KALISINDH SUPER THERMAL POWER

PROJECT, JHALAWAR(RAJASTHAN)

VACATIONAL TRANING REPORT

SUBMITTED BY:

NAME: MAHENDRA KUMAR MEENA

ROLL NO: 11/CHE/09

DURATION: 4 WEEKS

B.TECH(3RD YEAR) DEPARTMENT CHEMICAL ENGINEERING

ACKNOWLEDGEMENT

I would like to take this opportunity to thank everybody,

who has helped in course of undergoing training at

KALISINDH SUPER THERMAL POWER PROJECT,JALAWAR

(RAJASTHAN) from 18 may to 17 june

As special mention I extend my sincere thanks to Shri

S.SHARMA for providing me an opportunity to work under

such as an experienced faculty of

Also a sincere thanks to Mr S.S. MEENA (CHIEF MANAGER

OF THERMAL) FOR sincere guidance at each and every

stage during my training period in KaSTP.

We would like to express my gratitude to all those who

gave us the possibility to complete this institutions for

giving us the permission to commence this project in the

first instance.

MAHENDRA KUMAR MEENA

11/CHE/09 (CHE DEPT)

CONTENT

1. INTRODUCTION

2. SALIENT FEATURES

3. UNIT I AND II

4. COOLING WATER AND TYPES OF COOLING SYSTEM

A.ONCE THROUGH COOLING SYSTEM

B.CLOSED RECIRCULATING COOLING SYSTEM

C.OPEN RECIRCULATING COOLING SYSTEM

WATER LOSSES IN RECIRCULATION

5. STEAM MECHANICAL POWER

6. WATER TREATMENT

7. DE MINERALIZED WATER

KALISINDH THERMAL POWER PROJECT,JHALAWER

Kalisindh Thermal Power Project is located in Jhalawar.

The proposed capacity of coal based Thermal Power

Project is 1200 MW. The project site is about 12 km from

Jhalawar (Distt. Head quarter ) and NH-12. Site is

comprising of 5 villages viz. Nimoda, Undal, Motipura,

Singharia and Devri. It is 2km from state highway No.19

and 8 km from RamganjMandi - Bhopal broad gauge rail

line

The site was found techno-economical feasible for setting

up of a Power Project. The Govt. of Raj. included this

project in 11th five year plan. The estimated revised cost

of the project is

Rs.7723 Crores. M/s. TCE Bangalore was appointed

Technical Consultant for the project. The state irrigation

department has alloted 1200 mcft water for the project

from proposed Kalisindh dam. The origin of the Kalisindh

river is from northern slop of Vindhya Mountains. The

river enters from MP to Rajasthan near village Binda.

After flowing 145 km in

Rajasthan, the Kalisindh river merges in Chambal river

near Nanera village of Distt.Kota. Its catchment area is

about 7944

sq.km in Jhalawar & Kota Distt. The existing Dam is

located at Bhawarasa village, primarily for P.H.E.D.

purpose is being uplifted for providing a storage of

1200mcft water for this power project.

The GOR has allotted 842 bigha Government land and

acquired 1388 bigha private khatedari land for the

thermal project .Phase-1 will be constructed on 1400

bigha land only.EPC contract has been awarded to M/s.

BGR Energy System, Chennai on dt.09.07.2008. Total

project cost is Rs.7723 Crores (Revised).

Ministry of Coal, Govt. of India has allotted ‘Parsa East

and Kente Basan’ Coal Blocks to RVUN in Chhatisgarh

state. The

RVUN has formed a new company under joint venture

with M/s. Adani Enterprises for mining of coal blocks and

new

company started the work. Annual coal requirement for

the project is 56 Lacs TPA. Coal supply to Kalisindh Plant

has been started from ‘Parsa East and Kente Basan’ Coal

Blocks.

ProjectKalisindh Super Thermal Power

Project, Jhalawar

Capacity 1200 MW(2x600 MW)

Project Site

Village-Undel, Motipura, Nimoda,

Singharia & Deveri of Tehsil

Jhalarapatan, Distt. Jhalawar

Project Location

The project site is about 12 km

from NH-12, 2km from state

highway and 8 km from

RamganjMandi - Bhopal broad

gauge rail line.

