Two Challenging Valve Applications - Fly Ash Service & Recycle Paper Mill

November 3, 2020

Fly Ash Service Valves Perform Maintenance Free for a Year at One Third the Cost.

DeZURIK recently installed Dual Seat High Performance Butterfly Valves in Fly Ash Service to resist abrasion and prevent build up.  

After one year of maintenance-free operation in this service, eight 10" Dual Seat High Performance Valves were examined during the annual cleanout. Upon inspection, no evidence of wear or damage was apparent, and the valves remained free of calcium/slurry buildup.

DeZurik High Performance Butterfly Valve

The plant had previously used lubricated plug valves in this service, but found they required frequent maintenance because the build-up of fly ash slurry prevented the plug valves from sealing or operating. The plant also found that replacement with the same type plug valves would cost three times more than the DeZURIK BHP valves.

The double seat design of DeZURIK Dual Seat BHP High Performance Butterfly Valves enables them to withstand the severe abrasion of high pressure, fly ash slurry service in a power plant. Damage from abrasion is prevented by standard construction features including the 316 stainless steel disc with heat hardened nickel coating and the secondary metal seat. The valves were installed with flow direction into the seat side, thus allowing the metal seat to protect the primary PTFE seat from abrasion.

Careful scrutiny of the process conditions led to the selection of the DeZURIK BHP Dual Seat High Performance Butterfly Valve. Fly ash slurry from the plant's precipitators is pumped at a rate of 700 to 800 gpm at 275 psig a distance of 2.5 miles from the pump house to the settling pond. The valves, installed in the pump house, were required for on-off service. Composition of the slurry is 90% water, 8% fly ash, 1.5% sludge and 1,000 ppm calcinated lime.

For complete information on DeZURIK BHP Dual Seat High Performance Butterfly Valves — or any of DeZURIK’S manual, process, and control valves — contact us.

Recycle Paper Mill Cyclone Cleaner Valves Last 3 times Longer

DeZURIK recently installed Four 8" (200mm) DeZURIK KGC-MD Maximum Duty Knife Gate Valves in two High Density (HD) Cyclone Cleaners at a recycle paper mill.  The previous valves lasted only 2 months on average, but these new valves lasted 6 months - three times longer.

These metal seated DeZURIK KGC-MD Maximum Duty Cast Knife Gate "Trash Valves" perform successfully in this tough application.

Dezurik Maximum Duty Cast Stainless Steel Knife Gate Valves Kgc

This recycle paper mill’s rated production is between 1000 and 1500 tons per day. The repulper is constantly being fed residential recyclables which contain all types of post-consumer waste paper along with metal, plastics, glass and other abrasives that wreak havoc on valve seats.

After the repulper, the waste paper pulp mixture is pumped into ceramic-lined, high density cyclone cleaners that remove the high density rejects from the paper fiber. At the bottom of the cleaners are two 8" (200mm) valves that complete one full cycle every 1 to 2 minutes.

The cyclone action constantly propels abrasive materials against the interior of the valves at high velocity. After the top valve cycles, the bottom valve opens to dump the rejects. These valves are stroked about 43,200 times per month, and discard approximately 2.5 tons of rejects per day.

The mill has tried every possible valve recommended for this application. No matter what valve style or manufacturer they tried, the longest service life they received was 2.5 months. That was until they installed the DeZURIK KGC-MD Maximum Duty Cast Knife Gate Valves. They even outlasted the ceramic liners inside the cyclone cleaners, which have a 3.5 month life expectancy. The KGC-MD valves performed without issue for almost 6 months!

For complete information on KGC Maximum Duty Cast Knife Gate Valves, or any of DeZURIK’s other products, contact Carotek.