Boiler, Steam Trapes, Insulation and Steam Distribution System
A boiler is defined as "a closed vessel in which water or other
liquid is heated, steam or vapor is generated, steam is
superheated, or any combination , under pressure or vacuum,
for use external to itself, by the direct application of energy
from the combustion of fuels, from electricity or nuclear
Types of Boiler:
1) Fire Tube Boiler
2) Water Boiler
Fire Tube Boiler:
The fire tube boiler design uses tubes to direct the hot gases
from the combustion process through the boiler to a safe point of
discharge. The tubes are submerged in the boiler water and
transfer the heat from the hot gases into the water.
Types of fire-tube boiler
• Cornish boiler.
• Lancashire boiler.
• Scotch marine boiler.
• Locomotive boiler.
• Vertical fire-tube boiler.
• Horizontal return tubular
• Immersion fired boiler.
• Cornish boiler :
Cornish boiler is a simple horizontal
boiler which belong to the shell and tube
class of boilers. Cornish boiler is much like
the Lancashire boiler. Cornish boiler has the
ability to produce steam at the rate of 1350
kg/hr and can take the maximum pressure of
about 12 bar. Dimensions of the Cornish
boiler shell is 4 m to 7 m in length and 1.2 m
to 1.8 m in diameter.
• Lancashire boiler:
The Lancashire boiler is similar to the
Cornish, but has two large flues containing
the fires instead of one. It is generally
considered to be the invention of William
Fairbairn in 1844, although his patent was
for the method of firing the furnaces
alternately, so as to reduce smoke, rather
than the boiler itself.
• Scotch Marine Boiler:
The Scotch Marine Boiler is a
fire-tube boiler, in that hot flue gases
pass through tubes set within a tank
of water. The general layout is that of
a squat horizontal cylinder. One or
more large cylindrical furnaces are in
the lower part of the boiler shell.
Above this is a large number of
• Locomotive boiler:
Locomotive boiler is the horizontal
fire tube boiler in which hot gases pass
through the tubes and water surrounds
them. Transferred heat from the gases
to water and then converted into
steam. It may also be used as a
• Vertical fire-tube boiler :
A vertical fire-tube boiler or vertical
multitubular boiler is a vertical boiler where
the heating surface is composed of multiple
small fire-tubes, arranged vertically. These
boilers were not common, owing to
drawbacks with excessive wear in service.
The more common form of vertical boiler,
which was very similar in external
appearance, instead used a single flue and
• Horizontal return tubular boiler:
A fire-tube boiler is a type of boiler in
which hot gases from a fire pass through
one or (many) more tubes running through a
sealed container of water. The heat of the
gases is transferred through the walls of the
tubes by thermal conduction, heating the
water and ultimately creating steam.
• The immersion fired boiler:
The immersion fired boiler is
a single-pass fire-tube boiler that
was developed by Sellers
Engineering in the 1940s. It has
only firetubes, functioning as a
furnace and combustion chamber
also, with multiple burner nozzles
injecting premixed air and natural
gas under pressure. It claims
reduced thermal stresses, and
lacks refractory brickwork
completely due to its construction
Water Tube Boiler:
The water tube boiler design uses tubes to direct the
boiler water through the hot gases from the combustion
process, allowing the hot gases to transfer its heat through the
tube wall into the water. The boiler water flows by convection
from the lower drum to the upper drum.
Types of Water Tube Boiler:
• Horizontal Straight Tube Boiler.
• Bent Tube Boiler.
• Cyclone Fired Boiler
Burner is a mechanical device that burns a gas or liquid fuel
into a flame in a controlled manner.
Energy Efficient Burner:
An efficient burner provides the
proper air-to-fuel mixture
throughout the full range of firing
rates, without constant adjustment.
