Bleach Producer Cuts Cooling Costs

Kuehne Chemical Company, Inc., South Kearney, N.J., produces concentrated solutions of bleach (sodium hypochlorite). It starts by creating a concentrated ultrapure brine solution. Then, electrolysis of the brine generates gaseous chlorine, which is quickly reacted with sodium hydroxide to produce bleach.

"It appears to be a fairly simple process, but we have to control the heat of reaction," says Richard Wilkes, director of corporate engineering. "The process is cooled to the appropriate temperature range partly by heat exchangers that utilize cooling water as the exchange medium. That water, in turn, circulates through a cooling tower and heat is dissipated into the atmosphere. The cooled water then recirculates back to the heat exchangers, which continuously draw off heat."

However, the metal-clad cooling towers required frequent maintenance, including cleaning and fan-drive-system adjustments. This led to cooling tower downtime, which necessitated shutting down the bleach process for extended hours.

With the aging cooling tower reaching the end of its service life, the company in 2009 decided to replace it with an advanced engineered-plastic design from Delta Cooling Towers. Kuehne decided on a TM Series "two cell" model — a lightweight, compact, modular design with expansion capacity for upgrading up to a six-cell model (2,000 cooling tons).

In 2011, Kuehne purchased an additional one-cell cooling tower, which was placed online on March 23, 2012, and has been fully operational since then. The engineered-plastic cooling towers easily met the firm's cooling expectations. The biggest surprise came from the comparatively maintenance-free operation of the system.

"One of the things that we've found is that the surface tension for particles in the plastic cooling tower basin is much less than that of steel basins," notes Wilkes. "Even after more than two years since the startup, there has been no wind-blown particulate buildup and no mud whatsoever in the tower basin. We do scheduled blowdowns on the tower, which is standard, but, unlike the metal-clad basins, the blowdowns of the new plastic towers are completely washing any foreign materials right down the waste pipe. That means no cleaning of the tower basin." One of Wilkes' favorite features of the new cooling tower design is the direct-drive fan system, which also saves on maintenance costs and downtime.

"Instead of having a large shaft-driven or belt-driven fan drive, Kuehne liked the direct-drive unit with the new Delta system. As a result, Kuehne reduced its total horsepower requirements," says Wilkes. "Our old cooling tower had a 75-hp shaft-drive motor system. The new one has four independent 10-hp direct-drive motors. That's a reduction of 35-hp, which saves on energy costs for the same cooling tonnage."