The combination is cheaper than electricity
At a time when entrepreneurs, especially owners of small scale industries across the State, are feeling the heat due to unprecedented power cuts, an enterpriser in the district has surrendered one of his power connections and is keeping his unit humming with a generator that operates on a diesel-biogas combination. This combination ensures fuel saving and is cheaper than the electricity tariff.
P. Selvapandi of Alangulam is the managing partner of two small scale industrial units manufacturing popular detergent cakes. To trim the ever-growing power bill, he roped in Erode-based engineer K. Selvaraj of Grace Line Bio Energy, an expert in designing, fabricating and erecting non-conventional energy projects. With the cow dung available in Mr. Selvapandi’s dairy farm at Aladipatti, the duo devised an environ-friendly method of generating power.
The cow dung collected is immersed in about 40,000 litres of waste water that is generated from a rice mill nearby. This is then kept in a 11-feet-deep cemented pit with an area of 2,500 square feet. Methane, a coulourless and odourless gas thus produced,is piped to the 125 KVA generator that consumes diesel, the primary fuel, and biogas, the supplementary fuel, to generate electricity. The remaining gas is bottled in specially designed stainless steel cylinders and used for operating mini trucks.
"The 125 KVA generator, which consumes 15 litres of diesel an hour, now takes only 1.75 litre an hour as biogas is used as a supplement fuel," says Mr. Selvapandi, who has studied only up to Plus Two.
The excess biogas, after being cleansed in two stages, is cooled to minus 18 degree Celsius in a deep freezer, to increase its density, which has a bearing on the quantity of gas bottled in the cylinder. Again, the cooled gas is stabilized using liquid nitrogen before being stored in the specially designed cylinders at high pressure.
These are then loaded in the mini lorry, and gradually transferred to the truck’s air filter section, allowing it to mix with air, which is then taken to the engine where it is burnt along with diesel, the regular fuel, to operate the vehicle.
"Hitherto, the technocrats had developed technology to bottle only 4 Kg of biogas in the cylinder, which was enough to operate vehicles for a shorter distance. The technique we’ve developed ensures the bottling of 14 Kg of biogas, which is enough to operate the vehicle for about 14 hours continuously and saves 50 per cent of diesel consumption," says Mr. Selvaraj, adding that from the present set-up Mr. Selvapandi could get 400 cubic metres of biogas that can fill 16 to 20 cylinders.
Though one cylinder of biogas is enough to operate the vehicle along with diesel for about 400 Km, the maximum speed the driver can achieve is between 45 Km to 50 Km an hour.
However, Mr. Selvapandi is happy to be able to make a substantial saving on two counts – his electricity bill and fuel expenditure – while preserving the environment.