for providing heat They mix the fuel and air to create a stable flame. Position
can be:
in the firebox
In the floor In the walls
6
H eater Flo or and B ur ner L ayout
RADIANTCOIL
PEEP HOLES ACCESS DOOR REFRACTORY 7
Refractor y L in in g for Fi red H eaters
Contain high temperature combustion Protect steel casing and structure
Oxidation
Corrosion
Erosion
Minimize heat losses Inside of a stack with refractory lining of concrete 8
T ypes of Refractor y
Insulating Firebrick
Castables (concrete)
Hot-face layers. All areas of fired heaters
Ceramic fiber
Blanket, Block, Module
9
W hy Con vectio n Sectio n?
Improved heat recovery Flue gas inlet temperature760-2,500°C Flue gas outlet temperature260-400°F
10
Convection Section
Fluid and flue gas are in a cross flow arrangement.
Tubes are laid out in triangular pitch.
Flue gas flow area is rectangular. 11
Convectio n Sectio n Coils
BAFFLES
Bare tubes Extended surface tubes ¾ Finned tubes ¾
BARE TUBES
Studded tubes
Casing
Refractory corbels 12
Shield Section The
bottom part of the convection section shields it from direct radiation.
Receives
the heat from both radiant and convective means.
Bottom
2 or 3 rows are considered as shield or shock section. 13
Conv ection Coil s Bare
Tubes
Located in the shock section
Extended
Surface
Finned Tubes Studded Tubes
Studded
Finned
14
H eader Boxes The
header box houses the return bends.
They
are used in convection sections and sometimes in radiant sections
.
15
Upper Radiant and Arch Section
16
T ube Suppo rt s Tubes
in the radiant and convection section need to be supported.
Tube
supports keep tubes straight and support their weight.
17
I ntermediate T ubeSheet Convection Section Intermediate Tubesheet
18
Tube Supp or t M aterial Radiant
Section
25 Cr- 20 Ni ( SS 310 ) 25 Cr- 12 Ni 50 Cr-50 Ni
Convection
Section, in addition to above 19 Cr-9 Ni
21/4 Cr- 1 Mo
5 Cr- 1/2 Mo
Carbon Steel
19
Peep D oo rs One
of the most important components for operation.
Provides
a direct view of what is happening inside the firebox.
20
Stacks Purpose Safe disposal of flue gases
Creating for air supplydraft and flue gas flow
Dispersion
of flue gas pollutants like
SOx and NOx 21
M or e H eaters Com pon ent s Arch
Breeching Bridge wall Access door
22
M or e H eaters Com pon ent s Corbels Crossover
Tube Pulling Door
23
M or e H eaters Com pon ent s Stack damper
Pier
Ladders and platforms
24
O fftakes and Stack A rrangement Damper
25
Stack STACK TIP STRAKES
Strakes Platforms Ladders PLATFORMS
LADDERS
26
Fi rebox Conf igurati on Vertical Cylindrical
Box
H or izont al Coil vs. V ert ical Coil
Coil L ayout H orizonta l vs. V ert ical INLETS
BURNERS
CO N V ECT IO N SECTION
FIN N ED TU BES SH IELD
TU BES
RADIA
NT
TU BES
RADIA SECT
NT
RADIAN T
IO N
SECTION PEEP DO O R
BU RN E RS
OUTLETS
29
En d Wall Fired
Floor Fired H eater
30
N atural D raft
STACK
CONVECTION
RADIANT
AI R
BURNER
AI R 31
STACK
Balanced D raft CO LD FLUE
GA S
DAMPER WITH
ID fan
ACTUATOR HOT FLUE
GA S
FD fan AI R PREHEATER
CONVECTION SECTION
RADIANT SECTION R I A T O H
COLD AI R
BURNER
ID
FD
FA N
FA N
32
V ertical Cylind rical H eater w it h H or izon tal Co nv ectio n Sectio n Low
plot space requirement Economical Any number of passes Convection
section- compact design Large, few burners Tube lengths are limited to 18-20 m. Very popular design 33
H oriz onta l T ube Cabin H eater
Size 6 -40 MMkcal/hr
Even number of passes
Small burners
STACK
DAMPER
BREECHING
CONVECTION SECTION FINNED
TUBE S
SHIELD TUBES
Tube 26 ftlengths up to Large plot space requirements
RADIANT SECTION
RADIANT TUBES PEE P DO OR
BURNER
FLOOR
34
T win Ce ll H orizonta l T ube Cabin H eater
STACK
DAMPER
BREECHING
Size 25- 75 MMkcal/hr
CONVECTION SECTION
F INN E D TUBE S
Additional radiant cells
SHIELD TUBES
RADIANT
possible
TUBES
RADIANT
RADIANT SECTION
SECTION PEEP DOOR
BURNERS
35
D ouble Fi red V ert ical T ube Box H eater Features
Uniform heat flux Lower peak tube metal temperatures High temperature applications
36
A rbo r Coil H eaters STACK
Features
Large manifolds
Parallel passes
DAMPER BREECHING
CONV ECTION FINNED TUBES
SECTION
SHIELD TUBES
Floor fired or end wall fired RADIANT
Single or double fired
TUBES RADIANT SECTION
BURNERS
PEEP DOORS
FLOOR
37
Refin ery H eaters Four major building blocks
Atmospheric heater
Vacuum heater
Coker heater
Catalytic Reforming heater
38
A tmosph eri c H eaters Inlet temp = °C Outlet temp= °C kg/ 2 Outlet pressure = cm g kg / 2 Pressure drop cm Largest years run length kcal Avg. heat flux/hrm2 Coil material-
39
V acuum H eater Parameters Inlet/Outlet temp./ °C kg/ 2 Outlet pressurecm g Average heat transfer rate kcal/
hrm
2
kg/ 2 Pressure drop cm Outlet velocityof sonic velocity Peak fluid temperature Gradually increase pipe size of last 3-4 tubes towards the outlet
40
STACK
DAMPER
BREECHING
CONVECTION SECTION FINNED/ STUDDED TUBES
BARE TUBES
RADIANT TUBES
RADIANT SECTION PEEP DOORS
Coker H eater Inlet temp.Outlet temp. Outlet pressurepsia
°C °C
Average heat transfer rate 2 kcal/ hrm kg/ 2 Pressure drop cm Cold oil velocitym/s
BURNERS
41
Catalyti c Refor min g H eater Inlet/Outlet temp. / °C Operating pressure kg/ 2 cm Typical heat flux kcal /hrm2 Pressure drop kg /cm2per stage
