Decontamination of Process Streams Through Electrohydraulic Discharge (Final Report)

Contaminants present in paper recycling mills can degrade product properties and can also lead to substantial downtime. Of these, adhesive material such as hot melts and pressure sensitive adhesives are especially troublesome. These are known as “ stickies ” and their handling and re- moval requires process equipment such as screens and cleaners as well as chemical additives. In the preceding phase of the project we demonstrated that firing an underwater spark in a tank of stock reduces the tack of the stickies and reduces their impact. The present phase was to demon- strate the technology in full-scale trials, address any issues that might arise, and commercialize the process. Trials were run at the Appleton papers mill in West Carrollton, OH, the Graphics Packag- ing mill at Kalamazoo, MI, Stora Enso mills at Duluth, MN, and Wisconsin Rapids, WI, and the Jackson Paper mill at Sylva, NC. It was shown that the sparker not only detackified stickies but also increased the efficiency of their removal by centrifugal cleaners, improved the effectiveness of dissolved air flotation, and increased the efficiency of flotation deinking. It is estimated that the sparker improves the efficiency of hydrocyclone cleaner, deinking cells and dissolved and dispersed air flotation units by 10-15%. This translates to a corresponding energy benefit in operating these units. The technology has been licensed to Eka Chemicals, a division of Akzo Nobel