Skip to main content

Industrial Chimney

Chimney

A steam boiler assembly, be it any fuel (solid/liquid/gaseous) used for combustion, the flue gases coming out of the Induced draft fan, coming from air preheaters and dust collectors, enters the chimney to conclude this process before getting released to the atmosphere.
Self-supported type Chimneys can be provided suiting the boiler size. It can be designed and manufactured as per IS-6533 standard to ensure compliance.

Industrial Chimney
Industrial Chimney
Working
The chimney’s working is based on the natural draft or stack effect. As we know, the density of a gas reduces, with rising in its temperature, so because of this reason when the flue gases enter the chimney, the buoyancy forces of air come into action and help in carrying the flue gases out of the chimney. In the case of a Boiler assembly employing an Induced Draft Fan, the flue gases are brought to the chimney by this fan and then buoyancy forces deliver them to the atmosphere. These buoyancy forces depend upon the weight of the air displaced by the flue gases in the chimneys. Greater the weight, greater are the buoyancy forces present. And this weight can be increased by increasing the height of the chimney. Back in time, when Lancashire Boilers were in fashion, induced draft fans were not used. The reason was the extremely high temperature of flue gases at the chimney inlet, this high temp. of flue gases reduced the density of flue gases to a great extent. Now they were even lighter and the buoyancy forces produced were of greater magnitude. This removal of flue gases in the chimneys created a vacuum at the chimneys inlet. So, because of this vacuum (pressure difference between boiler furnace and chimney inlet), the flue gases traveled all the way from the boiler to the chimneys, eliminating the need for an Induced Draft Fan.
Buoyancy forces produced, are given by relation as given below:
Fb = (Pa  – Pf )xgxh
where
Fb = Buoyancy force (N)
Pa = Density of Ambient Air (kg/m3)
Pf   = Density of Flue gases at chimney inlet temperature (kg/m3)
g = Acceleration due to gravity (m/s2)
h = Height of chimney (m)
We, at thermodyne have successfully designed, manufactured, supplied and erected both structure and self-supported Chimneys in compliance with IS-6533 (part-1&2) to many of our clients.

Comments

Popular posts from this blog

SENSIBLE HEAT & LATENT HEAT

SENSIBLE HEAT Sensible heat produces a rise or fall in temperature of substance Sensible heat does not change physical state of substance LATENT HEAT Latent heat changes the state of substance i.e. Liquid to Gas, Solid to Liquid and Liquid to Solid in case of boiler . Latent heat does not cause temperature change in the substance

Why spirals are provided at the Idustrial Boiler Chimney

Chimney:- Chimney , as we know, is used to reject the flue gases to the atmosphere, coming from the Steam Boiler during operation. Also, it is a megastructure in Steam Boiler assembly and any discrepancy in its structural and foundation work can cause extremely serious damages, may even lead to casualties or plant shut off till its re-erection. The designer must consider all the factors while designing chimneys and one of the major factors amongst them is the wind factor. Blowing wind tries to overcome its static inertia but fails, if spirals are provided on the surface of the chimney. BUT THE QUESTION IS HOW????? Consider a chimneys (without spiral wings) , when the blowing wind comes in contact with its upstream surface, stagnation point (zero velocity) is achieved at that point i.e. pressure generated is high at that point and at the downstream end a vacuum is created as the wind coming in contact with the chimneys , gets deflected and meets after some point (wake regio

Critical Thickness of Insulation and It's Effect on Boiler Efficiency

Welcome to the THERMODYNE BLOG, today in this article we are going to explore the thickness of insulation and its effect on boiler efficiency and other parameters. Critical thickness of insulation and its significance             The information in this article gives a significant collection of data you need to know about the boiler and its performance, the parameter that affects the boiler efficiency .         Table of content INTRODUCTION THICKNESS OF INSULATION CRITICAL RADIUS EFFECT ON BOILER EFFIIENCY INSULATING MATERIALS CONCLUSION INTRODUCTION- The  thickness  up to which heat flow increases and after which heat flow decreases is termed  critical thickness . In the case of cylinders and spheres, it is called the  critical radius . The  critical radius of insulation  can be derived depending on the thermal conductivity of the insulation k and the external convection heat transfer coefficient h. THICKNESS OF INSULATION- CRITICAL RADIUS-   In boiler the shell and tube are cyl