PROJECT DESCRIPTION
BACKGROUND
The flue gas purification plant of the district heating power station at Neudorf/ Werndorf (Austria) is based on a wet separation of ash and soot contents; the state-of-the-art approach is to dispose of the residues (a mixture of oil ash, soot and gypsum) as waste. As the waste problem (and thus the costs of waste disposal) is likely to increase continuously, a technology for eliminating the residues and feeding them back into the materials cycles is attractive from both an economic and ecological point of view.
OBJECTIVES
The aim of the pilot project was to achieve a separation of the mixture of the residues from the flue gas dust purification (a mixture of oil ash, soot and gypsum) into solid residues in order to be able to re-use the major part of it as valuable substances and not to have to dispose of it as waste (gypsum as a valuable substance for the cement industry, complete utilisation of the solid residue by burning). The project was to be carried out in two phases: Phase 1 included: - the realisation of the pre-tests in order to verify the chemical, physical and mechanical properties of the process; - the installation of the necessary components on the existing plant - optimisation of soot separation and the separation of gypsum. In phase 2, an attempt is made to burn the oil ash/ soot mixture in the nearby district heating power station with hard coal dust which is also incinerated there. The anticipated results are a complete utilisation (100%) of the solid residue by burning and a separation of ash as a valuable substance.
RESULTS
Phase one was implemented as foreseen and the anticipated results were achieved: the retrieval of the valuable substance gypsum and a reduction of the residual materials for disposal (completely burned ash) to < 30% of the amount of solid residue. Phase two was modified in that the oil ash/soot mixture was not incinerated in the nearby district heating power station, but rather in a cement factory where the substances partly replaced the clay. With this project, the waste-material-free purification of flue gas from a heavy fuel oil-fired boiler has been realised for the first time ever. This tested method could be replicated on a European level - in all large-scale power stations and industries (e.g. refineries) operated by heavy fuel-oil fired furnaces with a flue gas dust purification. Phase one was implemented as foreseen and the anticipated results were achieved: the retrieval of the valuable substance gypsum and a reduction of the residual materials for disposal (completely burned ash) to < 30% of the amount of solid residue. Phase two was modified in that the oil ash/soot mixture was not incinerated in the nearby district heating power station, but rather in a cement factory where the substances partly replaced the clay. With this project, the waste-material-free purification of flue gas from a heavy fuel oil-fired boiler has been realised for the first time ever. This tested method could be replicated on a European level - in all large-scale power stations and industries (e.g. refineries) operated by heavy fuel-oil fired furnaces with a flue gas dust purification.