Aitazaz04InternshipReport

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DG-CementInternship ReportSubmitted By Aitazaz Ahsan 10-ME-04

Aitazaz AHSAN 10-ME-04 8/20/13 DG-Cement


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AITAZAZ AHSAN 10-ME-04 1

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In the name of Allah, the most merciful,

The most beneficent


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To my beloved parents and honorable teacher

Engineer Yar Muhammad Khan.


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First of all, we are very thankful to the almighty ALLAH, the most

Beneficent and the most Merciful for his blessing to all of us.

We would like to convey our sincere gratitude to our internship advisor

Engineer Yar Muhammad Khan, who believed in me and for his kind interest

and guidance without which this endeavor would not have been materialized.

Special thanks to him for his encouragement and support.

I would like to thank all those who directly or indirectly helped me in making

this report fruitful.


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Abstract

This Report is concerned with DG-Cement manufacturing and all

the processes involved starting from raw material to the packing of

final product. It mainly describes all the mechanical components

present in DG-Cement Plant. The plant was established in 2007 at

Khairpur near Kallar Kahar and it is producing 7000tons cement

per day. It is equipped with all latest equipment required for the

production of cement and has the major role in exporting ordinary

Portland cement from Pakistan which has maximum setting strength

of about 10000Psi. The report cover all the areas which are

important from study point of view. Hope everyone will find it as a

best material to study.


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Safety Section

It is the first portion of internship in which we have learned about safety

precautions in DG-Cement. In Khairpur plant all equipment of firefighting isavailable at every place and every person is equipped with safety helmets and

jackets. Internee are also provided with security helmet to prevent any

damage. Fire alarms are attached and one main security alarm which indicates

any emergency. In case of major emergency when the alarm rings, all the

workers are advised to come out of plant and stop working till that security

team covers the danger. There is a red line spread all around the plant which

also covers tunnel area so that in case of any damage workers can even pull a

single wire and emergency can be felt. AFF is added in 3% with water which

produces foam and used in firefighting. The company has firefighting Vanwhich is of about 10Million cost. Very costly equipment is present and all the

environment is safe and sound. There is no such danger while working at DG.

Pipes are present which sprays the water on fire during working in form of

mist and thus prevent the fire fighter also they have different kind of nozzles

which exhaust water at 7Bar pressure and covers an area of 100ft. Security

buzzers are present and also they are connected through cello phones with

each other. Main firefighting or danger area is of Kiln because in this region

the temp is almost around 1600C so there is a chance of fire spreading. After

visiting the plant we can say that it has best equipment of safety and has full

security of workers working over there.


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Image showing Fire Fighting Van and All Fire Fighting Equipment.


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INTRODUCTION

General Introduction about DG-Ordinary Portland cement Manufacturing

Cement is a mixture of argillaceous and calcareous minerals and has the majorportion ofCalcium Carbonate (60-80%) and Silica (20-30%) and has the

additives Aluminum Oxide (0-10%) and Fe2O3 (0-10%).

Additives are added to perform reactions at low temperature of 1600C

otherwise 2000C temp is required to perform Kiln reactions and to

decompose Calcium Carbonate into CaO and CO2. By mixing all of the above

reactants the product formed is called clinkers which has ball like shape and

they are stored in clinker silo. They are then mixed with gypsum in proper

portion as additive (5%) to increase setting time of cement and are grinded intwo cement mills having capacity of producing 175tons cement per hour.

They are then stored in cement Silo having 22000tons capacity each (total 3).

After that they are transferred to packing plant for packing of cement into

bags. All automation is present in packing plant. Plant has designed with a

capacity of 7000Tons/day. When we talk about power supply, the plant has

33MW power units and they also have supply through wapda. The plant is

under Nishat Group of industries and a paper manufacturing shop is also

present. It has complete safe and healthy environment which has complete

control of dust. Also coal manufacturing from RDF is present. Canteen is alsopresent and it is equipped with laboratory and clinic facility also it has CCR

and other main units for meetings like admin block. All the workers are well

corporation especially Safdar Kamal& Yar Muhammad Khan sb.


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Beautiful Entrance View of Plant

First Bag Produced By DG-Cement


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Top View of Complete Plant

Canteen of DG-Cement


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The production Starts from Quarry.

Quarry Section & Crusher Section

Quarry is the place from where raw material in extracted. Drilling and blasting

is done to extract the material. A hole of about 10-15 m is drilled and

ammonium nitrate in filled as an explosive in these holes. When this explosive

is ignited the rocks are broken into pieces of different sizes. These pieces are

then loaded on the dumper trucks and conveyed to the crusher. It is located

about 3-4 Km from the plant. Drilling takes place firstly and then blasting of

calcium carbonate take place which is then feed to apron feeder and move

towards crusher. Two main crushers are present which are CaCO3 crusher

(1500-1700tons/hour and additive crusher. Both have same mechanism but

numb of hammers and their weights are different. CaCO3 Crusher is of bigger

size and comparatively hard to crush lime stone into small pieces of almost 1-

2inch.

