Cement Plant Construction

Indian Institute Of Technology Delhi

Submitted by:Shyam Anandjiwala

(2014CEC2720)

Case study

Project:3750 TPD(Tonnes per Day) Pyro Project

Loctaion:Dabok(nearUdaipur),Rajasthan

Client: J.K.Lakshmi Cements Ltd.Civil Consultant:M/S Magcons

Consulting Engineers Pvt Ltd,MumbaiCivil Contractor:M/S K.B.Mehta

Construction Pvt Ltd,AhmedabadEquipment Supplier:M/S LNVT

Sinoma,China

Project Overview

• Dabok Cement Factory used to be a part of Udaipur Cement Works Limited(UCWL) some years back.This cement factory got down and was sold to J.K.Lakshmi Cement Company Limited.

• J.K. Lakshmi currently has the facility of grinding the clinker and a packing plant but cement production is not done here.

• J.K.Lakshmi decided for starting the production of cement at the current location.

Existing Coal mill Existing Packing Plant

Components of A Cement Plant

• Quarry• CS Silo/Blending Silo• Preheater• Kiln• Cooling Tower• Clinker Silo• Grounding Mill• Packing Plant

Current Status of Project

• The construction of the Blending Silo(85 m) is completed from outside.Preparation for the staging for the construction of the cone inside the blending silo is going on.

• The first two floors of the preheater are completed.Beam level of the 3rd floor(46 m) is almost reached.

• Foundation of the preheater boiler is going on.• Piers for the installation of the kiln are aready

constructed.

• Foundation work of the cooling tower is almost over.The tunnel for the transport of clinker from the cooling tower to the clinker silo is under construction.

• Construction of the clinker silo has reached almost upto the completion of the second floor.

Site Soil Conditions• The site is situated in Udaipur,Rajasthan which has got hard,rocky soil

conditions.• All the foundations are Raft foundations.

Foundation of Preheater Shaft Cooling Tower Foundation Slab

Quarry• The cement production plant

should be located where the raw material for the production is available nearby.

• The dark coloured rock in the picture contains limestone and two kinds of shale, all of which are used in producing cement. The light coloured material is called over-burden, which is not used in manufacturing, but is set aside to be replaced later during reclamation after the quarry has reached the end of its permit period and is closed.

• The flat area in the quarry wall, called the lift or bench, is the depth to which holes are drilled before charges are set for blasting. Because of security requirements, most quarries subcontract the blasting operations.

• After blasting, the waste stone is brought to the end of the quarry where quarrying first began. It will be the first material to be filled back in as part of the reclamation process. Usable stone is hauled by truck and either dumped into the primary crusher or piled nearby.

• The roads and piles must be kept watered to reduce airborne dust.

•After the stone is dumped into the feed chute from above, gravity moves it down through the crusher, which reduces it to about 3 inches in diameter. A bag filter helps reduce airborne dust.•From the crusher, the stone moves onto a conveyor belt that carries it to the manufacturing plant about 6 kms away in our case.•Long conveyor belts must be kept adjusted to the proper tension. This is done by using steel cables to suspend concrete weights inside the towers.•At each point where the conveyor changes height or direction, another bag filter helps to remove dust from the crushed stone and from the air.•The limestone and shale are finally stockpiled at the far end of the production line.

SAFETY PRECUATIONS UNDERTAKEN IN MINING AREA

• Only the authorized employees are permitted to handle the explosives.• There are demarcations around the blast location like barricades, flag

signs etc.• The blast holes are being loaded under the control and supervision of

the designated competent person.• The controlled blasting technique is being adopted.• Cellular phones are not allowed in the blasting zone.• The explosive vans speed should not exceed 25km/hr.• Warning signals are given within a radius of 500 meters from the place

of firing.• After the blasting a siren is blown as signal if it is all clear and safe.• As the blasting is very dangerous for the eye at some distance also,

safety glasses should be provided and used at the blasting site.

CS Silo/Blending Silo

• The stone is loaded with a front-end loader one bucketful at a time onto a conveyor that carries it into the blending silo.

• Limestone and shale is blended inside the blending silo.

• Blending silo consists a concrete/steel cone inside.

CS Silo/Blending Silo

• Blending silos are gravity blenders. Another prevailing term is homogenising silos instead of blending silos.

• Often the creation of horizontal layers with differing quality can be observed when silos are in batch production.

• Depending on the product characteristics and flow properties, different blenders are used in order to achieve a higher grade of homogeneity.

Types of Blending Silos1. Blending silo with pipe blender• The pipes, arranged on the outer wall of the blending silo, have different nominal

diameters. Because of the specially constructed product inlets, the product is pre-mixed both when it flows in and out of the mixing pipe.

