A leading flexible packaging printer learned how to "clean up" when it comes to using and handling solvent-laden presses and parts.

RJR PACKAGING, a leading printer of packaging materials using gravure printing presses, has incorporated some innovative practices into their package printing manufacturing processes for minimizing hazardous solvent usage in their press parts cleaning process.

One method is to stretch the cleaning solution—making a little go a long way. Another is to turn the cleaning residue into a high solid block of waste, which may be buried in an ordinary landfill rather than a hazardous waste site.

How do they do it? By integrating solvent recovery and sludge drying systems into their press parts cleaning operation.

Until 1991, RJR's press parts, including cylinders, pans, and doctor blade assemblies, were cleaned with solutions incorporating highly volatile organic solvents including methyl ethyl ketone (MEK). The spent solutions were classified as a hazardous waste and presented a significant disposal handling and cost problem. With the increase of federal and state regulations restricting tolerated levels of solvent waste, RJR was searching for the most environmentally friendly way to operate its press parts cleaning process.

A demonstration of Total Solution Systems, manufactured by Progressive Recovery, Inc. (PRI), caught the attention of RJR at a trade show. RJR was initially interested in the PRI-VAC 2000, a vacuum distillation unit, which is designed to recover solvents from cleaning solution residues through the use of electromagnetic microwaves and reduce the remaining waste into a single block of ink resin and pigments. If the residue is from PRI's non-hazardous wash solution, the block of solids may pass all environmental tests to allow disposal in a municipal landfill, making hazardous waste disposal unnecessary.

"As we evaluated the PRI-VAC 2000, we also explored PRI's cleaning equipment capabilities," says RJR Environmental Manager David Yount. The company recognized the ability to reuse a cleaning solution through many wash cycles would not only further its objective of reducing hazardous waste, but would also be cost-effective.

Four Gravure cylinders after being automatically washed, rinsed and dried in PRI's SWS-400 Washer System.

"We decided to test PRI's Total Solution Systems by sending some of our soiled cylinders and pans to PRI's test site," Yount recalls. "The tests were successful and led to the purchase of four washers." One washer unit serves four presses at one facility, while three washer tanks serve nine presses at another facility. Each facility has a primary vacuum distillation unit, a secondary distillation unit and associated pumps and holding tanks.

FLEXIBLE PACKAGING

"The systems have provided us with a safe, economical cleaning process."
David Yount;
RJR Environmental Manager

"Overall, the Total Solution Systems have reduced our hazardous waste by 90 percent," Yount states.

Yount reports that RJR has increased its cleaning room output by approximately 45 percent, with the increased output due to shorter cleaning cycles.

"We had anticipated running about 2,250 wash cycles per year. Instead, we are currently running about 3,300 cycles per year," he says. In addition, the systems' automation has reduced manpower required for cleaning by 40 percent. Operators are also working in a safer environment due to the sealed, automated system, which requires no operator handling of the wash solution.

"The systems have provided us with a safe, economical cleaning process," Yount says. "Our operators did need to be trained on the use of the systems, which require some technical know-how. But PRI provided excellent training, installation and supervision during the project." According to Yount, PRI additionally helped RJR develop a special cleaning formula for the safe removal of catalytic adhesives.

Solutions for the future

Because RJR customers and markets have become more specialized with short runs and higher quality demands, the company's cleaning requirements will increase as well.

"In addition, environmental laws are getting more stringent, and PRI has been able to help us meet our cleaning and hazardous waste reduction needs today and in the future."

EXECUTIVE SUMMARY

System Works Efficiently, Safely

Total Solution Systems include mechanical equipment to wash a variety of press parts, distillation equipment for solvent recovery, and cleaning chemistries.

The components of a system include a washer, clean and dirty tanks, a primary vacuum distillation unit, a secondary distillation unit (PRI-VAC 2000), and PRI’s proprietary non-hazardous wash solution, HCS. When hard-piped together, the components comprise a closed-loop system in which 80 percent of the used solution is distilled and reused.

Each Total Solution System automatically washes, rinses, and dries equipment and components while recovering VOCs from the air stream. The wash chamber is environmentally sealed. There is no operator contact with the wash solution.

Ink pans, pumps, doctor blade holders, buckets, and gravure cylinders are loaded onto specially designed carts. At the start of a wash cycle, a cart is pushed into the wash chamber and the door is closed and locked to seal the chamber. The wash solution is sprayed onto the parts through oscillating headers with high impact spray nozzles. A rinse solution is then sprayed onto the parts through separate headers.

Next, the wash sump is automatically isolated from the wash chamber and heated air is circulated throughout the chamber. This process serves two purposes: one, to dry the parts, and two, to absorb the solution into the air stream. When the solution-laden air is passed over a chilled coil, the solution is condensed back into the wash sump, reducing the VOC content in the wash chamber at exhaust. A complete cycle typically takes less than one hour. When the door is opened, the parts are ready to be placed back onto the press.

The systems minimize the waste stream in several ways. First, the wash solution is designed to be used for many wash cycles before it becomes too dirty for further cleaning. Secondly, when the wash solution does become too dirty, it is fed into the Dirty Solvent Tank (DST) for storage until it undergoes distillation in the Primary Vacuum Distillation Unit. Here, 70 percent to 80 percent of the solution is reclaimed and sent to the tank for reuse.

When the residual buildup in the Primary Distillation Unit reaches a certain level, it is transferred into the Secondary Vacuum Distillation Unit, PRI-VAC 2000. The residue, or sludge, undergoes ultra-high frequency microwave drying. The dried sludge is mechanically removed, and may be safely stored or immediately disposed of in a landfill if tests show it to be hazardous.

HCS is non-flammable and less volatile than other cleaning solutions, providing improved user safety. HCS has been specially formulated by PRI to increase operator safety and to provide the effective removal of both dried solvent-based and water-based inks. 



PRI's Model SCR-350E with PRI-VAC installed.
Reprinted from Package Printing & Converting® November 1996
Copyright 1996, North American Publishing Co., Philadelphia, PA 19108