Fuel Oil Burners
Fuel Oil Burner
► Fuel
Oil Burner must be capable of properly
atomizing the oil within a furnace of
minimum dimensions.
► The burner must be producing efficient
firing over a wide range of oil flow rates.
► The burner must be able to rapidly respond
to changes of load to meet maneuvering
requirements.
Fuel Oil Burner
► Before
combustions can take place the fuel
must be changed from a liquid to a
atomized condition and simultaneously
mixed with sufficient air.
► The burner assembly consists of two parts:
the atomizer which serves to deliver a flow
of atomized oil to the furnace, and the
register which serves to supply a flow of air
to the furnace.
Turndown Ratio
► Turndown
Ratio = Max oil flow / Min oil flow
► Turndown Ratio = (Max Pressure / Min
Pressure)0.5
► If the Fuel oil pump output is 300 psi and
the minimum pressure for atomization is
100 psi
► Turndown Ratio = (300/100)0.5 = 1.732
Burner Systems
► Straight
Mechanical type of atomizer
consists of an atomizer which converts the
potential energy of the oil pressure into a
flow of atomized oil particles.
► The register is designed to introduce and
mix the air with the oil spray produced by
the atomizer.
Mechanical Type Burner
► The
sprayer plate transforms the solid
stream of oil under high pressure into a
cone of fine fog particles by means of
tangential slots leading to the whirling
chamber and outlet orifice.
Mechanical Type Burner
► Sprayer
plates are designated by four digit
numerals, of which the first two digits
represent the size of the drill used in
making the orifice in the sprayer plate, and
the last two digits represent ten times the
ratio of the total cross sectional area of the
tangential slots to the cross sectional area
of the orifice.
Mechanical Type Burner
► The
sprayer plate designation number is
stamped on the face of the plate by the
manufacturer. It should be noted having the
smaller numbers have the larger capacity,
since the smaller number of the drill, the
larger diameter drill which is used to make
the orifice hole.
► The second number on the burner tip is ten
times the ratio of the area of the orifice.
Mechanical Type Burner
► This
ratio determines the angle of the cone.
It should be noted that for a particular
orifice, the larger the angle of the cone, the
shallower the oil spray will be in the
furnace. The capacity of the burner is the
amount of oil, in pounds per hour under
specific viscosity and pressure conditions.
Return Flow Burner Systems
► Return
Flow type of atomizer functions with
a constant pressure oil supply, and the
atomizer barrel contains a passage which
permits a portion of the oil to return to the
fuel oil settling tank.
► The firing rate is varied by regulating the
control valve in the return line.
Return Flow Burner Systems
► This
type of burner is capable of producing
a more uniform fuel oil distribution and a
complete atomization pattern over a much
wider range of load applications than the
straight mechanical type of oil burner.
Steam Atomized Burner Systems
► Steam
Atomizing type of atomizer utilizes a
flow of steam which mixes in the atomizer
tip with the oil flow.
► A portion of the energy in the steam serves
to break up the oil particles and better
atomization results.
Steam Atomized Burner Systems
► This
type of unit provides for a wide range
of firing rates without changing the sprayer
plates.
8Y - 47 – 55 – 50 – 80 - H
►8
– Number of Jets
► Y – Type
► 47 – Drill size of exit
► 55 – Drill size of Steam hole
► 50 – Drill size of Oil hole
► 80 - Angle
► H – High Carbon Steel
Air Registers
► Air
registers form the second part of the
burner assembly and performs the function
of delivering the air to the furnace required
for the combustion of fuel.
► It also serves to distribute the air in such a
manner that it mixes intimately with the oil
at it leaves the atomizer.
Air Registers
► To
a limited extent the air register may be
used to perform the secondary function of
controlling the amount and velocity of air
entering the furnace.
► This control is accomplished primarily by
regulating the dampers or by varying the
blower speed to control the rate or air
discharge of the force draft system
Air Registers
► Air
registers may be either conical or
cylindrical. The burner opening is at right
angles to the face of the front wall.
► The register door arrangement may be
classified as axial door, radial door or a
combination of both.
Air Registers
►Air
registers when open direct air flow
from the double casing into and around
the cone of fog like oil particles
produced by the atomizer.
►When closed, they prevent air from
entering the furnace.
►When closed, they are not air tight.
Air Registers
►Present
air registers employing pressure
atomizers, consist of two principle parts
the diffuser and air foils.
►The use of two separate air streams.
►The primary thru the diffuser.
►Secondary thru the air foils has enabled
capacity and flexibility to be increased
greatly..
Air Registers
►The
diffuser institutes primary mixing of
the oil droplets with air and prevents
blowing of the flame from the atomizer
►The air foils guide the major quantity of
air to mix with oil particles, after they
leave the diffuser and to envelop the
flame.
Air Registers
►The
construction of the diffuser, air foils
and register doors is such that the oil
and air are given a whirling motion in
the clockwise or counter-clockwise
direction.