Mathematical modelling has in recent years proven to be a useful and cost-cutting tool for designing and modernising coal-fired power plants. The OxyMod project supported by the European Union (EU) Research Fund for Coal and Steel (RFCS) has striven to extend existing combustion modelling capabilities to oxy-fuel combustion conditions. This should lead to preparation and pre-engineering of large demonstration power plants in Europe using modern and clean oxy-fuel CO2 capture technology in the near future.
© Fotolia, 2012
Oxy-fuel technology was proposed for conventional pulverised coal-fired combustion already in the '80s; however, recent developments have led to a renewed interest in the technology, with the ultimate goal of significantly reducing CO2 emissions via capture. During the process, pure oxygen is used as the primary oxidant (rather than air), and combined with recycled smoke exhaust, thereby producing a gas consisting of mainly CO2 and water vapour, which after purification and compression is ready for storage. The high oxygen demand is supplied by a cryogenic air separation process, the only commercially available mature technology. The separation of oxygen from air, and purification and liquefaction of the CO2-enriched smoke exhaust, uses considerable auxiliary power.
The OxyMod project has combined experimental work in Europe's largest oxy-fuel testing facilities with model development and implementation, and initial validation through comparisons to experimental data. An extensive database of oxy-fuel and air combustion trials in gas- and coal-fired testing facilities has been compiled. Initial validation in 20 kilowatt, 100 kilowatt and 500 kilowatt testing facilities has proved the combustion models developed can predict the more moderate combustion under oxy-fuel conditions. Room for further model development and evaluation work was, however, also identified.
"We were aiming to validate the methodology for safe, optimal scale-up and implementation of oxy-fuel technology. And we were successful," says Project Representative Göran Lindgren, Managing Director of Carbon Capture and Storage R&D in Vattenfall AB, Sweden. "We've developed toolkits, and validated technologies in several large-scale testing facilities. Currently, we're in stand-by mode, awaiting the opportunity to demonstrate it in full production scale", adds Lindgren.
With EU funding amounting to € 1,294,011 (60% of the total cost) the OxyMod project was implemented from July 2005 to October 2008 by a unique consortium suitable for the task, including: CFD model developers and users (Vattenfall Research and Development AB, IVD Stuttgart, and the National Technical University of Athens); experimental test facilities operators (Chalmers and IVD Stuttgart); a leading manufacturer of power boilers (Doosan Babcock Energy Limited); and a commercial code developer and manufacturer (Ansys UK Limited) .
OxyMod is one of many successful projects financed by the RFCS, which is now marking its 10th anniversary of supporting the competiveness of Community sectors in the industry. Since the first call for proposals, the RFCS has allocated almost € 500 million to support research, pilot and demonstration projects, bringing together industrial partners, SMEs, research centres and universities across the EU helping to develop knowledge and foster innovation.