Steam Distribution and Utilization
Steam Distribution and Utilization
Steam Distribution and Utilization
Equipment
Thermal Equipment/
Steam
Steam Distribution
and Utilization
Presentation from the
Energy Efficiency Guide for Industry in Asia
www.energyefficiencyasia.org
UNEP 2006
Thermal Equipment/
Steam
Introduction
Steam distribution system
Assessment of steam distribution
system
Energy efficiency opportunities
UNEP 2006
Introduction
Why do we use steam?
Thermal Equipment/
Steam
UNEP 2006
Introduction
What is steam?
Thermal Equipment/
Steam
UNEP 2006
Introduction
What is steam?
Thermal Equipment/
Steam
UNEP 2006
Introduction
What is steam?
Thermal Equipment/
Steam
UNEP 2006
Introduction
What is steam - Enthalpy
Thermal Equipment/
Steam
hg = hf + hfg
UNEP 2006
Introduction
What is steam Dryness fraction
Thermal Equipment/
Steam
UNEP 2006
Introduction
What is steam?
Thermal Equipment/
Steam
Temperature Enthalpy Phase Diagram (Spirax Sarco)
UNEP 2006
Introduction
Steam quality
Thermal Equipment/
Steam
UNEP 2006
Thermal Equipment/
Steam
Introduction
Steam distribution system
Assessment of steam distribution
system
Energy efficiency opportunities
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Thermal Equipment/
Steam
Boilers use
primary fuel
exhaust gases
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1. Pipes
7. Steam traps
2. Drain points
8. Air vents
3. Branch lines
4. Strainers
9. Condensate
recovery
system
5. Filters
10. Insulation
6. Separators
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Undersized pipework:
Lower pressure at point of use
Risk of steam starvation
Risk of erosion, water hammer and noise
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(Spirax Sarco)
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Design
Location
Distance between drain points
Condensate in steam main at shutdown
Diameter of drain pipe
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A Branch Line
(Spirax Sarco)
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(Spirax Sarco)
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Purpose
Stop scale, dirt and other solids
Protect equipment
Reduce downtime and maintenance
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Y-Type strainers
Handles high
pressures
Lower dirt
holding
capacity: more
cleaning needed
(Spirax Sarco)
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Y-Type strainers
(Spirax Sarco)
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(Spirax Sarco)
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Strainer screens
Perforated screens
Holes punched in flat sheet
Large holes
Removes large debris
Mesh screens:
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(Spirax Sarco)
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Fins generate
cyclonic flow
Steam spins around
separator body
Water thrown to wall
Drainage through
steam trap
(Spirax Sarco)
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(Spirax Sarco)
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Operated by
changes in fluid
Steam
Traps
density
Thermostatic
1.
2.
3.
Liquid expansion
Balance pressure
Bimetallic
Mechanical
1.
2.
Ball floating
Inverted bucket
Operated by
changes in fluid
dynamics
Thermodynamic
1.
2.
3.
Impulse
Labyrinth
Fixed orifice
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Application
Feature
Suitable trap
Steam mains
Thermodynamic,
Mechanical:
Float
Large capacity
Equipment
Variation in pressure and
Reboiler
Heater
temperature is undesirable
Efficiency of the equipment is
Dryer
Heat exchanger
a problem
etc.
Tracer line
Instrumentation
(BEE India, 2004)
Mechanical:
Float
Bucket
Inverted bucket
Thermodynamic,
Thermostatic:
Bimetallic
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Advantages
Disadvantages
Can be damaged by severe freezing
Different internals needed for varying pressures
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Steam in bucket
condenses or bubbles
through vent hole
Main valve opens
Condensate is
released
Steam arrives
Bucket rises
and shuts outlet
(Spirax Sarco)
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Advantages
Disadvantages
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Waterhammer
Condensate picked up by moving steam
Can damage steam trap
Continuous slope in flow direction reduces this
Dirt
Affects steam trap performance
Strainers
Help remove dirt and cheaper than maintaining
steam traps
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Steam locking
Can occur in rotating machinery
Only float trap has steam lock release valve
Diffusers
Installed to end of the pipe
Reduces sound and ferocity of flash steam discharge
Pipe sizing
Correct pipe size - traps affected by resistance to flow
Avoid pipe fittings close to trap back pressure risk
Air venting
Important for system warm up and operation
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Group trapping
(Spirax Sarco)
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(Spirax Sarco)
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(Spirax Sarco)
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Signs of air
Gradual fall of output of steam-heated
equipment
Air bubbles in the condensate
Corrosion
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(Spirax Sarco)
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(Spirax Sarco)
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What is condensate
Distilled water with heat content
Discharged from steam plant and equipment
through steam traps
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(Spirax Sarco)
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(Spirax Sarco)
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Classification of insulators
Temperature
Application
Medium (90
325 oC)
Low-temperature
heating and steam
generating equipment,
steam lines, flue ducts,
Materials
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Selection criteria
Operating temperature of the system
Type of fuel being fired
Material:
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Thermal Equipment/
Steam
Introduction
Steam distribution system
Assessment of steam distribution
system
Energy efficiency opportunities
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Stream traps
Heat loss from uninsulated surfaces
Condensate recovery
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Thermal Equipment/
Steam
Introduction
Steam distribution system
Assessment of steam distribution
system
Energy efficiency opportunities
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Thermal Equipment/
Steam
1.
2.
3.
4.
5.
6.
7.
8.
Minimize waterhammer
9.
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Routine maintenance
Replacement of internal parts
Replacement of traps
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Repair leaks
Regular leak detection program
Replace flanged joints by welded joints
Leakage estimate
Plume length 1400 mm
Steam loss 40 kg/hr
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Thermal Equipment/
Steam
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Thermal Equipment/
Steam
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(Spirax Sarco)
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Possible solutions
Stagnant film: product agitation
Scale
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Economic
Thickness of
Insulation (ETI)
I+H
Cost
Costs of
insulation
Insulation Thickness
Heat loss
savings
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(Spirax Sarco)
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Reuse as water
Compress with high pressure steam
for reuse as medium pressure steam
MOTI
VE
STEA
M
SUCTION
H.P.
STEAM
L.P.
DISCHA
RGE
STEAM
M.P.
Thermo-compressor
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Steam Distribution
and Utilization
THANK YOU
FOR YOUR ATTENTION
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Thermal Equipment/
Steam
UNEP 2006