipment available.

Stillage concentration

The DDGS (Distillers’ Dried Grains and Solubles) for cattle feed is another of the benefits that come from ethanol production. It is produced when the stillage is dewatered, evaporated and dried, and has always been an important source of income for ethanol producers.

Ever since the 1970s, Alfa Laval has been the leading supplier of stillage dewatering decanters.

The unique VecFlow rotating feed zone feature combined with Power Tubes, for example, delivers a very dry cake, while keeping the energy consumption low, while AlfaVap plate evaporators and AlfaFlash forced-circulation flash evaporators are used to reach high thin stillage concentrations in the most energy-efficient way.

yellow gold dried grains with solubles and corn grains

Further benefits of ethanol by-products

Stillage contains valuable products that can be extracted, such as proteins and corn oil, and Alfa Laval has the technology and expertise to maximize the value of your processes.

The Alfa Laval Prodec Oil Plus decanter delivers a patented solution for oil separation that results in corn oil yields well beyond industry standards. This decanter is purpose-built for efficient oil extraction, with a long extraction zone and a specific internal flight arrangement. These decanters can be used either on the whole stillage, on the evaporated syrup or even on both for the highest possible oil yield. Alfa Laval decanters can also extract valuable proteins that can be fed to cattle and poultry.

Energy efficiency

In recent years, the average energy balance in bioethanol plants has significantly improved. However, through talking to ethanol producers today, it becomes clear that there is still untapped potential for further energy savings.

Alfa Laval’s products are designed to improve the energy balance of bioethanol plants, while also delivering smooth operation and ensuring maximum uptime as:

High-performance heat exchangers provide maximum heat recovery from any process stream
Superior decanters eliminate the degradation of solids feed in ethanol process
Industry-leading separation efficiency delivers reduced energy consumption with the clearest centrate
Overall performance means improved bottom lines, increased production uptimes, and reduced carbon footprints

Alfa Laval service providers are always on hand to help maximize energy recovery and overall equipment performance.