OPERATING EXPERIENCES OF THE RHKW LINZ

摘要

Residue derived fuels are more and more used to substitute oil and gas fired power plants units close to large cities with high potential for district heating. Another driving force is the Kyoto protocol for CO2 reduction resulting in state support for green power electricity substitution of imported primary energy and multi-fuel concepts together with RDF. Additionally, to the conventional grate based waste to energy solutions combustion of RDF in fluidised beds gains more and more importance. This is driven by the fact that this technology is capable for a high degree in fuel flexibility combined with low emissions. In Linz STRABAG Energy Technologies (SET) has erected a new 72 MWth fired RDF fluidised bed boiler. The boiler is designed as a SETCIA bubbling fluidized bed operating in multi-staged combustion mode. The fuel is gasified in the bed to yield combustible gases (mainly H2 and CO) which are then combusted stepwise further in the post combustion chamber. The substochiometric bed operation allows a bed temperature control in the range between 600°C-900°C. Therefore, fuel with low ash melting temperature can be safely combusted and the alkali release to the flue gases is reduced. The stepwise combustion of the yielded gases reduces the formation of NOx as well as the formation of melted ashes.