Cogeneration Plant Efficiency Improved with Scalebreak®-MP
Steam condensers by nature include a large volume of tubes. For one cogeneration power plant in New York, that means over 4,000 tubes for the condenser serving the 25-megawatt steam turbine. Keeping those tubes clean is a big job with regular maintenance, but can be near impossible when something goes wrong.
Ken heads operations at the cogeneration plant. When the plant experienced a drop in efficiency, he knew it was time to find a different cleaning solution. "Our condenser is a very large unit. For the 25-megawatt steam turbine, we typically would open it up every outage, and were able to shoot plugs through the tubing." says Ken. "That pretty much kept it clean. But we had a chemistry issue. A chemical vendor gave us a little bad advice. The long and the short of it is, we had a calcium breakthrough in our cooling tower basin. So we had some fallout from this calcium that eventually plated out the tubes of the condenser."
The plant quickly began to lose efficiency and they were unable to clean it mechanically. Typically, even a small amount of calcium deposits can reduce efficiency. "We were running our condenser in alarm and as it would heat up, we would lose efficiency. Our vacuum would drop. Under perfect conditions we could get close to 28 inches, believe it or not, and easily make 25-megawatts, maybe a little more on the steam turbine. But as the plating got worse, we were running 20 degrees in alarm, and we were losing close to two megawatts, which is serious money."
That’s when Ken and his team turned to Goodway’s Scalebreak® industrial descaling product. "Regular maintenance just wasn’t getting it. We were brushing it four or five times and we were just spinning our wheels. That’s why I made the decision to go with ScaleBreak. So along with my crew and Goodway’s Director of Sales, Liquid Solutions Division, Tim Fregeau, we calculated how much ScaleBreak we would need to circulate, how big the pump would be, and approximately how long it would take." Ken and his crew circulated Scalebreak for only eight hours, compared to countless hours of manual brushing.
Ken and his crew were amazed with the results. "We ran the lights up there to watch and what we saw looked good. We might have had 50 tubes plugged just because we had something stuck, and all that stuff came free. So we knew we did good. When we ran the unit we were 25 degrees cooler, vacuum was back, and it was automatic. It was back to OEM specs."
Ken attributes the success with the plant to a good product and even better customer service. "The ScaleBreak was a success, but I have to give the Goodway engineers a lot of credit, too. I mean, obviously, the product was the answer. But the proper use of the product is just as important."
Scaling in large condensers can build up over time, decreasing the efficiency of equipment to critical production levels. In large industrial applications, this can mean huge amounts of cost. When this happens, regular cleaning methods aren’t enough to remove hard deposits. When it’s time to use chemical cleaning for your equipment, the engineers at Goodway can provide their recommendations and expertise to get your equipment in near new condition again.
• Inflatable plugs were used in the inlet & outlet to isolate just the condenser and not involve any piping. This minimized the volume to just the condenser.
• The total volume of the condenser was calculated at 3,884 gallons.
• Scale thickness was heavy.
• 1,320 gallons of descaler was used, a 33% dilution.
• There was a total of 4210 stainless steel tubes at 3/4” ID and 22’ long (.506 gal per tube).
• The end bells were 48” diameter by 72” long (846 gal each).
• The descaler was circulated for 8 hours with a 3” centrifugal pump.