Pulp and Paper Canada

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PAPRICAN’S BLEACHING PILOT PLANT


October 1, 2000
By Pulp & Paper Canada

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A major upgrade of the Paprican bleaching pilot plant, valued at more than $2 million, has been completed. The changes were driven by the need to address issues related to progressive system closure, …

A major upgrade of the Paprican bleaching pilot plant, valued at more than $2 million, has been completed. The changes were driven by the need to address issues related to progressive system closure, including those related to chemical recovery and regeneration.

Paprican is now better able to evaluate new bleaching processes and equipment, assess the effects of bleaching process changes and produce bleached pulp using modified processes for product evaluation. The pilot plant can now operate continuously and can run sequences with oxygen delignification (single and double stage), chlorine dioxide stages, and filtrate recycle. This new capability required the addition of a feed tank, a 40-minute pressurized tube, a 3-hour non-pressurized retention tower, and a chlorine dioxide generator. It also included a belt washer with vacuum pumps and seal tanks, two filtrate tanks, a jump-stage filtrate tank, and new monitoring and control systems. The modified pilot plant has already been used successfully to produce several tonnes of fully-bleached pulp by ODEoDED and DEoDED sequences for a Member Company.

We have also contracted to assess the possibility of using oxidative enzymes for oxygen delignification. This new capability complements that of the original pilot plant which had been used to evaluate ozone and peroxide bleaching on chemical, mechanical and recycled furnishes. A mobile screw press and new cold room storage facilities allow furnishes from any Member Company site to be removed and stored at Paprican before evaluation. The new pilot can run all elemental-chlorine-free and totally-chlorine-free bleaching sequences, with intra- and inter-stage recycling of filtrates.