Study and Characterization of Polyphenolic Compounds From Black Liquor of Kraft Pulping

Study and Characterization of Polyphenolic compounds from Black Liquor of Kraft Pulping

1. INTRODUCTION:

The focus of this project is to study the lignin yield after precipitation

of lignin in the wood and bagasse Kraft spent black liquor (chemical pulp

mill 1 &2 liquor) by acidification. The pulp mill of today produce an energy

surplus occurring from the combustion of wood residuals in the recovery

boiler. At the sometime, the recovery boiler is the battle neck of the process

at many mills. One way to utilize the energy surplus at the same time as a

production increase is obtained is to extract lignin from Kraft spent black

liquor before the combustion in the recovery boiler to produce a biofuel.

Extraction of lignin can be done by fractionation of Kraft spent black liquor

in a lignin rich and a lignin-depleted stream by ultrafiltration, another way is

to precipitate the lignin in the spent black liquor by acidification. The

precipitate is separated by filtration followed by a washing step. Both

methods involve problems. The fuel produced by ultra-filtration contains too

high an ash content. The ash contains high amounts of spent cooking

chemicals, i.e. sulphur and sodium, which would cause problems during

combustion of the fuel. By precipitation, the ash content is lower but

problems during combustion of the fuel. By precipitation, the ash content is

lower but problems are induced at the mills occurring from the need of after-

treatment of the filtrate and the wash liquid.

Fundamental research aimed at improving pulping and bleaching

processes almost invariably requires an understanding of the structural

details of residual Kraft lignin. For such endeavors it is essential that the

lignin remaining on the fiber be isolated from the black liquor in high yield

and purity, unaltered and in the absence of contaminants. Isolation of lignin

Department of Chemistry, Govt.SC, Bommankatte


can be done many methods in that of acid hydrolysis using hydrochloric

acid, sulphuric acid and hydrofluoric acid. Currently, a sulphuric acid

method is use for the isolation of residual lignin from black liquor. Despite

extensive research efforts, aimed at obtaining residual lignin that it would

completely comply with the above criteria both of these methods have

limitations that need to be addressed. The acid hydrolysis technique, while it

offers a residual lignin preparation of high purity, is plagued with relatively

low yields and the possibility of structural alterations induced during the

acidic treatment.

The Kraft process was developed by Carl.F.Dahl in 1879,with the

name of the process coming from the German word “Kraft”, meaning

strength/power. The Kraft process describes a technology for conversion of

wood into wood pulp consisting of almost pure cellulose fibres.The first

Kraft mill in the United States was not built until 1911 and was located in

Pensacola, Florida. Today, the process is used in approximately 80% of

paper production. Those companies using the Kraft process are easy to

recognize by their strong, offensive smell. This is because one of the

byproducts of the process is hydrogen sulfide gas and other sulfur gas

compounds. The Kraft pulping process involves the digesting of wood chips

at elevated temperature and pressure in “white liquor”, which is a water

solution of sodium sulfide and sodium hydroxide. The white liquor

chemically dissolves the lignin that binds the cellulose fibers together.

The invention of the recovery boiler by G.H.Tomlinson in the early

1930s was a milestone in the advancement of the Kraft process. Most Kraft



pulp mills adopted this technology to recover and burn much of the black

liquor, generating steam and recovering the “cooking chemicals” (sodium

hydroxide and sodium sulfide used to separate lignin from cellulose fibers

needed for papermaking).In fact this enhancement not only managed to deal

with pollution load reduction and chemical recovery increase but also made

it possible for Kraft pulp mills to become self-sufficient energetically. In

efficient recovery boiler mills the amount of energy is more than necessary

to run the process and the surplus can be sold. Approximately 7 tonnes of

black liquor (15%solids by weights of which 10% is inorganic).

Lignin is a complex chemical compound most commonly derived,

from wood, and an integral part of the secondary cell walls of plants and

some algae. The term was introduced in 1819 by De-Candolle and is derived

from the Latin word lignum, meaning wood. Lignin polymers are mostly

made of phenylpropanoid units linked to each other through different kinds

of bonds. As a biopolymer, lignin is unusual because of its heterogeneity and

lack of a defined primary structure. Its most commonly noted function is the

support through strengthening of wood (xylem cells) in trees and improves

water transport.

Resin is a natural or synthetic compound which begins in a highly

viscous state and hardens with treatment. Typically, resin is soluble in

alcohol, but not in water. There are a number of different classes of resin,

depending on exact chemical composition and potential.



WOOD CHEMISTRY:

1.1 TYPES OF WOOD:

Wood is the hard, fibrous substance found beneath bark in the stems

and branches of trees and shrubs. Practically all commercial wood, however,

comes from trees. It is plentiful and replaceable. Since a new tree can be

grown where one has been cut, wood has been called the world's only

renewable natural resource.

Two most important properties of any papermaking cellulosic raw

material are, how much cellulose fiber it has and how long the fibers are.

The amount of cellulose fiber in wood determines the pulp yield, ease of

pulping and cost of pulp produced. The importance of fiber length is

explained in pulp properties. The maximum average fiber length pulp will

have is that of wood because whatever pulping method, full chemical to full

mechanical, fiber is going to damage. In mechanical pulping the damage is

physical (cutting, bruising etc.) and in chemical pulping it is chemical

degradation (lower degree of polymerization).It has been estimated that

based on a mixture of softwoods and hardwoods 12 meters (40 ft) tall and

15-20 centimeters (6–8 in) in diameter, it would take an average of 24 trees

to produce 0.9 tonne (1 ton) of printing and writing paper, using the Kraft

process (chemical pulping).


http://www.paperonweb.com/pulppro.htm#Fiber%20Length%20of%20Pulp

http://en.wikipedia.org/wiki/Kraft_process



CHEMICAL COMPOSITION OF WOOD:

Average chemical contents of wood:

Element

s

Share, % of dry matter weight

Carbon 45-50%

Hydroge

n

6.0-6.5%

Oxygen 38-42%

Nitrogen 0.1-0.5%

Sulphur max 0.05

Wood is mainly composed of cellulose, Hemicellulose, lignin and

extractives. The following table provides main chemical components of

some wood species.

Constituents Scot Pine Spruce Eucalyptus Silver Burch

Cellulose (%) 40.0 39.5 45.0 41.0

Hemicellulose (%) 28.5 30.6 19.2 32.4

Lignin (%) 27.7 27.5 31.3 22.0

Total Extractive (%) 3.5 2.1 2.8 3.0

Wood Components Hardwood (%) Softwood (%)

Cellulose 40 - 50 40 - 50

Hemicellulose 25 - 35 25 - 30

Lignin 20 - 25 25 - 35

Pectin 1 - 2 1 - 2

Starch Trace Trace



PHYSICAL PROPERTIES OF WOOD:

ASH CONTENT:

Ash is a solid particulate, inorganic combustion residue left after the

wood is burnt.

