1. 1

2. INPLANT TRAINING
REPORT
BILT Graphic Paper Products Limited,
BALLARPUR
From: 16th
May to 12th
June, 2011
Compiled By:
Miss .Mayuri D. Kalane
( B.Tech. Pulp and paper Technology)
University Department of Chemical
Technology,
Sant Gadgebaba Amravati
university,
Amravati.
2

3. ACKNOWLEDGEMENT
We, the final year chemical technology students of University Department of
Chemical Technology, Amravati, thanks Mr. C. S. Kashikar Dy.General
Manager, Mr. Bhushan Awate (Manager R&D), Mr. Gajanan Rothe, Assistant
Manager- R & D for valuable guidance and kind assistance throughout our
training at BGPPL.
We are grateful to the staff and employees of all the departments, especially the
Research and Development section for making us acquainted with all the
processes carried out in the mill.
Miss. Mayuri D. Kalane
Miss. Chaulata R. Kale
Miss. Neha S. Marghade
(B.Tech Pulp and Paper)
University Department of Chemical Technology,
Sant Gadgebaba Amravati University,
Amravati.
3

4. INDEX
 Introduction : 5
 Raw Material : 6
 Chipper House : 8
 Pulp Mill : 12
 Digester House : 13
 Screening Section : 18
 Washing Section : 20
 ODL Plant : 23
 Bleaching Section : 25
 Stock Preparation : 29
 Machine House : 33
 Finishing House : 43
 Recovery Section : 45
 Effluent Treatment Plant : 56
 Water Treatment Plant : 60
 Research and Development
Section : 62
4

5. Introduction
BGPPL is one of the largest paper manufacturing company in India having
manufacturing operations in six units: Ballarpur, Sewa, Yamunanagar , Ashti,
Bhigwan and Kamlapuram.
The establishment of BGPPL, was took placed in the year 1952, when Lala
Karamchand Thapar acquired Shree Gopal Paper Mill Limited at Yamuna nagar.
BGPPL units account nearly 10-15% of country’s total paper production.
Ballarpur unit is an integrated pulp and paper mill with a capacity of 2,92,000
TPA of writing and printing papers manufactured from bamboo and hard woods.
The raw materials come from AP, Karnataka, Maharashtra. It is an ISO- 14001,
ISO- 9001 and 5’S certified unit and OHSAS-18001. It manufactures various
varieties of writing and printing papers e.g. Copier, Matrix, ESKP, Base Paper,
MICR Cheque Paper, etc.
It has 7 machines out of which 2 are MG and 5 are MF machines. PM-7 has
been recently installed with the capacity of 400-500 T/day in September,2009.
For BGPPL, the past few years were full of modernisation, technology
upgradation, provisional or distributed control system and microprocessors based
on control system etc. Almost every section of the mill is modernised. The thrust
was on selection of appropriate technology and equipments from quality as well
as pollution control consideration. BGPPL has the largest Effluent Treatment
Plant having a capacity of 35,000 m3
/day of effluent by Activated Sludge
Process.
5

6. RAW
MATERIAL
6

7. Raw Material
• Hardwood- Hardwoods consist of Eucalyptus, Casurina, Subabul and
Mixed fire wood.
• In addition to this, bamboo which is a grass is also used.
• Softwood – Softwood consists of imported pulp.
Feed composition- 90% hardwood and 10% bamboo is maintained here.
Softwoods yield stronger pulps than hardwoods and have long fibres, hence these
are preferred. Earlier the feed ratio was 60%hardwood and 40% softwood.
However due the growing scarcity of bamboo the current softwood utilisation is
reduced to 10% only. The major chemical composition of wood consists of 45-
50%cellulose, 20-25%hemicellulose, 20-30%lignin and 0-10% extractives.
• Fibre dimension- The optimum length of fibre is 25-35mm while the
desired fibre thickness is 6-8mm and width is 8-10mm.
• Material storage: material stored in the wood yard is highly inflammable
and hence needs to be protected against fire and decay.
• Fire protection measures:
 6 to 8 feet wide free space is left along each stack.
 Dry grasses and leaves are collected and disposed off.
 Fire hydrants are used.
 Arrangement of tower for continuous watching is done.
 Smoking is strictly prohibited in the yard.
 The employees are trained against fire fighting.
 Decay control measures:
 Unwanted materials like decayed wood are removed from the stack.
 Aluminium phosphide (celphos) tablets are used which evaporate and
prevent the decay of wood.
7

8. CHIPPER
HOUSE
8

9. Chipper House
The objective of chipping house is to treat wood log in such a way that it meets
the regularities and standard. For efficient cooking and processing of chips, these
are reduced to usually 25-30 mm size. The raw material in the form of wood is
received through trucks from various parts of Andhra Pradesh, Karnataka and
Maharashtra. They are washed in the loaded position with treated water coming
from the effluent treatment plant for easy and efficient chipping.
Chipper:
Pallamann chippers : 3 in number with a capacity of 45 TPH
Papco chipper : 1
Bezner screen : 4 (gyratory type)
Dust screen : 1
Chip silo : 480 MT chips capacity
Technical Data:
Make : Pallamann
Type : Drum type
Number : 3
Capacity : 24MT/hr
Feed : Horizontal
Feed Rate : 23.4MT/hr/chipper
No. of fly knives : 4
No. of dead knives : 2
Fly knife angle : 31o
Dead knife angle : 58o
Clearance between : 2-3mm
fly and dead knife
9

10. Blade change: Dead knife : Once in a shift
Fly knife : Twice in a shift
Dimension of: Fly knife : 1130 × 200 × 20mm
Dead knife : 30 × 60 × 20mm
Power required : 9.82-10.15KWH/MT
Drum speed : 450rpm
Chips Screening:
Technical Data:
Make : Bezner
Type : Gyratory
Number : 4
Capacity : 20-25TPH
Angle of inclination : 4-5o
Mesh size: Top deck : 50mesh
Middle : 30mesh
Bottom deck : 4mesh
Size : 4325 × 2515 × 657mm
Rechipper:
Technical Data:
Type : Drum Chipper
Feed : Horizontal
Number : 2
Fly knife : 8 (set of 4)
Angle : 45o
Dimension : 375 × 90 × 20mm
Dead knife : 4 (set of 2)
10

11. Angle : 72o
Dimension : 410 × 110 × 20mm
Clearance : 2-2.5mm
Capacity : 2-4TPH
Through the belt conveyors these washed logs of wood are fed to the chippers.
The chippers operate on the principle of a flat revolving disc with knives set
radially on the surface and projecting out from the plane of the disc. There are 4
fly knives, out of these 2 are dead knives which has 1130 mm total length, 200
mm breadth and 20mm thickness. The wetted logs of wood are fed horizontally
to the chippers and are chipped to the optimum size.
SCREENING:
Chips obtained from chippers vary largely in their size and hence are sent to
screeners. A stream of unclassified chips is fed to 4 vibratory screens that have
openings of decreasing size. The mesh sizes of screens are 50, 30, 5mm in
diameter respectively. Due to screenings the chips get separated into undersized,
desired size and oversized chips. The oversized chips are sent to rechippers which
are 2 in numbers and are rechip back, while undersized chips are blended with
saw dust pulp and are taken to the boiler house, as fuel for boilers. The required
size chips are transferred to the silo for storage through belt conveyors. Here the
silo is divided into 2 equal sections with each section further divided into 5
compartments, each having capacity of 45MT.
11

12. PULP MILL
Digester House
Digester refers to that part of paper manufacturing where the raw material in the
form of chips are cooked and converted to pulp.`Pulp` can be commonly called as
Cellulosic fibres, which are separated from the wood chips after cooking.
12