Land Area2230 Bigha/564 Hq. (1400

bigha/350 Hq. in I stage)

Water source and

quantity

Dam on Kalisindh river. 3400 CuM/

Hrs.

Fuel Source

Main Fuel- Coal from captive coal

blocks (Paras east and kanta Basin

in Chhatisgarh state)

Secondary Fuel- FO/HSD.

Quantity of Fuel

(at 80% PLF)

Coal-56 Lacs TPA

FO/HSD-13000-14000 KL/A

Electro Static

Precipitator99.98 % Capacity

Stack Height 275 Mtr.

Estimated revised

CostRs.7723 Crores

Synchronization

Date

Unit-I August 2013 achieved

Unit-II November 2013

Unit#I

Unit was synchronized on designated fuel on 17th

September’2013. Full load achieved & commissioned

(capacity addition) on 02.05.2014 and subsequently 72

Hrs. trial run for

COD completed on dt.06.05.2014 and put for Commercial

Operation w.e.f. 07.05.2014.

The Rail Linking between serving station i.e. Jhalawar City

to KaTPP Plant is completed and cleared for 50 KMPH for

receiving of coal by rail.

Unit-1: Full load i.e. 600 MW achived on 02.05.2014; Commercial Operaton

The Erection, Testing & Commissioning of Water

Conductor System i.e. Construction of Intake Well,

Pumps, Laying of Pipeline from Kalisindh Intake Well

(situated at Kalisindh Dam Site) to KaTPP plant have been

completed.

ActivityActual Date

(Unit# 1)

Actual

(Unit# 2)

Anticipated

(Unit# 2)

Boiler Civil Works Start 24.01.09 23.03.09 -

Boiler Erection Start 23.10.09 26.03.10 -

Boiler Drum Lifting 19.05.10 14.08.10 -

Boiler Hyd. Test (non-Drainable)

08.04.11 15.12.11 -

Boiler Light Up 30.12.12 16.04.14 -

Steam Blowing Operation 26.03.13 - 15.07.14

Condenser Erection Start 27.11.10 25.08.11 -

TG Erection Start 20.12.10 25.08.11 -

TG Box Up (Final) 31.01.13 - 05.05.14

TG Oil Flushing 25.01.13 - 25.05.14

Turbine on Barring Gear 03.02.13 - 15.06.14

Synchronization (on Oil) 30.05.13 - 10.08.14

Coal Firing 17.09.13 - 15.09.14

COD 07.05.14 - 30.09.14

Important Milestones for Unit - 1/2 & common

system

Unit#II

The erection work of Boiler for this unit has been

completed and lighted up on dt.16.04.2014. The erection

work of Turbine, Generator and its auxiliaries is in

advanced stage. The Oil Flushing, Steam Blowing and

Turbine Barring Gear is scheduled to be completed by

15.07.2014. The Rolling and Synchronization of the unit

on designated fuel i.e. coal is by 15.09.2014.

INTRODUCTION OF KALISINDH THERMAL POWER PLANT

Kalisindh super thermal power project,rajasthan rajya

vidyut utpadan nigam ltd.(a gov. of rajasthan

undertaking) is situated on 2km away from the mega

Highway between jhalaraptan (Rajasthan) near village

Undal.It is 12km from jhalawar town (District Head

Quarter) And approx. 95 kms from KOTA(divisional Head

Quarter) Rajasthan.

The project is under construction for 1200 MW In it’s

stage -1 having 2 units each of 600MW (Sub cricital units)

and likely to be commence the construction work in the

year 2014

Kalisindh super thermal power project located near the

kalisindh river. Thermal powe station requires large

quantity of water for formation of steam tubes.It also

requires water for cooling tower and for cooling of

different accessories for generation of steam fuel (coal)

require it should be available form mines to power plant

through rail/ship/road transportation. The near by station

jhalawar city is only 8km from the power plant

transmission line the 400/200 kv GSS is near the power

plant.Huge land also available in the near area for ash

disposal. These all factors make favour for site selection

for power plant at jhalawar city at present Ka.T.P.P.