Ash content varies with different components of trees.

Stem wood: 0.4-0.6%

Stem bark: 2.0-5.0% & 1.0-2.0%

As a mean value wood can be expected 1-2% ash content.

MOISTURE CONTENT:

Wood may contain 50% moisture. Wood moisture provides

lubrication to ground stone & keep the temperature low in grinding zone.

Wood moisture help better chemical penetration during cooking due to

diffusion.

1.2 PULPING:

Pulp is a dry fibrous material prepared by chemically or mechanically

separating fibers from wood or fiber from wood or fiber crops. Pulp can be

either fully or formed into thick sheets. The latter form is used if the pulp

must be transported from the pulp mill to a paper mill. Pulp which is shipped

and sold as pulp is referred to as market pulp. When suspended in water the

fibers disperse and become more pliable. This pulp suspension can be laid

down on a screen to form a sheet of paper, and this is the primary use for

wood pulp. Wood pulp is the most common material used to make paper.

The timber resources used to make wood pulp are referred to as pulpwood.



Wood pulp comes from softwood trees such as spruce, pine, fir, larch, and

hemlock and hardwoods such as eucalyptus,aspen,and birch.

1.3 BLACK LIQUOR

Black liquor is a byproduct of the Kraft process, during the production

of paper pulp. Wood is decomposed into cellulose fibers, hemicelluloses and

lignin fragments. Black liquor is an aqueous solution of lignin residues,

hemicellulose, and the inorganic chemicals used in the process. The black

liquor contains more than the half of the energy content of the wood fed into

the digester. Early Kraft pulp mills discharged black liquor to watercourses.

Black liquor is quite toxic to aquatic life, and causes a very dark “Coca-

Cola” color in the water. In chemical pulping a large part of the wood is

dissolved during digestion. The dry matter content of the generated black

liquor is typically 12 to 18 wt. %.In the case of Kraft liquors four main

groups of organic constituents are present,30-45wt% ligneous material,25-

35wt% saccharinic acids, about 10wt% formic acid and acetic acid, and 3-

5wt% extractives. It also contains about 1wt% methanol and many inorganic

elements, mainly sodium(17-20wt %) and sulphur (3-5wt%).The exact

composition of the black liquor varies considerably between different mills

depending on the cooking conditions and feedstock. The vast majority of

lignin in the spent liquors of pulp mills is used as in house fuel for the

recovery of chemicals.

2. VISION:

Million tonnes of black liquor generation in a small scale will be

money saving, time and energy.



3. MPM AT A GLANCE:

Mysore paper mill was established in the year 1936. It is one of largest

mill in India. MPM is located on the banks of Bhadra River. This mill used

bamboo, euca, acacia, pine and bagasse as raw material for paper making.

This mill has three pulping plant, out of 3, two are chemical pulp

mills that is CPM2 for hard wood and other one is for bagasse pulp plant

called CSRMP ( cold soda refiner mechanical pulp plant ) this pulp is used

to news print like papers.

Raw materials are used in MPM required mainly two sources

1. Captive sources

2. Privative sources

Captive plantation sources are requires mainly in 4 areas like

1. Tirathahalli

2. Sagara

3. Hosanagar

4. Bhadravathi

Hear all the activities are controlled by forest officer weighed woods

are stored in the different stocks based on their quality, size & durability. it is

very essential homogenize the different type of RM in the form 5-7 feet logs

& diameter in 5-6 inch & those logs are made free roots, barks, knots &

other undesirable impurities, which are not useful for paper making.

According to the need of for chipper house. The stored RM is issued.



Chipper house means the RM that is logs are cut in to small pieces

(chips) with the help of chipper, & the pieces are stored in a tank called

“SILO”. The materials rich in cellulosic fiber are used as RM. chipper are

classified Into 2 types MPM based on the wood. Each chipper contains two

types of blades for chipping. One is dead knife & other one is fly knife. Fly

knife rotates with the help of motors. Chipping converts heterogeneous type

of chipper into homogeneous & uniform type of chips.

1. Gsualiar chipper: - 5 chipper is working.

2. Pallmann chipper: - 2 chipper is working.

Gsualiar Chipper: - It is also called disk chippers. It is used to cut the hard

wood like euca and acacia. In this chipper fly knife are added to big disc

which is rotating with the help of motors.

Pallmann Chipper: - It is also called drum chipper. It is used to chip the

soft wood like bamboo. Here the fly knife is adjusted to drum which is

rotating with the help of motor. In pallmann chipper “Feed roller” are used to

crust the RM.

The chips will conveyed to chip screener for separating the dust &

oversized chips from accepted chips. The accepted chips are stored in SILO.

The dust is sent to boiler as a source of energy. The oversized chips will go

re chipper for making small chips.

Chipper size: - Very important to maintain the size of chips. Because in

CPM the liquor should penetrate easily.

Length ----------13 to 25 mm

Breadth ------------ 10 to 12 mm

Width --------------- 06 to 05 mm



SILO: - SILO is a big tank for storing the chips. This comes from the

chipper house. It has the capacity to store 700 tones of chips. It is classified

into 3 different chambers.

1. Bamboo storage.

2. Euca storage.

3. Acacia & bamboo mix storage.

PULPING TECHNOLOGIES AT MPM:

In MPM 3 varieties of pulp is producing. They are.

1. CSRMP: - (cold soda refiner mechanical pulping) for euca &

Acacia.

2. CPM 1: - Chemical pulp mill for bagasse

3. CPM 2: - Chemical pulp mill for bamboo & wood.



4. HISTORY OF LIGNIN:

For many years wood was considered to be uniform chemical

compound. In 1811, Gay Lussac and Thenard carried the elementary analysis

of wood and found its components consists entirely of carbon, hydrogen and

oxygen and that no other elements, and that no other elements, such as sulfur

and nitrogen, or only traces of the latter, are present. At about the same time,

Prout reported same analysis of wood fibers which he called “fibres

ligneux.” These chemists believed that wood is a chemical entity.

With the development of the organic chemical experimental technique

over a hundred years ago, however, chemists succeeded in separating wood

into individual components. About 1815, Raspail expressed the opinion that

wood may consists of several components and he suggested that the cell wall

is buildup of gum and lime. That wood is not a uniform chemical compound

was shown in 1819 by Braconnot and three years later by Authenrieth and

Bayer hammer, when they found that wood gives glucose in boiling with

dilute sulfuric acid. None of them, however, mentioned any other reaction

products.

