Module 3 Alkalies and Amine Treating Flashcards

1
Q
Amine SCC (ACSCC)
found where?
A

HAZ (non PwHT)

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2
Q
Amine SCC (ACSCC)
affected material?
A

CS/Low alloy

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3
Q
Amine SCC (ACSCC)
critical factors
A

a. type of amine
b. stress
c. temperature

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4
Q
Amine SCC (ACSCC)
is often associate with what type of amine? and at what %?
A

Lean / >2%

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5
Q
Amine SCC (ACSCC)
pure amine is \_\_\_\_\_ corrosion
A

not

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6
Q

Amine SCC (ACSCC)
appearance?
a. Amine SCC initiates on _______side (welds)
b. cracking typically ____to the weld (longitudinal or transverse)
c. could occur process side opposite external ________

A

a. process
b. parallel
c. attachment welds

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7
Q
Amine SCC (ACSCC)
c. thoroughly \_\_\_\_\_\_ non-PWHT
A

water wash

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8
Q
Amine SCC (ACSCC)
\_\_\_\_\_\_\_\_ effective for surface breaking cracks
A

a. WFMT/ACFM/ECT

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9
Q
Amine SCC (ACSCC)
\_\_\_\_\_\_ effect to detect size cracks
A

b. Angle beam (SWUT/PAUT)

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10
Q
Amine SCC (ACSCC)
\_\_(2)\_\_ may not be used/effective
A

PT/ RT

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11
Q
Carbonate SCC (ACSCC)
affected material?
A

CS / low alloy steels affected

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12
Q
Carbonate SCC (ACSCC)
critical factor? (3)
A

a.WATER/carbonate/stress

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13
Q
Carbonate SCC (ACSCC)
what pH >\_\_\_ is an issue and what level failure typically occurs?
A

7.5

8-10

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14
Q
Carbonate SCC (ACSCC)
ammonia (NH3) does what to the pH
A

increase

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15
Q
Carbonate SCC (ACSCC)
carbon concertation?
A

> 100 ppm BUT no specific threshold

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16
Q
Carbonate SCC (ACSCC)
does Cyanide have any effect
A

NO

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17
Q
Carbonate SCC (ACSCC)
increase N2 feed does what to pH
A

increase PH

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18
Q
Carbonate SCC (ACSCC)
H2S concentration?
A

d. H2S - no specific level of concentration

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19
Q
Carbonate SCC (ACSCC)
where does it occur most often location? (3)
A

Carbonate cracking has been most prevalent in FCC unit main fractionator OVERHEAD condensing and reflux systems,

regenerator cold wall shell

PWHT

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20
Q

Carbonate SCC (ACSCC)
appearance?
propagate ____to the weld in the HAZ OR adjacent base metal within___”

A

a. parallel / 2 in.

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21
Q
Carbonate SCC (ACSCC)
 found \_\_\_\_\_away from the toe of the weld than cracks resulting from SSC or SOHIC.
A

further

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22
Q

Carbonate SCC (ACSCC)
prevention?
PWHT to what temp?

A

1200-1225F

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23
Q
Carbonate SCC (ACSCC)
best mitigation?
A

monitor pH of SW most practical and cost-effective method

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24
Q
Carbonate SCC (ACSCC)
NDE?
A

WFMT/ACFM/ECT effective for surface breaking cracks

25
Q
Caustic SCC (ACSCC)
affected material?
A

Cs/ low alloys/ SS

26
Q
Caustic SCC (ACSCC)
description
A

caustic SCC due to elevated temp

27
Q
Caustic SCC (ACSCC)
critical factor? (3)
A

strength, temp, stress

28
Q
Caustic SCC (ACSCC)
concentration of caustic needed?
A

50-100ppm

29
Q
Caustic SCC (ACSCC)
affected equipment? (4)
A

a. non-PWHT
b. h2S and mercaptan removal units, caustic for neutralization in alkylation units
c. failures occurred in heat traced piping or equipment
d. occur in equipment as the result of steam cleaning after being in caustic service

