Bioethanol

Bioethanol is considered one of the most promising replacements of gasoline. There are several benefits from using bioethanol - for example:

• Bioethanol is made from renewable resources;
• Bioethanol has positive impact on air quality due to cleaner combustion;
• Bioethanol reduces net carbon dioxide (greenhouse gas) emissions;
• Bioethanol reduces dependence on oil import;
• Bioethanol expands the market opportunity of the agricultural sector;
• Bioethanol promotes biotechnology.

While the traditional production of bioethanol is based on cereals, corn, and grains (also called first generation production of bioethanol), a newly developed processing concept, in which bioethanol is produced from lignocellulosic materials such as straw, cornstalks and vegetable waste, is being pursued (called second generation production of bioethanol).

Bioethanol (or fuel alcohol) is ethanol produced from biomass and/or the biodegradable fraction of waste, to be used as a fuel. Bioethanol can be used in all petrol vehicles, without the need to change engine specification, when blended with petrol up to 10 to 15%.

For conventional fermentation of sugars, to produce bioethanol, all kinds of biomass, including crops as sugar beet and grain (feed wheat, barley, corn), are used.

Old technology

This technology is not new, since the principles for the production process are almost the same as for alcohol production by fermentation. The main difference in production process is the need for dehydration of the ethanol up to 99%. The technology to use and produce bioethanol as a fuel has been applied since 1900 and was first used by car manufacturer Henry Ford. At this moment bioethanol is already used in several parts of the world.

Bioethanol is an environmentally friendly fuel for vehicles that normally run on petrol. As a renewable source of energy, it reduces demand on fossil fuels while it burns more cleanly and with reduced emissions of CO2, a greenhouse gas. As an energy source, bioethanol is carbon neutral in that it reduces, by up to 70 %, the amount of greenhouse gas released into the atmosphere. The CO2 released during ethanol production and combustion in an engine has already been absorbed from the atmosphere during the growth of the crops due to photosynthesis.

Road fuel targets

The reduction of greenhouse gases, to meet the climate change targets set by the Kyoto Protocol, is responsible for fuelling the current boom in biofuels. The European Union set road fuel targets under its Biofuels Directive in order to meet its Kyoto obligations, with a view to introducing higher targets as the market was developed. Petrol blends containing up to 5 % ethanol are already available in parts of Europe and do not affect standard vehicle

Flexible fuel vehicles that use E85, a blend of 85 % ethanol and 15 % petrol, are in use in countries such as the USA and Sweden, while ethanol blends are used in Brazil and in parts of Canada, amongst others. Bioethanol is produced by the fermentation of sugar, a wellestablished process used in the production of beer and alcohol. Carbohydrates such as starch from cereal and tuber crops - which is enzymatically converted into simple sugars - and natural sugars from sugar beet, sugar cane and sweet sorghum crops are fermented using yeast to produce a mash containing ethanol, water and unfermented solids. Distillation columns separate ethanol from the fermented mash, with additional purification taking place in rectification columns to produce an ethanol and water mixture. Dehydration is the step of removing the last of the water, taking the mixture beyond its azeotropic equilibrium to produce anhydrous ethanol, or bioethanol.

Octane enhance

A significant advantage of bioethanol is that it can be blended with petrol as both an oxygenator and octane enhancer.

Environmental concerns due to the widespread use of MTBE (methyl tertiary butyl ether, a possible carcinogen) in unleaded petrol have prompted drives to seek alternatives. Bioethanol provides an ideal solution in that it is a renewable and environmentally friendly petrol extender, while providing a direct substitute for MTBE as an octane enhancer. Ethanol is also suitable as a feedstock for producing other octane enhancers such as ETBE (ethyl tertiary butyl ether) or TAEE (tertiary amyl ethyl ether), considered safer than MTBE.

What to do with your waste materials?

Additional revenue streams are available from the spent products that result from ethanol production. These are usually dried to produce DDGS (distiller's dried grains with solubles) marketed as a protein and nutrient rich animal feed for cattle, pigs and poultry. Alternatively, the biomass can be utilised as a renewable fuel source, producing electrical power and heat for the process, or for conversion into methane for use as a fuel. These energy conversion technologies enhance the overall production energy balance and enable further carbon credits to be earned.

Contact

For further information, please contact:

Ing. R.J.A. Korten MSc

T  +31 (0)6 109 25 309

F  +31 (0) 317 491 473

E  r.korten@dlvplant.nl