Many burners with complex linkage
designs do not hold their air-to-fuel
settings over time. Often, they are
adjusted to provide high excess air
levels to compensate for
inconsistencies in the burner
Energy Saving Due to Installation of an Energy Efficient Burner
Efficiency Improvement %
Annual Energy Savings
Annual Savings ($)
1 6,250 28,125
2 12,345 55,550
3 18,290 82,305
Cost Savings = Fuel Consumption * Fuel Price * (1-E1/E2)
If the installed cost is $50,000 for a new burner that provides an
efficiency improvement of 2%, the simple payback on Investment is:
Simple Payback = $50,000 ÷ $55,550/ year = 0.9 Years
Even a small Improvement in burner efficiency can provide significant
savings. Consider a 50,000 pound per hour process boiler with a combustion
efficiency of 79% (E1). The Boiler annually consumes 500,000 million British
thermal units(MMBtu) of natural gas. At a price of $4.50/MMBtu, the annual
fuel cost is $2.25million. What are the saving from installing an energy
efficient burner that improves combustion efficiency by 1%, 2%, or 3 %.
• Perform burner maintenance and tune your boiler.
• Conduct combustion-efficiency tests at full- and part-load
• If the excess O2 exceeds 3%, or combustion efficiency values are
low, consider modernizing the fuel/air control system to include
solid-state sensors and controls without linkage. Also consider
installing improved process controls, an oxygen trim system, or a
new energy-efficient burner.
• A new energy-efficient burner should also be considered if repair
costs become excessive, reliability becomes an issue, energy
savings are guaranteed, and/or utility energy-conservation rebates
• Install a smaller burner on a boiler that is oversized relative to its
• Air Properties:
For a burner originally adjusted to 15 % air, changes in
combustion air temperature and barometric pressure cause the
following in excess air:
Expressed as a percent of the stoichiometric
PASSES OF BOILERS
Three-pass firetube boiler:
A 3-pass firetube boiler design
consists of three sets of horizontal
tubes, with the stack outlet
located on the rear of the boiler. A
downdraft design keeps the cooler
water from having an effect on
the hot surfaces within the boiler.
3 pass firetube boilers offer:
• maximized heat transfer
• minimal refractory
• high steam/water storage
• effective handling of wide
A four-pass boiler design consists
of four sets of horizontal tubes, with
the stack outlet at the front of the
vessel. A downdraft design keeps the
cooler water from having an effect
on the hot surfaces within the boiler.
4-pass boilers leverage natural draft
operation which allows cool water to
contact the hottest part of the boiler.
4 pass firetube boilers offer:
• maximized heat transfer
• minimal refractory
• high steam/water storage
• effective handling of wide
BOILER PERFORMANCE TEST
Performance of the boiler, like efficiency and evaporation ratio
reduces with time, due to poor combustion, heat transfer fouling and
poor operation and maintenance. Deterioration of fuel quality and
water quality also leads to poor performance of boiler. Efficiency
testing helps us to find out how far the boiler efficiency drifts away
from the best efficiency.
• To find out the efficiency of the boiler
• To find out the Evaporation ratio
The purpose of the performance test is to determine actual
performance and efficiency of the boiler and compare it with design
values or norms. It is an indicator for tracking day-to-day and season-
to-season variations in boiler efficiency and energy efficiency
1. Boiler Efficiency = Heat Output/Heat Input*100
= Heat In Steam Output(kCals)/Heat in fuel Input(kCals)*100
2. Evaporation Ratio = Quantity of Steam Generation/Quantity of Fuel Consumption
Heat recovery equipment is available to preheat feed water
entering the boiler (economizer) and to capture Btu’s lost
through boiler blowdown (blowdown heat recovery or flash
tank heat exchangers). Such equipment is normally used on
installations where boiler size, operating pressures or the
amount of water make-up justify the economics for the
purchase and installation costs (normally units exceeding
100 hp and operating at 100 psi or more). Maintenance
costs also must be considered before a decision is made for
HEAT RECOVERY EQUIPMENT
Economizers are bent, finned-tube heat
exchangers. They are available in
rectangular or cylindrical styles. The
type of boiler and the overall boiler
room layout may dictate which style is
The products of combustion leaving the
boiler flow through the economizer,
over the finned tubes, transferring its
heat or Btu’s to the boiler feed water.
