CENTURY PULP AND PAPER INDUSTRIES

HISTORYTHE WORD PAPER IS DERIVED FROM PAPYROUS[ANCIENT GREEK FOR CYPERUS PAPYROUS PLANTPAPER WAS REPORTEDLY INVENTED IN ANCIENT CHINA DURING THE HAN DYNASTYFIRST PAPER MILL WAS FOUNDED IN SAMARKAND[MODERN DAY UZBEKISTAN]ALONG EUROPE[FRANCE1190,ITALY1276]PAPER MAKING HAD SPREAD TO AMERICA[PHILADELPHIA1690

CHINA IS THE LEADING PRODUCER OF PAPER IN THE WORLD FOLLOWED BY UNITED STATES,JAPAN,GERMANY,CANADAINDIA IS RANKED AMONG THE TOP 15 GLOBAL MANUFACTURERS OF PAPER.INDIA SHARES AROUND 1.6% OF TOTAL PAPER PRODUCTION OF WORLD,TOTAL TURNOVER OF AROUND 25,000 CRORES PER YEAR.THE INDUSTRY PROVIDES EMPLOYMENT TO 0.12 MILLION PEOPLE DIRECTLY AND 0.34 PEOPLE INDIRECTLY IN INDIA.

INDIAN PAPER INDUSTRY

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DE - BARKING CHIPPING

DIGESTOR

SCREENING

WASHING BLEACHING

DRIED / BALED

Debarking is the process of removing bark from wood. Debarking generally involves the use of industrial machinery into which the log or stake is placed. Generally they are powered by hydraulic motors.

1. DE-BARKING

The wood chips are then cooked in pressurized vessels called digesters. In a continuous digester, the materials are fed at a rate which allows the pulping reaction to be complete by the time the materials exit the reactor. Digestion is done to remove the lignin and hemicellulose content .

Wood chips + NaOh + Na2S ------> Black Liquor

2. COOKING

3. Blow Down Valve & Blow Tank

• Steam from the hot slurry passing through the tank is recovered. This steam is used for the preheating of chips. This tank has high concentration of pulp slurry and low concentration of water.

• Reduces the pressure of steam from 80 to 10 atm before entering the blow tank.

4. SCREENINGScreening of the pulp after pulping is a process whereby the pulp is separated from large shives, knots, dirt and other undigested residues. The accept is the pulp. The material separated from the pulp is called reject.5. WASHING

Cooking liquors are separated from the cellulose fibers.  Pulp washers use counter current flow between the stages such that the pulp moves in the opposite direction to the flow of washing waters.

• Bleaching of wood pulp is the chemical processing carried out on various types of wood pulp to decrease the color of the pulp, so that it becomes whiter.

6. BLEACHING

• Traditionally chlorine based oxidizing agents were used for this process but due to the formation of dioxins and other undesirable products, the usage of chlorine has been discontinued.

• In the modern and improved bleaching stage, hydrogen peroxide is added along with sodium hydroxide, which activates the peroxide.

ADVANTAGES :Q. WHY THIS PROCESS? 1. Pulp produced is stronger than that made by

other pulping processes.

2. Acidic sulfite processes degrade cellulose more than the kraft process, which leads to weaker fibers.

3. Mechanical pulping processes leave most of the lignin in the fibers.

4. The kraft process can use a wider range of fiber sources than most other pulping processes.

•The black liquor (lignin-rich) produced from the Sulfate pulp production contains 95-98% of digested chemicals.

• To reduce air and water pollution and to balance economy of operation, these chemicals should be removed before disposal.

CHEMICAL RECOVERY

FROM BLACK LIQUOR

BLACK LIQUOR IS SEPERATED FROM PULP IN WASHING

FLOW SHEET

MULTI EFFECT EVAPORATOR• It is a series of single

effect evaporators of 5-6 stages of calandria equipment followed by disk evaporators .

• After the first step the black liquor is about 20 - 30% solids. At this concentration the  rosin   soap rises to the surface and is  skimmed off.

. The weak black liquor is further evaporated to 65% or even 80% solids and burned in the  recovery boiler to recover the inorganic chemicals for reuse in the pulping process. .

MIX TANK

•Organic carbon burns in smelting furnace , supplying necessary heat and CO2 . • The combustion is carried out such that sodium sulphate is  reduced to sodium sulphide by the reaction : NaR(lignin salt) +air Na2CO3 + CO2

RECOVERY BOILER•Molten slag is produced • Here organic carbon present in black liquor is burned.• High pressure 28 atm to 30atm steam is produced.•The reaction that takes place inside furnace is : Na2SO4 + 2C------> Na2S + 2CO2

DISSOLVING TANK The molten salts from the recovery

boiler are dissolved in a process water known as weak wash.

This process water, also known as weak white liquor is composed of all liquors used to wash lime mud and green liquor  precipitates. The resulting solution of sodium carbonate and sodium sulphide is known as "green liquor .