In 1834, Runge discovered that wood gives a green color reaction with

phenol and hydrochloric acid, and a yellow color with aniline hydrochloride,

but he did not realize the significance of these reactions.

The first serious attempt to study the chemical composition of the cell

wall of lignified plants was made in 1838 by Anselme Payen by the

intelligent applications of different reagents; he succeeded in isolating a

uniform compound which he called Cellules. He treated wood alternatively

with nitric acid and caustic soda and in this way obtained cellulose fibres



which are considered as the basic substance of cell membrane. From the

elementary analysis of wood and their celluloses, from the lignin it uses to be

55.6% carbon, 5.8% hydrogen and 38.6% oxygen.

From this he arrived at a formula, C19H24O10, for lignin. The carbon

content he calculated ifs considerably lower than that he found for lignin’s

isolated by newer methods. This is not surprising because the lignin content

found by Schulze is much too high and includes a considerable portion of

carbohydrates which lowers the carbon content. All attempts by Schulze to

isolate lignin as such for a direct analysis failed. An attempt to isolate it by

alkali fusion and acidification of alkaline solution resulted in very small

amount of precipitate which had been altered chemically.

That interest in chemistry of lignin has continued to increase is shown

by the fact during that decade since 1948, when the manuscript for “The

Chemistry of Lignin” was completed, the amount of research carried out and

the numbers of reviews written on the subject have exceeded those of any

previous decade.

The brief history revives shows that the problem of lignin is an old

one. Although a tremendous work had been carried out, particularly during

the last quarter century, we are still remote from the final solution of its

constitution.



4.1 HISTORY OF RESIN:

Plant resins have a very long history that was documented in ancient

Greece by Theophrastus, in ancient Rome by Pliny the Elder, and especially

in the resins known as frankincense and myrrh, prized in ancient Egypt.[1] These were highly prized substances, and required as incense in some

religious rites. Amber is a hard fossilized resin from ancient trees. The

English word originates from the late 14th century Old French resine, from

L. resina "resin," from Greek rhetine "resin of the pine," of unknown earlier

origin.

The first commercial attempts to prepare resins from epichlorohydrin

were made in 1927 in the United States. Credit for the first synthesis of

bisphenol-A-based epoxy resins is shared by Dr. Pierre Castan of

Switzerland and Dr. S.O. Greenlee of the United States in 1936. Dr. Castan's

work was licensed by Ciba, Ltd. of Switzerland, which went on to become

one of the three major epoxy resin producers worldwide. Ciba's epoxy

business was spun off and later sold in the late 1990s and is now the advance

materials business unit of Huntsman Corporation of the United States. Dr.

Greenlee's work was for the firm of Devoe-Reynolds of the United States.

Devoe-Reynolds, which was active in the early days of the epoxy resin

industry, was sold to Shell Chemical (now Momentive Specialty Chemicals,

formerly Hexion, Resolution Polymers and others).

Early varnishes were developed by mixing resin, like pine sap, with a

solvent and applying them with a brush to get the golden and hardened effect

one sees in today's varnishes.[1] The ancient Egyptians were well acquainted

with the art of varnishing, but its origin appears to be far east of there

in India, China and Japan, where the practice of lacquer work, a species of


http://en.wikipedia.org/wiki/Lacquer

http://en.wikipedia.org/wiki/Ancient_Japan

http://en.wikipedia.org/wiki/Ancient_China

http://en.wikipedia.org/wiki/Ancient_India

http://en.wikipedia.org/wiki/Ancient_Egypt

http://en.wikipedia.org/wiki/Varnish#cite_note-0

http://en.wikipedia.org/wiki/Amber

http://en.wikipedia.org/wiki/Incense

http://en.wikipedia.org/wiki/Resin#cite_note-ancegy-0

http://en.wikipedia.org/wiki/Myrrh

http://en.wikipedia.org/wiki/Frankincense

http://en.wikipedia.org/wiki/Pliny_the_Elder

http://en.wikipedia.org/wiki/Theophrastus


varnish application, was known at a very early date. It has been claimed that

Japan was acquainted with the art of lacquering by 500 or 600 B.C., but the

majority of authorities place its first usage there to the 3rd century AD, as an

art acquired from their neighbors, the Koreans. The Chinese and Indian

peoples probably knew the art much earlier than the Japanese. Varnish and

lacquer work are, however, generally treated in the arts as separate and

distinct.


http://en.wikipedia.org/wiki/Ancient_Korea

http://en.wikipedia.org/wiki/Anno_Domini


Pulp is a lignocellulosic fibrous material prepared by chemically or

mechanically separating cellulose fibres from wood, fibre crops or waste

paper. Wood pulp is the most common raw material in papermaking. Pulp

can be manufactured using mechanical, semi-chemical or fully chemical

methods (Kraft and sulfite processes). The finished product may be either

bleached or non-bleached, depending on the customer requirements. The aim

of pulping is to break down the bulk structure of the fibre source, be it chips,

stems or other plant parts, into the constituent fibers.

Chemical pulping achieves this by degrading the lignin and

hemicellulose into small, water-soluble molecules which can be washed

away from the cellulose fibers without depolymerizing the cellulose fibres.

Pulp category Production [M ton]

Chemical 131.2

-Kraft 117.0

-Sulfite 7.0

-Semi chemical 7.2

Mechanical 37.8

4.1.1 TYPES OF PULPING

There are a number of different processes which can be used to

separate the wood fibres.

Thermo mechanical pulp

Thermo mechanical pulp is pulp produced by processing wood

chips using heat (thus thermo) and a mechanical refining movement (thus

mechanical). It is a two stage process where the logs are first stripped of


http://en.wikipedia.org/wiki/Thermo

http://en.wikipedia.org/wiki/Wood_chip

http://en.wikipedia.org/wiki/Wood_chip

http://en.wikipedia.org/wiki/Papermaking

http://en.wikipedia.org/wiki/Paper_recycling

http://en.wikipedia.org/wiki/Paper_recycling

http://en.wikipedia.org/wiki/Fibre_crop

http://en.wikipedia.org/wiki/Wood

http://en.wikipedia.org/wiki/Cellulose_fiber


their bark and converted into small chips. These chips have a moisture

content of around 25-30% and a mechanical force is applied to the wood

chips in a crushing or grinding action which generates heat and water vapor

and softens the lignin thus separating the individual fibers. The pulp is then

screened and cleaned, any clumps of fiber are reprocessed. This process

gives a high yield of fibre from the timber (around 95%) and as the lignin

has not been removed, the fibres are hard and rigid.

Chemithermo Mechanical Pulp

Wood chips can be pretreated with sodium carbonate, sodium

hydroxide, sodium sulfite and other chemicals prior to refining with

equipment similar to a mechanical mill. The conditions of the chemical

treatment are much less vigorous (lower temperature, shorter time, less

extreme pH) than in a chemical pulping process since the goal is to make the

fibres easier to refine, not to remove lignin as in a fully chemical process.

