It's money, stupid

Waste can fuel savings in cement plants

 
By Radhika Krishnan
Last Updated: Saturday 04 July 2015 | 02:50:09 AM



Bad experience Take, for instance, the experience of Shree Cement Limited, a cement plant in Rajasthan. It wanted to use Delhi's municipal waste, but could not finalise an agreement with the Municipal Corporation of Delhi (mcd) on who would pay for transportation, and whether the waste would be supplied free. The wrangling was typical of how a useful deal could be scuppered. mcd was apparently willing to supply waste free if Shree Cement bore the cost of transportation. On the other hand, the company said since disposal was mcd's problem it wouldn't go further than contributing partly to transportation.

In spite of the problems, some cement companies have taken an initiative to use municipal solid waste as fuel for the kilns. Jaiprakash Associates Ltd plans to set up a Rs 23.28-crore waste-processing plant at Chandigarh. The plant will produce fuel pellets from municipal waste that will then be used for its cement plant. The company has already signed a memorandum of understanding with the Municipal Corporation of Chandigarh.

Other cement manufacturers are also following suit. Grasim is, for instance, setting up a 500 tonnes-per-day waste-processing unit in Jaipur.

Blowing in the wind The roadblocks on the way to using municipal solid waste as a source of energy were prefigured by the problem in using flyash in the production process. The cement industry has been complaining for a long time about having to pay for the transportation of a waste product that it is using in a manner that makes excellent environmental sense.

Waste hazards Apart from municipal waste, cement kilns could also use a variety of other wastes like used tyres, plastics and hazardous industrial waste. The high temperatures inside the kilns -- about 1,450 c-- are sufficient to incinerate these waste products.

However, hazardous waste has to be used cautiously. For instance, the presence of chlorine in the waste may lead to the formation of chemicals like polychlorinated dibenzodioxins (dioxins) and polychlorinated dibenzofurans, which are known carcinogens.

India generates more than 9 million tonnes of hazardous waste every year, almost 60 per cent of which comes from Rajasthan, Madhya Pradesh and Maharashtra. These states also host several large cement plants. But proper testing and stringent regulations have to be put in place before the use of hazardous waste in cement kilns is allowed.

India is the world's second largest cement producer. It also has a high potential to use waste as fuel. But only a minuscule part of that potential has been realised -- its cement industry uses waste to meet barely 0.5 per cent of its kiln fuel requirement. The waste fuels used are small quantities of waste oil generated in-house and some agro-residues.

The global leaders in waste utilisation are the us and Germany (see graph: Waste energy). For the industry, using waste is a win-win situation -- not only is it economical, but it also reduces dependence on dwindling supplies of fossil fuels. Besides, in developed countries, the waste producer pays the cement plants for disposing its waste.

The Indian cement industry is one of the most energy efficient in the world. But in terms of using waste as fuel, it still has a lot of catching up to do.

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