13. Cooking carried out at high temperature and pressure leads to the rupturing of
bonds to break the wood structure into fibrous mass.
Digester operation-
The batch type stationary digesters are used for pulping operation for good yield.
Chips digester house operation is divided in 5 parts as below-
• Cooking.
• Blow heat recovery system operation.
• Condensate recovery system operation.
• Spill collection system operation.
• Non condensable gases recovery.
This operation is carried out in 7 sequential steps-
• Chip filling
• Liquor charging
• First stage steaming
• First stage cooking
• Second stage steaming
• Second stage cooking
Blowing
The primary objective of cooking operation is to separate the wood fibres,
joined to each other by lignin. Here, Kraft pulping process is employed for
cooking in which mainly NaOH+Na2S is used as cooking liquor or white liquor.
In this process, lignin gets dissolved in soda, and Na2S play an important role in
maintaining the strength of the NaOH in the cooking liquor for complete cooking.
White liquor is fed upto 3/4th
of the digester along with black liquor which is
added for dilution. Steam is added with the help of steam valve. Blowing is done
from the bottom of the digester where blow valve is provided. The liquor is
continuously circulated from top to bottom through a circulation pump. During
circulation, the liquor is allowed to pass through preheater where its temperature
13

14. increases at the inlet to the digester, which is ultimately beneficial on account of
steam consumption.
The table below shows the standard operating parameters of DIGESTOR.
Digester Type Voith(9 in no.) Inglis(2 in no.)
Capacity 80cu.m 60cu.m
White Liquor Charge 30m3
20m3
Chip Loading 30MT 25MT
Black Liquor Charge 14m3
20m3
Total Liquor Volume 54m3
40m3
First Stage Steaming 60min 60min
First stage Retention 45min 45min
First Stage Cooking Temperature 132o
C 132o
C
First Stage Cooking Pressure 2.1kg/cm2
2.1kg/cm2
Second Stage Steaming 60min 60min
Second Stage Retention 30min 30min
Second Stage Temperature 162o
C 162o
C
Second Stage Cooking Pressure 6.2kg/cm2
6.2kg/cm2
White Liquor Analysis:
Quantity Used (Voith) 40m3
Quantity Used (Inglis) 30m3
White Liquor Charged 3200kg/cook
White Liquor Strength 90-94gpl
Total Alkali 110.4gpl
Sulfidity 25-26%
Active Alkali 3200kg
14

15. Total Alkali 4450kg
Bath Ratio (Wood : Liquor) 1:3
White Liquor Temperature 75o
C
Black Liquor Temperature 75-80o
C
NaOH as Na2O 82.04gpl
Na2S as Na2O 27.94gpl
Na2CO3 as Na2O 22.6gpl
Blowing:
After digestion, the digester contents are discharged into blow tank where the
softened chips are disintegrated into fibres. This is called Blowing. In the digester
the material is under high pressure. The cooked material is fed into the blow tank
from the top from high pressure to low pressure, where the cooked chips get
disintegrated into fibres along with the release of hot vapours called blow
vapours. These vapours are then used in the blow heat recovery.
Parameters of Blow tank:
Blow Tank 2 in number
Make Voith and Empacel
Capacity 250m3
each
15

16. Inlet Consistency 14-15%
Outlet Consistency 4%
Steaming Method Direct
Time Taken 15min
K Number 14.5-15.5
Unbleached Pulp Production/day 350MT
Viscosity 16-22cps
Blow heat recovery system:
In this system the blow vapours from the blow tank are taken to the Voith
cyclone separators. Here the fibres separated are transferred to blow tank through
dump chest, while the vapours are sent to the spray condensers. At this stage,
water is added through nozzle at 500
C with the help of primary pump, while hot
water at about 900
C is recovered and taken to Voith PHE Feed Pump. The
primary pump is operated usually at lower temperature for efficient separation of
vapours. Here the efficiency of heat recovery is about 90%.
Condensate contamination:
The condensate gets contaminated due to mostly rupture of heat exchanger tube
or rarely due to suction of black liquor in steam line. Conductivity meter is used
to check the contamination of condensate whose reading can be seen on the
digester house control panel.
Spill control system:
There are 2 spill pits. One is used to collect the spills of INGLIS digester and the
other for VOITH digester numbered 1-9.
Main advantages of Alkaline Pulping:
• High strength pulp can be obtained.
16

17. • Different varieties of wood species can be
• Barks can also be tolerated.
• Efficient recovery of chemicals is possible.
17

18. Screening Section
In this operation, the pulp from the blow tank is first taken into junk traps. Here
the removal of heavy metal particles like iron takes place and the pulp is moved
onto pressure knotters where the knots are removed. There are two open vibratory
knotters provided. The screen plate has perforation of 3mm. The accepted stock
falls through the holes and is taken to the primary vertical screen.
At BGPPL, 3 stage screening is carried out. The perforation of the screen is 2mm.
The accepted is taken to the primary screen, while the rejected knots are taken to
the digester for cooking. The accepts from the primary vertical screen are taken
to brown stock washing, while the rejects are taken to knotters. The rejects from
the primary screen move to the secondary screen. The accepts from the secondary
screen are taken back to the primary screen, whereas the rejects from the
secondary screen are taken to tertiary screen. The accept from the tertiary screen
are again taken back to secondary screen , whereas the rejects move on to the
sand cleaner where the sand particles are removed from the pulp and send back to
primary screen. This is a continuous process. All the 3 screens are pressure
screens. The screening efficiency is around 90%.
Technical Data:
Screens Knot
Separator
10
Screen
20
Screen
30
Screen
Type Modu
Screen
Modu Screen Modu
Screen
Modu
Screen
Slot Size 8mm 0.22mm 0.22mm 0.22mm
Screen
Area
0.9m2
1.3m2
0.7m2
0.2m2
Design
Pressure
600kPa 600kPa 600kPa 600kPa
Speed 1000
rpm
1500
rpm
1500
rpm
1500
Rpm
18

19. Motor 37
kW
132
kW
75
kW
18.5
kW
19

20. Washing Section:
The objectives of washing are:
Remove of residual liquor that would contaminate the pulp during
subsequent processing steps.
Recovery of maximum amount of spent cooking chemicals with minimum
dilution.
Process description:
At the digester, chips are cooked and lignin dissolved in the cooking liquor
forming black liquor leaving behind the pulp. In the pulp screening plant, knots
and shives are removed. In the wash plant, pulp is washed in stages to render free
from black liquor.
The pulp mass coming as accept from primary screen is diluted further using
black liquor from the wash plant. The consistency is controlled to about 1% at
this stage. The stock is led to the wash plant, which consist of 4 rotary drum
vacuum filter arranged in series. The pulp is fed to the vat of first washer, where
from the pulp mat form on the first drum and subsequently falls into the repulper-
vat of the next washer. Thus, the pulp moves from one vat to another and finally
emerges as the washed pulp at the 4th
washer and discharges into high density
storage. However, wash water is added as drum shower on the 4th
washer. The
washer filtrate moves counter currently to the pulp and emerges as filtrate from
the first drum. This filtrate is known as thin black liquor. The thin black liquor is
used in the blow tank bottom case and for dilution purposes. The excess of this
black liquor from the sealed tank of first washer is screened on the Malone filter
to remove fibres present, if any. The screened black liquor is pumped to chemical
recovery section.
Equipment –
4 stage drum washer area : 3.5m dia/6.7m face & 73.8m2
Malone filter : 2 in number
High density unbleached pulp tower : 400m3
vol.
20

21. Technical data:
Number of storage
tower
1
Capacity 300m3
Consistency 10-12%
Total pulp washed 350TPD
Washing efficiency 96-98%
21
Make Dorr Oliver
Type Rotary Drum Vacuum Washer
No. of Stages 4
Type of Flow Counter-current
Speed 3rpm
No. of Showers 6
Type of Shower Pressure Nozzles
Size of Showers 3.5 × 6.7m
Wire Cloth Make Metallic Cloth
Washer Capacity 360TPD
Consistency before wash 1-1.5%
Consistency after wash 10-12%
Hot Water temperature 65o
C
Foul Water temperature 60o
C

