CEE Jan-Mar 2012

- .'I regular fuels; consequently AFR has to be pre-processed in an appropriate manner to get a constant quality and has to be handled in a constant mass flow, too. Therefore different types of truck unloading stations had been developed as a compact reception device by Vecoplan (Figure 10). Walking floor trucks or tipping trucks can unload solid alternative fuels, which will be transported to the following chain of storage and dosage. The receiving station is covered completely to keep the dust emission in the external area as low as possible. The truck drive initiates the truck unloading procedure, automaticall y also the material conveying to the silo box selected by the control room operator will start. After the rear doors of the truck are closed the device is in progress. The respective silo has to be selected by the control room before the material receiving can be carried out and the correct material is conveyed to the silo it is intended for. The loading and discharge conveyor consists of a distribution conveyor with the drive that can be moved up and down with steel wire ropes using a lifting device with drive that has two different speeds. The storage usually filled and discharged with AFR material nearly simultaneously. Additionally, during filling or discharge the storage material could be sampled by a subsequent sampl ing station. By means of the recent established joint-venture of Polysius and Vecoplan, FueiTrack offers the total chain from identification and sourcing, pre-processing to appropriate alternative fuels and raw materials for the preheater or refining for the main burner to co-process AFR. A tailor-made storage concept, quality monitoring and dosing arrangements up to adaptations of calciner, main burner or clinker production process itself completes the range from one hand for the clients target to save money as a long lasting effect. www . vecoplan-fueltrack.com Courtesy: ZKG International, Issue 10, 2011, Pp50-58. ALTERNATIVE FUELS TO COAL It is expected that at the present rate of coal consumption, the coal reserves in India will be exhausted in the next 70 years Coal is the primary fuel used for the manufacturing of cement. The increasing demand for coal for various purposes such as power generation, steel production has resulted in depletion coal supply. The present coal supply will last only for a century. Cement is one of the sectors which is totally dependent on coal for production of cement. In India, the power sector is given priority for supply for coal, whereas the cement industry is last on the list of priorities. For the production of cement, the industry requires high calorific coal. However, its availability is decreasing day by day. With frequent power shortages throughout the country, coal for the cement industry has become a scarce commodity. The government subsidized coal for gives cement companies so that cement is available to the common man. However, it means that cement companies are obliged to import coal from Australia. Africa and other continents where coal is available in abundance. Unfortunately, imported coal is not available at subsidized rate. Imported coal is not available at subsidized rate. Imported coal is sold at almost doubl e the cost of the indigenous product. Furthermore, the depreciating rupee against the US dollar adds to the increasing price of coal. Cement manufacturing is energy- intensive, due to the high temperature processing required . A cement plant consumes 3 to 6 GJ (giga– joules) of fuel per tonne of clinker produced, depending on raw materials and the process used. Burning alternative fuels in cement kilns offers several environmental benefits. This type of energy recovery conserves valuable fossil fuels for future generations, while safely destroying wastes that would otherwise be deposited in landfills. When combusting waste in cement kiln, the amount of coal displaced will be proportionate to the heat content of the waste. Therefore 1 tonne of biofuel will displace 0.62 tonne of coal, and one tonne of solvent waste will displace 1 tonne of coal. Assuming an energy consumption of 4 GJ/t of cement, 1 tonne of bio-fuel will produce 4 tonnes of cement, while 1 tonne of solvent waste will produce 6.5 tonnes of cement. Rapid industrialization has put a huge burden on resources throughout the world. Energy is one such resource having a wider impact on all aspects of human life. The cement industry is a major consumer of energy and in India, which has the third largest coal reserves in the world, it consumes around 6 per cent of 45