Quarry and raw materials:

The following raw material is required in the production

process:

1. Lime stone: This raw material is company owned and is

extracted from the nearby quarry Unit. Limestone has the

highest composition in the cement product. 76% of the cement

constitutes of limestone.

2. Clay: Clay is another natural resource. This raw material is

also company owned. 24% of cement composition comprises

of clay.

3. Iron Ore, Bauxites and silica sand: Iron Ore is theonly resource that is bought from contractors. Iron Ore, Bauxites and silica

sand are added in small quantities less than one percent and it helps to

strengthen the cement.


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4. Gypsum: Gypsum acts as a retarding agent. It slows down

the hardening process which in turn gives the constructor

enough time to use it.

Limestone Crusher: (EV 200*300):

Capacity: 1500 tons/hr.

Supplier: FLSmidth

Raw material such as limestone, clay, marl and shale are dumped into hoppers

by dump trucks and entered into a hammer crusher through an apron feeder.

Inside hammer crusher there are 48 Hammers attached to four main rotor

shafts each having 12 hammers each and each having weight of 100Kg

approx. They rotate at a

speed of 1200-1300 rpm

and is capable of crushing

feed of very large sizes.

Input is through hopper

and then apron feeder

takes the lime stone

pieces to main crusher

where a rotating disk and

steel chains are present to

prevent backward

movement of broken

pieces. Lamella plates are

used for movement of raw

stones of crusher. Magnet

separator is attached to

conveyor belt to prevent metallic particles from reaching the raw mill. Whenwe talk about additive crusher it has only one shaft having 12 hammers,

smaller in size and attached to a single shaft. They are then transferred to main

storage section and then move towards raw mill through belts.


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Storage Yard:

The crushed material is stored in the form of piles in the storage yard. There

are 6 piles in the storage yard. Mixed piles are used in larger quantity where

as high grade and additive piles are used

in small quantity.

e & clay)

Stacker:

A stacker is a device which form

conical piles of the crushed material.

Feed is conveyed to the stacker through

conveyor belts. This stacker then moves

to and fro to make a pile. The stacker belt

is called Jib in engineering terms.

Now, for conveying this material from

piles to the conveyor following

equipment are used :

Side scrapper:

Side scrapper is a device which picks the crushed feed from the piles through

its feedbelt called Hoist. This belt has a number of small buckets of lowcapacity. When this belt moves, the buckets picks feed from the pile and put

it on the belt conveyor. Side scrapper in used for those piles which are required

in low quantity like bauxite and iron ore.


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Raw Mill Section

Raw mill Feed area

The raw mill feed area consists of 4

feed hoppers:

The capacity of first two hoppers is 800 tons while the other two hoppers have

a capacity of 600 tons. The feed from each pile is conveyed to the hoppers

through conveyor belts in relevant hoppers. Each hopper has 4 load cells. This

section is one of most important section of plant where the crushed material

in form of piles is transferred to bins through belts and then to Raw Mill

through rotary feeder (28rpm) which permits only raw material to fall inside

the raw mill and air is not allowed to fall.


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Main specification of Raw Mill

ATOX Raw Mill

Grinding Capacity 500Tons/Hour. Vertical Roller mill with three rollers.

Sections of Raw Mill

There are 3 sections of a raw mill.

Table:The raw feed from the belt

conveyor directly falls on

the rotating t able of the raw

mill. The table contains 3

crushing rollers. The raw fed

is crushed to fine powder

with these rollers. The

coarse particles are collected

at the bottom of raw mill and

are sent to the vibrator from

where they are sent to theraw feed belt conveyor and again recycled to the ram mill for re

crushing. The vibrator is use to handle the quantity of the material

being put on the belt.


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Separator:

At the top of the raw mill, there is separator section. Hot gases from

the kiln comes from the bottom of the raw mill and lift very fineparticles with it. A suction fan

with motor power of 4500 kw

produces suction and sends dusty

air into the cyclones at the top.

Here the dusty air rotates and

particles are separated from the

air. These particles are collected at

the bottom of the cyclone and sent

to the CF silo with the help of air

slides. The air which still contains

dust particles are separated in

Conditioning tower and Electrostatic precipitator.

Two input ducts are coming inside the raw mill which provide hot

air having temp 108C almost and there in single outlet duct which

takes material and exhaust air in form of cyclones. Id fan is attached

which is used for rapid movement of air b/w inlet and outlet ducts.