22. Black Liquor Characteristics:
Number of seal tanks 4
Capacity 400m3
Black Liquor at seal tank 1 14-16o
Tw
Black Liquor at seal tank 2 4-5o
Tw
Black Liquor at seal tank 3 2-3o
Tw
Black Liquor at seal tank 4 0.5-0.8o
Tw
Vacuum at stage 1 120-130mmHg
Vacuum at stage 2 90-110mmHg
Vacuum at stage 3 150-160mmHg
Vacuum at stage 4 170-180mmHg
Black Liquor Temperature (1st
washer) 80o
C
Black Liquor Produced 31200m3
/day
22

23. Oxygen delignification plant (ODL)
ODL is the process of further removal of lignin from the entering pulp with 5%
lignin content to near about 2-3%. It begins with a pulp of 10-12% consistency
being discharged from the last stage of unbleached pulp washing. White liquor is
added in conventional way, the pulp is then pumped through a high intensity
shear mixer where oxygen is added and dispersed. The oxygen reactor is an
upflow tower usually pressurised. The pulp is diluted at the top and blown to the
blow tank, where gases are separated from the suspension. From the blow tank
the pulp passes to one or more washing stages before passing into the
chlorination stage for bleaching.
In this unit there are two oxygen reaction towers with the capacity of 360m3
each.
Having two towers increases the capital cost but it prevents the fibre loss due to
over reaction of oxygen with the pulp.
Technical data:
Final Pressure in ODL reactor : 3.5-4 kg/cm2
Retention time in I reactor : 30 min
Retention time in II reactor : 45 min
pH : 11.5
Temperature : 95o
C
Consistency : 9-10
Oxygen consumption : 20-21 kg/ ton
Blow tank capacity : 30 m3
Mixer capacity : 5.8 tons/hr
% ODL : 30-35%
23

24. 24

25. Bleaching Section
In order to get the pulp of desired brightness and purity, bleaching operation is
carried out. In this process the brown coloured pulp obtained from digester is
converted to white pulp with the help of bleaching agents like chlorine, calcium
hypochlorite, etc. At Ballarpur, bleaching is done in 4 stages-
• CD (using Cl2 , ClO2)
• Eop (extraction with caustic)
• H (using CaCl(OCl))
• D (ClO2 )
CD stage:
In the bleaching process, unbleached pulp from the tower is fed to the
chlorination tower, it is also called CD tower. In the CD tower, the chemicals
used are chlorine gas and chlorine dioxide liquid and hence called CD tower.
The chlorine gas is injected into the pulp from the bottom of the tower, as it is
used in the gaseous form. The ClO2, which is used in the liquid form, is fed from
the top.ClO2 added serves to minimize degradation of cellulose, reduce colour of
effluent and provide better brightness stability. Here lignin reacts with Cl2 by
oxidation substitution reaction to form chloro lignin. Here, the unbleached pulp
comes from the 1000m3
storage tank and it enters the CD tower from the bottom.
The CD tower is called as upflow tower in which the feed enters from the bottom
and the overflow is taken out from the top. Thus, the overflow of pulp obtained
after addition of Cl2 and ClO2 is taken to the bleached plant washer-1(BPW-1).
The pulp taken to BPW-1 is slightly brighter than the original unbleached pulp.
The washed, extracted pulp moves to the next stage.
Technical data:
pH : 1.8-2
Consistency : 3.5-4%
Temperature : Ambient
25

26. Retention time : 45min
Cl2 charge : 42.8kg/ton of pulp
ClO2 charge : 10.5kg/ton of pulp
Shrinkage : 4%
Eop stage:
In this stage the extraction of the pulp with caustic and O2 takes place. By using
alkali, the chlorolignin formed in the previous stage is dissolved and removal of
colour compound takes place. This tower is also an up-flow tower. The pulp
enters at the bottom and the over-flow moves on to the next operation. The main
chemicals used are O2 and H2O2. O2 is added to increase the strength of the pulp.
The retention time in this tower is 2.5 hrs. The Kappa number initially is 13 and it
is drastically reduced to 3-3.5 after this stage. The over-flow from this tower goes
to BPW-2. Mill water is added to BPW-2 from the top. The pulp from BPW-
moves for next operation to the hypo tower.
Technical data:
pH : 9.2-9.5
Consistency : 10%
Temperature : 60-70o
C
Retention time :90min
E charge :36kg/ton of pulp
O2 charge :7kg/ton of pulp
H2O2 charge : 10kg/ton of pulp
Brightness :38-40% ISO
Shrinkage :3%
H stage:
The chlorination and alkaline extraction will not give commercially required
brightness to the pulp and hence oxidative bleaching stage, where the active
component is sodium or calcium hypochlorite in an alkaline medium. The
brightening is achieved by destructive oxidation of lignin and the continuous
26

27. presence of alkali leads to the solution of reaction products, thus opening deeper
layers of lignin in the fibre for further attack. Sulfamic acid is added to control
the viscosity of pulp. It is important to maintain the pH because below this Ph,
hypochlorite is in equilibrium with significant amounts of hypochlorous acid
which is a powerful oxidant of carbohydrates. Since the pH is high, the lignin is
continuously extracted as it is depolymerised. The rate and extent of hypochlorite
bleaching reactions depend on the nature of the pulp, bleach demand of the pulp,
chemical application, temperature, pH, retention time and consistency.
Technical data:
pH : 7-7.2
Consistency : 10-12%
Temperature : 42-48o
C
Retention time : 2-2.5 hrs
H charge : 30kg/ton of pulp
Sulfamic acid charge : 0.9kg/ton of pulp
Brightness : 76-78% ISO
Shrinkage : 2.5-3%
Viscosity : 8-15cps
D stage:
It is the final stage used in the bleaching sequence to obtain final brightness. The
ClO2 bleaching stage is an oxidative bleaching stage conducted under controlled
and optimised condition to promote its reactivity with lignin and other colour
constituents of the pulp with minimum carbohydrate degradation. The main
function of this stage is high selectivity in dissolving lignin without degrading
cellulose and hemi-cellulose, thus preserving the pulp strength and resulting in
high brightness. The rapid adoption of ClO2 for pulp bleaching can be attributed
to its high selectivity in destroying lignin without significantly degrading
cellulose or hemi-cellulose, thus preserving pulp strength while given high, stable
brightness. The high selectivity of ClO2 for lignin makes it useful for later
bleaching stages where lignin is present in very low concentrations. This stage
can also be considered to be very useful in reducing the shives content. ClO2 is
usually considered to have 2.5 times the oxidising power of Cl2 on a mole per
mole basis.
27

28. Technical data:
pH :2-3.2
Consistency :10-12%
Temperature : 70-760
C
Retention time : 3-3.5 hrs
ClO2 charge : 10.5kg/ton of pulp
SO2 charge :1.1kg/ton of pulp
Brightness :87-90% ISO
Shrinkage :0.5-1%
Bleached pulp characteristics:
Bleached pulp production : 320 TPD
Brightness : 88-90% ISO
Viscosity : 8-10cps
Overall Shrinkage in bleached pulp is 10%.
28

