Cement Energy Environment

42 Figure 5: The polysius ® fuel substitution strategy aims at the usage of coarse fuels that need no pre-treatment. Due to its modular design, it can be well integrated into existing cement plants. High availability and simple maintenance are due to the design with no moving parts in the combustion chamber. In the production of cement, raw materials such as limestone, clay, sand and iron ore are burned at more than 1,400°C to form clinker and then ground with gypsum to produce the finished cement. The air generated in the preheater or during cooling of the cement clinker, which can reach temperatures of up to 400°C, is then often released unused into the environment. With thyssenkrupp’s waste heat recovery systems, the waste heat from cement production can be used to generate electricity. For this purpose, steam is generated in boilers which then drives generators. This sustainable use of waste heat reduces environmental impact and lowers production costs of cement. So far, Indian cement producers in particular have relied on the complete power plant solutions with waste heat recovery made by thyssenkrupp. No wonder, since they were developed by thyssenkrupp Industries India in 2008. With these plants it is possible to use up to 33% of the waste heat from the kiln and the waste heat from the preheater tower for power generation. In this way, the plants installed in India and the United Arab Emirates in recent years are capable of generating more than 290 megawatts of electricity on continuous basis. More and more cement producers are showing interest and want to optimize the energy management of their plant. Demand for thyssenkrupp heat recovery systems is growing continuously. For the conversion of waste heat into electrical energy, polysius ® Waste Heat Recovery - How Hot Air Becomes Green Energy thyssenkrupp produces customized boilers for its cement customers at the Indian sites in Pimpri and Hyderabad. Depending on the size of the plant, between 30 and 300 metric tons of steam can be generated per hour in the boilers. Turbo generators then convert the steam into electrical energy. The power generation plants built by thyssenkrupp have capacities of five to 33 megawatts & has capacity to build of higher capacity depends up on the kiln size & heat in-put. Another advantage is that the heat recovery plants can be installed and commissioned in a short time which makes it economically viable from the shortest pay back period. Existing cement plants can also be optimally retrofitted with this low maintenance technology (Figure 6).