The pulp and paper industry is a multi-billion dollar a year business in the U.S. alone. Chlorine and/or chlorine derivatives are used in the bleaching processes of most mills in the U.S. It is widely accepted that the effluents from these bleach plants are harmful to the environment. Considering the size, cost and importance of the pulp and paper industry around the world, much effort has gone into research to develop cost effective, environmentally friendly processes to take the place of those currently used.
The University of Georgia has recently opened two pilot plants, one for bleaching of pulp and another for deinking of recycled paper. These Pilot Plants, housed on the campus of the University of Georgia, are being used in research and development into commercial scale of Totally Chlorine Free (TCF) bleaching processes such as the EnZone process, developed at the University of Georgia. This process combines oxygen and enzymatic delignification of hardwood pulps with ozone treatment and a final peroxide bleaching stage to produce pulps of equal brightness compared to conventional chlorine and chlorine dioxide bleached pulps. To obtain fully bleached softwood kraft pulp, an alkaline extraction stage is inserted between the enzyme and ozone stages. Both hardwood and softwood kraft pulps bleached with the EnZone process have fully acceptable strength values.
Research into enzymatic deinking of laser and xerox printed mixed office waste, newsprint and magazine stock with the Enzynk process, also developed at the University of Georgia, is the focus of the deinking pilot plant.
The EnZone Process, producing brightness values of greater than 90% ISO with
hardwood pulp and 86-88% ISO with softwood pulp, looks to be an excellent alternative to
the conventional bleaching processes. Funding for the research and development of this
process has been obtained from NCASI (National Council for the Paper Industry, Air and
Stream Improvement), $450,000 during a period of five years. The USDA contributed a research
grant, $160,000 to clone a very thermostable xylanase to be used in the process. For the
construction of the pilot plant, a Georgia Environmental Technology Consortium (GETC)
contributed $453,000 to buy equipment and to cover certain costs necessary to run the plant.
Ahlstrom USA, and Canada, donated an almost complete pilot plant which is ideal to test our process. The value of this equipment is very high. The University of Georgia has also contributed generously in the first place with the building to house the pilot plants and with investments of more than $100,000 to upgrade this building regarding water, electricity, sewage, etc.
Housed in a 3,400 sq ft facility at the Driftmier Engineering Center at the University of Georgia in Athens, Georgia, the Pulp Bleaching Pilot Plant has a large range of processing and analyzing abilities. With the modern testing and research lab, the running and examination of new chlorine free bleaching processes is both convenient and cost effective. The bleach pilot plant has the ability to process 5 to 10 Bone Dry Metric Tons (BDMT) per day. The facility incorporates many treatment points for pH adjustment and/or addition of different chemicals. These treatment points can be moved and modified to facilitate precise process control over a wide variety of different processes. With a wide range of major equipment, including four 1,200 gallon holding tanks, two washing and de-watering belts, a large ozone generator, liquid ring compressor, a high capacity ring press and complete computerized process control the pilot plant has excellent flexibility for modifications.
The Deinking Pilot Plant, incorporated into the Bleaching Plant, contains an 800 gallon pulper capable of pulping all types of paper from mixed office waste to newsprint and magazine stock, all of which can be processed in a variety of different procedures. A large tank, equipped for flotation, allows for batch separation of ink while a pressurized cyclone deinking system provides continuous flow deinking. The Enzynk process, developed with funding from the Georgia Advanced Technology Development Center, and from the Georgia Consortium for Technological Competitiveness in the Pulp and Paper Industry, uses a mixture of enzymes in combination with surfactants and very few other chemicals. The enzyme mixture is very much dependant upon the furnish used. The Enzynk process gives a higher brightness, lower dirt count, higher freeness, and less sludge compared to chemical deinking.
Transportation of unbleached, bleached, and deinked pulp is done at 6-10% pulp consistency in a 4,800 gallon tanker truck and at 35% consistency obtained in the ring press with various transportation options.
The research and testing laboratory at the pilot plant is fully equipped with modern equipment and tests can be conducted by many TAPPI and ASTM methods.
If you would like more information about the Pilot Bleaching and Deinking Plants and details on specific functions and processes please Contact:
Ryan Adolphson - Pilot Plant Director
Dr. Karl-Erik Eriksson - Professor and Eminent Scholar in Biotechnology