• The different pipe diameters and lengths create a varying speed and flow profile in the pipes. This results in further product homogenisation.

2. Blending silo with central pipe blender• The product is concentrically drawn from various levels and fed into the mixing chamber

via a central pipe located in the middle of the silo. • Due to the specially constructed material intake zones, the product is already pre-mixed

when it flows in from the various zones. • The resulting crosswise mixing of the product has a significant and therefore reinforcing

effect on the efficiency of blending.• Furthermore, the product is guided concentrically to the blending pipe. This prevents

the development of asymmetrical flow zones to the greatest extent possible.

Types of Blending Silos(contd.)3. Blending silo with cone blender• A blender fitting integrated in the silo cone serves to distribute the product evenly. The product is mixed

via various flow zones and is guided to the outlet of the blending silo. • Due to the conical shape of the blender, the product flows from top to bottom with increasing speed.

Due to the different flow speeds, there are varying residence times for the product. This increases the blending effect.

• The blender is suitable both for the continuous and discontinuous blending of bulk goods. Thus existing silos can be retrofitted quickly and easily.

4. Blending silo with screw mixer• The intensive mixing takes place in the lower silo part. The product is continuously collected from the

cone by a central vertical mixing screw and conveyed upwards through the mixing pipe to the roof of the silo.

• The blended material is picked up by an ejector which distributes it in fine layers over the container's entire width.

• The silo can be filled or discharged at any time irrespective of the blending process. • The mixing screw is powered by a gear motor which is located in the middle of the silo roof.

General Layout of CS Silo

Construction of Blending Silo

• PCC of raft • RCC of raft • Starter of the shell • Erection of slip form assembly • Slipping (75 mtr) • Thickness reduction of shell • Dismantling of slip form system • Backfilling outside and inside plinth • PCC & RCC of floor slab• Staging of inverted cone

• Shuttering and reinforcement of inverted cone

• Concreting of inverted cone• Dismantling of staging• Erection of roof girder 80 mtr

level• Erection of rolladeck • Tying of reinforcement• Shuttering of roof slab• Casting of roof slab

STAGING FOR THE CONE INSIDE THE BLENDING SILO:

1. Welding of iron brackets to the inner wall of the silo

Triangular iron brackets

2. Erection of purlins and support

Purlins

Winch MachineGirder attached to winch machine by pulley system

3. Erection of girder on the bracketsGirder carried to the silo with the help of crane

4. Finished platform for the construction of cone

Embedded plates on the surface of the silo

Embedded Plate(EP)

Openings in the silo

Openings

Construction of Preheater• PCC of raft • Casting of raft including tying of

reinforcement bars• Shuttering etc. Complete• Casting of ‘l' column till + 6 m lvl• Backfilling & pcc in plinth• Erection of hydraulic jumpform rigs

- 8 nos.• Casting of ‘l' column upto 1st • Casting of ‘l’ column till + 6 m

lvl( conventionally)• Casting of 1st slab @ 8.5 m. Lvl.

• Casting of 'l' column from 2ndslab to 3rd slab

• Casting of 'l' column from 1st slab to 2nd slab

• Casting of 2nd slab @ 31.0 m. Lvl• Casting of 3rd slab @ 46.5 m. Lvl• Casting of 'l' column from 3rd slab to

4th slab• Casting of tie beam @ 21.0 m. Lvl • Casting of 4th slab @ 61.0 m. Lvl• Casting of 'l' column from 4th slab to

5th slab• Casting of 5th slab @ 73.0 m. Lvl.• Casting of 'l' column from 5th slab to

6th slab• Casting of 6th slab @ 85.0 m. Lvl

General Layout of Preheater

Operating Characteristics of Preheater

• High-efficiency cyclones with low pressure drop resulting in low fuel

and power consumption • Lowest NOx emission from unique high-temperature reduction zone • Simultaneous low CO emission specially due to calciner notch and

outlet loop duct • Uncomplicated operation with single entry locations of calciner fuel

and tertiary air • Suitable for firing both traditional and alternative fuels

Preheater Components

Cyclones

• Preheaters are based on proven low pressure loss (LP) cyclones. The unique design of the LP cyclone ensures high thermal efficiency and low pressure drop while enabling a flexible and space-saving layout.

• LP cyclones have no horizontal surfaces on the inside for material to accumulate, thereby securing stable operation.

• The top stage has a special geometry to provide the lowest dust loss while maintaining low pressure drop.

Typical LP Cyclone

Central Pipes• Central pipes (thimbles) are standard in all cyclone stages to provide high separation efficiency.•The lowermost cyclones feature a cast, segmented design with a hanging suspension system and common elements throughout. This enables easy installation and maintenance.