Material transfer in form of cyclones prevents the raw material from

reaching Id fan. This material is then transferred to silos four in

numb and the dusty air is transferred to conditioning tower where

foggy drops are sprayed from 30 nozzles each having 3mm dia to

decrease dusty air temp to a lower limit (80-100C) before it reaches

EP (Electrostatic Precipitators) In this section cooled dusty air ispassed between electrical plates where ionization of dust take place,

they are ionized into positive and negative plates and then stick to

respective plates. After this process hammering or shock is produced

in plates which removes dust from plates and this dust is then


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transferred through bucket elevators to the CF-silo. The same

process occurs with grinded material, they are conveyed through

duct to bucket elevators and then transferred to CF-Silo through

bucket elevators. Air from EP and exhaust air from raw mill isexhausted to the atmosphere using chimneys so that fresh air cycle

can be started again.

CF-Silo is main storage of crushed material.


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Raw Mill Closed View


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ID Fan Attached

with Raw Mill

Conditioning

Tower Bins, and

air inlet and outlet

flow through raw

mill.

Side View of Electrostatic Precipitator.


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A Complete Side view showing EP, Conditioning Tower & Preheater

Image Showing CF-Silo and Raw Mill Area


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Coal Mill is also present nearby which produces RDF and then convert

this coal into powder form before feeding it into Kiln. Coal mill has

following specifications

Coal mill grinds coal in

powder form and then feed

to pre heater which is the

next section of plant before

Kiln.

Image below is

representing main coal

storage and feed section


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KILN-ZONE

(a)Pre-Heater Section:

It is the main section before Kiln

where calciner is present, in this

section pre burning of (fuel+RDF)

takes place. Here the temp of

grinded mixtures reaches up to

850C. In this section there are

five diff zones of temp starting

from 150 and moving downtowards 850 in the final zone of

pre heater. Coal is burned in the

bottom of calciner while hot air is

sucked upward through fan and

different reactions take place as

the material falls down. Image is

shown and we can see that raw

material is feed to pre heater

through bucket elevator and the

zone is placed before

kiln.


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(b)KILN Section (Heart of Plant):In this section hot material from pre heater having temp 850C approx. is

feed to main Kiln. It is two support Kiln and is a friction drive having two

main driving wheels placed on four rollers, during combustion it keeps on

rotating to prevent any damage and a 500KV motor is driving the gear unit

of Kiln which consist of planetary and helical gears. Half sleeve bearing is

used to support Kiln shaft. Kiln has following main zones of temperature

(i) Calcining Zone(800-1200)(ii) Burning Zone(1200-1600)(iii) Cooling Zone(1600-800)

Kiln has revolution (0.2-4) according to requirement and has weight of800Tons. Kiln is made up of structured steel lined inside with refractory

material to sustain max temp.

Above pic explaining all data regarding Kiln. Kiln is not straight but

has 3.5% slope which is almost 2 for flow of paste material. When


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raw material goes to Kiln hood where remaining 40% fuel burning

take place. On the other end of the kiln, there is huge burner having

a supply of coal, furnace oil and air. The burner emits a flame which

is prolonged with high pressure air. The flame burn the material and

the product is formed and the material is converted into paste like

form. Cooling fans are attached with Kiln to decrease the surface

temp at required level as shown above. From Kiln Hood material is

transferred to Fuller or Clinker Cooler section.


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ABOVE PIC SHOWING KILN HOOD

CLINKER COOLER

The clinker cooler is used to lower the clinker temperature. There

are 10 ID fans five on each side which take fresh air from theatmosphere and send it to the cooler. At the bottom of the cooler

there are reciprocating rails which move with the help of hydraulic

motors. These rails convey the clinker forward to the clinker

crusher. In the end of cooler steel chains are present which prevent

the material from coming back after striking the crusher because


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there is a chance of refractory material due to strike of large particles

total 4 sections and coolers is purely hydraulic drive 75mm each

plate can move to and fro. They are easy to assemble and operation

is quiet safe and time saving. In clinker crusher section there aretotal 69 Hammers, 23 hammers per shaft of the rotor and having

weight of 60Kg each. After cooler section the material moves

towards main Clinker Silo having 110,000Tons capacity. The

crushed clinker is dropped on the deep pan conveyor at the bottom

of the conveyor which conveys it to the clinker storage. The clinker

from the deep pan conveyor is stored in the clinker storage. Its

capacity is 110,000 tons. Its length is 60 m and its width is 46 m.There are 3 gates at the bottom of the clinker storage from where the

clinker is sent to cement mill through belt conveyor. Besides the

main clinker storage bin, there is a temporary clinker storage hopper

with a capacity of 1400 tons. If the temporary hopper is also full


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then the clinker is removed from the hopper and dumped into clinker

storage yard.