The efficiency of the overall system can
be increased By 2% to 4%, depending
on fuel being burned, boiler size, and
There are several methods and
equipment used in blowdown heat
In most cases, the systems are used on
continuous or surface blowdown to
control the Total Dissolved Solids
(TDS) in the boiler water.
Blowdown heat recovery equipment
is used for automatic control of the
continuous blowdown, based on
water make-up and cools the
continuous blowdown to a point
where it can be safely dumped to the
sewer system. It transfers heat or
Btu’s to the make-up water, thus
raising the temperature of the make-
up water before it enters the deaerator
or boiler feed system.
An additional piece of equipment, the
blowdown separator , can be installed for
bottom blowdown. The blowdown
separator reduces the temperature of the
bottom blowdown water to a temperature
that would be safe for the sewer system.
However, because of the erratic flow of
bottom blowdown, there is little benefit to
use a blowdown separator as a means to
raise the temperature of make-up water
prior to entering the deaerator or boiler
Another system uses the
addition of a flash tank heat
exchanger. This system works
on the same principle as the
blowdown heat recovery
system, however, it also
provides the benefit of flash
steam. This flash steam can be
reused in the plant, such as
being piped to a deaerator and
mixed with the incoming steam
in the deaerator.
FLASH TANK HEAT EXCHANGER:
During daily operation of a plant, a
sample cooler is normally required to
draw samples of boiler water, so
chemical tests can be performed. The
boiler water, however, is above the
temperature that test equipment can
handle. In most cases, the situation is
resolved with the installation of a
Boiler feed water usually contains two
harmful dissolved gases: Oxygen and
Carbon Dioxide. If the dissolved gases are
not removed before entering the boiler, they
will be liberated by heat and may cause
severe corrosion in the boiler, steam lines,
condensate lines, and heat transfer
equipment, which can prove to be very
costly. The dissolved oxygen and carbon
dioxide can be removed with chemicals.
Depending on the overall system, it may not
be practical to chemically remove the
dissolved oxygen and carbon dioxide from
the feed water. In these cases, a deaerator
should be installed. Because the deaerator
mechanically removes dissolved oxygen
and carbon dioxide, the amount of
chemicals required could be reduced.
BOILER FEEDWATER EQUIPMENT
The deaerator is a pressurized
American Society of Mechanical
Engineers (ASME) tank and may be
the largest piece of auxiliary
equipment in the boiler room. A
deaerator is designed to heat water to
the temperature of saturated steam at
the pressure within the deaerator.
A deaerator provides an effective
means for recovery of heat from
exhaust or flash steam, provides a
location for returning condensate and
accepts condensate first to reduce
excessive make-up water. There are
three types of deaerators available.
The tray type is normally used in
large utility plants.
If plant conditions do not warrant the use of a deaerator, in most cases, a
Packaged Feed System is used. The packaged feed system is an atmospheric
tank that can heat feed water to a maximum of 210°F.
Because they are atmospheric tanks, they are equipped with an epoxy lining
or made from galvanized steel. The packaged feed system heats the feed
water and reduces the amount of dissolved oxygen and carbon dioxide in the
There are many additional pieces of
equipment available to remove
impurities in the make-up water before it
enters the boiler and system. The type of
equipment required is determined by a
water analysis. This equipment can be
classified as pre-treatment equipment.
Filters are available to remove
free chlorine, some dissolved
organics and sediment. They can
also remove suspended solids,
colloidal matter, sand and iron.
There are carbon filters,
multilayered filters, sand or iron
filters. There can be lined tanks,
American Society of Mechanical
Engineers (ASME) code tanks
and automatic operation based on
a time clock, pressure differential
switch or water meter. They can
protect such items as water
softeners, dealkalizers, and
reverse osmosis equipment, etc.