Cast Segmented Central Pipe

• To prevent gas from bypassing up through the material pipes between the cyclone stages, the pipes are equipped with sluice flaps (tipping valves) designed for full opening. • Good meal distribution in the cyclone riser ducts is ensured by adjustable spreader plates in the distribution boxes.

Sluice Flaps & Distribution Box

Material Pipe Sluice Flaps

Dividing gates

• Robust dividing gates are used to precisely and consistently distribute meal to the different sections of the riser duct and calciner. • One gate is capable of dividing meal into two, three, or four different streams.

Meal dividing gate

Tertiary Air Duct Damper • To balance the combustion air flow between the kiln and calciner, a tertiary air duct damper is provided for reliable regulation of the tertiary air gases. • The damper design features a solid refractory blade for long, reliable life.

Tertiary air duct damper

Preheater Operation• Raw meal is introduced at the inlet gas duct to the Stage I (top) cyclones.

It is subsequently preheated by hot, counter current gas flow as it is continuously collected and passed down the other cyclone stages in the preheater to the calciner. Fuel is burned in the calciner to achieve 92-95% of the total material calcination before collection in the bottom cyclone and entrance into the kiln. Combustion air for the calciner is taken from the kiln via the riser duct and through a separate tertiary air duct from the cooler.

• Design is based on dividing the meal from the second-lowest stage cyclone to the kiln riser and the calciner. These feed points are separated by an expanded riser duct that forms a NOx reducing zone. That is, the calcining chamber is built into the kiln riser. All of the calciner fuel is introduced to the kiln riser duct with less oxygen than required for complete combustion, thereby forming a reducing atmosphere.

Preheater Operation(contd.)

• Above the reduction zone is the main calciner vessel, which is divided into two or more sections separated by a notch. The changes in cross-sectional areas create turbulence that ensures effective mixing of fuel, raw meal and gas, improving heat transfer and combustion. The calciner outlet loop duct ensures optimum gas retention time, further mixing and complete fuel combustion.

• Optionally, the second or third-lowest stage cyclone material can be further split to allow for diversion of a portion of the meal directly into the upper section of the calciner. This creates a “hot zone” in the lower section of the calciner that is conducive to burning difficult fuels and further NOx reduction.

Jump Formwork used in Preheater construction Preheater Construction

Rotary Kiln• The rotary kiln consists of a tube

made from steel plate and lined with firebrick. The tube slopes slightly and slowly rotates on its axis at between 30 and 250 revolutions per hour.

• Raw mix is fed in at the upper end, and the rotation of the kiln causes it gradually to move downhill to the other end of the kiln. At the other end, fuel in the form of gas, oil or pulverized solid fuel is blown in through "burner-pipe“ producing a large concentric flame in the lower part of the kiln tube.

Rotary Kiln(Contd.)• As material moves under the

flame, it reaches its peak temperature, before dropping out of the kiln tube into the cooler.

• Air is drawn first through the cooler and then through the kiln for combustion of the fuel. In the cooler the air is heated by the cooling clinker, so that it may be 400 to 800 °C before it enters the kiln, thus causing intense and rapid combustion of the fuel.

General Layout of Rotary Kiln

Cooling Tower• Clinker cooler has two main

function to perform.1. To cool the hot clinker quickly.2. To provide necessary air for

burning of coal in pre-calciner and kiln.

• After introducing of red hot clinker into the cooler, mechanically driven gates moves it to the rear end of cooler. Three pair of gates are installed inside the cooler. A single pair consist of fixed gate and movable gate. To and fro moment of movable gate pressurized which cools it quickly.

Cooling Tower(Contd.)• Clinker cools down gradually as it

moves, due to the air blow by the fans which is taken from the atmosphere. Air falling over clinker is highly pressurized which cools it quickly. Clinker escaping out of the cooler is fed to a hammer crusher, since lumpy material requires crushing.

• Crushed material is transported to clinker silo through deep bucket conveyor. Temperature of clinker escaping out of cooler is about 208 degree celcius.

Grate Cooler Operation• The grate cooler operates with a cross current principle in which the clinker is

moved across the grate while cooling air blow in from below through the grate and clinker layer.

• The hot clinker falls from kiln and forms clinker bed on the grate and transported through the cooler over alternatively fixed and reciprocating grates. At the inlet of first great clinker is quenched and spread across the cooler width by the increased cooling air.

• The grate is fabricated to be as possible to obtained a thick clinker layer and a uniform distribution of air through the clinker bed in the interest of heat recovery.

• During the clinker transport from the cooler a part of dust and small size clinker is falls from the grates and collected into hoppers under the grates. The drag chain and rotary air lock system fed these clinker and dust in clinker transport system. A dust collection ESP is also installed beside the cooler known as cooler ESP. Exhaust gases from collection is fed to the ESP for dust collection.

Grate Cooler Operation(Contd.)

