FIELD OF INVENTION
The invention relates to an improved cyclone separator adaptable to circulating
fluidized bed combustor for separation of solids at high temperature.
BACKGROUND OF THE INVENTION
In a CFBC boiler, the cyclone is a vital component used for separation of high
temperature solids from flue gases coming out of the combustor. The flue gas at
750 to 900 Degree C is admitted into the cyclone, and the solids are separated
from flue gas and fed back into the combustor. The cyclone is made up of a
carbon steel shell, and lined inside with refractory materials to protect the shell
from abrasion and high temperature of the dust laden hot flue gases.
A cyclone separator constitutes a well known means for separating gases and
solid from the mixture of the same. Such a separator generally is constructed as
a cylindrical shaped main body connected to a lower tapered conical portion. A
tangential side inlet is provided near the top of the main body. A gas outlet tube
is provided and generally extends downwards through the cyclone top in to the
main body of the cyclone.
As per the existing process, the top portion of the separator is made into a
cylindrical shape (01) and the bottom portion is a conical shape (02) as shown in
figure 1. This manufacturing method calls for a precise rolling of the shell to
have a proper matching between the segments while erecting at site. Slight
distortion in the shell either due to improper manufacturing or due to damage in
transit makes the erection work difficult as correcting the distortion at site is
cumbersome job.
Presently, the cyclones used in CFBC boilers are of cylindrical/conical shape
manufactured by rolling process. As the size of the cyclone is very large, the
manufacture process is quite cumbersome and often lacks accuracy. Further, due
to the size constraints of the cyclones, the cyclone shells after trial-assembly are
dismantled and sent in loose segments to the site for final assembly and
erection. In order to prevent any deformation during handling and
transportation, the cyclone segments are provided with transport stiffener.
In spite of adapting such safety measures, some unexpected damage occurs and
deformation of the cyclone components takes place during transportation which
takes more time and means to rectify at the erection site causing delay in the
erection work. In order to eliminate the above mentioned constraints in
manufacturing, and the problem faced during transportation and erection, an
innovative design involving a simple manufacturing and erection process is
needed.
US patent application no. 6793013, European patent application no. EP 1581768
and WIPO patent application no. WO/2004/063626, each discloses a vertical
polygonal heat exchanger chamber adaptable as a cyclone which includes an
upper opening, a lower opening and an enclosure formed between the upper
and lower opening. The enclosure includes at least one tapered portion that
narrows in a direction towards one of the openings. The tapered portion is lined
with N first water tube panels arranged adjacent to and alternatively with N
second water tube panels, where N is an integer greater than two. Each of the
first and second water tube panel is angled inwardly from the widest part of the
tapered portion towards the interior of the enclosure, with each of the first water
tube panel angled inwardly to a greater degree than each of the second water
wall panel.
The cited patents are limited by use of water wall panels as the shell of the
polygonal heat exchange chamber as cyclones which is a complicated
arrangement.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a cyclone separator which
can be manufactured by adopting simpler manufacturing process of cutting and
welding of plates and eliminates costly rolling process of prior art.
Another object of the invention to propose a cyclone separator which minimizes
the transit defect being enabled for transportation in the form of flat walls
instead of cylindrical/conical segments.
A further object of the invention to propose a cyclone separator, which enables
an easy erection by providing corner angles with fit-up holes.
SUMMARY OF THE INVENTION
Accordingly, there is provided a cyclone separator comprising a shell configured
with a polygonal cross-section, the inner surface of the shell being lined with a
refractory material in such a way that a circular gas flow path is formed.
The inventive cyclone separator with polygonal wall reduces the transit risk as
the walls are formed as flat products. Further, the inner corner angles provided
in between the adjacent walls of the polygonal shell make it easy to assemble
the cyclone at site.
According to the invention the cyclone comprises of a polygonal outer shell,
internally lined with refractory; a plurality of corner angles with fit-up holes to
facilitate easy erection of the adjacent walls; and retainer plates for supporting
the refractory material at an interval of 3 to 4 meters. Though the outside shell is
polygonal in shape, the refractory inner surface which is facing the solid laden
hot gas is made of circular shape to retain the solid collection efficiency. The
cyclone separator according to the invention enables replacement of the prior art
manufacturing process of rolling by a welding process to form the cyclone with
polygon wall which inter alia reduces the transportation volume and risk as the
walls are manufactured in the form of flat walls instead of circular segments
which minimizes the cost of transportation.
Thus, the invention discloses an improved cyclone separator for CFBC boilers
wherein high temperature and highly abrasive solid particles are separated from
flue gas and sent back to the combustor.
Though the outside shell is polygonal in shape, the refractory inner surface which
is facing the solid laden hot gas is made of circular shape to retain the solid
collection efficiency.
DETAIL DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - Shows a prior art cyclone separator with cylindrical/conical steel shell
and uniform refractory disposed all around.
Figure 2 - Shows a cyclone separator with polygonal steel shell and non-uniform
refractory with a circular gas flow path all around according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
As shown in Figure 2, the cyclone separator is produced with multiple sided
polygon (04) depending upon the size of the shell. Each side member of the
polygonal shell is manufactured and dispatched loose to site and assembled at
site by welding the ends of the sides. The circular shape (05) of the cyclone (04)
is obtained by a suitable design of a refractory structure (03) inside the shell
(04). By such an innovative configuration of the cyclone, the disadvantages of
rolling of shell, distortion of shell segments during transportation and rework to
correct the distortion, are eliminated. Even, if there is any mismatch between the
walls, the same can be rectified with simpler operation of trimming and welding.
A plurality of corner angles (06) are used during assembly of the side members
to form the polygonal-shaped shell (04) of the cyclone separator . The corner
angles (06) having a plurality of fit-up holes (07) are used to pre-assemble the
adjacent walls through fastening prior to welding.
1. An improved cyclone separator adaptable to circulating fluidized bed
combustor for separation of solids at high temperature, the separator
comprising :
a cyclone shell (04) with polygonal cross section, the shell being
assembled by joining a plurality of flat members;
a refractory structure (03) comprising a top portion disposed on an
inside cylindrical surface (05), and a bottom portion disposed on an
inside conical surface (05), a plurality of retainer plates supporting the
refractory structure (03); and
a plurality of corner support members (06) each having a plurality of
fit-up holes (07) for pre-assemble the flat side members to form the
polygonal shaped shell (04).
2. The cyclone separator as claimed in claim 1, wherein the corner-
support plates (06) are joined to the adjacent walls by fastening prior
to welding.
3. The cyclone separator as claimed in claim 1 wherein the retainer
plates are provided at an interval of 3.00 to 4.00 meters.
4. An improved cyclone separator adaptable to circulating fluidized bed
combustor for separation of solids at high temperature as substantially
described and illustrated herein with reference to the accompanying
drawings.

The invention relates to an improved cyclone separator adaptable to circulating
fluidized bed combustor for separation of solids at high temperature, the
separator comprising a cyclone shell (04) with polygonal cross section, the shell
being assembled by joining a plurality of flat members; a refractory structure
(03) comprising a top portion disposed on an inside cylindrical surface (05), and
a bottom portion disposed on an inside conical surface (05); a plurality of
retainer plates supporting the refractory structure (03); and a plurality of corner
support members (06) each having a plurality of fit-up holes (07) for pre-
assemble the flat side members to form the polygonal shaped shell (04).