Using individual improvement ideas submitted by employees, a new type of waste heat recovery facility for the power plant at the Linz location was developed. This will enable a savings of EUR 900,000 annually for energy costs.
At the power plant at the Linz location, there were always many individual ideas that came from employees and dealt with waste heat recovery. The individual ideas coming out of the continuous improvement process (“CIP”) were ultimately combined and developed into a major project. The project consists of two partial sectors:
- Steam condensate recovery and
- Wastewater recovery
Using waste heat
In traditional power plants, only 30–40% of primary energy input is converted into electricity. However, with low temperature and pressure, a great deal of energy is wasted. The skill required here is to use this waste heat effectively. Part of this loss of waste heat, which escapes from power plants in the form of steam, can be utilized. With this new concept, finely atomized water is injected into the rooftop piping. This creates fog that condenses; warm water runs through the collector pipes into the heat recovery facility, where the energy is used. Therefore, heat that simply vanishes into thin air is now a thing of the past.
800.000 m3 of water from the Danube saved annually
Each power plant block generates wastewater with a temperature of 80–90 °C, which was previously cooled down to 30 °C using water from the Danube and then discharged into the river. The loss of 50–60 °C of heat, which was previously wasted, is now being used. A closed piping system transports the hot water to a collecting tank, the process water is pre-warmed using a heat exchanger, and—after a pre-cleaning process—the cooled-down water is returned to the water treatment system. Steam, which was previously required to heat up the process water, is no longer needed. As a “side effect,” there is a savings of up to 800,000 m3 of water from the Danube that was used annually as a cooling medium.
Thus, many individual CIP ideas from voestalpine employees were turned into a new heat recovery facility in the power plant. And the result is quite impressive: an investment of EUR 1.5 million has made it possible to save as much as EUR 900,000 a year. After just 1.7 years, the investment has paid for itself. As energy costs rise, the savings that this innovation makes possible will probably be even greater.