This liquid is mixed with calcium oxide , which becomes calcium hydroxide in solution, to regenerate the white liquor used in the pulping process through an equilibrium reaction :

Na2S + Na2CO3 + Ca(OH)2 ←→ Na2S + 2 NaOH + CaCO3

CLARIFIER A clarifier is

used as a filter to remove solid particulates or suspended solids from liquid

It separates as filtrate and sludge .

Filtering medium is monel metal .

WASHING TANK Impurities

are washed away in this tank after clarifying.

CAUSTICIZING TANK Calcium carbonate  precipitates

from the white liquor and is recovered and heated in a lime kiln where it is converted to calcium oxide  (lime):

CaCO3 → CaO + CO2 Calcium oxide (lime) is reacted

with water to regenerate the calcium hydroxide used in reaction :

CaO + H2O → Ca(OH)2 It precipitates lime mud.

Carbonate is causticized by adding Ca(OH)2 .

APPLICATIONS…. Paper can be produced with a wide variety of properties, depending on its intended

use.

For representing value: paper money, bank note, cheque, security , voucher and ticket

For storing information: book, notebook, magazine, news paper, art & letters. For communication: between individuals and/or groups of people. For packaging: corrugated box, paper bag, envelope, Packing & Wrapping

Paper,  and wallpaper. For cleaning: toilet paper, handkerchiefs, paper towels and facial tissue  For construction: papier-mâché, origami, paper planes, quilling, paper

honeycomb, used as a core material in composite materials, paper engineering, construction paper and paper clothing

For other uses: emery paper, sandpaper, blotting paper, litmus paper, universal indicator paper, paper chromatography, electrical insulation paper (see also dielectric and permittivity) and filter paper

Why should we recycle paper?Recycling 1 tonne of paper :

1.Saves approximately 17 trees.2.Don’t use approximately 380

gallons of oil.3.Saves 4000KW of power.4.Saves 3 cubic yards of landfill

space.5.7000 galloons of water.

.

Preparation of Pulp from Waste Paper

Waste Paper Pulper

Water Chemical Fiberizer Dump Tower

Drum Screen

High Density Cleaner

Hole Screen Stand tube Floatation Primary Cell

Venting Cyclone

Foam Tank Floatation Secondary Cell

CL1

CL2CL3

CL4

Slot Screen Disc Filter

HEALTH HAZARDS I. PHYSICAL HAZARDII. CHEMICAL HAZARDSIII. BIOLOGICAL HAZARDSIV. MECHANICAL HAZARDS

NOISEWOOD DEBARKING,PAPERMACHINE,BOILER RECOVERY

NOISE INDUCED HEARING LOSSNOISE LEVELS AT CHIPPING,PAPER MACHINES WERE NOTED TO BE ABOVE 90dB.

HEATPULP COOKING,PULPING CHEMICAL RECOVERY,PAPER DRYING INVOLVE HIGH TEMPERATURESTEMPERATURES AROUND PAPER MACHINES WERE RECORDED ABOVE 60 C CAUSING HEAT EXHAUSTION AMONG WORKERS

WOOD DUSTCHIPPING,INTIAL STAGES OF CHIPPINGRISK OF OCCUPATIONAL ASTHMAIRRITATIVE LUNG DISEASECARCINOGEN

CHEMICAL HAZARDSSOLIDS-SODIUM CHOLARATE,SODIUM SULPHATE,LIME,CALCIUM,ASBESTOESLIQUIDS-SODIUM HYDROXIDE,TURPENTINE,SULPHUROUS ACID,AQUEOUS CHLORINE DIOXIDE,BIOCIDESGASES-SULPHUR DIOXIDE,CHLORINE DIOXIDE,OTHER VOLATILE ORGANIC COMPOUNDSSULPHUR DIOXIDE- RESPIRATORY IRRITANT- DEATH DUE TO RESPIRATORY ILLNESSCONTACT DERMATITIS- CALCIUM HYDROXIDE,GLUES,ADDITIVESEYE IRRITANTS- CHLORINE,SULPHUR COMPOUNDS

BIOLOGICAL HAZARDSBACTERIA,VIRUSES,FUNGI PARTICULARLY IN

PAPER MACHINE,CLOSED LOOP SYSTEMS,TREATMENT PLANTS FOR WASTE WATER AND WATER COOLING SYSTEMS

HYPERSENSITIVITY PNEUMONITIS,CHRONIC LUNG SCARING,BAGOSSOSIS

MECHANICAL HAZARDSINJURIES & ACCIDENTS- MOSTLY DUE TO HANDLING OF HEAVY WEIGHTS OF PAPER BALES AND ROLLSCAUGHT BETWEEN ROTATING ROLLS AND EQUIPMENT[NIP POINTS]CRUSH BY FALLING AND TUMBLING OBJECTSOVER EXERTION INJURIES DUE TO REPETITIVE WORK

CANCER•IARC- POTENTIAL CARCINOGENS IN PAPER INDUSTRY•ASBESTOES-MESOTHELIOMA•TALC,BENZIDINE,FORMALDEHYDE,EPICHLOROHYDRIN- POTENTIAL CARCINOGENS•WOOD DUST- NASAL CANCER