having 2 nos units for generation of 1200MW as under

Stage1 2*600MW Date of C.O.D. for unit

Stage2 2*660MW Proposed

The design of steam power station requires wide

experience as the subsequent operation and

maintainance are greatly affected by it’s design. The

most efficient design consist of properaly sized

component designed to operate safely and conveniently

along with it’s auxiliaries and installation

PROCESSES INVOLVED IN POWER

GENERATION

PRODUCTION STEAM:

Coals from the coal wagons are unloaded in the coal

handling plant. This coal is transporated up to the raw

coal bunkers with the help of belt coveyors. Coal is

pulverized in the bowl mill, where it’s grind to powder

from. The crushed coal is taken away to the furnace

through coal pipes with the help of not and coald air,

taken away to the furnace.Through coals mixture PA Fan

takes directlly.to the mill , A part of which is sent to air

pre-heaters for hating whill a part goes directly to the mil

for temperature control,atm air from F.D.Fan is heated in

air heaters and send to the furnace as combustion air .

The HFO as well as LDO also used for intial firing the

furnace and HFO also used in addition to coal as

supporting fuel to maintain the flame as and when

required Demineralized water (DM H2O )which is

prepared in the DM plant is used in the boiler.in the boiler

drum,initially water is taken through boiler fill pump and

subseuentlly to get adequate pressure boiler feed pump

(MD BFP/TD BFP) is used BFP takes the discharged DM

water from De-aerator BFP takes the supply of DM water

from at high pressure passes through economizer and

reaches the boiler drum passes through down comes and

goes and goes to bottom ring the drum header. Water

from the bottom ring header is divided to all the four

sides of the furnace H2O wall tubes water is heat and the

density difference the H2O rises up in the water wall

tubes .water partly converted in to steam as it rises up in

the furnace. The steam is separated from water mixture

is again taken to the boiler drum where the steam

separate from H2O water follow same path while the

steam is sent to various super heaters gets heated

through high temp. of boiler while passing and ultimately

reach final heater for achieving temp.of 540 C and

finally it goes to turbine.

Flue gases from the furnace are extracted by induced

draft fan which maintain balance draft in the furnace with

forced draft fan. These flue gases emits their heat energy

to various super heater and goes to electrostatic

precipitator where the ash particle are

extracted ,electrostatics precipitator ESP consists of

metal plates plants which are attracted on these plates so

that they do not pass through the chimney to pollute the

atm.regular mechanical hammers blows cause the

accumulation of ash to fall to the bottom of the

precipitator where they are collected in ahopper for

disposal. The electrostatics precipitator are of very high

efficiency 99.9% as such almost all ash partical are

removed from the ESP hoppers with the dense ash

handling system and conveyed it to RCC silos for further

system transportastion to the cement companies

STEM TO MECHANICAL POWER

As can be seen from fig 1and 2 from the boiler, a steam

to the turbine through control valves are located in a

steam chest of HIP turbine and governor driven from the

main turbine shaft operates the control valves to

regulate the amount of steam used. This depends upon

the speed of the turbine and the amount of electricity

required from the generator.

Steam from the control valve enter the high pressure

cylinder of the turbine.where it passed through aring of

stationary blades fixed to the cylinder wall. These act as

hozzle and direct the steam in to a second ring turnsthe

shaft as result turbine steam pressure. The stationary and

moving blades together constitute a stage of the turbine

and particle many stages, are necessary, so that the

cylinder contains a number of ring of stationary blades

with rings of moving blades arranged between them. The

steam passes through each stage in turn until it reaches

the end of the high pressure steam passes some of it’s

heat energy is changed into mechanical energy.the

steam leaving the high pressure cylinder goes back to the

boiler for reheating and return by further pipes (HRH

steam line ) to the intermediate pressure cylinder.here it

passes through another series stationary and moving

blades.

Finally the steam as taken to the low pressure cylinder, in

which it enter at the center flowing outwards in opposite

direction through the row of turbine blades to the

extremities of the cylinder as gives up it’s heat energy to

drive the turbine,it’s temp.and pressure fall and it expand

because of this expansion the blades are much large and

longer towards the low pressure end of the turbine.