29. STOCK
PREPARATION
29

30. Pulp received from pulp mill is unsuitable for paper making, hence it is subjected
to various mechanical and chemical treatment to get the desired quality of paper.
This operation is carried out in stock preparation. The main objectives of stock
preparation is-
• Storage of the pulp obtained from the pulp mill
• Pulp refining
• Blending of pulp with necessary additives
• To supply stock to the paper machine as per requirement
• Pulp storage system:
• Both bleached and unbleached pulp obtained from pulp mill is stored in
the storage tower of capacity 100m3
each. Here the consistency of pulp is
maintained at 4-4.5% respectively.
Refining of stock:
It refers to the mechanical action on the fibre in water suspension to convert raw
fibre into a form suitable for the formation into a web of desired characteristics
on a paper machine.
There are three types of refiners namely-
• Conical refiner.
• Double disk refiner (DDR).
• Triple disk refiner (TDR).
The major effects of refining on fibre are-
• Swelling of fibre.
• Increase in fibre flexibility.
• Fibre shortening.
• External fibrillation of fibre.
• Breaking of the inner fibre bonds and replacement by water fibre bond.
• Increase in drainage resistance.
30

31. • Decrease in risk of flocculation
CHEMICAL ADDITIVES:
Dyes:
Dyes are the colouring agents added to the stock to impart desired colour to the
final product. Dyes may be acidic, basic, direct and pigment dyes. Acid dyes
being negatively charged have low retention and have poor bonding with fibres,
whereas basic and direct dyes have great affinity for cellulose. Pigment dyes have
a low affinity for cellulose but they are resistant to light, air and water and have a
good appeal. However, these are comparatively costly than others. Basic dyes
and pigment dyes are more commonly used.
Optical Brightening Agent (OBA):
The optical brightening agents are added to increase the apparent brightness and
whiteness of paper. For example, Bluton-AS, Bluton-BA, Tinopal, etc. The OBA
addition takes place both at the stock preparation as well as at the dry end.
Sizing:
Sizing chemical is added to the stock in order to impart water repellent property
to the fibre (Cobb value). Sizing can be acidic, alkaline and neutral. In acidic
sizing, the paper becomes weak, dull and brittle on ageing. It causes reversion of
brightness, strength and colour. It is also corrosive, dirty and causes damage to
the machine parts. Alkaline sizing prevents reversion on aging. Hence, alkaline
sizing is preferred. Some sizing agents are Alkene succinic anhydride (ASA). The
alkaline sizing is accomplished by ASA. Rosin is used for neutral sizing but this
paper has low life and turns yellow on exposure to sunlight due to reversion of
cellulose. Cationic starch is added which forms an emulsion with ASA on
external sizing whereas internal sizing increases the strength of paper.
Fillers:
Fillers are finely divided white minerals added to papermaking furnish to
improve the optical and physical properties of the sheet. These particles serve to
fill in the spaces and crevices between the fibres thus producing a denser, softer,
brighter, smoother and more opaque sheet. Filler make the paper chipper because
they are less costly than the fibre. Some of the commonly used fillers include
talc, finex, titanium dioxide, ground and precipitated calcium carbonate (GCC,
PCC).
Retention Aids:
31

32. Retention is a measure of how much material remains on the paper machine wire.
Natural and synthetic polymers are used as retention agents. They form bonds
with the fibre surfaces and the additives to be retained. Percol, hydrocol and
telioform are used as retention aids.
Defoamers:
To prevent foaming problem, thereby getting proper drainage and sheet
formation, defoamers are added. Sapco-KFS is used as a defoamer and is added
in backwater.
Slimicides:
Micro-organisms, particularly and fungi will grow around the paper machine and
produce slime consisting of proteins and polysaccharides. This slime may break
off in pieces and lead to pitting of paper, holes in light weight paper and even
break in the web, which leads to very expensive downtime, to avoid this
slimicides are being used. Trylon is used as a slimicide and is added at the paper
machine back water and in broke chest.
MACHINE
HOUSE
32

33. Machine House:
Paper machine is a device for continuously forming, dewatering,
pressing and drying a web of paper fibres. Until most recently, the
most common type of wet end was Fourdranier where a dilute
suspension of fibres typically of 0.3-0.6% consistency is applied to an
endless wire screen or plastic fabric. Water is removed by gravity or
the pressure difference developed by table rolls, foil or suction
equipment and drilled couch. The web at this point is at 18-23%
consistency. More water is squeezed out in press section to a
consistency of 35-50%. Finally the sheet is dried with steam heating in
the drier section.
Paper machine consists of-
• Forming section
• Draining section
• Pressing section
• Drying section
• Winding:
33

34. o In BGPPL, there are 7 paper machines 4 are MF and
3 are MG.
Machine
PM-1 PM-2 PM-3 PM-4 PM-5 PM-6 PM-7
Type MF MG MF MF MG MF MG
Make
John
Inglis,
Canada
J. M.
Voith
J. M.
Voith
Allimand
France
Bertram
Scott
(UK)
Bertram
Scott
Allimand
France
Vintage
1950 1962 1962 1965 1970 1962 2009
Speed
280
mpm
145 mpm 480
Mpm
220
mpm
220
Mpm
250
mpm
1100
mpm
Deckle
width
3.2m 3.48m 3.5m 2.84m 3.45m 2.9m 5.46m
Produc
-tion
per day
50-60
MT/day
30
MT/day
160-170
MT/day
45-47
MT/day
28.91
MT/day
72
MT/day
520
MT/day
GSM 44-85 26-60 68-120 58-100 26-60 68-140 54-90
Drive Left Left Right Left Left Right Left
Wire
Single
layer
Single
layer
Double
layer
Single
layer
Single
layer
Single
layer
Double
layer
Head
box type
Open Open Pressur
-ised
Closed
vacuum
Open Closed Closed
Dryers 22 1 MG 41 18 1 MG 21 63
Products
ESKP,
Duplic-
ating
paper
TD,
AR,
white
poster
NSD
premi-
um
Copier
grade,
Azure
laid.
white
poster
SSS ptg,
Copier,
NSD
premium
BPM
(Magna
print)
HEAD BOX:
The function of head box is to take the stock delivered by the fan pump
and transform the pipeline flow into an even, rectangular discharge,
equal in width to the paper machine and at uniform velocity in the
machine reaction. The head box lies between the distributer and slice.
34

35. In BGPPL, PM-I, II, V has open head box, PM-VI and VII has closed
head box and PM III and IV has pressurised head box in which pressure
is regulated through a compressor which either supplies air into and out
of the head box to maintain the definite head to bring down the rush to
drag ratio to the desired set point.
Functions of head box:
• To spread the stock evenly across the wire part.
• To correct the inequalities in velocity of flow.
• To equalise the turbulences and cross flows created in the
distributors.
• To create controlled turbulence to eliminate fibre flocking
Slice:
A slice is a rectangular orifice in front of head box it takes relatively
slow moving stock in head box at high speed and discharged it with a
velocity close to wire speed. At BGPPL projection and vertical slice
are in operation.
WIRE PART:
The wire, also called the forming fabric, is a continuous loop or finely
woven screen made from wire or plastic (nylon). The wire is used to:
• Transport the fibre.
• Permit draining the sheet.
• Transmit power
Parameters PM-1 PM-2 PM-3 PM-4 PM-5 PM-6 PM-7
Consistency 0.4- 0.4- 0.4- 0.4- 0.5-0.7% 0.4- 0.6-0.8%
35

36. 0.6% 0.6% 0.6% 0.6% 0.6%
Slices No. 31 226 32 20 30 24 77
Slice opening 12mm 13 13mm 13mm 13mm 13mm 14.9mm
Breast roll dia. 406mm
600m
m
600mm 550mm 610mm 508mm 920mm
Table roll no. 11 3 11 14 4 14 Nil
Table roll dia.
152.4m
m
208m
m
152.4m
m
152.4m
m
230mm - -
Hydrofoil 7 30 35 5 24 30 36
Breast Roll:
It supports the wire below the head box. It is made up of cast steel and
is covered with copper coating for corrosion protection. It is the
turning roll for the wire at the slice and is driven by wire. It also acts
as suction former.
Forming Board:
It is mainly use for supporting work which is made from polyester
monofilament made endless by a seam to form a continuous belt. The
mesh of fabric permits the drainage of the retaining fibre by shaking
action.
Hydrafoils:
Foil is a stationary blade held in contact with the wire at the front and
diverting from the wire at an angle of 1.5 to 2⁰. Foils are normally 2-8
m long. Foils have higher drainage and negligible fibre loss compared
to table rolls.
Table Rolls:
These are also used for water removal purpose. This must be straight,
rigid and dynamically balanced since the vibration will disrupt the
formation of sheet on the wire.
Wet and Dry Suction Boxes:
36

