it describes that ceramic is best for erosion and swelling effect demonstrated by my friend.

1. Performance and Wear
Characteristics of Ceramics,
Cemented Carbides and
Metal nozzles used in Coal-
Water-Slurry Boilers
Presented By:
Muhammad Hasnain Khan Babar (MM-07)

2. What is Coal Water Slurry Boiler ?
A coal-water slurry boiler is a boiler (External/internal) that operates from coal-
water slurry.
Coal-Water Slurry:
Coal-water slurry fuel is
a combustible mixture of fine coal
particles suspended in water. It
can be used to power boilers, gas
turbines,diesel engines and
heating and power stations.
The erosion of materials occurs upon
the frictional rubbing of surfaces,
wear, and cavitation, as well as upon
the action of strong gas or liquid
currents upon a surface, especially at
high temperatures.
Various parts of jet engines, nuclear
reactors, and steam turbines
and boilers are subjected to destruction
by erosion.
What is erosion ?

3. Introduction
• CWS boilers are used as they safe from dust explosions.
• Flammable oil and gas transportation risk is reduced .
• In this research paper, the burning process of CWS is discussed.
• When working temperature is around 1000 C then erosion , material damage,
Fracture , thermal shocks are experienced. That’s why nozzles are most critical part
of the CWS boilers.
Wear Characteristics
The wear and erosion characteristics of nozzles used in CWS boilers depends upon
the following factors :
1. Nozzle Material Properties and Microstructure
2. Nozzle geometry
3. CWS Mass flow rate
4. CWS Temperature (Incoming Temperature) etc.

4. Nozzles Materials:
• Here six different material are used i.e. A1 and A2 belonging to purely ceramic group
B1 and B2 belongs to Cermet (composite of ceramics and metals) and C1 and C2
are purely metals .
• Three point bending/flexure test is perfomed to determine the
Flexural strength as shown.
• Fracture toughness is determined by indentation method

6. CWS Burning Test
CWS boiler (DNS2-1.0-SM)
• Atomizing air pressure is 0.40 MPa and CWS pressure is 0.20 MPa.
• Internal diameter is 5.0 mm whereas external diameter is 12.0 mm and
• length is 10 mm
m1= nozzle mass loss
m2= burn mass of CWS
d= nozzle density

8. Results
Erosion Rate and Life of Nozzles

11. Worn Surface of the Nozzles (After 120 hrs of Operations)
Metals

12. Cemented Carbides

13. Ceramics

14. • In case of ductile material the failure ocurs by plowing and plastic deformation,
while
in brittle materials material removal is by indentation rupture , crack propogation etc .
• Impacts angles are impotant parameter is controlling the erosion behaviour of
nozzles.
• Low impact angles i.e. 15 degreeare favourable for ceramics and cemeted
carbides
while metals are best fit for high impact angles i.e. around 90 degrees.

15. Presume for it’s a steady state boundary
Condition, FEM gridding model of A2 ,B2 material
Is shown above explaining the temperature gradient
and thermal stresses respectively.
Future work in the thermal shock resistance of cermaics material nozzles is required
In which it lacks properties.