1. By
Edward Moschetti
Control Specialties
2503 Monroe Drive
Gainesville, GA 30507
770 532-7736 Toll Free 800 752-0556
Fax 770 535-0536 emoschetti@aol.com
See our website at
www.control-specialties.com
for more information
Boiler OperationsBoiler Operations
1

2. Steam
The Original Recyclable
Form of Energy
2

3. A Boiler is a Pressure Vessel
With a Burner or
Other Energy Source Used
To Convert Thermal
Energy From
One Form to Another
Example
Burn Natural Gas to Generate Steam
3

4. Average Steam System Efficiency
An energy survey and load balance on a typical steam
system in average condition will yield the following losses
Boiler Room Losses
Stack losses 21%
Blowdown losses 4%
Boiler radiation losses 3%
Total Boiler Room Losses 28%
Distribution Losses
Insulation losses 7%
Steam leaks 6%
Blowing steam traps 7%
Flash steam losses 13%
Return System losses 9%
Total Distribution Losses 42%
Total Steam System Losses 70%
Placed in perspective, if you are spending $500,000 per year for
boiler fuel, only about $150,000 of thermal work is being delivered
into your product or process.
Average Steam System Efficiency
An energy survey and load balance on a typical steam
system in average condition will yield the following losses
Boiler Room Losses
Stack losses 21%
Blowdown losses 4%
Boiler radiation losses 3%
Total Boiler Room Losses 28%
Distribution Losses
Insulation losses 7%
Steam leaks 6%
Blowing steam traps 7%
Flash steam losses 13%
Return System losses 9%
Total Distribution Losses 42%
Total Steam System Losses 70%
Placed in perspective, if you are spending $500,000 per year for
boiler fuel, only about $150,000 of thermal work is being delivered
into your product or process.
4

5. Steam
Boiler
Energy Sources
•Natural gas
•Oil
•Waste gas
•Coal
•Wood
•Other
Steam
Heating Hot Water
Heating Autoclaves
Heating Metal Platens
Heating Rotating Dryers
Heating Process Air
HVAC Equipments
Other Applications
Process and HVAC Equipment
Deaerator
Feedwater
5
Boilers Convert Primary
Energy Sources to Energy
In the Form of Steam
The Basic Steam Loop
For the most
efficient
operations, boiler
operations should
be integrated with
steam demand.

6. • Thermal energy is used in a wide range of applications to manufacture
products as well as provide comfort during cold weather. Take a
moment and glance around your current location and see if you can
identify anything you might see which did not use thermal energy to
produce it.
• BTU is the amount of heat to raise one pound of water one degree
Fahrenheit.
• One pound of water yields one BTU of thermal energy when cooled
one degree Fahrenheit.
• One pound of steam yields approximately 1000 BTU’s when
condensed.
• Steam is a common heat transfer media due to the large amount of
heat which can be transmitted through a pipe. Other heat transfer
media are offered such as thermal oils. We will limit our discussions
to steam and hot water for this presentation since the basic principals
and equipment are similar.
6

7. ENERGY DATA ALL ARE EQUAL TO
1,000,000 BTU
• 1 MCF of natural gas
• 1,000 cubic feet of natural gas
• 1 decatherm of natural gas
• 10 therms of natural gas
• 293.1 KW of electricity
• 7.29 gallons of # 2 oil
• 10.93 gallons of propane
• 1,000 lbs of steam
• 29.31 boiler horsepower
• 1 MCF of natural gas
• 1,000 cubic feet of natural gas
• 1 decatherm of natural gas
• 10 therms of natural gas
• 293.1 KW of electricity
• 7.29 gallons of # 2 oil
• 10.93 gallons of propane
• 1,000 lbs of steam
• 29.31 boiler horsepower
7

8. Gas Cost (MCF) # 2 Oil (gallon) Propane (gallon) Electricity
(KWH)
$5.00 $.82 $.46 $.0171
8
If natural gas costs $5.00 per million BTU’s-
•Number 2 oil would have to cost $.82 per gallon
•Propane would have to cost $.46 per gallon
•Electricity would have to cost $.0171 per KWH
Energy
Cross Over Costs

