Pump System Optimization

When the discussion turns to power plant pumps, boiler feed and cooling water pumps immediately dominate the discussion. And that’s as it should be as these pumps are critical to a plant’s availability and performance. They are also the most costly to purchase, install, operate and maintain, so optimizing their efficiency is imperative. However, plant operators expect reliability and performance at the lowest cost across the entire plant, so optimizing pump system performance throughout the entire plant is the prudent and economically rewarding thing to do.

Life cycle cost analysis shows that upgrading the feed water pumps for improved energy efficiency and availability will have a significantly positive financial impact. Today, bad-acting boiler feed pumps and cooling water pumps can be re-rated and upgraded to improve their reliability, with payback periods typically in two years or less.

For balance-of-plant (BOP) pumps (commonly referred to as auxiliary pumps), the general rule for industry cost effectiveness is to initiate repairs or pursue proactive improvement measures when pump performance degrades by more than 7%. Given the age of many fossil power plants and the systematic neglect of so-called auxiliary pumps, it is almost certain that many of these pumps are no longer operating at their original service conditions. Typically they are now running back on their performance curves. These pumps are excellent candidates for increasing efficiency and reducing maintenance costs.

The goals of upgrading BOP pumps are the same as they are for feed water and cooling water pumps. They are:

• Energy optimization
• Increasing reliability to increase the availability of power generation capability and capacity
• Improving corrosion and erosion resistance
• Solving vibration, pressure, pulsation and noise problems for increased reliability and MTBR
• Performance optimization to increase station output

"The Rewards of Pump System Optimization," Greg Herr, Power Engineering