Pulps made using these hybrid processes are known as chemithermo

mechanical pulps (CTMP).

Chemical pulp

Chemical pulp is produced by combining wood chips and chemicals

in large vessels known as digesters where heat and the chemicals break down

the lignin, which binds the cellulose fibres together, without seriously

degrading the cellulose fibres. Chemical pulp is used for materials that need

to be stronger or combined with mechanical pulps to give product different

characteristics. The Kraft process is the dominant chemical pulping method,

with process being second. Historically soda pulping was the first successful

chemical pulping method.


http://en.wikipedia.org/wiki/Soda_pulping


http://en.wikipedia.org/wiki/Cellulose_fibre

http://en.wikipedia.org/wiki/Cellulose

http://en.wikipedia.org/wiki/Digester

http://en.wikipedia.org/wiki/PH

http://en.wikipedia.org/wiki/Sodium_sulfite

http://en.wikipedia.org/wiki/Sodium_hydroxide


http://en.wikipedia.org/wiki/Sodium_carbonate

http://en.wikipedia.org/wiki/Timber

http://en.wikipedia.org/wiki/Lignin

http://en.wikipedia.org/wiki/Bark


Bleaching

The pulp produced up to this point in the process can be bleached to

produce a white paper product. The chemicals used to bleach pulp have been

a source of environmental concern, and recently the pulp industry has been

using alternatives to chlorine, such as chlorine dioxide, oxygen, ozone and

hydrogen peroxide.

4.2 KRAFT PULPING:

The kraft process (also known as kraft pulping or sulfate process)

describes a technology for conversion of wood into wood pulp consisting of

almost pure cellulose fibers. The process entails treatment of wood chips

with a mixture of sodium hydroxide and sodium sulfide, known as white

liquor, that break the bonds that link lignin to the cellulose.

The kraft pulping process involves the digesting of wood chips at

elevated temperature and pressure in "white liquor", which is a water

solution of sodium sulfide and sodium hydroxide. The white liquor

chemically dissolves the lignin that binds the cellulose fibers together.

There are 2 types of digester systems, batch and continuous. Most

Kraft pulping is done in batch digesters, although the more recent

installations are of continuous digesters. In a batch digester, when cooking is

complete, the contents of the digester are transferred to an atmospheric tank

usually referred to as a blow tank. The entire contents of the blow tank are

sent to pulp washers, where the spent cooking liquor is separated from the

pulp. The pulp then proceeds through various stages of washing, and

possibly bleaching, after which it is pressed and dried into the finished

product.


http://en.wikipedia.org/wiki/Lignin

http://en.wikipedia.org/wiki/White_liquor

http://en.wikipedia.org/wiki/White_liquor

http://en.wikipedia.org/wiki/Sodium_sulfide


http://en.wikipedia.org/wiki/Cellulose

http://en.wikipedia.org/wiki/Wood_pulp

http://en.wikipedia.org/wiki/Hydrogen_peroxide

http://en.wikipedia.org/wiki/Ozone

http://en.wikipedia.org/wiki/Oxygen

http://en.wikipedia.org/wiki/Chlorine_dioxide

http://en.wikipedia.org/wiki/Chlorine

http://en.wikipedia.org/wiki/White_paper

http://en.wikipedia.org/wiki/Bleaching_of_wood_pulp


Fig: Kraft pulping process



4.3 AIM AND OBJECTIVES

AIM:

Identification and Utilization of value added polyphenolic

compounds from pulp mill waste.

(Extraction of lignin from CPM-1 and CPM-2, wood and bagasse

Kraft spent black liquor which is a ‘byproduct of pulp mills, Kraft process

and yield obtained and IR characterization of the lignin.)

Objective:

Small scale Pulp mills generate a million tons of black which is

sewered. Where as large scale industries are installing chemical

recovery units to recover the chemicals. Due to environmental facts

utilization of value added products like polyphenols from black liquor in

bagasse Kraft pulping method could saves environment, energy and

money.

Is to extract the lignin present in the bagasse Kraft spent liquor which

is a bit expensive process but it is worth putting money for all the advantages

we are going to get from it. By doing so instead of only burning it in boiler

which is the bottle neck process for pulp industries for only power purpose it

can also be employed in many use full ways. Where pulp industries are

producing much more power than they are required to sustain, which can be

sold out, but along with that it is necessary to use part of it to extract lignin

which can be used in many ways. Lignin can be used to synthesize many

alternatives like, an alternative to plastic, vanillin, agricultural chemicals and

many more and also raw materials for several chemicals and high quality

bleached paper. Create new projects using lignin as raw material and in the

field of lignin characterization.



5. CHARACTERIZATION OF BLACK LIQUOR:

The Kraft black liquor used in this study was supplied by Mysore

Paper Mills, Bhadravathi, and Shimoga Dist. The Monsteras paper mill is

situated on the edge of the Bhadra River in the east of the Bhadravathi town.

The Monsteras pulp mill uses a continuous digester. The cooking

temperature is about 165-170°C and delignification is done to a kappa

number of 29-3 . The liquor was withdrawn between digester and pre-

impregnation as softwood pulp was being processed.



5.1 METHODOLOGY:

Production of Black liquor:

The Kraft pulping process involves the digesting of wood chips at

elevated temperature and pressure in “white liquor” which is a water solution

of sodium sulfide and sodium hydroxide. The white liquor chemically

dissolves the lignin that binds the cellulose fibers together.

There are 2 types of digester systems, batch and continous.Most Kraft

pulping is done in batch digesters, although the more recent installations are

of continuous digester. In MPM (Mysore Paper Mills) the batch digester

process is done, in a batch digester, when cooking is complete, the contents

of the digester are transferred to an atmospheric tank usually referred to as a

blow tank. The entire contents of the blow tank are sent to pulp washers,

where the spent cooking liquor is separated from the pulp. The pulp then

proceeds through various stages of washing, and possibly bleaching, after

which it is pressed and dried into the finished product. The “blow” of the

digester does not apply to continuous digester systems.

The balance of the Kraft process is designed to recover the cooking

chemicals and heat. Spent cooking liquor and the pulp wash water are

combined to form weak black liquor which is concentrated in a multiple-

effect evaporator system to about 55% solids. The black liquor is then

further concentrated to 65% solids in a direct-contact evaporator, by bringing

the liquor into contact with the flue gases from the recovery furnace, or in an

indirect-contact concentration. The strong black liquor is then fired in a

recovery furnace. Combustion of the organics dissolved in the black liquor

provides heat for generating process steam and for converting sodium sulfate

to sodiumsulfite.Inorganic chemicals present in the black liquor collect as a

molten smelt at the bottom of the furnace.



