Enhanced pulp screening

ENHANCED PULP SCREENING USING HIGH-PERFORMANCE SCREEN COMPONENTS AND PROCESS SIMULATION Advanced Fiber Technologies (AFT), Business Center Pukinmäki, Eskolantie 1, 00720 Helsinki, Finland PROMAR Polytech (Pty) Ltd., Centurion, Gauteng, PO Box 25184, East Rand 1462, South Africa. Advanced Fiber Technologies (AFT), AFT Technology Office, 5890 Monkland Avenue, Suite 400, Montreal, Quebec, Canada H4A 1G2 pulp screen, simulation, optimization, cylinder, rotor, pulp quality, efficiency, fractionation Optimization of a pulp screening system requires a combination of screening knowledge, high quality products and simulation tools for system design. Pressure screening is a key process in pulp and paper production and is used to enhance the quality of a wide range of pulp and paper products. While the usual goal of screening is to remove oversize contaminants from the pulp, screening is finding increased use for fibre fractionation. Screening is applied in virtually all pulping and papermaking operations. Advancements in screen cylinder design have been supported by a more detailed appreciation of the connection between performance and screening variables. Performance variables include the traditional parameters of capacity, debris removal efficiency, consistency drop, fractionation, minimum reject rate and power consumption. Technical advances in the industry have provided a more sophisticated definition of these parameters. For example, the increased use of image analysis has led efficiency to be evaluated as a function of contaminant size. The availability of optical fibre length analysers has heightened the awareness of how screens can be used to fractionate fibres on the basis of length. The ability of pulp screens to accomplish this wide range of tasks follows from the breakthroughs in technology that have occurred over the past few decades. The continuing development of the performance components of a pressure screen, i.e. the cylinder and rotor, has enabled screens to increase both the quality of the accept pulp and the screen capacity.