Leakage Minimisation – Littlebrook Power Station

Customer: RWE N Power

Value: £1m

Site: Littlebrook, Dartford Kent

The Opportunity

In 2006, RWE nPower, approached Power System Services as experts in Air preheater performance optimisation, to investigate ways in which Air Leakage can be significantly reduced. The aim of the exercise was to increase efficiency and establish an improved availability certificate for what is a peak demand operating station.

The Solution

Power System Services Produced a design, which effectively doubled the number of Radial divisions both hot and cold plus also Axial divisions, whilst retaining side loading cold end baskets. The Double Sealing was achieved by introducing radial walls onto which Corten Seals could be bolted. The additional seal clearly reduces direct leakage by creating interference to air flow and pressure pockets when passing the Sector plates.

Power System Services provided Air Leakage guarantees of 6.5% and achieved <5%. The scheme was a complete success and contributed significantly towards re-certification of available output to 680MW from 600MW. Unit 2 has now been modified in exactly the same way.

The Leakage saving achieve alone an availability certificate increase of 75MW (15 large wind turbines and a capability of £7,500-00 per hour generation extra generation with no extra cost). Albeit somewhat different from the Water industry this demonstrates how Power System Services adapt principles to practical solutions to produce financial and functional benefits

Project Repair Details

In addition to double sealing, the unreliable moving sector plate mechanism was fixed