A surge tank could be used under the
following conditions: If there are
intermittent peak loads of condensate
that can exceed the surge capacity of
the deaerator - varying pressures or
temperatures in condensate – gravity
or pumped condensate that have
insufficient pressure to enter the
deaerator on their own. Surge tanks
are atmospheric and accept condensate
and make-up water before it goes to
the deaerator. Surge tanks can be lined
with an epoxy coating to prevent
corrosion. The condensate and make-
up water mix into a blend temperature
as determined by the percentage of
The Flame Safeguard or Programming
Control on boilers are designed to ensure that
the start-up of the burner follows a definite
timed sequence of operation. In addition to
the sequence of operation and after the flame
has been established, the Flame Safeguard
monitors the flame and sets the firing rate of
the burner, as determined by the boiler firing
They also monitor, through the boiler controls, items such as boiler pressure or
temperature, fuel pressure or temperature and they provide for normal shut down of
the burner if the load demand is satisfied, or shut down and alarm if there is a safety
shut down condition.
The Flame Safeguards or Programming Control installed on a boiler can be
classified into three categories:
o Electro Mechanical
o Solid State Electronic
o Micro Processor
FLAME SAFEGUARD EQUIPMENT
The electro mechanical controls have been used from around 1950 until
Solid state electronic controls were introduced in 1984. This type of control
provides for more alarm or monitoring functions than the electro mechanical
controls. The micro processor controls introduced in 1989 not only provide
the functions as the other controls, but also have the ability to send
information to computers and work in conjunction with some energy
management systems. The micro processor type of controls are standardly
furnished on some of today’s modern boilers.
Solid state electronic controlsElectro mechanical controls
After the initial inspection is completed, the new boiler is ready for
startup. Startup can be the most critical period in the life of the
1. Steam piping, blow off and blowdown lines, etc. must be
inspected and ready for operation. All piping must be inspected
for adequate support and expansion provisions.
2. All fuel supply lines must be checked for tightness and leaks.
Strainers are most important to the safe operation of gas and/or
oil fired units.
3. Electrical power lines to the boiler/burner unit are connected
and the voltage required is verified.
4. Hydrostatic test has been completed.
5. Any walkways, platforms, stairs, and/or ladders, etc., that are
needed to permit proper access to the boiler/burner, are installed
and ready for use.
Before the boiler is permitted to go on the line, all of the safety controls
should be checked to make sure they are all operating properly.
The purpose of the flame safeguard control is to monitor the burner start
up sequence, the main flame and control the firing rate during normal
Following is a brief step-by-step:
1. The burner switch is turned on or the operating limit pressure (or
temperature) control closes. If all required limit controls are
satisfied, the blower motor starts and the automatic sequence
2. The programmer actuates the modulating motor and drives it to
high fire position and purges the boiler for a predetermined period
3. The programmer drives, modulating motor and burner linkage back
to low fire position.
4. The ignition transformer is energized and the pilot solenoid
valves are opened. The pilot must light.
5. Trial for ignition period.
6. If the pilot flame is proven, the programmer, after a timed
interval, energizes the main flame fuel valve(s) and trial for
main flame is started, at minimum fuel rate.
7. After a timed period, the main flame has to be established. If
this is completed, the programmer extinguishes the pilot and
then continues to monitor the main flame.
8. The programmer continues to monitor the main flame while the
burner continues to automatically modulate (if the burner is
capable of full modulation) on an increasing or decreasing
firing rate to satisfy the load demand.
9. The programmer cycles to off position and is now ready for
restart upon demand.
1. Know your equipment.
2. Maintain complete records.
3. Establish a regular boiler inspection schedule. The schedule
should include daily, weekly, monthly, semi-annual and annual
inspections or activities.
4. Establish and use boiler log sheets. Log sheets should be tailored
to your equipment.
5. Establish and keep written operating procedures updated.
6. Good housekeeping is a must.
7. Keep electrical equipment clean.
BOILER ROOM CARE
1. Check water level. Ensure there is water in the gauge glass every time
you enter the boiler room.