The smelt is dissolved in water to form green liquor, which is

transferred to a caustic zing tank where quicklime (calcium oxide) is added

to convert the solution back to white liquor for return to the digester system.

A lime mud precipitates from the caustic zing tank, after which it is calcined

in a lime kiln to regenerate quick lime.

The characteristic odor of the Kraft mill is caused by the emission of

reduced sulfur compounds, the most common of which are hydrogen sulfide,

methyl mercaptan,dimethyl sulfide, and dimethyl disulfide, all with

extremely low odor thresholds. The major source of hydrogen sulfide is the

direct contact evaporator, in which the sodium sulfide in the black liquor

reacts with the carbon dioxide in the furnace exhaust. Indirect contact

evaporators can significantly reduce the emission of hydrogen sulfide. The

lime kiln can also be a potential source of odor, as a similar reaction occurs

with residual sodium sulfide in the lime mud. Lesser amounts of hydrogen

sulfide are emitted with the non-condensable of off gases from the digesters

and multiple-effect evaporators.



5.2 LIGNIN ISOLATION FROM BLACK LIQUOR:

Several different enzymatic, chemical and mechanical methods have

been developed for the isolation of lignin from black liquor.however,due to

the heterogeneity that exists between individual fibres,no method is currently

available for the quantitative isolation of native or residual lignin without the

risk of structural changes during the isolation. Even if the perfect isolation

technique could be found, the product would at best represent the average

structure of native or residual lignin components. However, the information

gained about the chemical reactivity and structure of isolated lignin is

valuable. Thus, the three most commonly employed methods for isolating

residual lignin are described below.

Lignin can be isolated currently, by two methods they are isolation of

residual lignin from Kraft pulp that of enzymatic hydrolysis using

cellulolytic enzymes, and that of acid hydrolysis of black liquor using a

solution of hydrogen chloride and sulfuric acid in dioxane/water.

5.4 EXPERIMENTAL PROCEDURE:

Bagasse Kraft Spent Liquor obtained after production of paper, which

is highly dilute in nature is passed and stored in the CPM-2 processor plant

to evaporate to some extent. And then it is passed to CPM-1 plant to

evaporate it to much more extent than in the CPM-2 evaporator plant and

then it is passed to evaporator where it is evaporated to larger extent to get a

highly concentrated black liquor which is passed to boiler for combustion to

produce steam which in turn to produce power. The black liquor taken for

our project to isolate lignin is from the CPM-2 is highly dilute in nature and

its solid content is about 14-18%.Out of the three types of black liquor CPM-



2 is the better one to isolate lignin in good yield. Other than that CPM-1 and

evaporator black liquor are having concentration and solid content.

Precipitation:

About 1litre of Dilute Bagasse Kraft Black Liquor (CPM-2liquor) is

taken in a beaker and it is treated with 70% sulfuric acid which is added

slowly, the whole set up is kept in ice water bath, constant stirring is done to

prevent spilling. Constant pH is maintained in between 2-3 with the help of

the pH-meter. A gelatinous solution of dark blackish brown in color is

obtained. It allowed for 24hours settling down.

And then it is filtered using vacuum pump the filtrate is washed with

dilute sulfuric acid of 3% and washed with hot distilled water until the

sulfuric acid content is removed completely and also the sulphates and

chlorides. The sulfuric acid lignin often contains 2-5% sulfur which is



mostly removed by heating with 1litre 0.5%hydrochloric acid for about 8-10

hours. The cake is reddish brown in color, waxy in nature, dried in open hot

air drier at 60C a luster yellowish brown of lignin separates. A technical

sulfuric acid lignin is known as “Scholler Lignin”.

5.5 METHODS OF PREPARATION OF LIGNIN:

In order to isolate lignin from lignified substance, a carefully selected

starting material must be used like when woods are utilized knots, bark, and

resin are used, but when coming to industrial products or by products pulp,

bagasse, and Kraft spent liquor may be used. In our project We are using

Wood & Bagasse Kraft Spent Liquor as the starting material for the isolation

of lignin. Lignin can be isolated from black liquor by many methods they are

as follows,

Sulfuric Acid Lignin or Klason Lignin:

The isolation of lignin by means of sulfuric acid is based on a

discovery of Braconnot in 1819. In spite of earlier reports, Klason in198O

was the first to propose the use of 64 — 72% sulfuric acid for the hydrolysis

of the carbohydrates in the isolation of lignin. This method is therefore

generally associated with his name in the literature and the product obtained

is referred to as “Klason Lignin or Sulfuric Acid Lignin.” The conditions he

recommended for quantitative lignin determination can also be applied to the

preparation of lignin on a large scale.

5.6 GENERAL PROPERTIES OF LIGNIN:

It is a resinous material.

Soluble in Water, coagulates, colloidal solution.



Melting Point is 18000.

Lignin is co-precipitated with natural GRS and Nitrile Elastomers.

It provides sufficient formaldehyde reactants.

It follows condensation reaction due to polyhydroxy groups.

Inhibiting properties of lignin:

Inhibitory efficacy has been determined by the method of the weight

losses of steel in acid with native lignin, hydrolysis lignin, ammoniated

native lignin, chlorinated hydrolysis lignin, and ammoniated hydrolysis

lignin, and Without these additives. It has been established that the efficacy

of lignin and its modifications as inhibitors of acid corrosion increases with a

rise in the number of carboxyl groups in the macromolecule, and therefore

the ammoniated hydrolysis lignin is the most effective. It is capable of

forming water proof bonds and wood derivatives/substrates after hydroxyl

methylation.



5.7 GENERAL PROCEDURE:

5.8 CALCULATIONS:

Black liquor initial PH:

CPM 1 =13.27

CPM 2 =13.06

Black liquor +sulphuric acid:

CPM 1 =4

CPM 2 =4



CPM 1:

Weight of empty sintered glass crucible( W1) =50.170g

Weight of sintered crucible + precipitate (W2) =50.198g

CPM 1 (W) =W2-W1

=50.198 -50.170

=0.028g

CPM 1 =2.8g/liter

CPM 2:

Weight of empty filter paper (W1) =1.543g

Weight of filter paper + precipitate (W2) =1.721g

CPM 2 (W)= W2-W1

=1.721-1.543

=0.17g

CPM 2=1.78g/lite



6. GENERAL PROPERTIES OF RESIN:

High tensile strength,

Heat distortion temperature,

Low water absorption,

Mould shrinkage,

High surface hardness,

Volume resistance

Excellent mechanical properties over temperatures from below -40°C (-

40°F) to above 148°C (300°F)

Self-extinguishing, non-dripping characteristics

Excellent dimensional stability and low water absorption

Resistance to aqueous chemical environments

Excellent impact strength

The practical melting point varies with different specimens, some being

semi-fluid at the temperature of boiling water, others melting at 100°C to

120°C.

