FIELD OF THE INVENTION
This invention relates to Flue Gas Desulphurization (FGD) duct with titanium
cladded plate used in fossil boilers. More particularly, it relates to FGD duct
design without internal truss with titanium cladded plate.
BACKGROUND OF THE INVENTION
With continuously growing economy, coal dominated energy consumption has
caused serious So2 release in environment which causes acid rain. Therefore,
it is required for flue gas desulphurization for reduction of So2 according to the
10 environment norms for power plants. During flue gas desulphurization low
temperature zone is created which is responsible for So2 condensation. This is
basic phenomena behind acid rain. Commonly adopted structural design for
the ducts cannot work in FGD process because sulphuric acid is highly
corrosive. Existing FGD ducts are manufactured with internal truss which are
15 eventually very expensive. Present truss work requires internal beam, gusset
plate and truss pipe, all manufactured from titanium material because titanium
material can be welded by titanium only. Another disadvantage is that the cost
of titanium is approx. ten times cost of carbon steel materials. Therefore,
overall expenses become too high if truss is included in Duct manufacturing.
20
OBJECT OF THE INVENTION
It is therefore primary object of the invention to solve above mentioned
problem by proposing a duct without internal Truss with titanium cladded plate
and designed in such a way to ensure minimum cutting of plate. Development
25 of duct in such a way to collect the condensed acid to avoid So2 release in
environment.
Yet another object of the invention is cost minimization in FGD duct
manufacturing.
3
Still another object of the invention is manufacturing a stronger FGD duct with
better welding methodology.
SUMMARY OF THE INVENTION
5 The present invention is therefore intended to solve one or more of the above
problems by providing a method for compilation of titanium cladded FGD duct
without Truss.
Accordingly, Duct is designed from FGD bypass damper to chimney inlet
without internal truss. Cladded plate is cladding of titanium sheet with carbon
10 steel and a 5mm gap all-around the plate is provided without titanium cladding. Cladded plate is procured as raw material with 5mm gap around the plate
without titanium cladding.
compiling a cladded plate and a titanium sheet plate characterised in that the
cladded plate and the sheet plate connected by a channel box. Then
15 strengthening of said compilation by a stiffener, a sealing and welding; sealing
the corner of duct by titanium sheet plate formed angle and a titanium sheet
plate field joint and, welding corner of duct in single-square plate to plate type
welding, corner angle at ISA 75*75*6 welding and a beam welding at ISA
130*130.
20 Preferred embodiment of the invention having other features which are
disclosed in appended depended claims. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The illustrated embodiments of the subject matter will be best understood by
25 reference to the drawings, wherein like parts are designated by like numerals
throughout. The following description is intended only by way of example, and
simply illustrates certain selected embodiments of apparatus that are
consistent with the subject matter as claimed herein.
4
Figure 1 illustrates the constructional features of FGD duct without internal
truss with cladded plate. Figure 2 illustrates corner construction detail of FGD duct.
Figure 3 illustrates DUCT joint construction detail of FGD duct. 5 Figure 4 illustrates cladded plate detail. DETAIL DESCRIPTION OF THE INVENTION
While the embodiments of the disclosure are subject to various modifications
and alternative forms, specific embodiment thereof have been shown by way
10 of example in the figures and will be described below. It should be understood,
however, that it is not intended to limit the disclosure to the particular forms
disclosed, but on the contrary, the disclosure is to cover all modifications,
equivalents, and alternative falling within the scope of the disclosure.
15 Figure 1 illustrates the schematic diagram of FGD duct with titanium cladded
plate without internal truss. It consists of a titanium cladded plate (1) which is
a corrosive resistant material, primary stiffener member as a channel (2),
corner angle ISA 75X75X6 (3) for providing strength at corner outside of duct,
channel box (4) for connection of two duct, titanium sheet plate formed angle
20 (5) for sealing the corner of duct from inside, filed joint plate of titanium sheet
(6) for sealing the gap between two plate from inside of duct, secondary
stiffener Beam (7) for strengthen of duct as per analysis and ISA130x130 for
connection of beams.
25 Figure 2 illustrates the welding detail of titanium cladded plate (1), titanium
sheet plate formed angle (5) and corner angle ISA 75X75X6 (3).

Figure 3 illustrates the duct joint construction detail of FGD duct. Sealing of
gap “b” (for e.g.) between the two ducts with titanium sheet for having
required dimension such as “a” as shown in the figure. There is a channel (2)
for joining two ducts and a filed joint plate of titanium sheet (6) for sealing gap
5 from inside of duct.
Figure 4 illustrates the cladded plate detail. Cladded plate is the cladding of
titanium sheet with carbon steel with 5mm gap all-around the plate without
titanium cladding as shown in the figure. Cladded plate is procured as raw
10 material with 5mm gap around the plate without titanium cladding. 5mm gap
around the duct is maintained for welding feasibility of titanium-to-titanium and
carbon steel to carbon steel. The gap is provided such that there is no fusion
between the metals during the welding. So that, metals do not become brittle
after welding but provide more strength. Duct is designed such a way that
15 welding with carbon steel-to-carbon steel and titanium-to-titanium because
welding is not possible between carbon steel and titanium. The welding type is
square (SS) type welding when sealing the duct from inside with plate formed
angle (5) with titanium sheet, and sealing of gap between two cladded plate
joint with titanium sheet from inside of duct. FGD duct is designed without
20 internal truss. Manufacturing ducts with 3D view generated, which is easy to
understand for production of FGD ducts. Further sealing of gap “b” (for e.g.)
between the two ducts with titanium sheet for having required dimension such
as “a”. Note has been added in manufacturing for peeling of titanium material
wherever applicable for maintaining the welding with similar material (for e.g.
25 carbon-to-carbon and titanium-to-titanium)
6
WE CLAIM:
1. Method for assembling Flue Gas Desulphurisation duct in highly
corrosive environment, the method comprising steps of:
- compiling a cladded plate (1) and a titanium sheet plate (6)
characterised in that the cladded plate and the sheet plate connected
by a channel box (4);
- strengthening of said compilation by a stiffener, a sealing and welding;
- sealing the corner of duct by titanium sheet plate formed angle (5) and
a titanium sheet plate field joint (6); and,
- welding corner of duct in single-square plate to plate type welding,
corner angle (3) at ISA 75*75*6 welding and a beam welding (8) at ISA
130*130.
2. The method as claimed in claim 1, wherein said cladded plate is Titanium
cladded plate for accommodating highly corrosive environment.
3. The method as claimed in claim1, wherein said stiffener are a primary
stiffener as a channel (2) and a secondary stiffener as beam (7)
employed for strengthening of said duct compilation.

4. The method as claimed in claim 1, wherein titanium sheet plate formed
angle (5) and titanium sheet plate field joint to ensure the sealing of
duct with titanium cladded plate.