First Waste Heat Power Station in the Cement Industry to apply the Organic Rankine Cycle Method 

Heidelberg Cement has always utilized facilities and innovations that make production processes as effective and environmentally friendly as possible. 

In the Bavarian Lengfurt plant (Germany) a pilot project has been implemented, in which Organic Rankine Cycle (ORC) technology is being employed, for the first time in a cement plant, in the production of electrical energy from low temperature waste heat. Previously, it was not possible to capitalize on exhaust air rising from clinker coolers with a temperature of 275°. The ORC method is essentially based on the idea that an organic propellant, which vaporizes at markedly lower temperatures, is used instead of steam. In this process, the purified exhaust air flows through a waste heat boiler that transfers it to an inline ORC process, in which the heat is turned into electrical energy by means of a turbine and generator. 

The ORC system was commissioned in the autumn of 1999 and has since been running without any problems. Measurements taken have revealed that power generated by this method covers up to 12 percent of the plant's total electrical energy requirements and saves more than 7,000 tonnes of CO₂ per annum that would otherwise result from the production of this amount of energy by conventional means. 

On account of its innovative and environmentally-friendly nature, this project was supported by the German Federal Ministry for the Environment. The Bavarian Environmental Office has commissioned Heidelberg Technology  Center to carry out studies over the course of a year to optimize the ORC system, obtain proof of the concept's effectiveness and test its application in other types of installation.