Proposed equipment for flotation cleaning of high poly containing pulp

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The present paper proposes a new concept based on air bubble to promote cleaning of pulp containing large amounts of poly.

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Proposed equipment for flotation cleaning of high poly containing pulp

  1. 1. Proposed EquipmentProposed Equipment for Flotation Cleaningfor Flotation Cleaning of High Polyof High Poly Containing PulpContaining Pulp Concept: D K Singhal deveshksinghal@gmail.com
  2. 2. IntroductionIntroduction With more and more cup stock, milk cartons and similar wastepaper grades in market for recycling, we need good equipment for handling of the pulp thatequipment for handling of the pulp that contains high amount of poly. This presentation presents concept of Float-Pro, a flotation based poly removal equipment. 2 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  3. 3. Existing AlternativesExisting Alternatives Screen plate in Pulper Drum Screen Vibrating Screens Pressure ScreeningPressure Screening ◦ Hole ◦ Slot 3 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  4. 4. Screen Plate inScreen Plate in PulperPulper This option is possible only in selected pulper types. Some manufacturers have developed pulper add-on units (e.g. Contaminax,pulper add-on units (e.g. Contaminax, Poire etc.) which are also working fine. For bigger poly pieces, these are extremely good. However, small poly particles remain with the pulp. 4 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  5. 5. Drum ScreenDrum Screen Here, the operating consistency is much lower. Drum screens are very efficient, yet some fine poly still remains with the pulp whichfine poly still remains with the pulp which needs to be removed. 5 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  6. 6. Vibrating ScreensVibrating Screens As far as cleaning is concerned, vibrating screens are very efficient. However, these are not suitable for large production rates.production rates. 6 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  7. 7. Pressure ScreensPressure Screens Pressure screens (both hole and slot type) are good and efficient. Still, they have a limitation on contamination, and a too heavy polycontamination, and a too heavy poly percentage in inlet stream can result in clogging of screen basket. 7 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  8. 8. Present ObjectivePresent Objective With existing systems, if the poly content is limited to 10-12% or a little higher in water paper, there is generally no problem.problem. But in case poly content is increased, it becomes often necessary to reduce the production rates to efficiently clean the pulp. 8 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  9. 9. Present ObjectivePresent Objective Basically, there lies a gap between coarse screening (pulper cleaning/drum screening etc.) and fine screening (pressure screens).screens). We need some equipment in between the two so that the reliability of the whole process remains good. 9 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  10. 10. ApproachApproach In the proposed approach, the use of following properties is suggested- Poly is generally lightweight (0.91-0.93 sp. gr.), and slowly floats in pulp suspension. The shape factor of poly results in more drag andThe shape factor of poly results in more drag and hence retards easy removal due to low density. Fine air bubbles in the suspension tends to attach with different suspended particles, thus further reducing their apparent specific gravity. Bigger air bubbles move up in the suspension at a faster rate and cannot get attached to pulp fibers in the suspension. 10 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  11. 11. Equipment DesignEquipment Design The cleaning equipment is a rectangular tank shaped structure, with different partitions in between to allow having different zones.different zones. For ease, the equipment has been named as Float-Pro. A schematic of the same is given on the next sheet. 11 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  12. 12. Schematic of FloatSchematic of Float--ProPro 12 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  13. 13. DescriptionDescription As clear from the schematic, the unit looks like a tank with partitions to create different chambers. The pulp enters the first zone, where a coarse air diffuser (ADP-M) mixes thecoarse air diffuser (ADP-M) mixes the pulp to create turbulence and uniform mixture. From the bottom of separator plate S0, the pulp enters ‘Zone-1’ where the poly based contaminants float upwards. 13 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  14. 14. ConstructionConstruction Float-Pro looks like a rectangular tank. It can be either fabricated in SS, epoxy coated carbon steel or casted in RCC. The top of Float-Pro is open to allowThe top of Float-Pro is open to allow easy removal of poly. Separator plates S1, S2 and S3 have small openings/perforations at bottom that allow pulp to go to next zone. 14 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  15. 15. DescriptionDescription In ‘Zone-1’ pulp gets some time and poly contamination moves upwards.The pulp with lesser poly contamination moves to ‘Zone-2’, and in the process passes through ‘ADP-1’, where more air is injected in the‘ADP-1’, where more air is injected in the pulp. Air from ‘ADP-1’ does two jobs. First to get attached to poly so that its floatation in the next stage is faster, and second keeping away the separated poly on the top. 15 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  16. 16. DescriptionDescription Similarly, pulp passes through ‘Zone-2’ and ‘Zone-3’ and most poly is effectively removed from pulp. A drain valve at bottom is provided toA drain valve at bottom is provided to empty out the unit if required. The floated poly can be removed by robotic or hydraulic arm grabber, similar to one as shown in next slide. 16 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  17. 17. 17 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  18. 18. ADP DesignADP Design Thicker, larger poly floats first. That is why air diffuser pipes ADP-1,2,and 3 are designed in such a way that the size of air bubble decreases in each subsequent stage.stage. So, you get larger poly in Zone-1, and smallest poly in Zone-3. However, the bubble size should be significantly higher than the fiber size in any stage. 18 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  19. 19. Operational ParametersOperational Parameters The size of unit is a function of operating production rate and consistency, which should be less than 1%. Minor increase in production rate andMinor increase in production rate and hence operating consistency does not result in significant impact on performance, except that the poly removal efficiency decreases slightly. 19 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  20. 20. Water HardnessWater Hardness A soft water promotes longer bubble life, and makes the floated poly very bulky. That is why it is not desirable.Addition of suitable chemicals for increasing watersuitable chemicals for increasing water hardness, or defoamers will be better for the system. 20 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  21. 21. I’d like to hear from machinery suppliers or innovative paper mills that they have developed an equipment on this concept, and that is working fine.and that is working fine. ThankYou. 21 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014
  22. 22. About the Author: Born in 1968, D K Singhal is B.E., M.E. (Pulp & Paper, 1993) from Deptt. of Paper Technology, University of Roorkee (now IIT, Roorkee). He is a Certified Energy Auditor and Chartered Engineer also. With nearly 7 dozen publications, he has emphasized on development of low cost technologies and management practices for quality and profitability improvement. With publications on slideshare.net, energymanagertraining.com and paperonweb.com, he has been constantly contributing to IPPTA (Indian Pulp & PaperTechnical Association). He is also serving IPPTA as a member of Editorial Board.Board. An initiative by D K Singhal, a cyber campaign initiated against unjustified targeting of paper industry by “Idea” mobile, in their “Sirjee” advertisement campaign, after which this advertisement was taken off air. He also moderated aYahoo group,“PaperTechnology” with nearly 360 members from India and abroad to discuss problems related to pulp & paper making for five years. He can be contacted at deveshksinghal@gmail.com 22 Proposed Equipment for Flotation Cleaning of High Poly Containing Pulp, July 2014

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