9. Gas Cost (MCF) # 2 Oil (gallon) Propane (gallon) Electricity
(KWH)
$5.00 $.82 $.46 $.0171
$6.00 $.82 $.55 $.0205
$7.00 $.96 $.64 $.0239
$8.00 $1.10 $.73 $.0273
$9.00 $1.24 $.83 $.0307
$10.00 $1.37 $.92 $.0341
$11.00 $1.51 $1.01 $.0375
$12.00 $1.64 $1.10 $.0409
Energy
Cross Over Costs
9

10. Combustion Efficiency
10
Fuel Valve
Air Damper
Combustion
Analyzer

11. Combustion Efficiency
The optimum point
for most boilers is
3% O2
11
Heat up the
stack
Smoke

12. Fuel to Steam Efficiency =
Output BTUs
Input BTUs
Efficiency and Radiation Loss
• Efficiency is the ratio of output from a piece of equipment as compared to the input
• Radiation loss is the heat lost from the boiler shell
• The larger the boiler, the larger the radiation loss
• Typical values for radiation loss are ~ 4% of full capacity
• Boilers are typically under fired and operate in the 40-60% load range
• A boiler operating at a 50% firing rate would have a radiation loss of 8%
• As an example assume the combustion efficiency is 81% and the blow down losses are 2%
• The predicated Fuel to Steam Efficiency would be 71% (81%-8%-2%)
12

13. Radiation Loss
13
Radiation loss is rated as a
percentage of 100% boiler output
and is typically 4% for most firetube
boilers
Since the radiation loss off a boiler does not change,
a boiler operating at a 75% firing rate will have a
radiation loss of 6% as a percentage of boiler output.
At a 50% firing rate, the radiation loss rises to 8%.
The lower the percentage load, the higher the
radiation losses become since fuel is being wasted
to keep the boiler hot.
Boilers which cycle in and out of operation have
very high losses due to radiation and purge losses.

14. Boiler Size 200 HP
Firing Rate 50%
Delivered HP 100 BHP
Combustion Eff. 81%
Radiation Loss 8% (50% firing rate doubles the radiation loss)
Fuel to Steam Eff. 73%
Gas Use (MCF/Hr) 4.73
Cost per Hour $33.11
6000 Hours/Year $198,660
14
Cost to Produce 100 BHP
Using Various Boiler Sizes
Gas Cost $7.00 per Million BTU’s
6000 Hours of Operation per year
Boiler Specification of Radiation Loss-4%

15. Cost to Produce 100 BHP
Using Various Boiler Sizes
Gas Cost $7.00 per Million BTU’s
6000 Hours of Operation per year
Boiler Specification of Radiation Loss-4%
Boiler Size 200 HP 135 HP 100 HP
Firing Rate 50% 75% 100%
Delivered HP 100 BHP 100 BHP 100 BHP
Combustion Eff. 81% 81% 81%
Radiation Loss 8% 6% 4%
Fuel to Steam Eff. 73% 75% 77%
Gas Use (MCF/Hr) 4.73 4.60 4.48
Cost per Hour $33.11 $32.20 $31.36
6000 Hours/Year $198,660 $193,200 $188,160
15
Multiply these figures for larger or smaller boilers

16. Lead Lag Boiler Controls
Firing Rate 50% 75% 100%
Cost per Hour $33.11 $32.20 $31.36
16
Boiler
1
Boiler
2
Steam to Plant
A Simple Example
•Case 1-One boiler carries load at 100% firing
rate with a cost of $31.36 per hour.
•Case 2-Two boilers each firing at 50% carry
the load with a cost of $33.11 per hour.
•Lead Lag Savings is ~6% by using a lead lag
controller.
Lead Lag
Controller

17. Blow Down Considerations
• As water is boiled, sediment in the water settles and scum rises to the surface.
• Surface blowdown deals with the surface contaminants.
• Bottom blow down deals with the sediment.
• Proper water treatment on a daily basis if critical to the service life of a boiler.
17
Conductivity based
surface blowdown
controller
Heat exchanger bottom
blowdown heat recovery
system

18. Fuel to BoilerFuel to Boiler
Steam to
Plant
Steam to
Plant
Boiler
Consider
Meters
Consider
Meters
18
Measuring Fuel to Steam Efficiency
1 GPM = 500 Lb/Hr
Feedwater
Meter
Meter
Meter

