Bioethanol - What , Why and How?

What is Bioethanol?

The principle fuel used as a petrol substitute for road transport vehicles is bioethanol. Bioethanol fuel is mainly produced by the sugar fermentation process, although it can also be manufactured by the chemical process of reacting ethylene with steam.

The main sources of sugar required to produce ethanol come from fuel or energy crops. These crops are grown specifically for energy use and include corn, maize and wheat crops, waste straw, willow and popular trees, sawdust, reed canary grass, cord grasses, artichoke and sorghum plants. There is also ongoing research and development into the use of municipal solid wastes to produce ethanol fuel.

Ethanol or ethyl alcohol (C2H5OH) is a clear colorless liquid, it is biodegradable, low in toxicity and causes little environmental pollution if spilt. Ethanol burns to produce carbon dioxide and water. Ethanol is a high octane fuel and has replaced lead as an octane enhancer in petrol. By blending ethanol with gasoline we can also oxygenate the fuel mixture so it burns more completely and reduces polluting emissions. Ethanol fuel blends are widely sold in the United States. The most common blend is 10% ethanol and 90% petrol (E10). Vehicle engines require no modifications to run on E10 and vehicle warranties are unaffected also. Only flexible fuel vehicles can run on up to 85% ethanol and 15% petrol blends (E85)

Bioethanol Production

Ethanol can be produced from biomass by the hydrolysis and sugar fermentation processes. Biomass wastes contain a complex mixture of carbohydrate polymers from the plant cell walls known as cellulose, hemi cellulose and lignin. In order to produce sugars from the biomass, the biomass is pre-treated with acids or enzymes in order to reduce the size of the feedstock and to open up the plant structure. The cellulose and the hemi cellulose portions are broken down (hydrolyzed) by enzymes or dilute acids into sucrose sugar that is then fermented into ethanol. The lignin which is also present in the biomass is normally used as a fuel for the ethanol production plants boilers. There are three principle methods of extracting sugars from biomass. These are concentrated acid hydrolysis, dilute acid hydrolysis and enzymatic hydrolysis.

Gas Analysis - In and Out of Fermentation

Fermentation scientists in a wide range of biotechnology industries have been using mass spectrometers since the early 1980s. They monitor the composition of gas streams into and out of fermenters continuously, accurately and reliably. Unlike discrete analyzers they monitor all the air gases—oxygen, carbon dioxide, nitrogen and argon. They can also monitor a wide variety of volatile organics including ethanol. Because the concentration of ethanol in the vent gas is linearly related to the concentration in the fermenter broth, they give a continuous output of the ethanol production; this is particularly important for detecting the start of ethanol production and also for monitoring changes in ethanol production.

It is vital to maintain the precise environment that specific cells need to remain healthy and grow—this requires precise off-gas analytical data through every stage of the scale up process, from laboratory to pilot plant to bulk production.

With Union Minister of Road , Transport and Highways vision of 100% Ethanol based vehicles, it is important to know the dynamics of process and optimize the same!

"I want motorcycles, e-rickshaws, auto-rickshaws and cars to be 100 per cent ethanol-based in the next few years,"

Read more at: https://economictimes.indiatimes.com/industry/renewables/hydrogen-fuel-of-future-vehicles-will-run-on-100-ethanol-in-coming-years-nitin-gadkari/articleshow/109957028.cms?utm_source=contentofinterest&utm_medium=text&utm_campaign=cppst