It is very flammable, burning with a smoky flame, so care should be

taken when melting it. It is soluble in alcohol, ether, benzene and

chloroform.

STRUCTURE OF RESIN:


http://en.wikipedia.org/wiki/Chloroform

http://en.wikipedia.org/wiki/Benzene

http://en.wikipedia.org/wiki/Diethyl_ether

http://en.wikipedia.org/wiki/Ethanol

http://en.wikipedia.org/wiki/Tensile_strength


6.1 PREPARATION OF RESIN:

ALCOHOL BENZENE SOLUBILITY METHOD:

Reagent: Alcohol benzene Mixture: Mix one volume of

approximately 95 % Ethanol and two volumes of Benzene.

Sulphuric acid 72 % carefully pour 665 ml of concentrated sulphuric

acid into about 300 ml of water and after cooling, dilute to one liter.

Standardize against standard NaOH solution using methyl orange as

indicator.

Adjust the acid to strength of 72 +/- 0.1 % by addition of water or

concentrated sulphuric acid as may be found necessary.

6.2 METHODOLOGY:

Weigh the oven dried test specimen of approximately 10-g to the

nearest 0.01 g in tarred extraction thimbles.

Clean, and then dry the sox let- extraction flask. Place the extraction

flask with 150 cm of the required solvents. Connect the flask to the

extraction apparatus and start water flow to the condenser section. Adjust the

extraction apparatus and start water flow to the condenser section. Adjust the

heaters to provide a boiling rate, which will cycle the specimens for not less

than 24 extractions over a 4-5 hour period. Remove the flask from the

apparatus and partially evaporate the solvent in the extraction flask to a

volume 20-25 cm.



Transfer the extract to the tarred weighing dish by washing with small

amounts of fresh solvent. Handle the weighing dish with forceps or tongs. If

using benzene, evaporate the solvent to near dryness, while in the chemical

fume hood. Dry the dish and contents in an oven for 1 hr at 105degree c cool

in a desiccators, and weigh to the nearest 0.1- milligram. Run a blank

determination with the solvent used in the test. Evaporate 150 cm of the

solvent to dryness, and weigh the residue to the nearest 0.1 milligram.

Correct the weigh the residue to the nearest 0.1 – milligram. Correct the

weight of the dried extract by the weight of residue found.

6.3 CALCULATION:

Weight of thimbles+ concentrated sample=15.788g

Weight of concentrated moisture less thimbles=14.498g

Difference in Weight of concentrated sample=1.29g

Weight of thimbles + firing sample=15.880g

Weight of firing moisture less thimbles =14.748g

Difference in Weight of firing sample=1.132g

AFTER THE PITCH PROCESS:

FOR CONCENTRATED BLACK LIQUOR:

Weight of round bottom flask( W1)=179.776g

Weight of round bottom flask + Resin (W2)=180.901g

W=W2-W1

= 180.901-179.776

=1.125g

Percentage for concentrated liquor:17.33%



FOR FIRING BLACK LIQUOR:

Weight of round bottom flask(W1)=115.253g

Weight of round flask + Resin(W2)=116.338

W=W2-W1

= 116.338-115.253

=1.085g

Percentage of firing liquor =17.78%



7. CHARACTERIZATION

At Infrared -spectroscopy:

Infrared (IR) radiation is electromagnetic radiation whose wavelength

is longer than that of visible light (400-700 mn), but shorter than that of

terahertz radiation (100 um - l mm) and microwaves (~30,000 um). Infrared

radiation spans roughly three orders of magnitude (750nm and 100 pm).

Common Applications:

Identification of compounds by matching spectrum of unknown

compound with reference spectrum (fingerprinting).

Identification of functional groups in unknown subtend the light our

eyes see is but a small part of a broad spectrum of electromagnetic

radiation. On the immediate high energy side of the visible spectrum

lies the ultraviolet, and on the low energy side is the infrared. The

portion of the infrared region most useful for analysis of organic

compounds is not immediately adjacent to the visible spectrum, but is

that having a wavelength range from 2,500 to 16,000 nm with a

corresponding frequency range from 1.9*10‘3 to 1.2*10“‘ Hz.



Simplified optical layout of typical FTIR spectrometer.

A Fourier transform is a mathematical operation used to translate a

complex curve into its component curves. In a Simplified optical layout of

typical FTIR spectrometer.(Reprinted by Fourier transform infrared

instrument, the complex curve is an interferogram, or the sum of the

constructive and destructive interferences generated by overlapping light

waves, and the component curves are the infrared spectrum. The standard

infrared spectrum is calculated from the Fourier-transformed interferogram,

giving a spectrum in percent transmittance (%T) vs. light frequency (cm-1).

IR spectroscopy regions have been classified in to three regions,

Near IR (12,500 - 4000¢m")

Mid IR (4000 0- 4400¢m")

Far IR (400 - 10cm")

The mid region IR is fundamental IR region which is more useful

region for organic compounds and inorganic compounds. IR spectra of the



compounds were recorded by KBr pellet technique in the range of 4000 —

550 cm-1.

Structure of lignin:

A. Ketonic Structure of Lignin.

Lignin is a cross-linked racemic macromolecule with molecular

masses in excess of 10,000 amu. It is relatively hydrophobic and aromatic in

nature. The degree of polymerization in nature is difficult to measure, since it

is fragmented during extraction and the molecule consists of various types of

substructures which appear to repeat in a haphazard manner. Different types

of lignin have been described depending on the means of isolation. There are

three monolignol monomers, methoxylated to various degrees: p-coumaryl

alcohol, coniferyl alcohol, and sinapyl alcohol. These lignols are

incorporated into lignin in the form of the phenylpropanoids p-

hydroxyphenyl (H), guaiacyl (G), and syringal (S) respectively. Molecular

fonnula of Protolignin is C92H108O38.



B is the structure of on-Lignin and C is the B-Lignin.

7.1 CONSTITUENTS GROUPS OF LIGNIN:

Lignin structure consists of following constituents like methoxyl

group, hydroxyl group, carbonyl group, carboxylic group, double bonds.

