The power plant utilises lignite fuel to produce over 1’000 MW of power. The boiler infeed pumps at the site are critical to this – but recently one of the units was giving operators at the plant cause for concern. Dating from 2009, the Chinese OEM pump was showing its age with a range of issues.
Sulzer’s OEM-X line service provided an upgraded design that improved the efficiency, reliability and performance levels.
The mean time between failures (MTBF) for the pump was under six months, with resulting downtime being compounded by a lack of original equipment manufacturer (OEM) spares support when maintenance was required. For example, sourcing new equipment from the OEM could take up to a year, which presented an unacceptable risk to electricity generation and profitability. Furthermore, the pump was running inefficiently. Operators calculated it was only achieving 70% efficiency and was consuming 139 kW per hour. This higher power consumption inevitably erodes the plant’s margins.
Sulzer’s engineers proposed a custom pump design based on a pre-existing booster pump model. The new pump would be a replacement for the older unit. This would reduce downtime and plant disturbance while delivering improved reliability and efficiency at the required duty point. Overall pump efficiency was raised to 81.2%, an increase of over 11% compared to the legacy unit. This figure was also above any of the competitor pump replacements, which could only deliver around 78% efficiency.
The pump featured the same base plate design and orientation of the inlet and discharge connections as the previous unit. To ensure durability and corrosion resistance, the pump was produced from CA6NM MOC stainless steel alloy.
The project was delivered within eight months. After it was delivered to the plant, the pump was installed with no modifications to the surrounding infrastructure.
In operation, the Sulzer pump increased overall efficiency by more than 10%, while hourly power consumption was reduced by 14%. Additionally, it has lowered the net positive suction head required value from 5.2 down to 4.5. The optimal value was identified through engagement with Sulzer experts, as the customer was not quite sure on the ideal figure. Operators are now benefitting from reduced energy consumption for the boiler infeed application by 16%, which has improved the cost-effectiveness of power generation.
With regards to reliability, the Sulzer pump offers a MTBF of over two years, improving pump availability. If any issues do arise, the indigenous support network available from Sulzer’s local facilities will ensure reduced repair times compared to the previous Chinese OEM pump.