The document proposes a new flotation-based equipment called Float-Pro to remove high amounts of poly contaminants from pulp. It consists of multiple chambers that utilize differences in the densities of poly and pulp fibers, with added air bubbles of decreasing size, to separate poly upwards and away from the pulp over successive stages. This allows for higher poly content pulp to be processed at normal production rates compared to existing screening equipment that can get clogged. The design takes advantage of poly's low density and shape to more easily float to the surface with added air bubbles.

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. 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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

3. Existing AlternativesExisting Alternatives
Screen plate in Pulper
Drum Screen
Vibrating Screens
Pressure ScreeningPressure Screening
◦ Hole
◦ Slot
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
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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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

12. Schematic of FloatSchematic of Float--ProPro
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
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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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
of High Poly Containing Pulp, July 2014

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.
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Proposed Equipment for Flotation Cleaning
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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.
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Proposed Equipment for Flotation Cleaning
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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.
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Proposed Equipment for Flotation Cleaning
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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
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Proposed Equipment for Flotation Cleaning
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