Thermax develops India’s first boiler to generate energy from distillery waste

To help industry offset some of the costs due to the rising fuel costs, Pune-based energy and environment management company Thermax Limited has developed the first of its kind boiler to convert highly polluting distillery waste and spent wash into usable energy. The boiler has been installed at a leading distillery in Karnataka.

Spent wash is a brown liquid-waste that is generated as a by-product during the distillation of fermented molasses. A typical distillery generates six to 15 litres of spent wash per litre of alcohol. Spent wash is highly acidic with a very offensive odour and it is a major source of ground water pollution. A typical distillery generates about 1000 tons of spent wash everyday.

The  boilers designed by Thermax convert this spent wash waste into usable energy - steam and power. An evaporator concentrates this 1000-ton waste to around 200 tons before it's fed into the boiler. Steam from the boiler will be used in the distillery process and while co-generating 2 MW of power which will replace the distillery's requirement from the power grid.

A leader in energy and environment management, Thermax Limited is is one of the few companies in the world that offers total integrated  solutions in the areas of heating, cooling, power, water and waste management, air pollution control and chemicals.

Though Thermax has wide experience in burning an array of waste fuels (agri and industrial waste), the company's R&D team had to tackle the high moisture content and the corrosive properties of spent wash in designing this 23 TPH boiler, which uses coal as a support fuel.

''The alcohol business is highly competitive in India and overseas,"says M S Unnikrishnan, managing director, Thermax Limited. "This technology will enable Thermax to improve the competitive edge of its clients by improving productivity and reducing production costs. This will also mitigate pollution, which is a major issue with distilleries.''

By generating steam from spent wash, molasses-based distilleries can significantly reduce their energy costs. Every kilogram of concentrated spent wash replaces nearly 0.33 kg of Indian coal.  Thermax will install similar boilers at three other distilleries in the country.

Thermax, founded by the late Rohinton Aga over three decades back, reported an income of Rs3,246-crore ($760 million) in 2007-08.