Could you recognize a really huge gain or potential improvement if you saw it? I'm asking because I've often heard that when engineers spend months and years struggling to wring improvements of a few percent—or even fractions of a percent—out of their process applications, it can seem both unreal and impossible when potentially double-digit gains suddenly pop up. Of course, many folks are bombarded with so much baloney all the time that, when truly good news arrives, it can look exactly like just another sales pitch.
Fortunately, a little curiosity and an encouraging government program or two can help. For example, Frank Sentelle, automation leader at UOP's absorbents and catalysts plant in Mobile, Ala., was asked this past January to reduce his energy costs by 4.5% or about $445,000 for the 2010 fiscal year. This was because Honeywell and its UOP subsidiary agreed to be one of 32 companies in the U.S. Department of Energy's (DoE) "Save Energy Now" program (www.industry.energy.gov), which means it's volunteering to save 25% on energy over 10 years. Sentelle presented "Energy Management at UOP-Mobile" on June 15 at Honeywell Users Group 2010 in Phoenix.
The 305-acre plant and its 350 employees use six intermediate processing lines and 13 finished product lines to make about 75 to 80 million pounds per year of 120 clay-based products. Naturally, these products and processes require enormous amounts of natural gas to run process heaters and make 90-psi steam, as well as plenty of electricity. Together they account for 75% of the plant's operating costs.
Like other plants, UOP-Mobile assesses overall energy consumption via monthly invoices and assigns energy cost per unit of production using product standards. And, like most plants, it monitors energy costs, but hadn't done it in real time, didn't have the measurement system needed to produce granular metrics, and couldn't directly assign the relevant part of its energy costs to its products.
"We were making and using steam as needed, usually to heat water in our intermediates area, but it wasn't coordinated well, and there was a lot of waste. For example, we had spargic processes that were waiting 10 to 15 minutes to be scheduled to help limit some big swings in energy use," says Sentelle. "Basically, we needed better boiler controls and automatic equipment shutdowns to save energy."
Following its survey of how other companies and industries use energy, as well as an initial assessment of how UOP-Mobile was using and paying for energy, Sentelle reports that he identified several hundred thousand dollars in possible energy savings beyond his initial target.
As a result, UOP-Mobile is adding electrical measurements at 30 points; an automatic capacitor bank to control power factor; natural gas metering; and more steam measurement.The plant also is monitoring electricity, natural gas and steam usage per production line; adding product standards per production line to its energy management server (EMS); comparing performance to product standards; tracking and correcting variances; and updating its accounting methods. Also, UOP-Mobile is using several DoE-based software tools and Honeywell's Energy Dashboard software to measure its consumption, perform current and targeted energy calculations, and eliminate waste.
In addition, to optimize steam production, Sentelle adds that the plant is implementing model-predictive control and scheduling of its steam users and implementing a boiler master control scheme to meet rapid changes in steam demand. It's also improving steam use and condensate return and the design of compressed air distribution and usage and boiler efficiency by replacing firing trains.
Finally, Sentelle adds that UOP-Mobile will do an energy audit later this year, implement automatic shutdowns, expand its solutions to other lines and do modeling of energy users to track efficiencies. However, it seems like a lot of good news is already in. Get the picture?