2. Blow down boiler. Blow down the boiler in accordance with the
recommendation of your feedwater consultant.
3. Blow down the water level controls to purge the float bowl of
possible sediment accumulation. Operating conditions will dictate
frequency of this check.
4. Check combustion visually. Look at the flame to see if something has
5. Treat water according to the established program. Add chemicals and
take tests as outlined by your chemical feedwater consultant.
6. Record boiler operating pressure or temperature.
7. Record feedwater pressure and temperature.
8. Record stack temperature. Changes in stack temperatures could
indicate the boiler is sooting, scaling or there is a problem with
baffles or refractory.
9. Record oil pressure and temperature.
10. Record oil atomizing pressure. Changes in pressure could have
an effect on combustion in the boiler.
11. Record gas pressure. Changes in pressure could have an effect
on combustion in the boiler and indicate a problem in the gas
12. Check general boiler/burner operation. Maintaining top
efficiency is the simple and basic reason for having operating
personnel. Is anything different than it was the day before? If so,
13. Record boiler water supply and return temperatures. On hot
water boilers, record these temperatures to assist in detecting
14. Record makeup water usage. Excessive makeup water could be
an indication of system problems in both steam and hot water
15. Check auxiliary equipment.
1. Check for tight closing of fuel valves.
2. Check fuel and air linkages.
3. Check indicating lights and alarms.
4. Check operating and limit controls.
5. Check safety and interlock controls.
6. Check operation of water level controls.
7. Check for leaks, noise, vibration, unusual conditions, etc. Checking
for these items is a cost effective way to detect system operational
changes. Small problems can be corrected before they become
8. Check operation of all motors.
9. Check lubricating levels.
10. Check the flame scanner assembly.
11. Check packing glands on all pumps and metering devices.
12. Check gauge glass. Ensure there are no cracks or etching in the
glass or leakage around the packing.
1. Inspect burner operation.
2. Analyze combustion.
3. Check cams. Inspect the cam springs for scoring, tightness of set
screws, free movement, alignment of cam followers and other
4. Check for flue gas leaks.
5. Inspect for hot spots. Inspect the boiler to ensure no hot spots are
developing on the outside of the boiler.
6. Review boiler blowdown to determine that a waste of treated water
is not occurring.
7. Check all combustion air supply inlets to the boiler room and burner
to ensure sufficient air is being supplied.
8. Check all filter elements. Clean or replace as needed
9. Check the fuel system to make certain that strainers, vacuum
gauges, pressure gauges and pumps are properly cared for.
10. Check all belt drives for possible failure.
1. Clean low water cutoff . Remove the head assembly or probes and
inspect and clean out any sediment or contamination in the column
2. Check oil preheaters by removing the heating element and inspect
for sludge or scale.
3. Repair refractory. Immediately upon opening the fireside areas, give
the refractories an inspection and start repairs as soon as possible.
4. Clean oil pump strainer and filter.
5. Check pump coupling alignment.
6. Reset Combustion. The entire combustion process should be
carefully checked, O2 readings taken and necessary burner
7. Inspect mercury switches. Inspect mercury switches for
contamination, loss of mercury, and cracked or broken wires.
Replace if any of these conditions are found.
1. Clean fireside surfaces by brush or use a powerful vacuum cleaner to
2. Clean breeching. Inspect breeching and stack and remove any soot build
3. Clean waterside surfaces. Remove all hand hole and manway plates,
inspection plugs from water column tees and crosses and float
assemblies from water columns.
4. Check fluid levels on all hydraulic valves. If any leakage is apparent,
take positive corrective action immediately.
5. Check gauge glass for possible replacement. If internal erosion at water
level is noted, replace with new glass and gaskets.
6. Remove and recondition safety valves. Have them reconditioned by an
authorized safety valve facility.
7. If oil fuels are used, check on the condition of the fuel pump. Fuel pumps
wear out and the annual inspection time is the opportune time to rebuild
or replace them.
