?????????boiler and pressure vessel

1
?????????boiler and pressure vessel

• ?????? ???????????,????????????,??????????????,??
  ??????????several regulations??
• ???boiler ????steam,??(???)??hot water or
  heating media,????small boiler??
• ?????pressure vessel ???????1st type,???????2nd
  type,????????small vessel?????????????????????
• ? ??classification???????????????????,??????????,?
  ????????different management for different scale
  of potential danger?

2
????nomenclature

• ????small boiler???
• ??????pressure smaller than??1 kg/cm2, ?????heat
  transfer area?1 m2???????
• ????????1 kg/cm2, ??????300 mm ??,???600 mm
  ???????steam boiler
• ?????3.5 m2???,?????25 mm???U????,??????5m???????
• ?????3.5 m2???,?????25 mm?????????????????
• ?????10 m ??,??????8 m2???????
• ???????10 kg/cm2, ??????10 m2????????

3
???????pressure vessel

• ???????1st type ???????????steam,?????pressure
  higher than 1 atm??????? ??????????????????????
• ???????2nd type ????????????,?????2-10 kg/cm2
  (??????2 50 kg/cm2), ?????0.04 m3???,??????200
  mm??,???1000 mm???
• ??????small vessel (a) ???????1
  kg/cm2??,?????0.2 0.04 m3????????? (b)???????1
  kg/cm2??,??????500-200 mm?,???1000mm??????????
  (c) P (kg/cm2) x V (m3) ?0.2 0.04 ??????????

4
??Marshall, 1987 ??????????schematic of an
ordinary pressure vessel
5
?????(??)??more terms

• ??container ???????????????
• ????gas-containing ?????????1/2over half???
• ????residual gas container ?????????1/2less than
  half?
• ????low temperature
• ?????ultra low temperature ????-50oC???????liquef
  ied gas?
• ??storage tank ???????????????
• ?????? high gas pressure ??????????
• ????treatment equipment ???,????????????????????
• ????pressure reducing equipment

6
??examples on special high pressure gas

• ????high pressure air
• ????high pressure hydrogen
• ??,??,??,???liquefied ammonia, oxygen, nitrogen,
  chlorine
• ?????,?????liquefied oil gas, LNG
• ????high pressure acetylene
• ??????epoxyethane,?????bromoform
• ?????high pressure reactor ??????,???

7
??????????Pressure range for some common chemicals

• Nitric acid 2 10 bar
• ???????????liquefied gas storage tank?? 15 bar
• ????hydrogenation reaction 20 500 bar
• urea 200 500 bar
• methanol 50 500 bar
• ammonia 300 1000 bar
• PU 50 2000 bar
• acetic acid 50 1500 bar

8
??????????a few points on management

• ?????????qualified person in charge,????????one
  person for one vessel,????during
  operation,????????????????????
• ????????????boiler in designated
  building,??????????separated by walls?????fuels
  away from boiler??????1.2m, ??????2m????
• ???????????????no entrance sign,????????,?????????
  ????,????????show copy of certificates for
  equipment and person
• ????????????level meter for high and low levels
  one of safety device,??????????

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• ???safety valve??????????????,???????,????????rema
  in unchanged during operation
• ???????,??????????????mark for highest allowable
  pressure,?????????to remind operators
• ????????????,???????
• ??????????safety distance,???????????,?????????,??
  10 m ?????
• ?????combustible gas,?????red mark or
  letters?????????????

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• ????????????dike or embankment
• ??????high gas pressure equipment???????1.5???????
  ??(1.5 x ordinary pressure for pressure-resistance
  test),????????????ordinary pressure for
  gas-tight test
• ???????sustain earthquake effect???????
• ??????safety valve????rupture disc?????,??????,???
  ??????inside toxics removing system
• ???????????large liquefied gas storage
  tank,??5m???,????????emergency shut-off valve
• ?????liquefied gas storage tank??,????????????not
  over90 capacity

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??????????inspection of dangerous equipment

• ???before construction ??type??(document)
• ???during construction ????welding,??structure??
• ???installation ??completion?? (????to issue
  certificate) ?????,?????re-exam for imports
  ?????????,??????inspection for modification
• ????during use ????regular inspection
  ????,???????????,??????

