Andritz will be supplying a modern CTMP process followed by a high-consistency peroxide bleaching system and a medium consistency dithionite bleaching system, which will assure the highest possible brightness. The washed and depithed bagasse will be impregnated with a caustic and sulphite solution followed by first stage pressurized refining with an Andritz Sprout-Bauer 62 MRSD Refiner. The refined pulp is then interstage-washed so that chemicals and dissolved solids are removed from the fibers prior to the second stage atmospheric refining in a 62 MRSD Refiner. The solids are removed together with the rejects from the screening system.
Interstage washing improves the refiner loadability and prevents fiber darkening.
A washing stage between the high-consistency peroxide bleach plant and the medium consistency dithionite bleach plant optimizes the chemical consumption and further reduces the effluent load into the paper machine. Quena Newsprint Paper has chosen Andritz as supplier because of its experience in high-yield pulping of bagasse and the latest in bleaching processes providing highest possible brightness at lowest possible operation costs.