37. These are placed before dandy roll or wet suction boxes and after
dandy roll or dry suction boxes. Suction boxes are used for removing
water from the mat by applying vacuum system in the range of 7.5-25
mm Hg.
Parameters PM-1 PM-2 PM-3 PM-4 PM-5 PM-6 PM-7
No. of suction
Boxes
4 3 2 2 4 8 3
Vacuum applied
mmHg
180-
200
460-
470
100-
120
100-
120
180-
200
200 45kPa
No. of slots 50 50 9 9 20 4 4
Slot angle 600
600
600
600
600
600
600
Dandy Roll:
This is used to improve the finish and formation. It is also used to
produce water mark in paper.
Couch Roll:
This roll is usually the drive roll for the entire machine. It removes
sufficient amount of water so that the web leaving the wire part will
have considerable strength.
Lump Breaker Roll:
This roll is a solid roll with a suitable soft cover that is mounted over a
couch roll to assist the sheet by pressure.
Straight and Guide Rolls:
These are used automatically to maintain the correct tension on the
wire.
Showers:
A series of showers are used to keep the wire clean.
PRESS SECTION
37

38. The primary function of the press is to remove water, impart favourable
sheet properties and impart higher wet web strength for good run
ability in the drier section. The pressing operation may be considered
as an extension of water removal process by mechanical means. Here
following types of presses are used-
Plain press- It is used to remove water mechanically without applying
any vacuum.
Suction press- In the suction press a rotating outer shell and a
stationary suction quadrant, the rotating one is drilled to allow air and
water to be drawn into the suction quadrant, the shell of the row is
usually rubber covered to give it with little softness and prevent the
whole pattern from being transmitted to the web through the felt.
Smoothening press- This type of press is used in MG or Yankee type
of machine. The sheet passes through first press and comes to
smoothening press. Here the roll is in contact with the surface of MG
dryer. As the sheet passes through the nip, water removal takes place.
Offset press- In this press the paper is passed between two metal rolls
under pressure, the sheet is pressed and passed to next section
Parameter PM-1 PM-2 PM-3 PM-4 PM-5 PM-6 PM-7
Top roll dia.
(mm)
750 710 790 550 710 610 770
Bottom roll
dia.
(mm)
710 750 710 510 760 686 852
Vacuum
(mmHg)
525 460-
470
240-
260
300 460-
470
400 45kPa
Dryer section:
Drying is removal of moisture or water from the wet web leaving the
press mainly by evaporation throu7gh steam heated cylinders.
Parameters PM-1 PM-2 PM-3 PM-4 PM-5 PM-6 PM-7
38

39. MF MG MF MF MG MF MF
No. of dryers 22 - 41 16 - 21 43
No. of groups 2 - 6 4 - 5 8
Dryer dia.(mm) 1524 4200 1500 1500 4200 1524 1830
No. of felt dryers 2 - Nil 7 - 4 8
Dryness (last
dryer)
97% 96% 97-
98%
97-
98%
91% 97-
98%
94%
Calendering:
The calendar stack is a series of solid rolls mounted horizontally and
stacked vertically. During machine calendering, the paper from dryer
passes between the rolls under pressure.
Functions of Calender:
To build even reels, it provides calliper control throughout the width of
sheet.
• To produce smooth well finished sheet.
• Correct irregularity in the sheet formation.
• To improve surface flatness and density of the paper.
• To improve glaze of the paper sheet.
Technical Data:
Particulars PM-1 PM-3 PM-4 PM-6 PM-7
No. of
stacks
1 1 1 1 1
No. of rolls 2 2 2 2 2
Nip
pressure
Self
loaded
110
kg/cm2
60-100
kg/cm2
110
kg/cm2
30-
150kg/cm2
39

40. Surface Sizing:
Surface sizing refers to the application of dry and wet strength
additives to the paper usually at the size press.
Objectives of surface sizing:
• To improve water penetration resistance.
• To obtain wet rub and wet pick resistance.
• To improve the surface and internal bond strength.
• To reduce the porosity.
• To improve the printing properties.
Technical Data:
Particulars PM-3 PM-4 PM-6
Type Horizontal Horizontal Horizontal
Movable roll
material
Rubber
covered
Rubber
covered
Rubber
covered
Fixed roll
material
Micro rock Micro rock Micro rock
Loading Hydraulic Hydraulic Hydraulic
Paper feeding Rope carrier Rope carrier Rope carrier
Winding/Reeling:
The paper after calendaring is sent for winding where paper is bound
over cast iron roll. The paper is passed through tension roll so that the
paper being wound on core is under uniform tension across the width.
This is called pope reel. This is the last unit of paper machine.
40

41. Common Flow Sheet of Paper Machine
41
Fibre Slurry
Head Box
Wire Section
Press Section/Size Press
Dryers/MG Drying/Pre
Drying/Post Drying
Calendars
Pope Reel
Re-winders
Suction Back Water
Suction Pressing Water
Steam Condensate

42. FINISHING
HOUSE
42

43. Finishing House
The main function of the finishing house is to process the paper
manufactured on machines in wheel or in sheet form as per the
requirement of the customer. The paper finishing plant includes the
following-
• Rewinder
• Cutter
• Counting
• Packaging
• Labelling
Rewinder:
The function of the rewinder is to rewind the paper manufactured on
the pop reel and also to remove the defective paper. The bigger sized
reels are reduced to smaller size of required width and diameter as per
the customer demand. A typical rewinder consists of parent reel,
tension roll, camber roll, top and bottom slitters, D bar, drum roll, core
shaft, ejector and rider rolls.The parent reel is the reel to be rewound,
hydraulic break is provided in the shaft of parent reel. Tension and
camber rolls are provided to give tension to the paper and thereby
avoid creeping. The shear force between slitter roll and slitter knives
accomplishes slitting and trimming of the sheet and it is wound on the
core shaft. Over this shaft a pneumatically operated rider roll is
provided to ensure proper reel building.
Cutter:
The function of the cutter is to cut the paper reel or rolls into sheets of
required dimensions. A typical cutter consists of a backward stand,
cutting section and delivering section. In the back stand the rolls are
mounted, from this reels the cutting section draws the paper. The
incoming paper is slit width wise in the slitters and lengthwise in the
chops.After paper cutting, the sheets and reels are sent to the finishing
section where they are counted, packed and weighed. After the
completion of packaging checker count, the number of reams and
finished report is prepared. This contains information about lot
number, quality, size, weight, no. of reams. Then reel finishing and
labelling is done. Wrapmatic machine is provided which wraps the
43

44. reams which are cut at the Pasaban Cuttters. Finishing loss is around
10-11%.
RECOVERY
SECTION
44

45. Recovery Section:
Chemical recovery is the process of recovering pulping chemicals from
the spent liquor and reuse. The main objectives of chemical recovery
are:
• To recover the cooking chemicals from the spent liquor.
• To generate large amount of heat by burning the organic material
derived from the wood present in the black liquor .
• To reconstitute these chemicals to form fresh cooking chemicals.
• To minimise air and water pollution.
Recovery process consists of 6 steps:
• The concentration of weak black liquor in multiple effect
evaporators from 15% TDS (total dissolved solids) to 50% TDS.
• Further concentration in forced circulation evaporator from 50%
TDS to 65% TDS.
• The combustion of concentrated liquor in a suitably designed
furnace for burning matter from the sodium salts for reduction of
sulphur containing salts to sodium sulphide and for utilising the
heat produced in the generation of steam.
• Green liquor production and clarification.
• Causticising of green liquor, withdrawal of clarified and
causticised solution or white liquor used in another cycle.
• Burning of mud to recover lime.
The chemical recovery plant can be divided into 3 sections-
• Evaporation
• Recovery
• Causticising
45