12
??Marshall, 1987 ????????????????
13
??????

• NDE nondestructive examination
• ???visual
• ????? x-ray or ?-ray
• ???ultrasonic detection???? ???? 1 25 MHz ??
• ??????magnetic powder flaw detection
• ??????liquid or dye
• Eddy current ????circular pipes,????????????imped
  ance, ????
• ???? holographic interferometry
• ?????acoustic emission
• ?????gel electrode

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???????Test on overall container

• ?????????,??????????????,???????,??????????
• ? ????water pressure test
• ? ????gastight test
• ? ????pressure-resistance test
• ???????high risk,????????????by specialized
  company

15
??Marshall, 1987 ???????????????(?????????)
??????????,???????????(??????,???????)
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???????causes of accidents

• ???????????,????????,??????(loss of containment
  rupture of leak) ,??????,???????
• ?????????reasons
• ? ????material problem ???????,???????,?????????
• ? ????design ??????,???????
• ? ????construction ????????,?????
• ? ????during use ??????operating condition
  different from design???????,????poor
  maintenance?????

17
???????design of pressure vessel,??????????
????material behavior,????(??)stress-strain
analysis,??????(quality assurance?????)???????????
safety factor???3-5?
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????????? reasons for material rupture

• ???????deadly impact from others ?????????due to
  accident
• ????(fatigue), ????????(cyclic actions)????,
  ????(creep deformation), ??????
• ????(brittle) ?????low temperature,???hydrogenati
  on????????,???????????,??????bubble formation
  from certain molecules due to high
  temperature,?????????

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• ????high temperature effect
• ??? thermal shock
• ??vibration
• ????chemical effect ????????corrosion,???????????
  under stress,?????stress corrosion cracking (SCC)

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??Marshall, 1987 ?????????????statistics of
rupture of pressure vessel
21
???????different choices
Temp both high and low temperature ???????
??plastics,??glass,??rubber, Teflon?
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???????weak points in a pressure vessel

• ??????????most frequent locations of leak
• ? ????connector between pipes ??????poor
  installation,???????expansion/contraction
• ? ????gasket/packing/washer ??????
• ? ??????flange ???,??????,???????,??????????
• ? ???????welding parts ???????corrosion or stress

23
??Marshall, 1987 ???????????
24
??????????(????)if smell something,????????,????
?????,????????????it could turn into a point of
rupture?
25
An Accident Involving Fire Extinguisher

• ????????a safety check-up, ???????(remove fire
  extinguisher to weigh), ???, ?????,??????,
  ??????, ????, ?????, ??600 psig ( 41 bar)
  cylinder ??????like a rocket, ?400???!! ? What
  Can we do?
• ?????????????recognize danger
• ???????????prevent from falling
• ???????? (protective cap)
• ?????????????handle by experts

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Taken from CEP, June, 2008, p.30
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(No Transcript)
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?????????strategy for safe operation of boiler

• ??????keep normal liquid level,???????not too
  high nor too low
• ?????? ???safety valve????pressure
  gauge??????normal
• ?????water treatment to avoid scale or corrosion
  ????,???
• ??????????????regular cleaning of heat transfer
  area ???? (?????,???????,????????)
• ????good ventilation

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???????????gas cylinder in semiconductor factory

• ???large quantity,?????many different
  kinds,??????????????combustible,??toxic,??PH3,
  AsH3, SiF4, etc.
• ??????,????pipelines,????storage
  room?????system???,??????????????????????many new
  technologies
• ??????????????????for storage room,???????pneumati
  c controller, ??????????????????shut-off
  remotely?

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• ?? ??RFO (restrictive orifice flow???????)???????
  ?at the outlet of cylinder (e.g. SiH4),
  ?????,?????????
• ???????new development?? ?????????(sub-atmospheri
  c)???(delivery)????????? ????porous,????high
  surface area material????????,????(???)?????,?????
  ???????????????,????????????,?????????????? (much
  smaller leak rate??60,000?)
• ??????? ???????limited delivery
  rate??????????????

31
????SST, 153-158, July, 2001