Organic Rankine Cycle (ORC) based power plant to utilize low-grade waste heat sources

The paper presents an ABB ORC (Organic Rankine Cycle) power plant that is currently under construction at a cement plant in Switzerland. It describes the process engineering solution and the technical advantages of the ORC technology, which uses waste heat from the suspension preheater gas and the clinker cooler waste air, without any need for additional fuel. One unique aspect of the project is the heat extraction process in the intermediate cycle, which uses pressurized hot water. The benefits of pressurized hot water as a heat transfer medium are compared to the alternative, thermal oil. The estimated improvements in energy efficiency and operating costs at the cement plant are given. In conclusion, the lessons learned are shared and an overview of the technology drivers and technical parameters is given. These are important for other cement plants that are considering how best to harness their low-grade waste and convert it profitably into electrical energy.