While routine build-up and clogging in process applications is annoying, process scaling is more persistent, causes unplanned downtime and increases costs in many industries. It's typically composed of calcium carbonate, wax, grease or similar compound combinations, but it can also include non-traditional chemical and biological substances that can quickly clog pipelines and equipment. For example, struvite, or magnesium ammonium phosphate, often occurs on digester exit lines in wastewater treatment applications.
"Remedies for scaling include mechanical or chemical cleaning or pigging pipelines," says Todd Loudin, president, North American operations at Flowrox Inc. "Keys to proper scaling treatment include knowing when to add chemicals, when to run pigs, or when to shut down processes for mechanical cleaning. While the oil and gas industry spends lots of money on instrumentation to monitor and control its processes, many operations monitor scale deposits mostly by watching for pressure drops in their pipelines. However, this method isn't precise because many factors can influence pressure drops. For instance, when pumps begin to wear out, their pressure outputs may decrease, but this doesn't always indicate scale deposits. It could just be a worn-out impeller."
Loudin adds that newer scale-detecting instrumentation uses electrical capacitance tomography (ECT) to visualize pipeline scaling without opening them up. ECT instrumentation monitors hard and soft scaling in many process applications, and lets users determine where and how thick scale is so they can deploy and monitor their chemicals more effectively. Likewise, manufacturers of anti-scaling chemicals can tweak their products, and evaluate the success of new formulas.