When as much energy as possible has been extracted

from the steam it is exhausted dircitly to the

condenser.the condenser consists of a large vessel

containing about 1900 tubes ,each units having two

condensers cold water is circulated though these tubes

and as the steam from the turbine passes round them it

is rapidly condensed into water. Because water has a

much smaller comparative volume then steam, a vaccum

is created in the condenser. This allow the steam to

reduce down the pressure below that of the normal atm

and more energy can be utilized.

From the condenser,the condenser is pumped to the de-

aerator through low pressure heaters by the extraction

pumps,after which it’s pressure is raised to boiler.

Pressure by the boiler feed pump.it is passed through

further high pressure heater to economizer and the boiler

for re-conversion into steam.

Mechanical Power To Electrical Power

The turbine CHIP (LP=-1 & LP-2) shaft coupled with the generator shaft, turbine usually rotate as 3000 r.p.m (revolution per minute). This speed is determined by the frequency of the electrical system. Used in the country and is the speed at which a 2 phase generator must be driven to generator is having hydrogen cooling system. The generated electrical power transfer to generator transformer where it step up to 400kv for transmission to grid through 400kv/220kv.

Electrical Power Transmission

The electric power at KATPP will be generated 22kv and step up by CJT on 400kv subsequent transmit to 400kv switched situated in the plant. One number interconnecting transformer (400/220kv) is provided for interconnection bertwwn 400kv and 220kv transmission lines.

The control centre of the power solution is situated at the unit control room at EL175 mtr. In main power house building, where the engineers

monitor the output voltage switchgear and directing power to the grid system as required. Instruments on the control panel show the parameters and conditions which exists on all the light and maintain a miniature diagram indicates the precice state of the electrical system. One separate switchyard control room is situated switchyard in front of main powerhouse.

Water cooling

Water cooling is a method of heat removal from

components and industrial equipment. As opposed to air

cooling, water is used as the heat conductor. Water

cooling is commonly used for cooling automobile internal

combustion engines and large industrial facilities such

assteam electric power

plants, hydroelectric generators, petroleum

refineries and chemical plants. Other uses include cooling

the barrels ofmachine guns, cooling of lubricant oil

in pumps; for cooling purposes in heat exchangers;

cooling products from tanks or columns, and recently,

cooling of various major components inside high-

end personal computers. The main mechanism for water

cooling is convective heat transfer

Nomenclature:

Cooling water is the water removing heat from a machine

or system. Cooling water may be recycled through

a recirculating system or used in a single pass once-

through cooling (OTC) system. Recirculating systems may

be open if they rely upon cooling towers or cooling

ponds to remove heat or closed if heat removal is

accomplished with negligible evaporative loss of cooling

water. A heat exchanger or condenser may separate non-

contact cooling water from a fluid being

cooled, or contact cooling watermay directly impinge on

items like saw blades where phase difference allows easy

separation. Environmental regulations emphasize the

reduced concentrations of waste products in non-contact

cooling wate

Advantages:

Water is inexpensive and non-toxic. The advantages of

using water cooling over air cooling include water's

higher specific heat capacity, density, and thermal

conductivity. This allows water to transmit heat over

greater distances with much less volumetric flow and

reduced temperature difference.

For cooling CPU cores its primary advantage is that its

tremendously increased ability to transport heat away

from source to a secondary cooling surface allows for

large, more optimally designed radiators rather than

small, inefficient fins mounted directly on the heat

source.

The water jacket around an engine is also very effective

at deadening mechanical noises, which makes the engine

quieter. However, the primary disadvantage is that it

costs significantly more than an air-cooled engine system

Disadvantages:

Water accelerates corrosion of metal parts and is a

favorable medium for biological growth. Dissolved

minerals in natural water supplies are concentrated by

evaporation to leave deposits called scale. Cooling water

often requires addition of chemicals to

minimize corrosion and insulating deposits

of scale and biofouling. In water cooling systems for

electronic devices the use of deionized water is required,

which must be carefully controlled in order to avoid

contamination, which would cause a decrease in

resistance of the water and subsequently increase risk of

short circuits

TYPES OF COOLING SYSTEM:

Three types of cooling water system in use today

1. Once through system

2. Closed recirculating system

3. Open recirculating system

Once Through Cooling :