• Grate cooler consist of1. Cooling grate Plates 2. Standard Plates 3. Cooling housing 4. Drive unit5. Grate aeration system 6. Clinker crusher 7. Conveying unit8. Cooling fan

Tunnel Construction under cooling tower Columns construction of Cooling Tower

Coal Mill• The coal mill works for producing the pulverized coal

for burning to increase the temperature of kiln, pre-heater, raw mill .It works as same as raw mill for lime-stone grinding & the coal mill grind & transfer the coal to the furnace for burning.

• The raw mill is grounded dried swept away by fan through the separator to bag filter or ESP. finally it is stored in to the fine coal bin hot air for coal mill is supplied by cooler exhaust hot gases or pre-heater outlet gases before GTC circulation. The function of coal mill is to ground suitable grate coal and for feeding the same in to the kiln and calciner in fluidized form.

• Coal from stock yard is fed for stacking and reclaiming in to the stacker and reclaimer. Pre-homogenized raw coal is feed in to the coal mill hopper with the help of belt conveyer.

Coal Mill(Contd.)• The raw is then fed to the coal mill VRM via weigh

feeder, drag chain and screw conveyer. • Coal Mill is an important integral part of cement plant.

Here large size of approx size 600mm, is ground fine to the size of 90 micron. Coal from coal mill is used to feed kiln and calciner. Outlet temperature of coal from coal mill is different in different seasons.

• Coal from mines is initially crushed at crusher site. Coal is then sent to stacking making mixture homogenized. Reclaimer picks up the coal and coal is fed to the coal mill hopper through belt conveyer.

• Coal taken out from hopper is feed inside VRM with the help of a screw conveyer which is mounted just below the hopper.

• Coal inside VRM is grounded between roller and table.

Coal Mill(Contd.)• Hot air from cooler ESP fan is taken inside VRM and is

used for drying of coal. • Fine coal from VRM moves to the cyclone, where most

of the coal is separated from air and the coal which does not get collected due to ultra fine size is separated with the help of ESP. LV separator is for separating coarse and fine particles.

• Coal is fed to screw conveyer through rotary lock, which transport it to the FK pumps. Two FK pump delivers material to the storage bins. There are two Storage bins1. Kiln Bin 2. Pre-calciner Bin

• Fine Coal is then transported to the kiln and pre-calciner by kiln firing FK pump and pre-calciner FK pump respectively.

Clinker Silo

• Storage of cement clinker is a prerequisite for continuous kiln operation. Constantly increasing kiln capacities ensure storage volumes of 200,000 cubic meter or more.The situation on site as well as the specific properties of the material determine the configurationof the storage and handling equipment. Above all the following aspects need to be taken into consideration here:• Available space• Statics, soil bearing capacity and groundwater situation• Bulk material temperature and flow properties• Environmental regulations and aesthetics• Investment and operational costs• Capacity and unloading capacity (in automatic operation)

Construction Of Clinker Silo

1. PCC of angular raft 2. RCCof angular raft 3. Shell wall (1100 mm thick) From top of

raft to GL by conventional method4. Backfilling in foundation 5. Casting of shell wall (600 mm thick)

From GL to +6.00 mtr by conventionally

6. Erection of self climbing hydraulic system

7. Casting of shell from +6.0 mtr to 35.0 mtr

Construction Of Clinker Silo(Contd.)

8. Dismantling of self climbing hydraulic rigs

9. Casting of 1st lift of tunnel with starter

10. PCC of tunnels including sand filling upto 536.00 lvl

11. Casting of wall of tunnels12. Casting of top slab of tunnels 13. Back-filing in foundation of tunnels 14. Laying of floor PCC 15. Laying of grade slab over PCC

Jump formwork used in Clinker Silo Clinker Silo Construction

Quality Control• Quality control is error prevention rather than error detection.• Online reaction to special cause of variation will lead to progressive

improvement in the process, performance and cost.• Fundamental improvement in quality results from testing rational prediction

about special process using statistical method. The effective pursuit of quality permanent commitment through out an organization.

• Pitfall of the successful implantation of the permanent quality improvement culture are:

Lack of top management support. Lack of middle management support. Commitment to only department. Haphazard approach a little of this and that with no meaning change in the

system. Measurement of success and guidance program on the basis of short-term

profile.

Inference

• The Indian cement industry has been on a high growth trajectory for more than a decade, led by buoyancy in sectors such as real estate and construction. The industry has witnessed continuous modernisation and adoption of new technologies in recent years.

• The modern Indian cement plants are state-of-the-art plants and amongst the best in the world. In order to meet the expanding demand, cement companies are fast developing new plants.

• Cement plant construction is quite a specific construction and it requires high quality and precision with adequate safety.

Thank You