30
Q
Caustic SCC (ACSCC)
a. propagate \_\_\_\_\_ in HAZ
A

parallel

31
Q
Caustic SCC (ACSCC)
a. propagate \_\_\_\_\_ in HAZ
A

parallel

32
Q
Caustic SCC (ACSCC)
 PWHT to \_\_\_\_min with 1 hour min for CS
A

1150F

33
Q
Caustic SCC (ACSCC)
300 SS offer resistance to cracking? alloy 400
A

No and Yes to alloy 400 will offer resistance

34
Q
Caustic SCC (ACSCC)
type of NDE
A

a. WFMT/ACFM/ECT effective for surface breaking cracks

b. Angle beam (SWUT/PAUT) effect to detect size cracks

35
Q

Amine Corrosion
description?
a. localized corrosion (at high velocity) / general (low velocity)
b. corrosion is not from amine but from ____and______and _______

A

dissolved acid gases (CO2 and

H2s) / heat stable amine salts (HSAS)

anime degradation products (bicines, oxalate, salt)

36
Q

Amine Corrosion

material affected?

A

CS

37
Q

Amine Corrosion

critical factor? 4

A

corrosion depend on type of amine, contaminants, temperature, velocity

38
Q

Amine Corrosion

Most problem can be traced to ____&_____or solution contamination

A

faulty design, poor operating practices

39
Q

Amine Corrosion

Type of amine from most to least corrosion –>

A

MEA, DGA, DIPA, DEA, MDEA.

40
Q

Amine Corrosion

Lean amine not corrosion , unless salts above ___% lean amine is (2) _____

A

2%

low conductivity/high pH)

41
Q

Amine Corrosion

what happen at >220F?

A

can result in acid gas flashing

42
Q

Amine Corrosion

velocity limit for rich amine / lean amine

A

3 to 6 fps for rich amine, and

20fps for lean amine

43
Q

Amine Corrosion

affected units?

A

amine units

44
Q

Amine Corrosion

appearance

A

uniform thinning (localized)

45
Q

Amine Corrosion

what happens to weld when flashing occurs

A

preferentially attacked

46
Q

Amine Corrosion
prevention?
a. Proper operation to the ____ system
b. control local pressure drop to minimize ____
c. upgrade to 300 SS or other materials.
D. avoid ____ to prevent formation of corrosive heat stable salts

A

a. amine
b. flashing

d. air ingress

47
Q

Amine Corrosion

NDE ? (3)

A

VT/ Rt/ UT

48
Q

Caustic Corrosion

affect material

A

a. CS / low alloy steels / 400SS are affected / 300SS

49
Q

Caustic Corrosion

when is 300SS good till ?

A

300 SS is good until passitivity is damage which occurs at 160F to 210F (depends on concentration)

50
Q

Caustic Corrosion

critical factor? (2)

A

High solution caustic, temp >170F in CARBON STEEL

51
Q

Caustic Corrosion

temp limit >___F for CS?

A

170F

52
Q

Caustic Corrosion

localized _____due to a concentration mechanism must exist (DNB, evaporation, deposition of salts)

A

gouging

53
Q

Caustic Corrosion

Caustic gouging typically in boiler tube that may appear as ____

A

grooves

54
Q

Caustic Corrosion

steam generating equipment is BEST prevented through ______

A

proper design

55
Q

Caustic Corrosion

Cs/SS have serious problem at high -__-(2)___

A

high concentration / temp

56
Q

Caustic Corrosion

best material?

A

alloy 400 or nickel

57
Q

The regenerator reboiler and the regenerator are areas where the temperature and __________ of the amine stream are the highest

A

turbulence

58
Q

While the amine does remove other contaminants, the targeted material for removal is which of the following?

A

Mercaptans, CO2 and H2S