Cement mill feed area:

There are 2 cement mills and 6 hoppers (3 for each mill) in the

cement mill feed area. The 1st hopper contains the clinker which is

major constituent of the cement. The cement contains 95 % clinker

which is conveyed through weigh feeder to the main belt conveyor

which takes it to the cement mill.

Gypsum addition:

The crushed gypsum from a separate crusher is conveyed by belt

conveyor to the cement mill. It is mixed in the clinker while


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crushing. Gypsum is added to about 45 %. Its purpose is to increase

the settling time of the cement.

Mixing of additive:

The additive which is pure limestone is also added in the cement

mill. Its added to about 2 %. Its function is to increase strength of

cement.

Metal Detector:

To protect the cement mills from damage, a metal detector is

installed which analyzes the feed and if a metal object is found itopens the dividend gate automatically and sends the feed containing

metal objects to the rejected bin, which is again recycled to the main

belt and magnetic separate removes it.


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CEMENT MILLS AREA

Cement mills specifications OK 36-4:

The feed which is free from impurities falls on

the table of cement mill which contains three

rollers. Each roller has weight of 35 tons and

the clearance between table

and rollers is 0.5 mm. These

rollers move hydraulically

using nitrogen gas as

hydraulic fluid. The rollers

crush the feed to a very fine

powder. The air slides

conveys the ground product to

the bucket elevator which liftsit to enter into the 1st storage

silo and so on.


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Separator present Inside Cement Mill.

Storage Silos:

Specifications of storage

Silos:: 22,000 tons

: 45 m

: 22.4 m

There are 3 cement storage

silos in which crushed

cement is stored up tillpacking. To convey the

cement to the other 2 silos

air slides are used. From

these silos the cement enters

air slides by air circulations

through blowers. Now these

air slides take the cement to

the packing plant.


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Schematic view of silo: The old

cement was blocking the air slides

as well as bridging preventing the

flow of cement from the silo.

Sockets installed above discharge

gates and lower air slides proved

the ideal solution to blocking of

silo and can be used whenever

there is build-ups.

Packing Plant:

The packing plant comprises of 6 packers and 12 terminals. Each

packer has a capacity of 100 tons/hr. Each Packer has 8 nozzles and

shooting of bag on these nozzles is done by shooters which are latest

techniques applied over there. Also manual installing of bags on

packing is done through workers. Alarm is attached with each

packing unit so that it can be turned on whenever there may be ademand of cement. From slide bars the cement falls to hopper

through screen to remove any impurities. There is a weight sensor

attached with each packing unit which dispose of any bag having

weight more than 50.5Kg or less than 49.5Kg. A blower is present

which removes dust present on cement bags. Nylon and paper bags


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are used according to requirement and they have valves made up on

the top side for automatic sealing.

The cement bags are attached manually to the rotating packer whichfills the cement bag. When the bag is filled up to the required weight,

it automatically falls on the conveyor belt which takes the bags to

the roller conveyor. From these rollers the bags slide to different

channels and finally cement bags are loaded on the trucks for

dispatch.


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DISPATCHING SECTION


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Some Important Installations In DG-Cement Plant For Dust Control:

Bag Filter :The dust produced by crushing process can cause damageto the equipment and may produce dust, to overcome this problem a bag

filter is employed. A fan blows air and all the dust goes to the bag filter. Inside

the bag filter a special type of canvas cloth is used. When air passes through

this filter cloth, the dust particles stick to the cloth and clean air passes

through. The dust particles are then collected and sent to the conveyor. After

sometime when the filter is choked with particles, Purging system is used

in which high pressure air is used, this air removes all particles from the

filter cloth.

Electrostatic precipitator :

The clean air from the conditioning tower still contains some particles which

have to be removed. These particles are separated from air by passing it

through the


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In Electrostatic precipitator there are 2 corona wires which are mesh like.

These wires are negatively charged. There is a positively charged electrode inthe center which is equidistant from both corona wires. Dusty air passes

through these corona wires and the particles get negatively charged. The

negatively charged particles in air are then attracted by the positively charged

electrode and the particles stick with it and clean air is exhausted from the

chimney. In order to remove particles from the electrode. A Wrapping

device is used. This device hits the electrode as a hammer and particles fall

down from it. These particles are collected and conveyed to the CF silo via

screw conveyor.


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References:

www.sick.com/.../cement/Pages/cement.aspx

www.siamrefractory.com/cement_cyclone.php

www.freepatentsonline.com

www.DGcement.com

Report Prepared By:

Aitazaz Ahsan 10-ME-04

Mechanical Engineering Department UET Taxila.

DG-Cement Internship 2013 Phase-III

Contact 03035500424
http://www.freepatentsonline.com/http://www.dgcement.com/http://www.dgcement.com/http://www.freepatentsonline.com/

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