Which are conformed as follows bellow,

i. Methoxyl Groups;

A qualitative test for alkoxide groups in lignin was developed by

Kratzl and Osterberger. In this method the alkoxide iodide as obtained in the

Zeisel determination is allowed to react with thiourea, and the alkyl thiourea

is isolated as its picrate. Kratzl and Gruber separated and determined

quantitatively the methoxyl and ethoxyl groups in lignin preparation by

means of gas-liquid chromatography [3].Lignin mainly contains methoxyl —

OCH3; which show a very little affinity towards water molecule. It cannot

participate in the hydrogen with the available electronegative atoms or

groups either in the water or cellulosic fibers.



ii. Hydroxyl Groups;

The hydroxyl groups, there differentiation and quantitative

determination have played an important role in recent lignin chemistry.

There is no doubt that lignin contains phenolic and aliphatic hydroxyl groups

and, since some them may be etherified and form either alkyl ether or

heterocyclic (furan or pyran) rings, their quantitative determination may

contribute to the elucidation of structure of lignin molecule.

iii. Carboxyl Groups;

The presence of carboxyl groups in lignin and lignosulphonic acids

has been the subject of controversy for many years. While it is generally

believed that protolignin does not contain any carboxyl group, Regestad and

Samuelson and Freudenberg and co Workers reported that they had found

such groups in lignosulphonic acid; Kullgren also reported their presence in

the lignosulphonic acid in unbleached sulfite pulp.

iv. Double Bonds;

The presence of aliphatic double bonds in lignin is still doubt.

According to Aulin Erdtman, ultraviolet absorption analysis show that

spruce protolignin contains less than 0.03 to 0.04, double bond, conjugated

with a phenolic ring, per methoxyl groups.

Alder and Ellmer believed they have definitely proven the presence of

coniferyl aldehyde groups in lignin by the phloroglucinol-hydrochloric acid

color reaction given by lignosulphonic acid after treatment with sodium

hydroxide. This treatment splits off not only the sulfurous acid which is

loosely combined to the aldehyde group but also the sulfonic acid which is

attached to the oi carbon atom of the coniferyl aldehyde side chain in

lignosulphonic acid and thus regenerates the double bond in this side chain.



Weather this double bond is present in protolignin is still debatable, since a

hydroxyldihydriconiferyl structure with a hydroxyl group at or position may

occur in protolignin and this hydroxyl would be replaced by a sulfonic acid

group in the lignosulfonic acid. In protolignin and soluble native lignin, the

hydroxyl group may be split off as water by the action of the mineral acid in

the Wiesner reagent.



8. APPLICATIONS OF LIGNIN:

1. Lignin in Wood Adhesives:

Lignin-based wood adhesives are obtained that satisfy the

requirements of relevant international standards for the manufacture of

exterior-grade wood particleboard, They are prepared and tested for

application to wood panels such a particleboard. The adhesives yield good

internal bond strength results for the panels which are good enough to

comfortably pass relevant international standard specifications for exterior-

grade panels. The adhesives also show sufficient reactivity to yield panels in

press times comparable to that of formaldehyde-based commercial

adhesives.

In the manufacture of certain types of water soluble glues and

adhesive lignosulfonates is due partly to their sugar content. Adhesive of

superior performed and with a wide range of applications are made from

lignosulfonates in solution of high viscosity. Typical examples are glues

from mixture of lignosulphonates with polyvinyl alcohols and

polyacrylamide.

2. Agriculture:

Lignosulfonate from suspension or dispersion in variety of stable

insecticide, fungicide, or herbicide. They are compactable with other anionic

tension active and are frequently used in conjunction with wetting agents,

improving the action of lost.

By precipitating their black liquor with acid or acids evolved gases

like CO2 are sustentions used in conjunction with wetting agents Agricultural

pesticides. Generally, agricultural pesticides are manufactured in the form of



dilute suspension or dispersions for doing so, it is necessary to incorporate a

high active dispersant lignosulfonates act as grinding acids, as well as

dispersants.

The suspension should not only from spontaneously but should also be

maintained during the period of application, zinc, copper, iron, magnesium

etc. complexes of lignosulphonates be incorporated in the composition of

fertilizers t supplement micro nutrients to the plants.

3. Lignin in biodegradable composites:

Composites from alkali lignin and wheat gluten, modified with

different percentages of sodium silicate, were prepared and characterized.

Moreoreover, the addition of silica to the aforementioned composites was

studied with the aim of improving the thermal and mechanical properties.

The effect of wheat gluten percent and the extent of its modification on the

blends properties were investigated via diametric tensile strength, thermo

mechanical analysis (tma), scanning electron microscope (SEM), thickness

swelling and thermo gravimetric analysis (tga). The results showed

significant improvement in the diametric tensile strength, thickness swelling,

uniformity in the fracture surface, and the shift of glass transition

temperature (tg) toward higher values with increasing wheat gluten percent

and its modification extent.

4. Engineering plastics from lignin:

Hydroxypropylation of lignin in a batch reactor under alkaline

conditions at 180°C was studied using propylene oxide (PO) by itself and

PO in combination with several lignins like model compounds and with

Kraft lignin.



5. Lignin based paint:

A method is provided for producing a painted article comprising: (a)

preparing a lignin solution comprising lignin and a dye or pigment; (b)

mixing the lignin solution with a phenol oxidizing enzyme; (c) incubating

the mixture from said step (b) under conditions and for a time sufficient to

form a solution of a desired viscosity; (d) contacting or spreading the

mixture from the step (c) on an article to be painted; and

6. Fire Extinguishers:

Lignosulfonates have as applications as foam stabilizers for the

extinguishing foams (such as in airports, oil refiners etc) lignosulfonate

stabilized foams are prepared from hydrolyzed protein extracts.

7. The Biological application of Lignin-Contained Compounds:

The investigation of biological properties of lignin-contained

compounds (LCC) as multitonnage wastes of woodworking industry is very

actual from the viewpoint of estimation of their treatment on ecosystems.

The purpose of this work was to study the relationship between

macromolecular, mutagenic and growth-regulating properties of LCC. LCC

in water medium and in swelling state (at moisture 3 60%) behave as

polyanions and/or neutral molecules according to value of pH, whose action

on biological objects is connected with competition mechanisms. They

disturb the structural-functional systems of cells: genetical, membraneous,

ferment-protein.



8.1 APPLICATION OF RESIN:

1. Wood Protection:

Hydrocarbon resins are widely used in wood protection coatings

because of their water-repellant and fixing properties, i.e. fixing fungicides,

insecticides and helping to prevent "blooming" of wood preservatives.

2. Agriculture:

Most recent studies point out that resin is a good inducer for defense

mechanisms in plants. It has also been assessed as a fertilizer that can

improve overall crop yields. The EPA regulates chitin for agricultural use

within the USA. Chitosan is prepared from chitin by deacetylation.

3. Industrial:

It used in industry in many processes. It is used as an additive to

thicken and stabilize foods and pharmaceuticals. It also acts as a binder

in dyes, fabrics, and adhesives. Industrial separation membranes and ion-

exchange resins can be made from chitin. Processes to size and strengthen

paper employ chitin.

