Fuel System - Burners tanta universitydd

for engineering

1. FUEL SYSTEM
Furnace Burner Design
Prof. Dr. Eng. Medhat A. M. Elkelawy
[email protected]
[email protected]

2. Burners is the device that is used to combust the fuel with
the oxidizer (usually air) to convert the chemical
energy in the fuel into thermal energy.
Competing Priorities.
Design consideration that have been used in burners
primarily concerned with efficiently combusting of
fuel and transferring the fuel energy to a heat load.
New and increasingly more stringent environmental
regulation have added the need to consider the
pollutants emissions produced by the burners.
Burners

3. Garg [1989] Burners Specifications
•Burner Fuel type
•Heat release and turndown
•Air supply (natural draft, forced draft,
balanced draft)
•Excess air level
•Fuel composition
•Firing position
•Flame dimensions
•Ignition type
•Atomization media for liquid fuel firing
•Noise level
•NOX emission rate
•Whether waste gas firing will be used.

4. General Burners Types
1.Mixing Type.
2.OXIDIZER TYPE
3.Fuel type.
Gas, oil, or combination of gas + oil fuel. Burner firing oil
require some type of liquid atomization commonly
mechanical.
3.Combustion air temperature.
4.Draft type.
Most industrial burners are known as forced draft,
mechanical draft burner, balanced draft.
5.Location.
Burners are often classified by their location in the furnace
or heater.

5. General Burners Types
Mixing Type
A-In Premixed Burners the fuel and oxidizer
are completely mixed before combustion
begins.
Premixed burners often produce shorter and
more intense flame (high temperature
region in the flame leading to no-uniform
heating of the load and higher NOX
emission)

6. Premixed Burners

7. General Burners Types
Mixing Type
B- Diffusion-mixing burners, the fuel and oxidizer are
separated and unmixed prior to combustion, which
begins where the oxidizer/fuel mixture is within the
rang (like candle)
Diffusion-mixed gas burner, or “raw gas” burner,
because the fuel gas exits the burner essentially as
raw gas.
Diffusion Burner have longer flames, lower temperature
hot spot and more uniform temperature and heat flux
distribution

8. General Burners Types
Mixing Type
C- Partially Premixed Burners, Is often used for
stability and safety reasons because it helps
anchor (
فااقياواةقاعا
) the flame, but also
reduces the chance for flashback.
This type of burner often has a flame length,
temperature, and heat flux distribution
somewhere between the fully premixed and
diffusion flames.

9. Partially premixed burners

10. General Burners Types
•Mixing Type
D- Staged
Staged air and Staged fuel,
Secondary and sometime tertiary injectors in the burner
are used to inject a portion of the fuel and or the air
into the flame, downstream of the root of the flame.
Staging is often used to reduced NOX emissions and to
produce longer flame configuration , lower peak
temperature and more uniform heat flux distribution
than non-staged burners.

11. Staged Air Burners
Diagram of a staged-air burner

12. A schematic diagram of a low-NO
x pulverized coal burner. The addition
of oxygen is staged to produce an initial fuel-rich zone in the burner,
resulting in reduced formation of the nitrogen oxides.

13. Modern Zero NOX Emission

14. An example of a coal-fired
combustor designed for
reduced sulfur oxide
emissions. The calcium
adsorbent is typically
limestone. The sulfur in
the fuel is bound to the
limestone, which is
removed with the ash from
the combustion product
gas by a cyclone
separator.

15. Staged Fuel Burners
Diagram of a staged fuel burner

16. Oxidizer Type
Preheated air have been used to increase the
overall burner efficiency .
Oxidizer is also sometime blended with some
the products of combustion(flue gas
recirculation)FGR
•

17. Burners and flames are often classified according to the type of oxidizer that is
used. The majority of industrial burners use air for combustion. In many of the
higher-temperature heating and melting applications, such as glass production,
the oxidizer is pure oxygen. In other applications, the oxidizer is a combination
of air and oxygen, often referred to as oxygen-enriched air combustion.
Schematic shows an air/fuel burner,
which is the most commonly used type
in industrial combustion applications
Schematic of an oxy/fuel burner Schematic of an air-oxy/fuel burner
Oxidizer Type

19. Howard W. Newton
Fluidization, Solids Handling and Processing

20. What is Pneumatic Conveying
System ?
Pneumatic conveying system is a method of
conveying dry powdered material in a pipeline
through air without any moving parts. Pneumatic
conveying system can be routed conveniently (in
horizontal
  or vertical  direction, at an vertical
angle is prohibited) above the working area and
can have bends and elbows to reach the
destination point which gives pneumatic
conveying mode lot of flexibility.

