Secondary re-burn boilers reduce NOx emissions
Mitsui Babcock Europe limited was established in 1895 as Babcock and Wilcox and they produced the boiler for the world's first power station. Since that historic date, they have contributed to some of most innovative boilers including the world's first vertical low mass once through boiler in Yaomeng, China in 2001. Their latest offering is two innovative 600MWe class supercritical coal fired two-pass boiler designs. The project began by studying three distinct designs for supercritical pulverised fuel-fired boilers, and was eventually reduced down to two. The specific design application was to establish an optimum steam cycle with minimal risk that would integrate fuel re-burn and reduce the NOx emissions. The two designs also utilise the latest available materials and they do not have vestibule between the furnace and the second pass; and this reduces cost significantly. The designs incorporate a spiral wound furnace that carries the vertical boiler loads from the lower furnace to the upper furnace. Also a conceptual strap has been developed to carry the load of the lower furnace due to hot flue gases of the second pass. Further innovative features include; vertical internally ribbed tubing, improved steam/water separator designs, and improved mechanical details and properties. The potential market for these boiler designs rests in the Asia-Pacific rim, with China being a major player and the US emerging as another. In addition to the solid fuel (coal) fired applications, other market applications include liquefied natural gas and steam distribution. The ultimate result of these innovative supercritical boiler designs, means that their application potential permits them to compete more effectively with sub-critical plant currently used in the Asian market. With over 100 years of experience behind them, Mitsui Babcock has won contracts in Vietnam, India, Zimbabwe, and one plant in China can now produce over 3000MW. This is the type of company that participates in the local economy, develops alliances with local suppliers and shares skills by investing in people and giving on the spot support. As a result, they are currently seeking further research or development support, Licence agreements and are available for consultancy purposes.
