State-of-the-art boiler feed pump upgrade for Ratcliffe Power Station

摘要

The FR 375 main feed pump is a design originating from the early 1960's. It was essentially a design for base load 2,000 MW power stations and this particular design was installed at both Ratcliffe and Ferrybridge. With good operational practice and steady state, high load rating conditions, it is not uncommon for these pumps to have an operational life of about 40,000 hours before a refurbishment is required. The power generation market conditions now dictate that 2,000 MW stations work ever more flexibly, two shifting operation of the plant and low/intermediate load operation is now commonplace. This places more onerous requirements on the main feed pumps such that the pumps provide the required boiler feed under all operational conditions. The operational envelope of the main feed pumps at Ratcliffe now needs to be widened to allow generation between about 180 MW to 520 MW with the pumps operating at the best compromise of efficiency. This paper presents the need to upgrade the existing pumps, along with the hydraulic design and development activities required to provide a pump designed for the flexible operation. The state-of-the art design is discussed along with the extensive site work required to allow the 35 year old barrel casings to accept a modern day boiler feed pump cartridge.