paper & pulp industry by er. sanyam s. saini (me regular) (2012-14)

Paper IndustryPresented By-

Er. Sanyam S. SainiME (I&CE) (Regular)

2012-14

The pulp and paper industry converts wood or recycled fibre intopulp and primary forms of paper.

The pulp and paper industry is one of India's core sector industries.

Pulp mills separate the fibres of wood or from othermaterials, such as rags, wastepaper or straw in order to createpulp.

Paper mills primarily are engaged in manufacturing paper fromwood pulp and other fibre pulp, and may also manufactureconverted paper products.

The socio-economic importance of paper has its own value to thecountry's development as it is directly related to the industrial andeconomic growth of the country.

Introduction

Indian Paper Industry in Global Prospective

World Paper & Board consumption is dominated by three major regional blocks- North America, Western Europe & Asia.

Global paper production is 340 million tons.

India consumes nearly 5% of the Asian and 1.6% of the worlds consumption of paper and paper board

North America, 31.0%

Asia, 30.4%India, 1.6%

Europe, 28.0%

Rest, 9.0%

Source : ICRA report to IPMA : 2011

Paper Industry at a Glance

Total number of Pulp & Paper Mills 706

Wood Based 33

Agro Based 165

Recycled Fiber Based Mills 508

The industry is fragmented with capacities ranging from 2 to 800 tonnes per day.

Production million tonnes

P & B 6.0

Newsprint 0.8

Installed Capacity of Mills 8.3

Source : ICRA report to IPMA : 2011

Generalized of Paper Making from different types of Raw Materials

Typical process for paper Manufacture

Raw Material Preparation

Section

Pulping Section

Pulp Washing & Bleaching Section

Stock Preparation System

Paper Machine

Raw Material, Water

Chemicals ,Water

Water

Alum, Rosin, Water

Additives

Waste Water

Waste Water

Waste Water

Finished Paper

Different Industrial processes

Based on the type of raw material used, the manufacturing processes are classified into:

Wood Based Pulp and Paper manufacturing Process

Agro residue based Pulp and Paper manufacturing Process

Secondary fiber based Pulp and Paper manufacturing Process

Step 1- Raw Material Preparation:

Debarker ChipperChip

StorageDigester Blow Pit

Paper Manufacturing

Debarker

Chipper

Digester

Practical Digester

Various Methods of Pulping:

Mechanical Method of Pulping

Chemical Method of Pulping

Semi Chemical Method of Pulping

Step 2- Pulping:

Mechanical Pulping

Chemical Pulping:

Types of Chemical Pulping:

Mechanical pulping uses mechanical abrasion to separatecellulose fibers which are held together by lignin.

There are three chemical pulping methods…

Soda Chemical Pulping

Kraft (or Sulfate) Chemical Pulping

Sulfite Chemical Pulping

Chemical pulping achieves fiber separation by dissolvingthe lignin.

Various Methods of Pulping:

Soda Pulping:

Kraft(Sulfate) Pulping:

Sulfite Chemical Pulping:

Soda pulp is the original chemical pulp and is produced bycooking chips of deciduous woods in a solution of caustic sodaunder pressure.

Sulfite pulping uses sulfurous acid and an alkali to produce pulps of lower physical strength and bulk, but exhibits better sheet formation properties.

In the Kraft process, an aqueous solution of sodium hydroxide and sodium sulfide, known as white liquor, selectively dissolve the lignin and make it soluble in the cooking liquid.

Types of Chemical Pulping:

Semi-Chemical Pulping:

Semi-chemical pulps are essentially mechanical pulps thathave been pre-treated with a sulfite or sodium hydroxideliquor to improve breakdown and reduce energyrequirements during processing.

Types of Chemical Pulping:

Step 3: Pulp Washing

After the wood is pulped, the pulp that is created is washed toremove the dissolved lignin and chemicals.

The washing process occurs at high temperatures which generates alarge volume of exhaust gases containing hazardous air pollutantswhich are released to the atmosphere.

Paper Manufacturing

Batch Washer

Continuous Washer

Step 4: Pulp Bleaching

After washing, if a white product is desired, the pulp mustbe bleached to remove color associated with remainingresidual lignin.

Typically, in the bleaching process, the bleaching chemicalsare injected into the pulp, and the resulting mixture iswashed with water.

Paper Manufacturing

Unit operations in a bleaching stage

Mixer Mixer Reactor Washer

Steam Chemical Water

Effluent

WashedPulp from

Previous stage

Washed pulp from Next

Bleaching Tower

Bleached and unbleached pulp:

Waste paper pulping

Recycled paper (Waste), newsprint and magazine is chargedin Hydraulic Pulper with adding water and it is beingprocessed till waste paper is converted into slurry form withhigh consistency pulp. This is also known as Hydrapulper.

Then it is transferred to machine chest where addition ofdye, chemical takes place. This pulp then is fed to the machinechest. This machine is known as Blend Chest.

Hydro pulper used for pulping wastepaper/recycled material

Hydropulpers

De-inking Process

Deinking is a recycling technique that can produce highquality recycled pulp from recovered papers.

Flotation Deinking which makes ink particles hydrophobic bymeans of a collector in a flotation cell. The air bubblesgenerated at the bottom of the cell carry the ink particles tothe surface where they are confined in foam which isremoved.

Conventional Chemical Washer

Paper Machine Overview

(Fourdrinier-type paper machine)

Paper Machine

The blended pulp is again centricleaned to remove impurities andfinally fed to the paper machine through a head box.

From the dewatering and paper making angle, the machine hasthree principal stages:

i. The gravitational and vacuum dewatering stage (wire part)ii. The mechanical dewatering stage (press rolls part)iii. The thermal drying stage (indirect steam dryers)

On the wire part of the paper machine, the dewatering of pulp takesplace by gravity and vacuum.

The water from the wire mesh is collected in a fan pump pit and iscontinuously recycled to dilute the pulp fed into the paper machinecentricleaner.

Paper Machine

After the wire part, the edge cutting operation is carried out toobtain paper of a definite width.

The edge cuts of the pulp web falls in the couch pit and are recycledto the machine chest.

Towards the end of the wire part of the machine, the consistency ofpulp rises to about 20 per cent.

Further dewatering is carried out by press rolls to raise theconsistency to about 55%.

The paper is finally dried through an indirect steam dryer to about94% solids and is collected in rolls as the final product.

Paper Machine Section

Environmental Impact of Pulp & Paper Process Industries

Pulping often releases a range of pollutants, including organicproducts which cause eutrophication in water, aluminum salts andsometimes also generation of sulphur dioxide.

When bleaching is carried out with chlorine or hypochlorite, it maygenerate dioxin. These pollutants have direct impacts on freshwaterand marine ecosystems near pulp mills.

Air Emissions

Air pollution mainly occurs from digesters blow tanks, steam boilers chemical recovery boilers

Environmental Impact of Pulp & Paper Process Industries

Solid waste

Solid waste is generated in the form of sludge, ash, woodwaste, screening, centricleaner rejects, sand and grit.

The major concerns with these wastes is their disposal.

Conclusion

Thank You