19. Boiler Losses
Combustion Efficiency 75-86%
Radiation and Convection Losses 0.3-6%
Boiler Design and Load Management 2-7%
Scale Buildup in Boiler 7-11%
Excess Boiler Blowdown 0.1-1%
Excess Air 0-7.5%
Range of Efficiency 42.5-76.6%
(Source ASHRAE Journal September 1994)
Boiler Losses
Combustion Efficiency 75-86%
Radiation and Convection Losses 0.3-6%
Boiler Design and Load Management 2-7%
Scale Buildup in Boiler 7-11%
Excess Boiler Blowdown 0.1-1%
Excess Air 0-7.5%
Range of Efficiency 42.5-76.6%
(Source ASHRAE Journal September 1994)
19

20. Watertube Boilers
•Efficiencies to 76-80%
•Gas, oil, coal and other
solid fuels
•15,000 lb/hr and up
•Large site built units for
power generation and
very large loads
•Expensive to purchase
and maintain
•The choice for large to
very large applications
20

21. Firetube Boilers
•Efficiencies to 78-81%
•Gas, oil, and propane
fired
•Limited options on solid
fuels
•10-1200 BHP (1
BHP=34.5 lb/hr)
•Work horse boiler for a
wide range of applications
•Moderate cost to
purchase and install
•Construction and design
spec’s can affect price
21

22. Electric Boilers and Heaters
•Efficiencies to 98-99%
•Electrode and resistance types
•Sizes up to 1000 BHP
•No products of combustion
•No alternate fuel options
•Expensive to operate
•Expensive to install-power side
•RTP rates can be very expensive
•Power company will add
incentives
22

23. Electric Boilers and Heaters
•Efficiencies to 98-99%
•Electrode and resistance types
•Sizes up to 1000 BHP
•No products of combustion
•No alternate fuel options
•Expensive to operate
•Expensive to install-power side
•RTP rates can be very expensive
•Power company will add
incentives
23
Electric Boilers-a few thoughts
•Sold on the basis of 98-99% efficient, zero emissions, and simple installation.

24. Electric Boilers and Heaters
•Efficiencies to 98-99%
•Electrode and resistance types
•Sizes up to 1000 BHP
•No products of combustion
•No alternate fuel options
•Expensive to operate
•Expensive to install-power side
•RTP rates can be very expensive
•Power company will add
incentives
24
Electric Boilers-a few thoughts
•Sold on the basis of 98-99% efficient, zero emissions, and simple installation.
•1.02 BHP = 10 kWh A 200 BHP boiler would require a 2000 kWh power source.
•Cost of steam = 293.1 x kWh rate for an electric boiler ($.07 x 293.1 = $20.52 per million BTU’s.
•Cost of steam for a gas fired boiler = (Gas cost)/(Efficiency) $5.00 at 80% = $6.25 per million BTU’s.
•Power audits used to understand steam loads and switch customers from natural gas.
•Carbon footprint for natural gas about 25% less than coal and oil.

25. Summary of Boiler Types
• Watertube Boilers (Many Brands)
• Firetube Boilers (Many brands)
• Low Volume Watertube Boilers (Miura)
• Steam Generators (Clayton)
• Electric Boilers (Many Brands)
• Old Boilers
• Best suited for high volume steam
production from 25,000 lb/hr up to
building sized boilers.
• Size range up to ~ 1200 HP (41,400
lb/hr). Most boilers installed are FT’s .
• Modular concept with high efficiency
and PLC based control. Small footprint
and good for retrofit applications.
• High efficiency coupled with high
range of operating pressures. Small
footprint and good for retrofit
applications.
• Suitable in specialized applications
such as no boiler stack possible, small
loads, point of use need for steam, no
flame requirement and others.
• New Boilers
25

26. Boiler Link-less Controls
Improve Boiler
Efficiency 3-5%
Most boilers use a
mechanical system to
manage the air fuel
mixture. Mechanical
combustion systems are
hard to maintain, drift in
adjustment and lead to
extra fuel being burned to
operate your boilers.
26

27. Servo operator for
air damper
Servo Operator
for gas valve Servo operator for
FGR controlsServo operator
for oil valve
Control Panel
Full feature PLC controller allows for precise programming
of fuel, air, FGR and number 2 oil setting.
•Complete data display of boiler operations.
•Easily integrated with building management control
systems.
27

28. 28
Boiler Stack Economizers
Boiler stack economizers
will typically increase
combustion efficiency by ~
4%.
The typical temperature
drop across a stack
economizer is ~ 100 F.
The heat removed from the
stack gas is used to boost
the feedwater temperatures
into the boiler or preheat
boiler feedwater.
Stack dewpoint must be
carefully considered to
prevent acid formation in
the stack.

