Production of ethanol

Production of ethanol

The procedures used to produce ethanol and other biofuels from lignocellulosic materials are referred to as second generation, while those used to produce ethanol from materials high in sugars or starches (which are sugar polymers) are referred to as first generation. While first generation technologies have reached a high level of commercial maturity, it will take the second generation years or perhaps decades to catch up.

Fermentation is the term used to describe the common process for turning biomass into ethanol. Plant sugars are metabolized by microorganisms (such bacteria and yeast) during fermentation to create ethanol.

A pretreatment procedure is used to reduce the size of the feedstock, break down the hemicellulose to sugars, and open up the structure of the cellulose component in order to make ethanol from biomass feedstocks. Enzymes hydrolyze the cellulose component to produce glucose sugar, which is then fermented to produce ethanol.

ESSENTIAL RAW FILES

The majority of ethanol is made from renewable raw materials, which mostly consist of sources of carbohydrates in the form of sugars (fruits, Jerusalem artichokes, beets, sweet sorghum), starches (corn, wheat, cassava, and sweet potatoes), and lignocellulosic materials. The reason why maize is currently the primary raw material for ethanol production is due to its enormous popularity as a part of the global culture. In the US, the technology for turning corn into ethanol is quite advanced. It is currently the world's biggest producer of ethanol.

Wet milling and dry milling are the two methods utilised, both of which have respective advantages.

Ethanol production technique:

The earlier and more established method of making ethanol from maize is dry milling. The steps include grinding, cooking, saccharification (hydrolysis), fermentation, and distillation, all of which are clearly defined.

1. Mechanical mills are used for grinding, producing the right granulometry for saccharification. Gelatinizing starch during the heating process enables enzymes to hydrolyze it into sugar. The maize bran is transported to the pre-cooker, which runs at 60 oC and with mechanical shaking; the maximum precooking period is 5 minutes, after it has been combined with water and stillage to obtain a solids concentration of 35%.

2. The moist dough is then transferred to the continuous cooker, which maintains a temperature of 180 oC and a pressure of 11 bar. It will stay in the continuous cooker for around 2 minutes.

3. Under pressure, the cooked gum is discharged onto the saccharificator, where some of the water flashes away.

With the exception of the SSF process, fermentation and distillation methods are comparable to those used for sugarcane. In this instance, the entire operation takes over 40 hours. Distillers Dried Grain with Solubles, also known as DDGS, is the primary byproduct of the dry milling procedure and is used as cow feeding. With the increased rise of corn ethanol in the US, the wet milling technique was more recently developed and first used on a wide scale in the late 1970s. It was initially intended to create pure starch, which is used to make corn fructose syrup (high fructose corn syrup, or HFCS), dishwashing detergent, and other products.

Ethanol, distillers' grain, and carbon dioxide are all products of dry mills. The fermentation produces carbon dioxide as a byproduct, and the distillers' dried grain with solubles (DDGS), a non-animal, high-protein livestock feed additive, is created during the distillation and dehydration process. Distillers' wet grain (DWG) is the term used for distillers' grains that have not been dried.

The 'bio-refineries' known as wet mill facilities create a variety of high-value products. Processing facilities that use wet mills generate more value byproducts than those that use dry mills. Using maize as the feedstock, for instance, wet mill facilities can make ethanol, corn gluten meal (which can be used as a natural herbicide or as a high protein supplement in animal feeds), corn gluten feed (which is also used as animal feed) and corn germ meal.

TOTAL PRODUCTION COST

The capital cost, capital-related expenses, and production cash costs are added together to provide the overall cost of making ethanol.

To make ethanol, any grain that has starch can be used. Starch is commonly found in grains including wheat, barley, corn, sorghum, and other cereals in amounts between 55% and 70%. The cost of starch, not the cost of the grain, is the most crucial element. Approximately 620 litres of ethanol may be produced from one tonne of starch. This is equivalent to:

A tonne of grain with 60% starch will provide 360 litres of ethanol, while a tonne with 70% starch will yield 420 litres of ethanol, an increase of 17%.