Once through is used where the water will not be

re-circulated.  Water is cooled down to fill a batch

or spray over a product.  Although most

applications require the water to be re-circulated

but in some cases the water is used to clean a

vegetable then discarded because you don't want

to re-circulated the dirty water on the clean

vegetables.  Typically food processers use once

through cooling.  Each system is different

processes range from 35F-70f water

DIGRAM OF ONCE THROUGH COOLLING:

o

CLOSED RECIRCULATING SYSTEM:

The closed recirculating cooling water system evolved

from methods used for the cooling of early engine

designs. In a closed system, water circulates in a closed

cycle and is subjected to alternate cooling and heating

without air contact. Heat, absorbed by the water in the

closed system, is normally transferred by a water-to-

water exchanger to the recirculating water of an open

recirculating system, from which the heat is lost to

atmosphere.

Closed recirculating cooling water systems are well suited

to the cooling of gas engines and compressors. Diesel

engines in stationary and locomotive service normally

use radiator systems similar to the familiar automobile

cooling system. Other closed recirculating cooling

applications include smelt spout cooling systems on Kraft

recovery boilers and lubricating oil and sample coolers in

power plants. Closed systems are also widely used in air

conditioning chilled water systems to transfer the

refrigerant cooling to air washers, in which the air is

chilled. In cold seasons, the same system can supply heat

to air washers. Closed water cooling systems also provide

a reliable method of industrial process temperature

control.

OPEN RECIRCULATING SYSTEM :

An open recirculating cooling system uses the same

water repeatedly to cool process equipment. Heat

absorbed from the process must be dissipated to allow

reuse of the water. Cooling towers, spray ponds, and

evaporative condensers are used for this purpose.

Open recirculating cooling systems save a tremendous

amount of fresh water compared to the alternative

method, once-through cooling. The quantity of water

discharged to waste is greatly reduced in the open

recirculating method, and chemical treatment is more

economical. However, open recirculating cooling systems

are inherently subject to more treatment-related

problems than once-through systems:

1.cooling by evaporation increases the dissolved solids

concentration in the water, raising corrosion and

deposition tendencies

2.T he relatively higher temperatures significantly

increase corrosion potential.

3. the longer retention time and warmer water in an open

recirculating system increase the tendency for biological

growth.

4. airborne gases such as sulfur dioxide, ammonia or

hydrogen sulfide can be absorbed from the air, causing

higher corrosion rates.

5.M icroorganisms, nutrients, and potential foulants can

also be absorbed into the water across the tower.

WATER LOSSES IN RECIRCULATION:

1.Evaporating loss

2.Windage loss

3.Bleed off

EVAPORATING LOSS:

E is approx. 1% of the water circulated per 10 F drop

temperature.

When H2O evaporates off it leaves behind all the salts

hence increses total solid concentration.

WINDAGE LOSS(W):

Small droplets of H2O carried away by wind since it

carried salts along with it windage loss actually have

dilution effect in salt concentration of cooling water.

BLEED OFF:

Bleed off (B) necessary to control maximum solid in

cooling water . Bleed off gives dilution effect.

Cycles of concentration:

Cycles of concentration represents the accumulation of

dissolved minerals in the recirculating cooling water.

Discharge of draw-off (or blowdown) is used principally to

control the buildup of these minerals.

The chemistry of the make-up water, including the

amount of dissolved minerals, can vary widely. Make-up

waters low in dissolved minerals such as those from

surface water supplies (lakes, rivers etc.) tend to be

aggressive to metals (corrosive). Make-up waters

from ground water supplies (such as wells) are usually

higher in minerals, and tend to bescaling (deposit minerals). Increasing the amount of minerals present in

the water by cycling can make water less aggressive to piping; however, excessive levels of minerals can cause

scaling problems.

As the cycles of concentration increase, the water may

not be able to hold the minerals in solution. When

the solubility of these minerals have been exceeded they

can precipitate out as mineral solids and cause fouling

and heat exchange problems in the cooling tower or

theheat exchangers. The temperatures of the

recirculating water, piping and heat exchange surfaces

determine if and where minerals will precipitate from the

recirculating water. Often a professional water

treatment consultant will evaluate the make-up water

and the operating conditions of the cooling tower and

recommend an appropriate range for the cycles of

concentration. The use of water treatment chemicals,

pretreatment such as water softening, pH adjustment,

and other techniques can affect the acceptable range of

cycles of concentration.

