Cottam power station

British coal-fired power station uses PennguardTM linings to prepare its existing multi-flue chimney for wet stack operation.

EDF Energy Cottam Power Station is a 4 x 500 MW coal-firing power station near Lincoln, England. In 2003, with tightening SO2 emissions regulations threatening to restrict its operational capacity, EDF Energy Cottam decided to install flue gas desulfurization (FGD) plants in all four units.

Since 2000, EDF Energy’s other large coal-fired station – the 2,000 MW West Burton Power Station, situated only 5km away from Cottam – had been operating four wet limestone FGD plants. This same wet limestone FGD technology (which produces gypsum as the end product) was selected for Cottam. EDF Energy Cottam used a specific approach to minimize both the investment cost and the future operating costs of the FGD plants.


To begin with, Cottam’s existing 200m high, four-flue chimney was carefully inspected. Its concrete shell and four concrete flues, and their sectional brick linings were found to be in good condition. It was concluded, that the chimney could continue to be used after the FGD retrofit, provided that the flues could be prepared for FGD operating conditions.

Furthermore, it was agreed Cottam Power Station could run the FGD plants without flue gas reheat, allowing the FGD units to be placed closely around the chimney, with a relatively simple ductwork design. One of the main challenges of this approach was to minimize any risk of droplet carryover resulting from operation with water saturated flue gas. EDF Energy Cottam selected Alden Research Laboratory from Holden, Massachusetts, to assist in the design of the FGD outlet ductwork and chimney flue linings.

Based on Alden’s recommendations, EDF Energy Cottam decided to remove the brick linings from the four concrete chimney flues and to protect the inner concrete surface of each flue directly, using the PennguardTM Block Lining System.