|
Power generation industry always faces rigorous demands and Regenerative Rotary Heat Exchanger undoubtedly faces the toughest of them.
If optimum boiler performance is what
one might rightly demand – highest quality
of air pre-heater is a must. Design of Air Pre-heater
Baskets with Elements has to take into account sulphur
content of the fuel, erosion and fouling characteristics
of the fly ash, soot blowing and periodic cold end
temperatures as recommended and other sources of
moisture. Thus Air Pre-Heaters are important components
of Coal fired Power Stations. By Pre-heating the
combustion air with hot flue gas leaving the boiler
a gain in efficiency is obtained. Today’s call
to RAPH manufacturers is to design for reduction
of maintenance need and longer gap between overhauls.
Metal thinning due to corrosion by build
up of deposits will eventually lead to reduction
in service life of the Elements. Excessive corrosion
will call for frequent overhauling / replacement.
This will result in costs and reduction in unit efficiency.
If on the other hand pressure drop across the heater
increases, a higher capacity fan may have to be installed
at a considerably higher price. With a large range
of profiles at its command BTL can supply direct
replacement of all elements. Many of BTL profiles
have been individually tested. Elements can be supplied
in a variety of baskets including BTL design, which
has been developed to maximize rotor area and to
reduce gas bypassing the elements. Various types
of element surface profiles have been designed each
with special properties for the many different type
of application and operational conditions. The types
are DU Element having a high heat transfer coefficient
and at the same time a relatively low pressure drop
factor. The parallel notches make the elements amenable
to soot blowing. The CU element is a very efficient
element in relation to heat transfer but has a relatively
high pressure drop factor. This means a pre-heater
but with more surface. The UNF element is especially
easy to clean, which is used in cold end of Air Pre-Heater.
There are also corrugated flat (CF) and notched flats
(NF). The standard profiles are shown below:
While designing and manufacturing heating elements as per customer’s requirements, the following consideration are kept in the designer’s mind.
| a) |
 |
Solid and Strong Structural formation |
| b) |
|
Reduced pressure drop across the Heater |
| c) |
|
Increased efficiency in Heat Transfer |
| d) |
|
Trouble free assembly and disassembly |
| e) |
|
Higher corrosion resistance |
| f) |
|
Easy to clean |
| g) |
|
Assured reliability |
| h) |
|
Easy access while cleaning |
 |
|
The use of cold elements of higher-grade
steel or enamel coating will reduce the effect
of corrosion. |
|
|
With tough ash particles in the
hot end elements, the profiles are such selected
so as to reduce fouling and facilitate easier
cleaning. |
|
|
Often due to inadequate ash in
the flue gas not absorbing condensing acid.
Answer could be closed profile elements. |
|
|
Heat recovery and boiler efficiency
can be had by using higher efficiency elements
and by use of unused space within the rotor. |
BTL is a leading Indian supplier of regenerative Air and Gas Heater Replacement Baskets since 1967 in major Power Plants in India. BTL is equipped to supply all types and makes of RAPH.
|
|
|
Carbon steel |
|
|
Corten Steel |
|
|
Stainless Steel |
|
|
Enameled Coated Steel |
|