Concentration cycles in the majority of cooling towers

usually range from 3 to 7. In the United States, many

water supplies use well water which has significant levels

of dissolved solids. On the other hand, one of the largest

water supplies, for New York City, has a surface rainwater

source quite low in minerals; thus cooling towers in that

city are often allowed to concentrate to 7 or more cycles

of concentration.

Since higher cycles of concentration represent less make-up water, water conservation efforts may focus on increasing cycles of concentration

. Highly treated recycled water may be an effective

means of reducing cooling tower consumption of potable

water, in regions where potable water is scarce.

WATER:

The purest available from water vapour in

atmosphere as rain ,show or produced by

melting or ice.

This H2O reaching ground different type of

gases from atmosphere like N2, and lesser

extent carbon dioxide.

Apart this H2o travels to various place and

catches various organic matter suspended

solid (macro size sand, rite, slit etc.).

Colloidal micro size particles (0-100nm).

Dissolved forms alkaline salts, neutral salts

and organic matter

Alkaline salts are mainly bicarbonates rarely

carbonates and hydrates of Ca, Mg and Na

Neutral salts are sulphate chlorides, Nitrates

of Ca, Mg and Na.

WATER CONDITIONING IN THERMAL POWER PLANTS FOR PROCESS AND BOILER USEVarious water qualities inside thermal power

plant

Cooling Water( BCW, ACW)

Boiler water

Consumptive water

H2O TREATMENT:

Pre-treatment of raw H2O

Filter H2O for softening and DM Plant

DM H2O for Boiler

H2O TREATMENT WHY ?:

To avoid formation

To avoid corrosion

To control microbiological growth

The purpose of H2O treatment programme is to provide real exchanger surface that are sufficiently intact and free of deposits, so that designed specification are met at KSTPS. Suspended and soluble H2O impurities are removed with the help of PAC( Poly Aluminium Chloride) while treatment of organic impurities are removed with the help of raw H2O and circulating cooling H2O is being carried out with the help of liquid chlorine

CLARIFICATION:

Remove all types of solid and large particle

sediments oil, natural organic matter, color

etc.

Consist of four steps:

Coagulation-Flocculation

Screening

Sedimentation

Filtration

Medium screening ( Spacing 10 – 40 mm)

Coarse screening ( Spacing > 40 mm)

Coagulation – Flocculation removes

suspended solids and colloidal particles

Screening protect downstream units form,

easily separable objects

ION EXCHANGE:

Resins-acidic/basic radicals with ions fixed on

them, exchanged with ions present in H2O.

Theoretically removes 100% of salts,

organics, viruses or bacteria.

2 types of resins-

o Gel type (micro porous) micro porous or

loosely cross-linked type

3 system of resign beds:

Strong acid cation + strong base anion.

Strong acid cation + weak base anion + strong base

anion.

Mixed bed Deionization.

Ion exchange plant softens, removes heavy metals, and

produces demineralised H2O.

Various cooling water system:WA

Once through cooling water system.

Open recirculation cooling system.

Closed cycle cooling H2O system.

D.M.PLANT:

Dissolved solids present in water is removed in DM Plant

by ION exchange process and for this ION exchange

Resins are used.

I ON EXCHANGE RESINS:

ION Exchange Resins are synthetic organic

polymers. Most commonly used resins are gel type

polyserine resins.

Acrylic-resins/macroporous/microporous resins are now

available in market.

CATION EXCHANGE RESINS:

Cation Exchange Resins are nothing but acid and can

be simply represented us:

R-H+, where R is resin matrix, completely insoluble

in water and only H+ is mobile in water.

Cation resins are of two type. Strong Acids Cation

Exchange Resins (SAC) and Weak Acid Cation Exchange

Resins (WAC).

SAC:

When the functional group attached to resins matrix is

strong acid group. It is called Sac resins.

SAC can split all the salts and its performances is

not influenced by pH of water. Operational exchange

capacity and regeneration efficiency of SAC is less than

WAC.

WAC:

When the attached functional group is of weak acid is

called WAC resin.

WAC can only split weak electrolyte (Carbonate

and Bicarbonate).

