Energy costs for rotating equipment are many times larger than maintenance costs. Even a small percentage energy savings can quickly exceed the total cost of lubricant purchases. Here is a case that illustrates this:
A large, Midwestern, coal-powered energy producer tested a boiler feed pump to see if upgrading from a mineral-based lubricant to a purported high performance synthetic would reduce energy consumption. Data on the voltage and draw of the motor powering the pump was collected using MotorSTATUS™ monitoring equipment to determine energy consumption.
It was necessary to know the following to determine any reductions in energy consumption:
- The average full load heat rate as a measure of how efficiently the coal was converted to electricity
- The actual power that the unit generates
- The cost of coal
Benchmark readings were measured over the course of seven days using the mineral oil. At the end of the seven days, the lubricant was changed to the high performance synthetic. The equipment then ran, and was monitored, for another seven days. With the mineral oil, the motor ran at an average of 455.33 amps. With the high performance synthetic, the motor ran an average of 425 amps.
THE FOLLOWING CALCULATIONS WERE USED TO DETERMINE ENERGY CONSUMPTION:
(30.33 A change in amps * 4000 volt motor) / 1,000,000 watts = .12132 MW additional power generated
9581 BTU per kilowatt hour mineral oil heat rate * 238,000 kilowatts produced = 2,280,278,000 BTU per hour coal utilization
2,280,278,000 BTU per hour coal utilization / (238,000 kilowatts produced using mineral oil + 121.32 kilowatts additional power generated using synthetic lubricant) = 9576.13 BTU per kilowatt hour synthetic oil heat rate
(9581 BTU / kWhr original heat rate) – (9576.13 BTU / kWhr new heat rate) = 4.87 BTU change in heat rate
4.87 BTU change in heat rate * 238,000 kW power generated * ($1.26 / MBTU cost of coal) * (1 MBTU / (1 * 106 BTU * 4760 hours of operation per year) ) = $6,959.53 in energy savings from one boiler feed pump
The additional cost for upgrading lubricants worked out to less than $260 per year. The internal rate of return on the investment was dramatic with a payback rate of less than one month. The potential energy savings to a plant with numerous pumps could be dramatic as well.
Companies can make significant improvements to their bottom line by simply upgrading the quality of the lubricants they select and use. To stay competitive, companies must shift their mindset from seeking the lowest cost lubricant to seeking out the lubricant that is most likely to help them improve plant reliability and reduce maintenance costs.
Seeking the best performing lubricant will require some research and the return on investment is well worth the minimal time and effort involved. The first step is to contact your lubricant supplier and / or research high performance lubricant manufacturers to request performance data specific to equipment used in the power generation industry. The next step is simply to choose a lubricant (or lubricants) based on the available documentation, determine performance criteria, and begin testing on a few pieces of equipment. Few changes, if any, can reduce maintenance expenses so dramatically, quickly, and easily as upgrading your lubricants.