Cement plants mull used as source of fuel

Oil, Gas and Power

Karachi: The phenomenal rise in prices of coal last year has come to a halt. The commodity market watchers consider an amount of stability taking over in the worth of coal.

Yet, cement manufacturers have started to look for an alternative source of fuel, old or used tyres, technically termed: “Tyre-derived fuel (TDF).

Managers at cement companies contend that used tyres would cost 20 per cent less than coal. It could substitute 15 to 20 per cent of the coal quantity requirement in cement kilns.

”In the use of old tyres, Lucky Cement has adopted a pioneering stance and the company is expected to begin utilising used tyres by mid-FY12”, say analysts at AKD Securities.

For the transformation to used tyres, some minor modifications are needed in the existing plant, which analysts calculate could cost around Rs350 to Rs400 million.

A report prepared on the “Tyre-Derived Fuel” prepared by David Constans and David Gossman noted that hazardous waste fuel had been in use globally, as an alternate or supplemental fuel in cement kilns since 1980.

The driving force behind the desirability of alternate fuel to fire cement kilns was to reduce total fuel costs through substitution of primarily coal, used in these facilities. Consequently, there was renewed interest in the use of non-hazardous waste fuels. One of the most readily useable and highest heat content non-hazardous wastes was thought to be used tyres.

The authors of the report stated that TDF could be provided in a number of forms. The tyres could be ground into “crumb”.

Tyre “chips” of varying size are routinely utilised as cement kiln fuel.

The use of whole tires as kiln fuel was common in the cement kiln industry, in many countries. As a procedure, truck loads of whole tyres, usually carried in enclosed vans, were delivered to the end of a conveyor. Tyres were manually unloaded from the truck onto the conveyor.

The conveyor fed the tyres to a mechanism then inserted one tyre at a time into the kiln at specified time intervals. Both whole tyres and tyre chips were utilised as fuel with essentially similar results.

For the purpose of utilising tyres, there were two cement processes: long wet/long dry process kilns, or preheater/precalciner process kilns, said the experts.

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