MARINELINE® & CHEMLINE® COATINGS FOR INDUSTRY

ChemLine® E-Newsletters

Preventing Corrosion -  News on High Performance Coatings for Industry
Issue 01
Chemline Case Study in Action
ChemLine® Coatings Provide $100,000 Savings at Power Plant
ChemLineAdvanced Polymer Coatings (APC), the Avon, Ohio, USA-based manufacturer of the well-known family of polymer-based protective coatings — ChemLine® and MarineLine® — wants to continue to hear about the great applications work being accomplished in industry today. APC is geared up to help present corrosion prevention solutions for companies with extra-ordinary applications.

As APC hears more from our customers, we want to share these stories with other users who will find this information valuable. So we are launching this new email marketing newsletter, to bring you case studies on how various APC coatings solve particular industry needs. We hope you enjoy reading these, and contact us with your own working problems and solutions.

Reheater tubes detailing corrosion.Background

Two wet scrubbers at this Coal Fired Power Plant in Michigan were designed and built 30-40 years ago. The FGD system at this 65 MW plant is equipped with an electrostatic precipitator and a wet flue wet flue gas desulfurizer (FGD) system for emission controls. The plant consumes approximately 550 tons of coal per day.

The alloy construction of reheat tubes was being attacked by the flue gas after wet scrubbing. The apparent problem is that the coal being burned is high in chlorides — 0.03% by weight — resulting in a huge spike (10X) in slurry chlorides around 12000 ppm. The 316 L outlet reheater tubing is showing pitting from chlorides in the flue gas. Internal water temp is 200°F in the tubes with external flue gas at 180°F. Steam at 600°F is sprayed into the scrubber column below the reheater tubes at scheduled intervals. These conditions are similar to conditions experienced in Jet Bubble Reactors, scrubbers and ductwork made of alloy that are being attacked by high chloride coal burning.

Actions Taken

Tubes were coated from above and below with specialized spray equipment using Chemline® 784/32 Gray top coat. After Scrubber #1 was coated, the client decided to immediately line the reheat tubes in Scrubber #2. The client was satisfied that the stainless tubes were lined within budget and will extend the life expectancy of the tubes. No significant heat transfer loss has been detected and the scrubber is working at peak performance.

ChemLine® Reheater tubes after lining from APC has proved that under the most challenging environments of heat, corrosion and wear, the ChemLine® coating will provide long term solutions to coal burning with chloride contamination of the flue gas.

Reheater tubes before and after ChemLine coating.

Results

The owner of the facility talked with several coatings companies about coating the reheater tubes, however, two backed out, as well as several contractors, noting they “did not have a lining to handle this aggressive exposure.”

Ultimate Corrosion Control (UCC) was the only local contractor to bid on the project, submitting ChemLine® 784/32 as the lining. After six months of service, UCC and Chemical Containment Systems (CSS) inspected the tubes. It was noted that the underside of the tubes was where the most severe corrosion was previously found, and yet now this area was fully intact. Build up on the tubes of carbon, mineral and ash easily came off from the tubes by hand or water hose. The owner decided to coat an additional tube bank with ChemLine® 784/32 after this inspection was completed and accepted, and advised UCC and Chemical Containment Systems that the utility saved at least $100,000 by coating the existing tubes versus upgrading to new tubes.

Thus ChemLine® has proven to be an excellent lining for flue gas desulphuriziation process and can handle the high temperature and abrasion requirements of FGD systems. (Information for this case provided by Paul D. Turner from Chemical Containment Systems, Inc.).

For more information on how ChemLine® Coatings can solve your corrosion problems, contact your ChemLine® Representative and visit the APC website.