9. Boiler feed pumps. Strainers should be reconditioned.
10. Condensate receivers should be emptied and washed out. Make
an internal inspection, if possible.
11. Chemical feed systems should be completely emptied, flushed
and reconditioned. Metering valves or pumps should be
reconditioned at this time.
12. Tighten all electrical terminals. All terminals should be
checked for tightness, particularly on starters and movable
13. Check linkages. Check to ensure the linkage ball connectors
have not worn out. Worn connectors can cause inconstancy in
the linkage movement and result in unrepeatable excess air
levels in the combustion process.
1. The boiler room is for the boiler.
The boiler room should not be considered an all-purpose storage
area. The burner requires proper air circulation in order to prevent
incomplete fuel combustion and production of carbon monoxide.
Therefore, keep the boiler room clean and clear of all unnecessary
2. Knowledge is powerful, as are boilers.
Ensure all personnel who operate or maintain the boiler room are
properly trained on all equipment, controls, safety devices, and
up-to-date operating procedures.1.
3. Look for potential problems.
Before startup, ensure the boiler room is free of all possibly
dangerous situations, such as flammable materials or mechanical
or physical damage to the boiler or related equipment. Clear
intakes and exhaust vents; check for deterioration and possible
BOILER ROOM GUIDELINES
4. Observe new equipment.
Monitor all new equipment closely until safety and efficiency are
4. Develop a maintenance schedule.
Use boiler operating log sheets, maintenance records, and
manufacturers’ recommendations to establish a preventive
maintenance schedule based on operating conditions, as well as on
past maintenance, repairs, and replacements performed on the
6. Inspection matters.
Ensure a thorough inspection by a properly qualified inspector,
such as one who holds a National Board commission.
7. Reinspection matters, too.
After any extensive repair or new installation of equipment, make
sure a qualified boiler inspector reexamines the entire system.
8. Create thorough checklists.
Establish a checklist for proper startup and shutdown of
boilers and all related equipment according to manufacturers’
9. Don’t overlook automated systems.
Observe equipment extensively before allowing an automated
operation system to be used with minimal supervision.
10. Keep safety at the forefront.
Establish a periodic preventive maintenance and safety
1.) Points about the steam trap
a. Mechanical steam trap
b. (On/Off Operation)
c. Test point – downstream of the discharge orifice
2.) Visual inspection
a. Steam trap should be level to the eye
b. Check flow arrow to insure steam trap is installed correctly
3.) Temperature measurement
a. Take temperatures before and after steam trap
b. Temperatures below 212°F or 100°C, steam trap is not in
c. Take temperature at the process inlet. Temperatures at the process
inlet and the steam trap inlet will be relatively close.
4.) Off position during operation
a. Ultrasound level should be low
or zero on the ultrasound meter
b. Long off periods can cause
“loss of prime”
5.) Discharge Operation (discharging condensate)
a. When the inverted bucket drops due to the loss of buoyancy, this
will bring the valve away from the discharge orifice. This action
will allow the steam trap to discharge the condensate.
b. The ultrasound indicator will rise due to the increase in ultrasound
from the discharge cycle. The ultrasound will stay high or full scale
until condensate is discharged from the steam trap. The ultrasound
level (meter) should deflect more than 30% of scale.
c. When condensate is
completely discharged, the
inverted bucket will rise,
due to buoyancy, and bring
the valve in contact with the
discharge orifice .The steam
trap is now in the off
position. The ultrasound
level should be at zero or
d. Ultrasound level should proceed to full or high ultrasound level
during the discharge cycle and return to minimum scale reading or
zero after the discharge is complete.
e. Condensate will crackle and steam will whistle during testing with
the ultrasound equipment, therefore during the cycling there will
be a crackling + whistling sound during the discharge cycle (steam
and condensate passing through the orifice of the steam trap).
f. The steam trap should stay in the off position for a least 15 seconds
before cycling (less than 15 seconds if the steam trap is
g. Discharge – ultrasound meter should increase the ultrasound level.
h. The steam trap has a fast on/off operation.
