DESCRIPTION OF PULP AND PAPER MANUFACTURING
The agro-wastes such as bagasse etc. are received from nearby
area. The raw material contains pith, dust and fins etc. which
are considered non-process elements. These are removed by dry-depithing
or dry de-dusting before being fed into washing section. The
pith so obtained from the dry depithing are fired in boiler as
it has a good calorific value in washing section, The raw
material is passed through pulper/ drum washer. The raw
material is washed only with the available backwater from the
process sections. Due to vigorous Agitation in the pulper, the
other non-process elements are also removed. Some part of free
water is carried along with the raw material which is then fed
into aqua-separator. The aqua-separator helps in removing the
excess water from raw material.
The depithed/ dedusted & washed material is then squeezed into
screw press. The water so obtained from aqua—separator & screw
press is collected & screened in B-2 thickener for reuse again
The raw material from screw press is carried by conveyors on
to metering screw into the plug feeder which makes a compact
plug to feed raw material to digester where steam & caustic
are added. The digester tubes are provided with timer screw so
that residence time of material can be controlled. After
cooking, the pulp is passed through cold blow discharge into
blow tank In cold blow discharge, the cool liquor is passed to
dilute the pulp & to reduce the temperature.
The pulp from blow tank is pumped into vibrating screens to
remove unwanted & uncooked material & recycled bock for
recovery of valuable fibers from it.
The low consistency pulp (about l.5% cy) contains black liquor
and fiber. The brown stock pulp or the unbleached pulp is then
fed into 3-sloge brown stock washers where the pulp is washed
in counter-current sequence with the foul condensate from
recovery section. The liquor obtained from the first stage is
pumped to recovery section for recovery of valuable caustic
from black liquor. The process details of recover section ore
After brown stock washing, the pulp is again cleaned in
centricleaners and sIotted screens so that maximum non-process
elements can be removed. The clean brown pulp is then subject
To thickening in decker—Thickener to increase the consistency
(B) Chlorine Di·Oxide Preparation
The sodium chlorate (NaCIO3) is imported in safe HDPE bags.
The sodium chlorate is allowed to react in two—stage reactor
system with hydrogen peroxide in strong sulphuric acid
solution to produce CIO2. The reaction by-products are oxygen
& waste acid containing sodium bi-sulphate. The main
advantages of this system are lower capital cost, chlorine
free product, high yield of CIO2, reduced pollution load on
The unbleached pulp is subject
to bleaching by Chlorine Di-oxide - Extraction with Alkali,
oxygen & peroxide — Chlorine Di-oxide (De- Eop- Di) sequence.
The sequence is adopted so that the AOX levels are retained
within the permissible limits. The chlorine di-oxide is added
in first stage to loosen the Iignin from the cellulose fiber.
The caustic is added in extraction stage to raise the pl-I &
to precipitate the chloro-Iignate compounds. Oxygen & peroxide
are added in the pulp at extraction stage that produces
bleaching effect on the pulp. The chlorine di-oxide is again
added in the 3rd stage of bleaching to achieve the desired
brightness level of 85-88% ISO. The main advantages of
adopting this bleaching sequence are —
Reduction in BOD, COD &
AOX in bleaching plant effluent by 30-35%.
Gain in concentration of
black liquor resulting better runnability of soda
Improvement in pulp
quality, i.e., gain in brightness, viscosity & strength
Pulping/ Broke Pulping -
The imported soft wood pulp and broke obtained from
manufactured paper is subject to mixing & slushing with water
in separate pulpers.
The wood pulp/ broke street is then cleaned in vibrating
screen to remove unwanted material contained in them. Then the
pulp is passed through high density cleaners to remove dirt
particles. The cleaned pulp is then mixed with the bleached
agro-pulp in certain required proportion.
Soap stone is added to pulp which works as filler and improves
properties of paper. Soap stone is available in powder form
and it is mixed with water and the solution so obtained is
processed through vibrating screens to remove the undesired
particles from it.
The agro-pulp, soft wood/ waste paper pulp & broke pulp are
mixed in certain proportion in the mixing chest. Other
chemicals like retention aid, optical brightening agents,
dyes, soap stone and sizing chemicals are added in blending
chest in the pulp to improve the pulp optical & physical
properties. The final pulp is then ready for paper
manufacturing at paper machine.
(E) Paper Machine
The pulp is then pumped into machine chest and then to
approach flow system containing of fan pump, centricleaner and
pressure screen. The final clean pulp goes to paper machine
head box which spreads the fiber uniformly across the
synthetic forming fabric. From head box, the fiber passed over
fourdrinier table where approx. 50% of total water is removed
from the pulp.
The pulp now is in sheet form and contains some amount of free
water. The sheet is then pressed into series of presses to
remove the free water from it. The paper sheet is then passed
into series of steam heated driers so that the inherent
moisture from paper fiber is removed.
Before fully drying the paper, it is subjected to sizing. The
paper web is rewetted with a starch based solution. The
process is called surface sizing. The size — starch solutions
are applied to the paper web by means of mechanical presses
(size press). Together with surface sizing agent the surface
starches impart additional strength to the paper web and
additionally provide water hold out or "size" for superior
printing properties. The sized paper has improved smoothness,
hardness, whiteness and gloss and thus improves printing
(G) Calendaring & Reeling
Finally, the sized paper is calendared to improve the
smoothness of paper & reeled onto spools over pope reel.
The paper spool roll is taken on rewinder where the paper is
rewinded into certain specific sizes as per the demand from
the market. The paper demand of sheets is met through 3 nos.
of sheet cutters where paper is cut into sheet form as per the
These reels or sheets of bundle are packed & weighed before
final dispatch to the respective customers.
The use of environment-friendly techniques and eco-friendly
products in pulp & paper manufacturing gives a whole new
dimension to the industry. Today, as the population increases
at rapid rate, the demand for paper increases too. To feed
this demand, the forest based raw materials are becoming
scarce. So the industry & research institutions are searching
new products for preparation of Pulp & paper. Shinco Paper is
among one of the prominent supplier of Eco-Papers, produced
using eco-friendly technology and is earning a good name in
the market by producing quality paper using the agro-based raw
The management is eager to introduce new concepts in
development of new products by using safe & sound technologies
that also pose no danger to the environment & natural
resources by keeping itself sustained in the market. Use of
enzymes is one such approach in which the industry is keen to
venture further to reduce the production cost and to develop
clean & green products.
The word "paper" is etymologically derived from Latin
papyrus, which comes from the Greek πάπυρος (papuros), the
word for the Cyperus papyrus plant. Papyrusis a thick,
paper-like material produced from the pith of the Cyperus
papyrus plant which was used in ancient Egypt and other
Mediterranean cultures for writing before the introduction
of paper into the Middle East and Europe. Although paper
is etymologically derived from papyrus, the two are
produced very differently and the development of modern
paper is separate from the development of papyrus. Papyrus
is a "lamination of natural plants, while paper is
manufactured from fibres whose properties have been
changed by maceration or disintegration.