Chimneys

Chimney & Cooling Towers-GET Induction Meeting at H.O-

22.07.2011

275Mtrs - Single Flue Brick Lining Chimney Bellary

Ukai

275Mtrs - Double Flue Steel Chimney

Attipatu

Korba

• INDIA has been striving to alleviate the electric power crisis, recently aggravated due to the economic boom in the country.

• Out of the two major sources of power, i.e. Hydro Power and Thermal Power, the latter has become more popular due to its adaptability towards larger production capability.

• Thermal power is obtained through burning coal, which is required to operate the steam boilers.

• When burnt, the coal produces polluting gases that need to be discharged at an elevation high enough to dilute the pollution and to keep it within acceptable limits at ground level.

• An adequately designed tall chimney serves this purpose.

What/Why/where - Chimney

• As the pollution norms have become stringent with time, the chimney heights have gone up progressively from 100m to 150m to 220m to 275m.

• In most thermal power plants, 275m tall concrete chimneys have now become the standard norm.

• It may be worthwhile mentioning here that a bi-product of burning of coal is fly ash, which is produced in the process line between boiler and chimney.

• This fly ash is extracted using electrostatic precipitators, which incidentally can be used in blended cement and as mineral admixture in concrete.

Chimney Construction

• Excavation - ____ ____Cum• Raft - ________ Cum• Shell -_________Cum• Structural Erection - _________MT

Top view of Raft Foundation

43 Mtrs

11 Mtrs

Chimney Raft

The purpose of this work is to provide uniform, pre-defined and well defined method for the construction of RCC chimney.

Slip formwork system is a system in which slip forms are continuously raised by hydraulic equipment. By this means the rising from 150 to 300 mm per hour depending on the concrete hardening rate as the cast concrete can become self-supporting very rapidly.

Shell Construction by Slipform Technology

• The system uses steel panels of special height, which are fixed to working carcass consisting of steel

frames (yokes), trusses and fixing devices.• Carcass provide stability of the system design and is a reliable base for the wooden

flooring used as a working platform for placement of concrete, reinforcement and embedded parts for doors and windows on its surface.

• A hydraulic jack is placed on the top of each frame. • A high tensile steel jacking rod is passed through the jack and is casted into the walls as

it rises.• The jack consists of a cylinder and a pair of upper and lower clamp mechanisms

gripping the rod and working in cycles. • The principle is that the jack works against the lower clamp to lift the frame.• When the pressure is released upper clamp grips the rod and the lower clamp is

released and come up by spring action.

• Large capacity jacks are usually used with steel tubes of big diameters and greater stiffness.

• Concreting with slip formwork can be carried out on a continuous basis, 24 hours a day, or with

intervals, to be exact, the concrete is poured on up to a predetermined height usually within one day.

• Vertical reinforcement is retained in the correct position using guides, which are fixed on the top of the frames.

• Horizontal reinforcement is laid under the frames and is bounded with the vertical reinforcement.

• Inserts for doors and windows can be made of wood and steel. They are set during the lifting process and removed in the end.

Checks conducted in chimneys:

1.Verticality

2. Wall thickness

3. Centering and twisting

4. Radius

5. Curing

Verticality Check:• Verticality is checked by

calibrated laser beam.• Tolerance 1 / 1000mm

0r 75 mm maximum.

TARGET PLATE

Shell wall thickness:• Chimney shell Wall thickness is measured with tape at every yoke between shuttering plates

for every lift. • Tolerance of wall thickness (-)5mm and (+)25mm.

Twist:

• The 2 no's of Twist plate is fixed on slipform before starting of operation .

• Twisting is checked every one meter of concreting, if twist observed it will be control opposite force direction given by storing reinforcement or leveling of slip form.

Radius Checking:

Radius is to be checked with center point and inside wall shuttering with measuring

tapes . The tolerance of radius is +/- 25mm.

List of Executed Projects

• Chimneys • Cooling Towers

List of Executing Projects

• Chimneys • Cooling Towers

LANCO KONDAPALLI POWER PRIVATE Ltd

LANCO AMARKANTAK POWER PROJECT LTD

LANCO UDIPI POWER CORPORATION LIMITED

LANCO ANPARA THERMAL POWER PLANT

A.Ghosh- GM –ProjectsG.K.Singhi- Sr.DGM – ProjectsTushar Padmawar – Dy. ManagerRobin – Asst. ManagerKarthik Bysani – EngineerNarendar – EngineerLakhsmi – MT

Construction | Power | Infrastructure | EPC | Property Development | Wind Energy | CSR

Thank YouByChimney & CT Team

A.Ghosh- GM –ProjectsG.K.Singhi- Sr.DGM – ProjectsTushar Padmawar – Dy.Manager