46. Standard operating procedure for recovery department-
• To receive black liquor from pulp mill at 170
Tw and minimum
780
C temp.
• To prepare semi concentrated thick black liquor in evaporator
plant no. 1, 2, 3 and 4 and blending at FCE plant header.
• Prepare thick black liquor of 68+20
Tw in FCE plant and supply
to recovery boilers.
• Supply pure condensate to DM plant.
• Supply foul condensate to causticising plant.
• Receive and blend white and yellow salt cake in proper
proportion.
• Feed salt cake to salt cake bins.
• Mix salt cake in thick black liquor in recovery boiler 1 and 2.
• Fire black liquor in RB-1 and RB-2 at 325-340 TPD and 220-240
TPD dry black liquor solid respectively.
• Collect ash in recovery boilers ESP and reuse by mixing in thick
black liquor.
• Supply high pressure steam to high pressure header.
• Supply green liquor of 114gpl to causticising plant.
• Receive lime from various vendors and blend in proper
proportions.
• Feed lime to lime bin by running lime crusher.
• Ensure continuous running of white liquor clarifier, dreg washer
and lime mud washer rake machine.
• Run causticising plant for supplying white liquor to pulp mill
having active alkali strength of 90+3gpl. In cake, active alkali
goes below 87gpl start caustic dosing at white liquor polisher
outlet.
46

47. • Ensure continuous running of causticizers, lime mud slurry tank
and drags mixer agitator.
• Ensure white liquor, mud washer and filtrate clarity and
strength.
• Supply weak white liquor to recovery boiler.
• Dispose grits and stones generated in slakers and rake clarifier.
• Wash and filter lime sludge produced from causticizing plant to
get filtrate strength of 4-5.5gpl in new mud filter and 6-8gpl in
old mud filter.
• Dispose lime sludge through dumpers through DDC department.
Evaporators:
Cooking chemicals which are separated from pulp after screening in the
Malone filter in the pulp mill, along with wood residues is called as
black liquor. This black liquor having initial concentration of 16-17%,
containing 0.110gpl of constant suspended solids, 5.9gpl of free alkali,
organic content 50.2% and inorganic content 49.8% comes to the
evaporation unit. The aim of evaporators is to concentrate thin black
liquor from 16-17% concentration to 60-65% solid content. In BGPPL,
4 multiple effect evaporators (MEE) having long tube vertical
evaporators (rising film) are used which concentrate the thin black
liquor from 16% to 50% solids, while rest of the concentration is
increased in forced circulation plant having 3 vapour separators. The
most important physical properties of black liquor that affects the
evaporation process are specific gravity, viscosity, specific heat and
boiling point characteristics.
Multiple Effect Evaporators:
MEE consists of series of evaporators with indirect heating for removal
of water.
MEE-1: It is backward feed multiple effect evaporator having 4
effects. The black liquor is fed at the fourth evaporator and it moves
backwards, while the steam is added at the first evaporator and it flows
forward. The black liquor coming out of the first street reaches a
concentration of 25o
Tw. The steam used is flash steam from vapour
separator two (VS-2). Condensate collected from each effect called as
47

48. foul condensate is collected and sent to hot water tank. It is used in
causticizing section for mud washing.
Liquor Flow: IV-III-II-I
Steam Flow: I-II-III-IV
MEE-2: It is mixed feed multiple effect evaporator having 6 effects.
The black liquor is introduced at the 4th
effect from where it goes to 5th
effect. From here, it is taken to the 4th
body internal heater, which is
provided to facilitate higher evaporation at lower steam cost. Then the
liquor moves to the 2nd
effect and then to the 2nd
. Later the liquor
moves forward to the 1st
effect B-section and A-section and finally to
6th
effect C, B and A sections. The vapours are condensed in the
surface condenser where the pressure is maintained at 2.1kg/cm2
.
Liquor Flow: IV B→ V B→ IV H→ III H→ III B→ II B→ I B→ I A→
VI B→ VI A
Steam Flow: IV→I→II→III→IV→V
MEE-3: It is a mixed feed multiple effect evaporator having 5 effects.
Here thin black liquor is fed to the 4th
effect from where it goes to the
5th
effect and then to the 3rd
effect next to the 2nd
effect B section, 2nd
effect A section and finally to 1st
effect C, B and A section
respectively. The black liquor concentration obtained at the last effect
of MEE-3 is about 38o
Tw. Here the water evaporation capacity is 35.6
TPH. The number of tubes in each effect is 300 , diameter of the tube
is 50.8 mm while the tube length is 7.927 m.
Liquor Flow: IV B→ V B→ III B→ III A→ II B→ II A
Steam Flow: I→II→III→IV→V
MEE-4: It is a mixed feed multiple effect evaporator having 6 effects.
The thin black liquor having 16-18% solid content is fed to the 4th
effect. The black liquor is fed from bottom to the tube while steam is
passed from shell. In the 4th
effect, the calendria pressure is maintained
around 9 cm of Hg and ad 76o
C. The final black liquor concentration is
38o
Tw.
Liquor Flow: V B→ VI B→V H→ IV H→IV B→ III H→ III B→ II
H→ II B→ II A→I H→I B→I A
Steam Flow: I→II→III→IV→V→VI
48

49. Particulars Street I Street II Street III Street IV
Make Inglis Inglis Inglis Inglis
No. of effect 4 6 5 6
Capacity 9.2 TPH 54 TPH 36 TPH 37 TPH
Heating
surface area
100m3
740m3
380m3
375m3
BL feed rate 40-42m3
40-42m3
40-42m3
40-42m3
BL feed temp 80-88o
C 80-88o
C 80-88o
C 80-88o
C
BL inlet
concentration
14-15o
Tw 20-22o
Tw 14-15o
Tw 14-15o
Tw
BL outlet
concentration
27o
Tw 52o
Tw 40o
Tw 40o
Tw
Tube
diameter
50mm 50mm 50mm 50mm
Technical data:
Effects 1 2 3 4 5 6
Vapour
head
0.7mm
Hg
0.05m
mHg
Bypa
ss
330mm
Hg
`510m
mHg
677mm
Hg
Tempera
ture
125o
C 100o
C - 84o
C 68o
C 54o
C
Calendri
a
Pressure
1kg 0.33m
mHg
- 0mmH
g
270mm
Hg
500mm
Hg
Calendri
a
130o
C 112o
C - 100o
C 90o
C 75o
C
49

50. temperat
ure
Forced circulation plant:
A forced circulation unit is mainly used to concentrate the black liquor
of 48-50o
Tw to the desired concentration of 70o
Tw. Here the liquid
circulation takes place continuously by mechanical means. Black liquor
coming out of the evaporators (MEE- II, III & IV) is collected in
common header. Here the concentration of the black liquor coming out
of different evaporators is evenly maintained at 45o
Tw. The rapid
circulation of liquor carries all resin, soap, pulp and other suspended
matter through the evaporator without fouling the tubes. The vapours
and the black liquor are separated in the vapour separators. The black
liquor is concentrated in successive stages of forced circulation plant
while the vapours are sent to the flash steam.
Technical data:
Number 3
Number of heaters 6
Number of tubes 232
BL feed concentration 44-48o
Tw
BL outlet concentration 70o
Tw
Steam pressure 4.5-5kg/cm2
BL from pulp mill 3200-3300m3
/day
BL to boiler section 1450m3
/day
Steam economy 4-4.5TPD
Recovery Boilers:
The main function of the recovery boiler is to recover the inorganic
pulping chemicals by burning of the organic materials in the kraft
liquor and to make use of the heat energy generated for high pressure
steam generation. The thick black liquor coming from the evaporator
plant and entering the recovery boiler consists mainly of 62.2% of total
solids, 52.15% organic matter, 47.85% inorganic matter. It has a gross
50