Also, there is potential for applications in solar cells and cell phone

screens; when chitin is treated in hydrochloric acid, sodium hydroxide and

ethanol to strip the material of minerals, proteins, lipids, fats and pigments,

and supplemented with acrylic resin monomer, a clear product results.

Crushed and spread into a nanocomposite film it forms a useful component

for solar cell and cell phone screens.


http://en.wikipedia.org/wiki/Paper

http://en.wikipedia.org/wiki/Sizing

http://en.wikipedia.org/wiki/Resin

http://en.wikipedia.org/wiki/Ion-exchange

http://en.wikipedia.org/wiki/Ion-exchange

http://en.wikipedia.org/wiki/Reverse_osmosis

http://en.wikipedia.org/wiki/Adhesive

http://en.wikipedia.org/wiki/Fabric

http://en.wikipedia.org/wiki/Dye

http://en.wikipedia.org/wiki/Pharmaceutical

http://en.wikipedia.org/wiki/Chitosan

http://en.wikipedia.org/wiki/Fertilizer

http://en.wikipedia.org/wiki/Plant_defense_against_herbivory

http://en.wikipedia.org/wiki/Plant_defense_against_herbivory


4. Paints and Varnishes:

Many traditional solvent based coatings contained a so-called hard

resin. These resins are used to improve hardness, gloss, dry time and

improve water repellency and resistance to saponification. Hydrocarbon

resins with softening points of 100 -120 °C are often used in the formulation

of aluminum and bronze paints, aerosol paint, primers and alkyd paint

modifiers.

5. Temporary Rust Protection Coatings:

In steel construction as well as other applications, temporary rust

prevention is very important. Hydrocarbon resins are commonly used along

with waxes, anticorrosion agents and a low KB solvent such as mineral

spirits.

6. Floor Tiles:

Hydrocarbon resins are commonly used in the manufacture of floor

tile based on PVC or SBR rubber. They are mainly used as processing aids.

A wide range of resins may be used with choice depending mainly on price

and end use requirements.

7. Medicine:

Resins are flexible and strong material make it favorable as surgical

thread. Its biodegradability means it wears away with time as the wound

heals. Moreover, it has some unusual properties that accelerate healing of

wounds in humans.


http://en.wikipedia.org/wiki/Biodegradation

http://en.wikipedia.org/wiki/Surgical_suture

http://en.wikipedia.org/wiki/Surgical_suture

http://en.wikipedia.org/wiki/Tensile_strength


9. RESULTS:

Characterization of the lignin is an extremely difficult task because of

their diversity in respect with both sources and extraction methods. The

heterogeneity of lignin is due to the changes in polymer composition, size of

morphological units, crosslinking, nature of the functional groups, linkage

types between various moieties such as phenylpropanoic.p-hydroxylphenyl,

guaicyl, siryngyl,etc. Lignins from Black liquor with different chemical

composition and properties can be obtained by use of several extraction

methods. Commercial chemical pulping processes produce lignosulfonates

and Kraft lignin’s as residues. Recently commercialized alkaline pulping-

precipitation process supply sulfur-free, free-flowing lignin.



Figure 1: FT-IR Spectrum EBL-M



10. DISCUSSION:

The result given by the IR spectra shows and confirms the lignin

present in the bagasse Kraft spent liquor. With this result we can say that

using black liquor only for power purpose is not the only use it can be used

to isolate lignin for commercial purpose which can be used in alternative for

many products, in the alternative form of lignin. In this method of isolation

of lignin is easy and there is not much complicated or risk it can be adapted

in pulp mills as an additional plant which helps in converting the spent liquor

not only to produce power but also to isolate lignin. From that lignin many

derivatives can be synthesized which can be used in many fields, like

Agriculture, paint industries, adhesives, and many more.

Lignin can undergo many reactions which give derivatives of lignin in

which one of the important derivative is the sulfonated lignin and vanillin.

Some of the reactions which lignin undergo are as follows,

Sulfonation of lignin.

Nitration of lignin

Alkylation of lignin

Amination

Methylation

Compost formation.

Synthetic Vanillin is one of the most important derivative which is

synthesized from the lignin which is a flavoring agent used in the

alternative for the natural lignin.



Lower molecular weight compounds and polymer products are

synthesized from the lignin.

Low molecular compounds are,

Vanillin

Phenolic compounds

The Polymer products are,

Lignin Sulfonates

Cement and Concrete.

Binders and Adhesives

Rubber Additives

Emulsifier and Stabilizers



11. CONCLUSION:

In small scale ,Its better usage of lignin from black liquor

Small scale Pulp mills generate a million tons of black liquor, which is

sewered.

Where as large scale industries are installing chemical recovery units

to recover the chemicals. Due to environmental facts utilization of

value added products like polyphenols from black liquor in bagasse

Kraft pulping method could saves environment, energy and money.

Using better quality raw material to achieve desired brightness,

Manipulation of raw material quality enables use of lesser quantity of

bleaching chemicals, hence requires less water quantity of bleaching

and washing.

Black Liquor spills can be collected in tank and recycled back to the

system. This reduces fresh water consumption required for floor

washing.

All native lignins are heterogeneous biopolymers linked to

polysaccharides

Alkaline or acidic processes result in both lignin degradation and re-

polymerisation

The up-grading of technical lignins require purification steps

Several options exist for an increased lignin use

Increased pulp production in small scale.

Reduced thermal load in the recovery boiler.

Reduced oil consumption – Go Green

Excess energy can be avoided.

IR data showed that lignin particles are present in the black liquor in

their altered form.



Lignin was precipitated successfully from black liquor at

different pH values, precipitates of good quality

It is very difficult to elucidate the structure of lignin because of

different structure of lignin is present in different wood.

Instead of using lignin for only combustion to produce power but it

can be used to isolate lignin which is commercially demanded.

Not all the lignin produced from black liquor is used for power

production, some of it is treated and let to water recourses.

Lignin can be used to synthesis many alternatives like, an alternative

to plastic, vanillin, agricultural chemicals and many more and also raw

materials for several chemicals and high quality bleached paper. From

which we can conserve our natural resources from getting vanished

from the face of the earth and preventing pollution of our

environment.



PHOTOS:

Fig: Semisolid Black Liquor.

Fig: Wood Barks


http://en.wikipedia.org/wiki/File:Svartlut_76.jpg


Fig: Wood chips

Fig: black liquor



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http://en.wikipedia.org/wiki/Digital_object_identifier

http://dx.doi.org/10.1002%2Fanie.201000044

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Study and Characterization of Polyphenolic Compounds From Black Liquor of Kraft Pulping

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