For many years, scientists and companies have been working on ways to convert methanol and ethanol into fuels used in vehicles and aircraft. Two main methods are widely used. One converts methanol into petrol, while the other turns ethanol into jet fuel, which is also known as kerosene, biofuels international reported.
Methanol is better suited for producing petrol because it has a smaller structure. Ethanol, which has a larger structure, is more suitable for making jet fuel needed for sustainable aviation fuel.
Traditionally, bio-ethanol has been produced on a large scale by fermenting sugar-based liquids. The process is similar to brewing beer from grain and then distilling it to produce stronger alcohol.
In Asia and the Americas, maize and sugarcane are the main crops used to produce bio-ethanol. Rice, sorghum and cassava are also used in smaller amounts. In Europe, wheat and sugar beet are commonly used instead.
Because these crops are also food sources, large areas of farmland are being used to produce fuel instead of food. This has increased pressure on global food supplies and pushed up prices for staple items. While small price increases may not strongly affect wealthier households, they can have serious consequences in poorer countries.
Experts say there is a growing global need to find new sources of ethanol that do not rely on food crops. Producing ethanol from industrial emissions is seen as a promising solution.
One US company has developed a method that uses special bacteria to convert carbon-rich waste gases into ethanol and other useful chemicals. The process captures carbon monoxide from industrial gases and transforms it into fuel.
Certain industrial activities, such as steel production, release gases that contain carbon monoxide. Some of these gases are currently used to generate heat and electricity, while others are released into the air. Instead of being burned or wasted, these gases can be captured and converted into ethanol.
The ethanol produced can later be turned into jet fuel using additional processing steps.
Studies show that this approach can reduce emissions, mainly by replacing fuels and products made from fossil sources with materials derived from ethanol. The overall environmental benefit depends on whether the industrial gases would otherwise have been released or already used for energy.
The technology has been tested in pilot projects and has since been expanded to larger demonstration facilities in different countries. It is now operating at industrial sites that use waste gases from steel production, as well as at a facility in the United States that produces ethanol and other chemicals. A related system has also been used to produce sustainable aviation fuel.
To turn ethanol into jet fuel, it must go through several steps. First, the ethanol is heated to remove water and create a simpler chemical form. This step requires significant energy.
Next, the new compound is combined in a controlled process to form longer fuel molecules. Careful management is needed to ensure the result becomes jet fuel rather than plastic material.
Finally, the fuel is treated to remove any remaining oxygen and then separated into different fuel types, including petrol, diesel and jet fuel.
The entire process is designed to maximise production of sustainable aviation fuel, which is considered the most valuable end product.