51. calorific value of 3222.50cal/gm, SVJ of 8.53ml/gm, viscosity of 308cp
and free alkali of 5.80. The concentration of solid content at 90o
C is
71.75o
Tw.
The major operations carried out in recovery boilers are:
• Evaporation of the residual moisture from the liquor solids.
• Supply of heat for steam generation.
• Reduction of oxidised sulphur compounds to sulphite.
• Recovery of inorganic chemicals in molten form.
• Conditioning of the products of combustion to minimize
chemical carry over.
Process Description:
The thick black liquor coming from the evaporation plant is burnt in
two recovery boilers RB-1 and RB-2 respectively for the production of
smelt and steam generation. The black liquor leaves the forced
circulation evaporators at 70o
Tw and is collected in a strong black
liquor tank from where it is taken to the salt cake mixing tank. The
black liquor is taken to the primary heater where it is heated from 110-
150o
C. Then it is taken to secondary heater where it is heated to 120-
122o
C. The remaining black liquor from the ring header is taken to the
electrostatic precipitator ash tank where it is mixed with ash generated
at ESP. From here, it is passed back to the salt cake mixing tank and
finally the smelt from the bottom section is dissolved in the tank to get
green liquor. This green liquor is then sent to causticising section.
Conversion of sodium salts:
2NaOH + CO2 Na2CO3 + H2O
Na2O + CO2 Na2CO3
Reduction of make-up chemicals:
Na2SO4 + 4C Na2S + 4CO
Na2SO4 + 2C Na2S + 2CO2
51

52. Preparation of Green Liquor:
The smelt from the recovery furnace is collected in dissolving tank. It
is dissolved with weak white liquor. The green liquor so formed
contains suspended solids called dregs which are present in the form of
flocculants at high temperature and settled to give clear green liquor
solution. This clear solution of GL overflows out of the clarifier and is
stored in GL storage tank while the drags are sent to the dreg washer to
separate out carbonaceous material, silica, metal and sulphites. These
are used in recausticisers while the suspended dregs are disposed off.
Slaking and Causticising:
The clear green liquor from the clarifier is sent to the GL splitter box
through the heater to maintain high temperature of liquor. The splitter
box is used to divide the GL flow to the rotary slaker drum. A uniform
flow rate is maintained to the rotary drum slaker. In the slaking unit,
the GL is mixed with lime from the lime bin through a table feeder at a
controlled rate. About 10-15% of the reaction takes place here. The
slaking unit consists of 2 sections:
• Slaker Section Compartment:
This compartment has large vent stack and separate lime feeding
arrangement. Lime is brought to an intimate contact with GL in the
slaker. About 85-90%, the action is completed in the slaker.
• Classifier:
Insoluble material present in the liquid mixture is kept in suspension
by turbulent intake and is classified into the classifier section where
the conditions allows the coarser material to settle and be scrapped up
by the sloping bottom of the classifier to discharge and remove from
the system. Water sprays are provided to separate soda from grits
material.
White Liquor Clarification:
This unit is provided in order to remove substantially all of the
suspended solids to provide cooking liquor of adequate clarity. The
over flow of the clarifier is sent to the white liquor polishers which are
used to remove most of the remaining suspended solids. The clarified
52

53. and polished WL is stored in the WL storage tank from where it is
supplied to pulp mill. The under flow of the black liquor clarifier i.e.
lime sludge is drawn from the bottom by means of ODS pump and is
pumped to the 2 streets of lime mud washers, each street having three
mud washers.
White liquor characteristics:
Contents Concentration(gpl) as Na2O
NaOH 70
Na2S 22
Na2CO3 18
Active Alkali 90-92
Total Alkali 110
Lime Mud Handling:
The lime from WL clarifier is collected in the recausticising tank and
washed into 2 streets of mud washer by dividing the slurry through the
splitter box. Washing is done counter currently i.e. mud flows from
LMW-1 to LMW-3 while the hot water flows from LMW-3 to LMW-1.
The under flow mud from the last washer is taken to the lime mud
agitator tank. The overflow of the mud washer is called weak WL and
is used in the dilution of smelt to convert it into green liquor. The lime
mud from agitator tank is finally filtered off over vacuum drum filter
using hot water. The filtrate from the vacuum drum filter is fed into the
lime mud washer, while the filter cake is disposed off.
consistency 35-40%
Soda loss 0.9-1.6%
Avg. CaO 0.1-0.6%
pH 12-12.6
Lime mud washer:
The weak white liquor from lime mud washer is then washed in
washers (3 in no.) in 3 stages counter currently. The lime mud is then
washed on rotary drum filter. BGPPL has 2 rotary drum filters. The
drum comprises of 3 zones.
53

54. • Suction zone:
Here the lime mud along with washer forms sheet on drum
surface by vacuum.
• Filtrate zone:
Here the water present in the mud is removed along with
caustic.
• Mud removing suction:
The mud is removed by scrapper and disposed off through
trucks.
Strength of the caustic removed from mud is 4.2gpl, which is fed to the
lime mud washer 3A and 3B.
Lime kiln:
The open disposal of lime mud creates hazardous effects to land as well
as human life and hence recovery of lime mud is done to prevent
pollution and to fulfil the environmental legislation. Lime mud from
the lime mud washers is taken to the lime kiln for the recovery of lime.
Here the lime mud along with some fresh calcium stones is burnt in the
huge rotary lime kiln at high temperature to get back lime.
Technical data:
Capacity of lime kiln : 180 T/Day
Length of kiln : 82m
Diameter of kiln : 12.5m
Speed of rotation : 0.65-0.75rpm
Fuel consumption : 20kg/hr
54

55. EFFLUENT
TREATMENT
PLANT
55

56. Effluent Treatment Plant
The main objective of modern pulp and paper mill operation is to
reduce the losses from the process and to treat the effluent so that their
impact on the environment is minimized. It is an important to preserve
environmental quality for the benefit of present inhabitant and future
generation.
The ET plant is economic as it helps in better control on fibre and
chemical losses of plant by selling the sludge generation in ET plant
which contains nearly 50-55% organic content which otherwise was
going waste in effluent. Here activated sludge process is used to treat
the effluent. Some portion of the clarified effluent from ET plant is
used in showers for washing bamboo to remove silica, in Andritz filter
press and for plantation purpose.
Process flow:
Mechanical bar screen:
The effluent from all sections comes to ET Plant through pipelines.
The effluent is passed through bar screen to remove big sized particles
like stones, chips, rags, plastics and other unwanted particles that could
choke the feed lines of the pump. The combined effluent is stored in
the sump at a pH of 6.5 to 7.5. HCl is used to maintain the pH.
Primary Clarifier:
Clarifier is a large tank with a rotating rake system. The mill effluent,
which consists of suspended solids, is taken in this clarifier and given a
settling time of 6 to 8 hours to enable the solids to settle at the bottom.
The overflow clear water flows to aeration tank and the underflow or
sludge goes to the thickener. Defoamer is added to the primary clarifier
in order to reduce any foam generation from the effluent.
Sludge Treatment:
The sludge generated at the primary clarifier is sent to the thickener
where it is thickened upto 4 to 5% consistency. The thickener has a
capacity of 800 m3
. Further it is sent to Andritz filter press where
dewatering takes place and the consistency of sludge is increased from
4 to 20%. Dorr Oliver filter, which is a vacuum filter where the sludge
consistency is increased from 2 to 14%. High consistency sludge,
which consists of about 50 to 55% organic content is sent to the board
making unit.
56