21. Any pneumatic conveying system
shall have four basic components :
1.Prime mover which develops motive force (roots
blower, compressor or centrifugal fan)
2.Feeding device which introduces product into
conveying line (rotary valve, ventury, pressure
vessel)
3.Piping (include bends, elbows and Y- tees, use for
combine 2 or more piping system)
4.Product to air separator (cyclone, bag filter)

22. How many types for Pneumatic
Conveying System ?
1.Vacuum type, usually use blower or fan for prime
mover, its popular for short conveying distance (+/-
15 m) with 1 or 2 bends or elbows. Vacuum type
allow multiple product inlets through the use of
simple diverter valves.
2.Pressure type, usually use compressor for prime
mover, its popular for long conveying distance with
many bends, elbows and Y-tees. Pressure type are
generally used where the feeding point is one and
there are multiple discharge points

23. Generally, The Dilute phase, the
material to air ratio varies between 3
to 10 kg of material to kg of air.
•Conveying velocities are in the range of 18
to 28 m/sec depending on the product
characteristics.
•The quantity of material that is fed into an
air stream is also dependent on material
characteristics like bulk density, particle
size, sieve analysis, frequency distribution
etc.

24. Dense phase (high pressure system,
above 0.1 Mpa) conveying is a widely
known as plug flow systems which is non-
suspension flow.
The material to air ratios is
higher in dense phase conveying
varies between 20 to 100 kg of
material to kg of air.

25. There are 4 (four) system that
are use in common.
A.Solid Dense Phase
B. Discontinuous Dense Phase
C. Continuous Dense Phase
D. Dilute Phase

26. Lean Phase Pneumatic
Conveying System

27. Dense Phase Pneumatic
Conveying System

28. Convey material in the solid fuel phase
condition systems
1-The Gatty system has air injected from a sub-pipe mounted inside
the main conveying line. Since this system is without controls, it
performs better for well-behaved plastic pellet systems. It is difficult
to maintain a low velocity conveying condition with this system,
Marcus et al. (1990).

29. The Buhler Fluid-stat system was first developed by Munschelk-nautz
using a series of bypass pipes every half meter or so. Solids having
good air retention properties are handled nicely with this system. A
variation of this technique is the Moller Turbuflow system. The
designers of this system claim that turbulence is regenerated in the
conveying line.

30. Buhler has also developed a Takt-Schub system which incorporates a
double pulse system. The blow vessel has two gas inlet valves whose
timing can be controlled. The system is operated in an alternating
pulsing manner.

31. A trace air system uses a series of boosters employing a pressure
regulator and a check valve. The Semco systems is depicted in the next
figure. Dynamic Air incorporates a similar concept controlling the air
volume rather than the pressure.

32. Plug Pulse System
The discharge valve is alternatively activated with a gas pulse. This
system works well for free flowing materials. The Miniport is a
ariation of the plug pulse system.

33. Waeschle has developed a pressure
sensing plug system. The boosters in this
system are actuated by pressure rises in
the line.

34. The Fluid-Schub system of Buhler uses valves to inject
air from an auxiliary air line.

35. A system that produces extruded flow of long plugs
can also be devised as shown in the next figure

36. A new low velocity conveying system has been devised by Molerus and
Siebenhaar (1990). This system relies on vibrations being put into the
system by an unbalanced motor. These vibrations cause the materials
to move with a low velocity throughout the system. This system is
particularly useful for fragile materials.

37. Blow Tank Design
This type of feeder has been used successfully in industry to handle a
wide range of products over relatively short distances (e.g., L = 100 to 200
m).

38. However, the application of this type of blow tank to greater distances
and/or capacities (usually in conjunction with a second blow tank unit
in series or parallel to ensure an essentially continuous mode of flow)
resulted in a number of problems.
•Incomplete and/or inefficient discharge of material from each blow tank
mainly due to rat-holing or funnel-flow effects promoted by low pressure drop
across the bed of material, cohesive properties of the bulk solid, and/or,
inappropriate method of blow tank air injection
•Flow instabilities or even pipeline blockage during start-up procedures due
to surge effects caused by the initial high pressure drop across the blow tank
(and hence high instantaneous flow rate of material)
•Pipeline blockage during shutdown procedures due to surge effects caused
by the sudden venting of high pressure air down the pipeline (and hence,
acceleration of product towards the end of the pipeline)

39. To avoid these problems, a number of significant
developments have occurred in the area of blow
tank design, such as:
•Method of air injection
(Kennedy, et al., 1987),
in particular the
fluidizing-discharge-
cone (Wypych, 1995a)
Preferred tandem blow tank feeding system for long-
distance pneumatic conveying

40. Cone-dosing valve (Cürten, 1982) to control and meter the product
into the pipeline. This is achieved by the movement of a double cone
in the vicinity of the blow tank outlet. The cone moves continuously
up and down inside the vessel but the stroke is adjusted by a
proportional-integral (PI) controller based on a conveying line back-
pressure measuring signal and set-point. The higher the conveying or
operating pressure, the lower the cone set point inside the vessel thus
restricting the flow of solids into the conveying pipeline (until a
satisfactory conveying pressure is restored).

41. ADVANTAGES OF DENSE SOLIDS
PHASE CONVEYING

42. DELIVERING COAL FUEL BY USING
ORDINARY CONVEYOR METHOD

43. DELIVERING COAL FUEL BY USING
ORDINARY CONVEYOR METHOD

45. The
End

54. كرحمىفمكحتلاةموظنم
ةرايسلا

56. Continuously variable
transmission

57. مادختسابريياعملاددعتمرارقذاختا
…
طاقنلاةفوفصم
Scoring
 Matrix

58. ءارشرارقذاختاةفوفصم

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50%
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