Electrostatic Precipitator (Esp)
Location: Graymont Superior, Wisconsin, USA
Product: PAS-75 & PAS-230 Acoustic Cleaners
Principle: Primasonics International Limited (UK)
Problem: ESP cleaning, ESP Dust Build up
Graymont is the second largest producer of lime in North America, with close to 20 locations serving key market regions across Canada and the United States. The Superior plant has 5 kiln lines that need to be shut down periodically for cleaning and maintenance. When this happens, cleaning the ESP dust build up is a priority to bring their removal efficiency back up for the next production run.
Cleaning the ESP dust build up is a manual operation that entails employees entering the bottom hopper to hammer on the individual plates. This poses a significant safety risk to the employees because they are below the plates and therefore, the dust that they are knocking off is falling down on them. Lime dust can burn areas of exposed skin. In addition, the area that they are working in is both hot and cramped.
The original emphasis for installing the Primasonics Acoustic Cleaners in the ESPs was to reduce risk and exposure to their employees that are tasked with the ESP cleaning on shut downs. Typical ESP cleaning time with three employees was around 16 hours prior to installing the Primasonics Acoustic Cleaners Even though employees would wear full faced respirators, the ash and dust was continuously falling on them.
Graymont's Process Engineer, Bill Kaptonak needed to find a better ESP cleaning solution, however not being familiar with Acoustic Cleaners he was a little hesitant in placing an order with Primasonics. His concern was allayed when Primasonics outlined their Acoustic Cleaner Rental Plan which offered Graymont the opportunity to rent the Acoustic Cleaners on a monthly basis before committing to purchase. Initially two Acoustic Cleaners and ancillary equipment were rented from Primasonics and installed in Graymont's #3 ESP.
Primasonics supplied two 75 Hz Primasonics Acoustic Cleaners to be installed on the first field of the ESP, along with the accessories required.
The use of the Acoustic Cleaners kept the ESP dramatically cleaner. Clean up time is now less than 8 hours with more of the ESP cleaning done at the top as opposed to the bottom. This is safer because at the top of the ESP, the dust falls below the workers.
The Acoustic Cleaners also improved the performance of the ESP while it was on-line. When the Acoustic Cleaners were first run in conjunction with the rappers, the load on the hopper screw would spike when the cleaners sounded. This indicated that the cleaners were knocking down additional dust from the plates compared to just using the rapper system.
Bill reduced these spikes by changing the Acoustic Cleaners sounding pattern. The ability of the Acoustic Cleaners to knock down more of the ESP dust build up during operation has improved their environmental performance. This has stabilized the operation by minimizing any tendency toward opacity issues when the kiln process changes.
The effectiveness of the two Acoustic Cleaners in the Kiln #3 ESP has prompted the plant to purchase a total of six Acoustic Cleaners which will be installed in Kiln #2 and Kiln #3. The plant is currently considering additional future applications for Primasonics Acoustic Cleaners.