FIELD OF INVENTION
This invention relates to a method of lining a flue gas duct with ceramic for
reducing erosion of steel parts. More particularly, it relates to a method of
splicing abrasion resistant ceramic tiles on the surface of critical areas of severe
erosion like horizontal and vertical deflector plates, expansion joint seal plate and
nozzle area of the flue gas duct.
BACKGROUND OF THE INVENTION
The flue gas duct is the rectangular duct through which the mixture of fly ash
and air passes from boiler to electrostatic precipitator (ESP). The operating
temperature at this place is about 150 to 160 deg C. Mild steel plates are being
used in this area. In some area the erosion is so severe that they need
replacement once in a year. Abrasion resistance ceramic linings are being used
presently in pulverised fuel lines such as line bends, straight pipes, elbows and
orifices. However, it has been observed that the flue duct experiences severe
erosion due to high temperature and velocity of flue gas carrying fly ash
particles. The problem of erosion is more in horizontal deflector plates, vertical
deflector plates, expansion joint seat plate and nozzle area. These areas need to
be protected by fixing abrasion resistant ceramic tiles.
Therefore, there exists a need to find a method of lining flue gas duct wit
ceramic tiles for reducing the erosion of steel parts.

OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a method of fixing abrasion
resistant ceramic tiles in flue gas duct in critical areas of severe erosion which
eliminates the disadvantages of prior art.
Another object of the invention is to propose a method of fixing abrasion
resistant ceramic tiles in flue gas duct in critical areas of severe erosion which
reduces erosion of steel parts to improve the life of the flue gas duct area.
A still another object of the invention is to propose a method of fixing abrasion
resistant ceramic tiles in flue gas duct in critical areas of severe erosion which
reduces shutdown time and maintenance cost.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.l - shows a schematic diagram of ceramic lining in flue gas duct
Fig.2 - shows vertical deflector plates lined with 6 mm thick ceramic tiles and 15
mm thick weld-on tiles pasted and welded to the plates
Fig.3 - Vertical and Horizontal inclined plates lined with ceramic tiles at nozzle
area
Fig.4 - Horizontal plates lined with ceramic tiles using silicone sealant adhesive

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
The present invention relates to a method of splicing the abrasion resistant
ceramic lining by fixing thinner tiles on larger area and fixing weld-on tiles at the
outer edge and at the centre like strips for protection and interlocking of ceramic
tiles together.
The plurality of abrasion resistant ceramic tiles (1) of varying thickness is spliced
on the surface of horizontal deflector plates (2), vertical deflector plates (3),
expansion joints (4) and nozzle area (5) of flue gas duct (6) as shown in fig.1.
High abrasion resistant ceramic tiles of varying thickness and suitable sizes are
manufactured from high alumina (85-90%). The splicing of a plurality of abrasion
resistant ceramic tiles is done in such a way that thickness of the abrasion
resistance ceramic is increased in the areas where underlying metal plates
experience higher erosion. This is achieved by using for example, 15 mm thick
weld-on tiles and for example, 6 mm thick tiles depending on the area of
opening required. The strips of 15 mm thick weld-on tiles are fixed at the outer
edge and in the center of the plates.
The ceramic lining is spliced using silicone sealant as adhesive which will
withstand a temperature of 160 deg C. The horizontal deflector plates (2) and
nozzle area (5) is spliced by 6 mm thick ceramic tiles. This critical parameter of
thickness is decided considering the design factor of area of opening through
which flue gas passes. The velocity of flue gases plays very important role in the
operation of boiler as well as electro static precipitator (ESP) which is located
after the nozzle area (5). The vertical deflector plates (3) are spliced by 6 mm
thick ceramic tiles with 15 mm thick weld-on tiles strip surrounding and in the
centre. When weld-on tiles are pasted and welded to the plate using mild steel
plugs. One vertical plate is kept unlined. Horizontal plates (2) are lined with

ceramic tiles of 6 mm thick using silicone sealant adhesive when one plate is
kept unlined. The expansion joint seal plates are spliced by 15 mm thick ceramic
tiles.