New Technologies in Process Heating
-
Upload
national-productivity-council-hyderabad-india -
Category
Engineering
-
view
571 -
download
0
Transcript of New Technologies in Process Heating
C & H - Heating
Key drivers for the innovation.
• Efficiency
• Emission
• Reduction in carbon foot print
• Compactness
• Life cycle cost
• Serviceability & maintainability
C & H - Heating
Fossil fuel : Combustion technology
• Classification of combustion technology-
*Grate combustion
- Stationary grate
- Travelling grate
- Reciprocating grate
*Fluidised bed combustion
*Dust combustion
C & H - Heating
Biomass : An alternative fuel
• Challenges in biomass combustion-
*Fuel with low density, higher moisture level and
low calorific value- difficulty in handling.
*Inconsistent supply of fuel & seasonal variation
in fuel properties – Boiler should be designed
with fuel flexibility
*Higher level of emission
*Slagging & fouling
• Need of an appropriate combustion technology
C & H - Heating
Thermax Lambion combustion technology
Inclined reciprocating grate
Horizontal reciprocating grate
Combined reciprocating grate is
being developed.
C & H - Heating
Combloc- A packaged biomass
boiler
A Packaged
biomass boiler
with horizontal
reciprocating
grate
C & H - Heating
Future of combustion technology
• Gasification
• Oxyfuel combustion
• Unmixed combustion
• Chemical looping combustion
C & H - Heating
Development in the boiler design
• Boiler development- Size, fuel flexibility,
emission & efficiency
• Development in combustion technology
• Heat transfer enhancement- Tube inserts
& special tubes
C & H - Heating
TEON 300
SIBR,7Kg/cm²
TEON 500
SIBR 7
Kg/cm²
TEON 750
IBR 7
Kg/cm²
TEON 1000
IBR,
10.54Kg/cm
²
TEON 1500
IBR 10.54
Kg/cm²
Thermeon – A compact
boiler
C & H - Heating
Fluegas heat recovery
• Conventional heat recovery technology
*Feed water preheating
*Combustion air preheating
• Challenges
*Economics of heat recovery
*Low end corrosion
C & H - Heating
Need for condensing technology.
• Flue gas still contains approximately 6-8 % heat of the net calorific value of the fuel.
• Natural gas has a significant portion of hydrogen, which gets converted in to water vapour after the combustion. In the process of combustion, a significant portion of the heat is lost to provide the required latent heat for the evaporation of water. If we consider this heat, approximately 15-17 % heat is still left with the flue gas. This can be easily explained by noting the difference of efficiency on the basis of GCV and NCV. Even with conventional heat recovery system, the efficiency on the basis of GCV is in the range of 83-85 %.
• If the condensation of water vapour of the flue gas is allowed, flue gas temperature can be further reduced to maximise the boiler efficiency.
• This opens a significant opportunity for the flue gas heat recovery, as the latent heat of condensation is recovered in the process of condensation. If the sufficient heat sink is available and system is optimally designed, approximately 10-12 % heat can be recovered higher than the sensible heat left with the flue gas (6-8 % of the NCV).
• If we consider efficiency on the basis of NCV, the efficiency of boiler can go beyond 100%. Using condensing technology, The latent heat of water vapour is received back, which was considered as lost in the definition of Net calorific value.
C & H - Heating
Challenges :Condensing technology.
• Criticality of material selection- Material selection is very critical for the design and selection of the condensing heat exchanger. The suitable material should be anti corrosive to deal with acidic condensate. Material should have higher thermal conductivity and non sticky.
• Chimney corrosion- Other challenge of the condensing heat exchanger design is the problem of chimney corrosion.
• Higher cost- Due to poor heat transfer performance and the special metallurgy, the cost of condensing exchanger system is normally high.
C & H - Heating
Efficient method of steam utilisation
• Focus on system efficiency- Closed loop
system & open loop system
• Combined heat & power
• Process integration
C & H - Heating
CFD- Computational fluid dynamics
Higher stack temperature problem of
thermal oil heater has been analysed
and solved by using CFD.
Flo
w m
al d
istrib
utio
n
iden
tified a
nd
corre
cte
d fo
r oil fire
d
fire tu
be b
oile
r.
CFD helped to develop new
correlation for the heat transfer
coefficient of the coil type heater.
C & H - Heating
FEA- Finite element analysis.
*FEA has served as a major
tools for design and
development of many new
product,
*It has also helped to
identify and solve some of
the chronic problem.