A joint research and development project on oxy-fuel combustion technology is making headway in reducing the CO2emissions of power plants.

The work being done by Helsinki-based Metso and Fortum in Espoo, Finland, has taken place at a Metso 4-MW test plant in Tampere, Finland, which was modified for the technology. The project is based on circulating fluidized-bed technology because it can be operated with a range of fuel types such as coal, biomass or a fuel mixture.

The research involves switching from air combustion to oxygen combustion. In oxy-fuel combustion, the flue gas consists of almost-clean water vapor and CO2, which can be captured. Adding a carbon dioxide recovery system to a biomass-fired power plant creates a carbon sink that abates climate change.

“We have carried out a comprehensive series of tests ranging from laboratory measurements to continuous pilot-scale tests,” says Jussi Mäntyniemi, general manager of technology at Metso’s power business segment. “In the pilot-scale testing, we focused on developing both the actual boiler process and safe operation of the boiler plant during oxy-fuel combustion. Modifying Metso’s 4-MW test plant for oxy-fuel combustion has been challenging, and we are pleased with what we have achieved. With circulating fluidized bed technology, coal and biomass can be co-fired, thereby turning the power plant into a carbon sink.”

The pilot program has ended and results now are being evaluated.