ITC Limited_Bratin_46

ITC Limited
Paperboards and Specialty Papers Division, Tribeni

Bratin Sengupta
Department of Chemical Engineering
National Institute of Technology, Durgapur.
EFFECT OF PCC SLURRY IN WET
END AND RUNNABILITY

Contents
 Wood and Pulp
 General Process of Paper Making
 Study

Wood and Pulp
“Paper is a thin material produced by pressing together
moist fibers, typically cellulose pulp derived
from wood, rags or grass, and drying them into flexible
sheets.”
The unit at Tribeni produces different types of paper which
are defined based on their functional properties such as
caliper, gsm , porosity, tensile strength etc.
It mainly produces cigarette paper.

Pulp from Wood ~
Hard Wood Soft Wood
• Deciduous forest
• Faster growth
• Difficult Conversion
• Fiber length 0.5-2mm
• Short fiber length and act as
filler material
• Improves formation,
smoothness and opacity
• Coniferous forest
• Slower growth
• Easy Conversion
• Fiber length 2-5mm
• Improves strength, bonding
and tear strength

Pulp is fibrous material made out of cellulose and lignin majorly.
Cellulose Structure
These are polymers of glucose, with each unit
connected by a beta-1-4-glycosidic linkage .

Paper Making Process
Pulp
Sheets
Pulper
Refiner
Head
Box Press
Drier
Rewinder Reeling
Packing
Dispatch

Stock Preparation ~
Materials Required :
1. Pulp Stock
2. Chemicals
• Filler: Clay, Chalk, Talc, Titanium Dioxide
• Retention Aids
• Biocides: Oxiclean, Busan
• Acids and Bases
• Sizing Agents: Resin , Waxes
• Dry strength additives: starch
• Wet strength additives: cross-linking polymers

Refiners
The refining is an operation wherein the pulp slurry passes
between a pair of discs, one of which is stationary and the
other rotating at speeds of typically 1,000 or 1,200 RPM.
The discs have raised bars on their faces and pass each other
with narrow clearance.

Fibrillation
The refining process causes fibrillation. fibers in the pulp are subjected to
shearing and compression forces. One of the things that happen during
refining of fibers is fibrillation, the partial delamination of the cell wall,
resulting in a microscopically hairy appearance of the wetted fiber
surfaces.
The amount of refining is
measured as the capacity of the
refined pulp to absorb water. This
is measured in terms of degree Sr.

Approach Flow
Centri-cleaner
• Equipments used to remove air,
dirt, shives and specks from the
pulp stock.
• Inlet consistency is around 1%.
• Generally consist of 3-4 stages
and reject of each stage flows
through the nozzle to a common
tank.
• Inlet and outlet valve of each
bottle is controlled to maintain a
required pressure drop.
Pressure Screen
• Cylindrical body with tangential
inlet and outlet along with a
reject outlet.
• Metallic screen drum having
required slots(0.15-0.8mm) is
fitted in drum co-centrally.
• Rotor placed at centre provides
centrifugal force .
• Stock which passes through
holes flows through outlet pipe
and reject goes for further
treatment.
Mainly composed of mechanical separation equipments to remove dirt and other
Impurity from the pulp before allowing it into the paper machine.

Paper Machine
•Stock enters from head box with 0.5% consistency
•Paper coming from wire part have 13-14% consistency.
•Paper exiting from press section have 30-40% consistency.

PAPER MACHINE-3
Installed in 1978 – Bertrams Sciences, UK
Deckle : 3.35 metres
Speed : 400 mpm
Grades :
Thin printing : 28 to 48 gsm
Wax match tissue : 44 gsm
Anti rust : 27 to 35 gsm
Insulating grades : 40 to 90 micron
Medical insert : 40 gsm
White tipping : 36 gsm
Daily capacity : 55 T

OBJECTIVE
 The objective of this project is to study the
effect on different paper quality due to
variation of different chemicals and
particularly the Chalk that is added to the
paper. The paper properties are being
studied under different conditions of chalk
and the variations in paper quality are
reported as the unit switched over from Bags
to PCC Slurry as their principal source of
Calcium Carbonate for the chalk

STUDY DETAILS
 Period: March ‘14 to
June ‘14.
 Paper Grades Selected
for study ~
 Opaque Tissue 28
 Pharma ptg 40
Data Collected
 Chemical Consumed
per ton paper produced
per day.
 Paper Quality for each
day – Opacity, Roughness,
Brightness, Ash content,
porosity.
 Runnability data – Chalk
Retention.