It performs better with high pH water and with lower pH

water its performance decreases and when pH falls below

4 actually regeneration take place.

ANION EXCHANGE RESINS:

Anion resins can be simply represented by R+ and OH-

and is nothing but an alkali / base. OH- is only mobile in

water.

Anion Exchange resins are two types. Strong

base anion resins (SBA) and Weak base anion resins

(WBA).

SBA:

When the functional group is strong base it is called SBA

resins. SBA performance is not influenced by water pH

and it can exchange with both strong and weak acids.

WBA:

When the functional group attached with a weak base it

is called WBA resins. WBA performs better at low pH and

increased pH decreased its performance. When pH is

more then 11 actually regeneration takes place.

Operational capacity and regeneration efficiency of

WBA is higher than SBA. WBA can only react with strong

acids.

PRINCIPLE OF DEIONISATION :

All impurities expect dissolved solids are removed in

pre-treatment plant.

Only dissolved solids are removed in D.M. Plant.

Dissolved solids in water dissociates into ions(as

water is polar solvent and it is dissolved in electro-valent

compound.

Positive charged ions are called cations and Negative

charged ions are termed as anions.

In normal river water most common salts presented

are calcium, magnesium and sodium salts, associated

with corresponding equivalent ions like Cl-, SO4- etc.

If above water passes through a cation exchanger all

cations are exchanged with H+ of cation exchanger

resins.

Similarly all cations are exchanged and retained by

resins and ultimate product will be corresponding acids.

pH drops around 3.5 and it becomes soft.

The above water when passed through a anion

exchanger, all anions exchanged with OH- of SBA resins

and equivalent of water is produced.

Similarly all acids are convertible to H2O. It appears

that by passing water containing salts through a cation

and anion exchange resins all isolable salts can be

removed.

However actual process is a little bit different.

SELECTIVITY OF IONS:

Resins has a preference for exchange and it depends

on charge and size. Triple charge is preferred to double

and double is preferred

to single charge. Charge being same preference is given

bigger size ions.

SODIUM SLIP:

When water containing Ca, Mg, Na ions is passed

through cation exchanger bed, Ca ions are retained in 1st

layer then Mg ions and in the last layer Na retained.

Ions exchange are reversible( for regeneration and

reuse).

The reaction in the bottom part of the bed is with sodium

salt (say NaCl).

Now even at very low concentration of R-Na some back

reaction produces NaCl.

Thus effluent coming out from ion exchanger is not 100%

acid but contain a little amount of sodium salt. This called

sodium slip. Increased bed depth reduces this amount of

slip but can never be nil. Further it is not techno

economically feasible to increase bed depth indefinitely.

Hence some amount of sodium slip is accepted in design.

The cation effluent containing some amount of sodium

when passes through ion exchanger, acids are converted

to water to NaOH.

So the effluent coming out of anion bed contain NaOH

that increases the pH and conductivity of the anion

effluent.

Further similar to Na slip, silica slip takes place from ion

exchanger.

Thus water coming out through cation and anion

exchanger has high pH/ conductivity and silica and is not

as per requirement of H.P. units.

MIXED BED UNITS :

After passing water through cation then anion exchanger

it passed through mixed bed unit. In mixed bed cation

and anion resins are mixed and while water passes

through thousands of cation / anion exchanger ‘resulting

final effluent of very good quality. So, minimum

requirement is, SAC→SBA →MB. Further H2SO3 produces

in SAC can be easily removed at low running cost in

Degassifer. Thus simplest DM Plant for High pressure unit

is:

SAC → Degasser → SBA → MB

D.M.PLANT:

From filter water chlorine is removed before allowing

to enter ion exchanger. It can be done by:

(a) Passing through a activated carbon filter

which absorbs chlorine.

(b) Dosing calculated amount of sodium sulphate

which reduces chlorine to chlorine ion.

(c) Depending upon the amount of water to be

treated and quality of filter water, Different types of

demineralisation schemes are made:

(1) Cation Unit-Degasser-Anion Unit- M.B. Unit

SAC SAB

This is the simplest arrangement. Capital cost less

and running cost more.

(2) Cation Unit – WAB – Degsasser- SAB – MB -

SAC