6.) Light Condensate Load Operation
a. Ultrasound levels will cycle on and
off at low ultrasound levels. This is an
indication of low condensate flows.
7.) Failure Modes
a. Leaking steam
Steam trap valve wear or linkage will cause the steam trap to
leak steam. The following are indicators of leaking steam:
• Ultrasound meter does not return to zero or baseline
after condensate discharge cycle.
• Ultrasound levels are continuous off base line and there
is not distinct cycle/no cycle operation.
b. Blowing steam
Steam trap valve or linkage
failure or over sizing (loss of
prime) will cause the steam
trap to blow steam directly
through the steam trap.
The following are indicators
of leaking steam:
• Ultrasound meter is at
• Hearing a dominant
whistling sound and no
STEAM SYSTEMS IN INDUSTRY
AND OTHER SECTORS
• Steam can be used for heating, drying, moistening and
sterilization of products in industry and other fields
• Steam has advantages in effective heat transfer, indirect or
direct heating and hygienic.
• Special attention shall be given in productivity of steam
production (exhaust gas and blowout losses), distribution
networks and steam users.
• Water treatment and high maintenance needs may increase
• Steam can be produced by steam boilers and steam generators.
• Key factors in economic steam production
o boiler plant
o continuous consumption monitoring
o skilled personnel
• Considerations in boilers
o boiler capacity meets steam requirements
o meters are in good condition
o out-blow is not excessive
o economizer is in operation
o heat transfer surfaces are clean
o boiler has no air leakages
o boiler insulation is in good condition
• Steam use can be either direct or
indirect, but the used energy
amount is the same, but heat
losses may differ.
• In direct use the valuable
condensing water return shall be
• Superheated steam has lower heat
transfer coefficient than saturated
• Moist steam stress equipment
more than dry steam
• Air mixed in steam reduces the
heat transfer coefficient
• Leaks in steam systems
o waste continuously energy (24/7)
o reduce network pressure and energy
o waste valuable condense water
o reduce work safety (blasts)
• To be checked visually or with ultrasonic
o safety valves, steam traps, orifice
connectors, gate valves, unattended
o leakage inspections shall be made at
least twice per year
PIPE AND EQUIPMENT INSULATION
• Pipes, flanges, equipment and
valves shall be insulated
because of heat losses and
• Condense pipes always
insulated, except condense
• Wet insulation causes energy
waste and outside corrosion
• Un-insulated DN 200 valve
may have up to 200 C
temperature and 5 kW
continuous heat loss
• Condense return is important in indirect steam use. Condense
traps are important.
• Precise condense return causes:
o good utilization of condense heat content
o reduction in make-up water needs
• Closure of open condense tank causes
o reduction in heat loss
o reduction in tank corrosion
• Condense tank should be blanketed from oxygen entry by steam
FAILURES IN CONDENSE TRAPS
• Condense return rate shall be monitored and maximized
• Fault trap causes steam-condense mix in condense pipe
leading to increased temperate and backpressure, increased
steam consumption, higher condense and high feed water
• Faults in condense traps should be seek by listening (man /
machine) and by temperature metering (every 2 to 4
UTILIZATION OF BLOWOUT STEAM
• Benefits of blowout
o Reduced steam
o Lost blowout steam
o Capacity of condensing
• Utilization of blowout steam
o Blowout steam usage in
low pressure systems
o Preheating of combustion
air, compressed air and
o Heating of sub-cooled
condense or preheating of
process-water in condense
ECONOMICAL USE OF STEAM
• Steam pressure
o Is defined by required temperature /pressure level
o It is important that temperature/pressure meets the
o It is important that pressure fluctuation is as small
o Steam networks can be divided by pressure
reduction valves to different pressure subnets
• Very important that process automation works properly
• Steam network and equipment shall be started slowly
• Steam heated equipment shall have thermal insulation
• Open liquid surfaces shall be covered against evaporation
• Bypass valves shall be kept closed and watertight
• Minimization of steam pressure, finally replacing steam with
• Drying first by mechanical water removal, then steam-drying
and avoid over-drying
• Avoid unnecessary stand by use of steam systems
Install air-atomizing and low-nitrogen-oxide (NOx) burners for oil-
fired boiler systems.