Paper Grade: Opaque Tissue 28
0
20
40
60
80
100
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Consumption:kg/tonspaperproduced
Daily Chemical Consumption-Opaque Tissue 28
Native Starch
Alum
Cationic Starch
*Ton = 1000kg

Opaque Tissue 28
0
2
4
6
8
10
12
14
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Consumption:kgpertonspaperproduced
Daily Chemical Consumption - Opaque Tissue 28
Salt
DVP 4X102
Nalco 8699
Nalco 64059
Nalsize 105
Nalco 7670
Nalco 7530

Opaque Tissue 28
0
50
100
150
200
250
300
350
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Chalk consumed per ton

Opaque Tissue 28 - Properties
70.5
71
71.5
72
72.5
73
73.5
74
74.5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Opacity

0
10
20
30
40
50
60
70
80
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Roughness

9.5
10
10.5
11
11.5
12
12.5
13
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Ash Content

90
90.5
91
91.5
92
92.5
93
93.5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Brightness

Opaque Tissue 28 – Properties Vs
Chemicals
0
10
20
30
40
50
60
70
80
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Roughness
PVA

Opaque Tissue 28 – Properties Vs
Chemicals
0
10
20
30
40
50
60
70
80
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Opacity
Alum

Chalk in Paper Making
Cost of Fiber is very high. For the purpose of increasing
weight
of paper, other cheaper filler material is widely used –
chalk being the principal filler material.
The paper making industry tries to increase the retention of
the chalk in the paper it produces.
The retention varies day to day, with a positive increase
being displayed during the month of may, than in March.
These variation are displayed via graphs in the following
slides.

Variation of Chalk Retention
0
5
10
15
20
25
30
35
40
45
50
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Chalk retention

Variation of Retention
0
5
10
15
20
25
30
35
40
45
50
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Chalk retention
DPV 4X103

0
5
10
15
20
25
30
35
40
45
50
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Chalk VS Cationic Starch
Chalk retaintion
Cationic Starch
0
5
10
15
20
25
30
35
40
45
50
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Chalk VS PVA 173
Chalk retaintion
PVA 173
ChalkRetention
ChalkRetention

PAPER QUALITY : PHARMA PTG 40
0
20
40
60
80
100
120
140
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Consumption:kg/tons
Chemical Consumption
Native Starch
Alum
Cationinc Starch

PHARMA PTG 40
0
1
2
3
4
5
6
7
8
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Consumptiom:Kg/tons
Chemical Consumption
PVA 173
Salt
Nalco 7530
Nalco-7607
Nalsize 7543
Nalco 8699
DVP4X103

PHARMA PTG 40
0
50
100
150
200
250
300
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Chalk Consumption

PHARMA PTG 40
70
71
72
73
74
75
76
77
78
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
opacity

PHARMA PTG 40
0
10
20
30
40
50
60
70
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Roughness

PHARMA PTG 40
0
2
4
6
8
10
12
14
16
18
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Ash

PHARMA PTG 40
82
84
86
88
90
92
94
96
98
100
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Brightness

PHARMA PTG 40
0
50
100
150
200
250
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Porosity

PHARMA PTG 40
0
10
20
30
40
50
60
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Chalk retention

ANALYSIS
Opaque Tissue – 28
The brightness has decreased after the use of PCC slurry as
the source of chalk.

ANALYSIS
The opacity has decreased after the use of PCC slurry as the
source of chalk.

ANALYSIS
The roughness has decreased after the use of PCC slurry as the
source of chalk.

ANALYSIS
The ash content has decreased after the use of PCC slurry as the
source of chalk.

ANALYSIS
There has been considerable increase in chalk retention with PCC
slurry.

ANALYSIS
Pharma Tissue – 40
The opacity has decreased after the use of PCC slurry as the source
of chalk.

ANALYSIS
The roughness has increased after the use of PCC slurry as the
source of chalk.

ANALYSIS
The ash content has increased after the use of PCC slurry as the
source of chalk.

ANALYSIS
The brightness has increased after the use of PCC slurry as the
source of chalk.

ANALYSIS
The porosity has increased after the use of PCC slurry as the source
of chalk.

ANALYSIS
There is considerable increase in retention.

PROBLEMS IN PROJECT UNDERTAKING AND
IMPLEMENTATION OF R&D SUGGESTION
• Time lag between sample collection and result communiqué.
• All tests are not done at the same time instance.
• Time delay in communication of results to control unit.
SOLUTIONS
• Proper management of a online database for production
parameters which should be accessible at every operation
points.
• Online and real time Sampling of back water and finished
paper rolls.
• Automated control and metering of chemicals and fillers
added at the ‘chemical kitchen’ department of the plant.

ITC Limited_Bratin_46

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