57. Areation tank:
The overflow from the primary clarifier comes to the aeration tank.
This tank is a large rectangular tank with a capacity of 13,500 m3
. It
has 12 aerators which are agitated to induce the necessary oxygen to
meet the BOD. Here microbial floc is suspended and waste water from
primary clarifier is fed continuously. A retention time of 4 to 5 hours is
provided and the activated sludge solids multiply as dissolved organic
waste is metabolised. Chemicals like urea and diammonium phosphate
(DAP) are added to the aeration tank as nutrients to microorganisms.
The effluent is continuously drawn off the secondary clarifier.
Secondary Clarifier:
The effluent from the aeration tank comes to the secondary clarifier.
Here flocculants are added, which bind together the suspended
particles. A retention time of 5 to 6 hours is given. Whenever there are
an uncontrollable amount of microorganisms, addition of bleached
liquor (hypo) is done which results in the formation of dead mass. The
addition takes place after the sludge has been sent back to the aeration
tank. About 50 to 85% of underflow sludge is sent back to the aeration
tank. The bleached liquor also helps in removing the slimy nature of
sludge. The remaining sludge is sent to the primary clarifier. The
overflow, which is treated effluent, is discharged to Wardha River and
a part of it is used for mill purpose and plantations.
Effluent Characteristics:
Parameters Untreated Treated MPCB
pH 6.4 – 6.8 7.4 – 7.8 5.0 – 5.9
Temp (o
C) 35 – 40 30 - 35 -
COD (ppm) 500 – 700 160 – 230 250
BOD5 (ppm) 150 – 250 10 - 12 30
DO (ppm) 0.8 – 1.0 Nil 0.5 – 2.0
Sulphates as SO4 (ppm) - 185 -
(MPCB- Maharashtra Pollution Control Board)
57

58. Chemical dosage:
Urea : 590 kg/day
DAP : 285 kg/day
Flocculant : 20 kg/day
Sludge Characteristics:
Sludge generated : 150 TPD
Consistency : 20 – 25%
Organic Content : 50 – 55%
58

59. WATER
TREATMENT
PLANT
59

60. Water Treatment Plant:
Water is main necessity of BGPPL which gets fulfilled by its own well
and from river Wardha.
Water consumption:40-45cu.m/day.
The water is drawn through the pump to the mill site which have
impurities like suspended and floating impurities. Then the water is
collected in receiving channel in two line one for well another for
river. In receiving channel the water is treated with coagulating agents
like polyammonium chloride and calciumhypo chlorite to coagulate
particle and kill bacteria respectively. Then the water is send to
clarifier where clear water overflows which is then supplied to
different sections of mill and colony. The another clarifier is also use
for m/c back water which after treatment send back to machine house.
60

61. RESEARCH
AND
DEVELOPMENT
61

62. Research and Development:
The R and D department consists of four branches viz.:
• QAS Input Lab
• QAS lab
• Environmental lab
• R and D lab
62

63. ENViRONMENTAL LAb:
The environment legislation has made it imperative for every pulp and
paper industry irrespective of scale of operation, to adopt
environmental friendly and cleaner technologies within stipulated time
frame in order to ensure its substance. It is in this perspective that the
whole of R & D Environmental lab becomes important and also in
order to strengthen the indigenous capability for resolving the
environmental issues and challenges. In paper industry, the sources of
waste water are mainly from:
Fibrous raw material washing:
• Digester house
• Pulp washing
• Centri cleaners
• Pulp bleaching
• Paper machine
• Chemical recovery
Activities under Environmental Lab:
Characterization of mill effluents for various pollution parameters:
• To generate data based information on magnitude pollution load
in paper mills.
• Development of cost effective methods for treatment of liquid
waste.
• Monitoring of ambient air quality, stack and fugitive air
emissions.
• Meteorological testing.
63

64. Characterisation of solid wastes:
• Conversion of solid wastes to value added products.
Facilities available:
BGPPL has well equipped environmental lab with modern analytical
equipments for efficient environmental monitoring. These include-
AOX analyser, BOD track apparatus, Auto sampler, Turbidity meter,
Respirable dust sampler, Gas Tech apparatus, Noise meter,
Spectrophotometer, etc.
Testings done:
• Analysis of effluents for various pollution parameters including
AOX.
• Evaluation of bio energy potential in pulp and paper mill
effluents.
• Performance evaluation of effluent treatment system.
• Determination of AOX in paper products.
• Ambient air, stack and fugitive emission monitoring.
• Quantification of gaseous and particulate emissions.
• Analysis of gaseous pollutants including non-condensable gases.
• Efficiency evaluation and troubleshooting of effluent treatment
plants and other pollution control devices.
• Determination of COD and BOD in effluent water.
64

65. QAS LAb:
Quality Assurance System (QAS) refers to planned and systematic
production processes that provide confidence in product suitability for
its intended purpose. It is a set of activities intended to ensure that
papers satisfy customer requirements in a systematic and reliable
fashion. However, QAS cannot absolutely guarantee the production of
quality products, but makes them more likely.
Two key principle characteristics of QAS:
• To make the products fit for customer demands.
• To eliminate their mistakes occurred during paper
manufacturing.
QAS Lab testing:
Different grades of paper require different properties depending upon
their end use. Hence, a paper maker has to make requisite adjustments
so as to get desired results without affecting the allied properties of
paper to greater extent. Paper properties can be broadly classified as:
• properties- Grammage, thickness, density, porosity, smoothness.
• Strength properties- Tensile strength, breaking length, burst
strength.
• Optical properties- Colour, brightness, opacity, etc.
These properties are checked in QAS lab. If all these properties meet
the customer demand then the products are packed and supplied,
otherwise recycled for paper formation. Thus the acceptance or
rejection of paper is performed in QAS lab.
QAS Input Lab:
65

66. In this lab, various chemicals like lime, PAC, NaOH, H2SO4, fillers,
pulp, coal, water samples, starch, dyes, etc. are tested. These testings
can be broadly classified as:
• Dyes – Irgilite Violet, Rhodamine.
• Starches- Maize starch, Cationic starch, etc.
• Sizing agents- ASA (Alkene Succinic Anhydride), Rosin, AKD
(Alkene Ketene Dimer).
• Fillers- GCC, PCC, TiO2, soapstone.
• Coal analysis- Moisture content, volatile organic content, ash, fixed
carbon content, gross calorific value.
• Furnace Oil Analysis- GCV, viscosity, etc.
• Recovery Contents Analysis- Black liquor, White liquor, Green
liquor.
• Sodium Sulphate Analysis- White, brown, yellow.
• Pulp Analysis- Optical properties, viscosity of pulp.
• Packing Material analysis- High density polyethylene (HDPE),
Low density polyethylene (LDPE), core pipe, mill board.
66

67. R & D LAb:
The Research and Development Lab is responsible for carrying out
following analysis:
• Pulping
• Bleaching
• Pulp Analysis
• Microbiological Experiments
• Evaluation of chemicals used in paper manufacturing, etc.
Working:
Chips from chipper section are brought in R & D lab for pulping
analysis. These are then air dried and tested for paper properties. Any
new species of wood are first analysed in R & D lab before it is used in
plant. If its yield and allied properties are good enough, then the
species is selected, otherwise rejected for drawbacks. If any problem
regarding pulp bleaching, stock preparation, etc. occurs in the plant,
then the sample is sent to R & D lab to find out the problems and the
solution concerned. Chemicals like OBA, starch, dyes, sizing chemicals
and other new chemicals which can replace the earlier ones, are also
sent to R & D for its evaluation. If its performance is better than the
routine chemical used, then it is replaced. Various microbes develop in
the stock sample and also in the back water. To control them, biocides
or slimicides are used. In addition, Bug Count is carried out in R & D
lab. The strength properties of the paper obtained after refining,
bleaching, etc. are also studied here.
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68. THANK YOU
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