After a comprehensive feasibility study NamPower decided to embark on a project to rehabilitate the aging 120 MW coal-fired Van Eck power station. The project will see the restoration of three turbines, four generators and four boilers culminating in much needed increased local power generation capacity. Marthinusen & Coutts, a division of ACTOM, commenced work on all three turbines in 2012 with the aim of increasing the reliability and efficiency of the power station to meet its original design output of 120 MW.

The first two units are already performing according to specifications. Targeted completion of the remaining two units is end November 2015 and end January 2016respectively.

The scope of work for Marthinusen & Coutts comprised the complete refurbishment of three of the 30 MW turbines and the overhaul of one turbine. “A typical coal-fired power plant has multiple generating units, each with its own steam generating boiler. Essentially, steam turbines are the heart of coal-fired power plants. The refurbishment of the turbines will see these units brought back to OEM specifications by overhauling all major components,” Mike Chamberlain, operations executive at Marthinusen & Coutts explains.

The first step in the rehabilitation process involved a thorough on site assessment of the turbines by Marthinusen & Coutts’ engineers to determine the existing condition of the aged equipment. This assessment included the HP and LP cylinders, shafts, diaphragms, lubrication systems, emergency stop valves, steam chests and governors.

In order to provide an accurate analysis, the team completely disassembled the turbines on site. The customer was then provided with a comprehensive report on the work which would be required to bring these turbines back into service.

“An important aspect of the repair process is when parts no longer meet the original equipment manufacturer’s standards; these are refurbished, replaced or remanufactured so the components once again comply with OEM specifications ensuring ongoing operational safety and efficiency. In this instance, the governor valves were refurbished by Marthinusen & Coutts and the turbine blades were replaced. Furthermore, machining and polishing was done on most components to restore the surface finish,” says Chamberlain.

The refurbishment of the turbines included work on the HP and LP turbines, the cylinders, the diaphragms, the shafts, the bearings, all the oil pumps, all the HP and LP shaft glands and the lubrication systems, as well as the steam chests.

With 57 years of extensive experience in the local and global market, Marthinusen & Coutts was ideally positioned to undertake the turbine refurbishment work at Van Eck power station. Within the power generation market, Marthinusen & Coutts undertakes both electrical and mechanical repairs, overhauls and complete refurbishments.