Install automatic boiler blow-down control.
Conduct flue gas Test of boilers.
Install an automatic flue damper to close the flue when it is not
Install tabulators to improve heat transfer efficiency in older fire tube
Install low-excess air burners.
Install condensing economizers.
Install electric ignitions instead of pilot lights.
Install an automatic combustion control system to monitor the
combustion of exit gases and adjust the fuel-air ratio to reduce
excess combustion air.
Install isolation valves to isolate off-line boilers.
ENERGY CONSERVATION MEASURES FOR
BOILERS AND FIRED SYSTEMS
Maintain insulation on the heat distribution system. Replace
insulation after system repair, and repair damaged insulation.
Provide proper water treatment to reduce fouling.
Replace central plant with distributed satellite systems.
Downsize boilers with optimum burner size and forced draft
Operate boilers at their peak efficiency; shut down large
boilers during summer and use smaller boilers.
Install expansion tanks on hot-water systems that are properly
sized for the system.
Employ heat recovery through desuperheating.
Preheat combustion air, feed water, or fuel oil with reclaimed
waste heat from boiler blowdown and/or flue gases.
Install automatic controls to treat boiler makeup water.
Check steam trap sizes to verify they are adequately sized to
provide proper condensate removal.
Adjust boilers and air-conditioner controls so that boilers do not
fire and compressors do not start at the same time but satisfy
Clean boiler surfaces regularly to reduce scale and deposit,
which will improve heat transfer.
Replace noncondensing boilers with condensing boilers (15%–
20% higher efficiency when compared to new noncondensing
Prevent dumping steam condensate to drain.
Survey and fix steam/hot-water/condensate leaks and failed
Convert steam system to low-temperature sliding temperature
hot-water system. Install complementing steam boilers where
Improve boiler insulation. It is possible to use new materials
that insulate better and have lower heat capacity.
Boiler Horse Power (HP):
BHP = (Lb/hr) * FE/34.5
Where Lb/hr is pounds of steam per hour and FE is the
factor of evaporation.
Cycle of Concentration of Boiler Water:
CYC = Bch / FCh
Where Bch is ppm water chlorides and FCh is ppm feed
Deferential Setting (lb):
Delta s = p1 – p2
Where p1 is the cutout pressure and p2 is the cut in
Factor of Evaporation:
FE = SH + LH / 970.3
Where SH is the sensible heat and LH is the latent heat.
F = P/A
Where P is pressure (psi) and A is area (ln^2).
HP = (d * t) / (t * 33000)
Where d is distance, Fis force, and t is time.
Inches of Mercury (in):
lnHG = p / 0.491
Where p is pressure.
Percent of Blowdown:
%BD = (PP - RP) / PP
Where PR is popping pressure and RP is Reseat pressure
Rate of Combustion (Btu/hr
RC=H / (Vf * t)
Where H is heat released (BTU), Vf is volume of
furnace (ft^3), and t is time (hr).
Return condensate Percentage in feedwater
RC% = (MC - FC) / (MC – CC)
Where MC is the makeup conductivity (μohms).
Static Head pressure (lb)
SHP = Bpr * 2.31
Where Bpr = boiler preesure (psi)
S = HP * 34.5 * t
Where HP is Boiler horsepower and t is time (h).
F to C
C = (F – 32) / 1.8
C to F
F = (1.8 * C) + 32
Total Force (lb):
TF = P * A
Where P is pressure (psi) and A is the area of valve
disc exposed to steam (sq.in.)
Water Column (ln):
WC = P / 0.03061
Where P is pressure (psi)