Exam - FurnicoHeat Engineering Co.

Fired heater design multiple choice test.
Conditions:
1. 45 questions, 1-hour time
2. No negative point
3. Once “FINISH” button is pressed the answers cannot be changed.

Fired heater design project.
Conditions:
1. A VC fired heater shall be designed for EOR case based on below datasheet.
2. Solution shall be submitted to:
E-Mail: f.naghsh@gmail.com
Subject format: Gastesh – Engineer name
3. The project shall be submitted no later than Saturday 23rd of Tir 1403

2001-82-ED-PR-DS-H8201-A1-50-ppm-EOR-test Download

QUIZ START

Results

#1. Which one is not a safety concern in direct fired heaters?

cold end corrosion in preheater

low O2

low draft in firebox

accumulation of combustibles

#2. Which one is caused by the excessive heat recovery in mechanical draft heaters?

increased radiant heat flux

reduction in thermal efficiency

Cold End Corrosion at APH

none

#3. Which one is not an architecture to control combustion air on natural draft direct fired heaters?

RSP set by fuel line for FFC on flue gas.

RSP set by fuel line for FFC on combustion air.

RSP set by excess O2 in flue gas for FFC on combustion air

RSP set by draft in the arc for FFC on combustion air.

#4. Chemically bonded plastics are from which group of refractories?

brick

soft

Mg-C

monolithic

#5. For single-fired, box-type, floor-fired heaters with sidewall tubes only, what is the maximum height to width ratio?

2.5

#6. Burning which stream generates fuel NOx?

acrylonitrile

acetaldehyde

vinyl alcohol

Isopropyl acetate

#7. What the maximum apex angle of transitions in cylindrica stack diameters? (degrees)

#8. We intend to post-treat a flue gas using SCR system. Which reagent is NOT used for this purpose?

cyanuric acid

ammonia

urea

caustic soda

#9. What is tramp air?

air burned during combustion

unburned combustion air

unburned air infiltrated into heater

unburned air entering breeching

#10. What is another name for arch?

breeching

ceiling

bridge wall

transition

#11. Which one is not a mechanism for air and fuel mixing in a burner?

eddy formation

entrainment

cross-flow mixing

agitation

#12. What is the difference between combustion and oxidation?

no difference

molar volume of oxygen

phase of water produced

existence of flame

#13. What is the minimum thickness of end tube sheets required by API-560?

16.3 mm

32 mm

12 mm

25.4 mm

#14. Where is a heater draft controlled as a minimum?

radiant section

burner levels

breeching

arch

#15. Assume a natural draft heater. Which cause & effect is necessarily correct?

closing stack damper & opening burner damper reduces draft.

increasing mass velocity of flue gas increases draft.

increasing firebox temperature reduces draft.

none

#16. How much pressure of the total airside pressure drop should be used at the throat of burner as per API-560?

75%

90%

15%

30%

#17. Why are burners staged?

to prevent after burning

to increase thermal efficiency

to increase flame temperature

to control emissions

#18. Which one is a reactor heater?

naphta heater

fired tube boiler

steam methane reformer

water tube boiler

#19. Which one is a more acceptable reason to choose a fired heater over a heat exchanger in a process?

price considerations

high temperature required

foot-print considerations

high heat transfer surface required

#20. If not previously completely dried out to operating temperature, what is the maximum heating rate of castable refractory as per API-560? (deg.C/h)

150

100

#21. Which liquid fuel needs atomization but not preheating?

No.2

No.4

No.6

No.1

#22. Which heater type is normally economical to be used for lowest duties (up to 5 MW)?

cabin

helical

arbor

vertical cylindrical

#23. Which one is the flame color wave length color in direct relation with? (Note: yellow has a higher wave length than blue in visible spectrum)

C/H (vol.)

1/EA

H/C (vol.)

#24. Which is the radiant tubes manufacturing technology?

hot rolling

electrical fusion

SAW

centrifugal casting

#25. Which pressure drops does NOT induced fan make up in a well-designed vertical cylindrical heater?

stack damper

burner airside pressure drop

convection tubes

stack wall friction

#26. What is the result of (HHV-LHV)?

latent heat of fuel per unit air mass flow rate

latent heat of water per unit air mass flow rate

latent heat of air per unit fuel mass flow rate

latent heat of water per unit fuel mass flow rate

#27. Which one causes hot spot in a properly designed heater?

low draft

low process fluid flow

high process fluid flow

high draft

#28. How can we mitigate effects of vanadium ashes generation in fuel gas?

using vanadium removal unit

using bag filter

using soot blowers

using high excess air

#29. We intend to burn a waste gas stream. What is the suitable equipment for this purpose?

direct fired heater

indirect heater

Thermal incinerator

reactor heater

#30. Which liquid fuel vaporizes when it comes into contact with a hot surface?

No.4

No.1

No.2

No.6

#31. Assume we have 250 deg.C process fluid with the fuel having high degrees of sulphur. Which choice of material is better for radiant tubes?

low alloy

stainless steel

carbon steel

inconel

#32. Why are heaters designed for negative pressures?

better combustion in radiant section

lighter structure and casing

higher process fluid exit temperature

personnel safety

#33. Which one is better defined as an air preheater type?

superheater

de-superheater

regenerative

evaporator

#34. How much is the limitation of radiant floor firing density? (Btu/h/ft2)

600,000

160,000

300,000

150,000

#35. What is the range of overall thermal efficiency of a mechanical draft direct fired heater?

78% - 92%

87% - 91%

85% - 92%

75% - 91%

#36. Which burner type has a danger of flash back?

forced draft

pre-mixed

natural draft

raw gas

#37. Increase in average allowable radiant heat flux:

decreases initial cost

increases tube life

decreases peak flux

reduces coking rate

#38. What is the allowable travel time range from damper fully open to damper fully closed? (seconds)

7-10

10-20

7-15

10-15

#39. Which one is not correct? The higher the API degree gravity, ….

the higher the hydrogen content of fuel

the lower the carbon content

the higher the rate of combustion

the longer the flame length

#40. Which one does NOT the flame speed depend on?

stack height

flame interaction with heat absorbing surfaces

fuel gas composition

dimensions of combustion device

#41. 21 % excess air equals how much excess O2 in combustion products?

15.8%

16.59%

4.2%

4.41%

#42. Assume we have 900 deg.C as the exit temperature of process fluid from radiant section. The fluid in preheated in convection section up to 350 deg.C. If nickel alloy is selected as the radiant tube material, what is a good choice for shield tubes?

low alloy

inconel

carbon steel

stainless steel

#43. What is main usage of strakes on stacks?

to hold stack insulation in place

to prevent wind induced vibrations on stack

to help heat transfer from stack

to provide structural stiffening against internal pressure

#44. How much excess air is needed for natural draft heaters with oil as the primary fuel?

15%

20%

25%

10%

#45. Which one is not considered a pollutant in heater design?

SOx

NOx

CO2

Finish