29. Feedwater Conditioning
Removing O2 and CO2
29
Deaerator
Pressure Vessel
Boils feedwater to drive off gases
225-227 F Water Temperature
Operating Pressure 5-7 psig
Feedwater Heater
Non code Vessel
Chemicals added to bind gases
190-200 F Water Temperature
Operating Pressure O psig
O2 Causes Oxygen
Pitting on Boiler Tubes
CO2+H20 =
Carbonic Acid
Corrosion
Red Brown Rust

30. Boiler Feedwater Pumps
30
NPSH
Net Positive Suction Head
(NPSH)
Required distance in feet to
prevent pump cavitation
Cavitation occurs when water
is pumped out faster than it
can enter the pump which
leads to water vapor forming
inside the pump which
destroys seals and impellers

31. Water Softeners
Typical Make Up Water Spec’s
0 CaCo3 Hardness
pH 7-9
Less than.5 ppm O2
Less than 30 mg/L Chlorides
Less than 30 mg/L Silica
Below .5 mg/L Iron
Below .5 mg/L Manganese
31

32. Blow Down Separators
Cold Water
Inlet
Surface and Bottom
Blowdown from
Boilers
Steam to Outside Vent
160 F Boiler and Cooling
Water to Drain
32

33. Older Boilers
• The average boiler in service is typically 30+ years old.
• Consider an 1979 automobile to a 2009 model.
• Older boilers can be upgraded with linkage less controls, economizers, and
better PLC based control systems.
• Boilers should be tuned at least twice per year.
• Boilers should be matched to the connected load.
• Two boilers running in parallel to carry a load wastes fuel.
• Lead lag systems typically reduce fuel use by at least 5%.
• Consider setting back or shutting down boilers over a weekend-do the math.
• Water treatment is critical to boiler life.
• Water softeners are critical to boiler life.
• Consider meters to provide a basis of system health.
33

34. Boiler Considerations-Before You Buy Be Aware
• First cost vs. long term cost. A boiler will use 3-4 times the
purchase cost of the boiler installed in energy per year.
• Understand boiler efficiency vs. manufacturer claims.
• Be aware of efficiency claims by other utility companies.
• Match the boiler to the connected load.
• Emission requirements. All boilers over 10 million BTU’s must
be air permitted and low NOx.
• Fuel options and back up.
• If a single boiler installation, will failure of the boiler shut down
operations?
• Space and installation issues?
• In most states, the installer must be licensed and the boiler
permitted.
• Avoid buying a boiler. Buy a boiler room.
34

35. Average Steam System Efficiency
An energy survey and load balance on a typical steam
system in average condition will yield the following losses
Boiler Room Losses
Stack losses 21%
Blowdown losses 4%
Boiler radiation losses 3%
Total Boiler Room Losses 28%
Distribution Losses
Insulation losses 7%
Steam leaks 6%
Blowing steam traps 7%
Flash steam losses 13%
Return System losses 9%
Total Distribution Losses 42%
Total Steam System Losses 70%
Placed in perspective, if you are spending $500,000 per year for
boiler fuel, only about $150,000 of thermal work is being delivered
into your product or process.
Average Steam System Efficiency
An energy survey and load balance on a typical steam
system in average condition will yield the following losses
Boiler Room Losses
Stack losses 21%
Blowdown losses 4%
Boiler radiation losses 3%
Total Boiler Room Losses 28%
Distribution Losses
Insulation losses 7%
Steam leaks 6%
Blowing steam traps 7%
Flash steam losses 13%
Return System losses 9%
Total Distribution Losses 42%
Total Steam System Losses 70%
Placed in perspective, if you are spending $500,000 per year for
boiler fuel, only about $150,000 of thermal work is being delivered
into your product or process.
35