Turkey – Use of Biofuel
Dikili, one of Imerys’ most important perlite-producing sites, has been using olive pits as an alternative source of energy for over 15 years.
The raw material contains 4% free moisture. Every year, 3,200 tons of water has to be evaporated. The ore drying phase uses up a great amount of energy. 15 years ago the site consumed 400 tons of oil fuel per year, expense that accounted for a large share of its production costs and that motivated the team to find an alternative.
Olive pits seemed an obvious answer. The renewable resource was available in large quantities with extensive reserves nearby. Initial research took place in 1995, and studies confirmed the project’s feasibility. As long as the shell is intact, olive pits contain no dust, so ash is not generated during combustion. They are also very solid; they burn slowly, keeping the dryer at an even temperature. Since the pits don’t contain any volatile radicals or sulphur, no airborne pollutants are generated. The material is crushed into 1-2 mm particles by suppliers and can be fed into the furnace without further processing. No waste is generated, no prior preparation is required and the process is four times cheaper than fuel oil.
Since 1996 the furnace has operated 24 hours a day, 5 days a week, consuming 1,700 tons of olive pits per annum. The biomass covers 100% of the energy needed for the dryer, which heats air to over 650°C.
The Turkish olive pit market has been under some stress in recent years, leading the site to explore other options. For instance, pine cones and miscanthus, a plant in the bamboo family whose outstanding calorific value gives it great potential as fuel, could be additional local resources.