Lean Amine Corrosion

Line from regenerator to lean amine pump; at regenerator outlet

Temperature

°C

TBD / Site specific

Standard / Monitoring (Max.)

Outlet reboiler (liquid and gas (and liquid-gas) return lines.

Temperature

°C

TBD / Site specific

Standard / Monitoring (Max.)

Lean solvent

Amine residual H₂S loading
(acid-gas loading)

ppmw

TBD / Site specific

Standard / Monitoring (Min.)

Lean solvent

Amine residual CO₂ loading
(acid-gas loading)

ppmw

TBD / Site specific

Standard / Monitoring (Max.)

All lean amine lines

Flow rate

m/s

Site specific (e.g., depends on stability of the operation)

Monitoring (Max.)

Lean Amine

Solvent strength

wt.%

Typically, once a day (depends on frequency of fluctuations of the solvent strength)

Standard / Monitoring (Max.)

Lean Amine

Chloride content

ppmw

TBD / Site specific

Monitoring (Max.)

Lean Amine

pH

TBD / Site specific / typically 3 times a week (but much more frequent than the "fingerprint" or "Huntsman" analyses).

Standard / Monitoring (Min.)

Lean Amine

Temperature

°C

Continuously

Critical (Max.)

Lean Amine

Maximal content of heat stable salts (HSS).

wt.% on total solvent

Site specific but recommended at least once per quarter and additional when the pH IOW is on or nearing the limit.

Monitoring (Max.)

Lean Amine

Maximal Total Suspended Solids (TSS)

ppmw

TBD / Site specific

Monitoring (Max.)

Degradation mechanism can be properly controlled.

• "Yes": HSAS, minimum acid gas loading and the other IOWs in the table above are properly controlled; residual acid-gas loading under control and minimum value established.
• "No": When one or more IOW limits are frequently exceeded.

Relevant process parameters are reliably monitored.

• "Yes": All relevant process variables known and actively monitored.
• "Intermediate": Relevant process variables known but not actively monitored; no limits for operations.
• "No": No IOW available.

Reliable inspections were carried out.

• "Yes": 3 inspections above ‘usually effective’.
• "Intermediate": 1 – 2 inspections above ‘usually effective’.
• "No": No inspections or ineffective inspections.

A (Highly) Effective

Visual examination of 90 -100% of susceptible areas (with removal of internal packing, trays, etc.) and thickness measurements.

90-100% coverage using (automated) ultrasonic scanning or profile radiography of susceptible areas. Inspection of a smaller percentage area is acceptable if the corrosion mechanism is well understood, and susceptible areas known; lower coverage could still provide the level of confidence needed.

B (Usually) Effective

Visual examination of at least 70% of susceptible areas (with partial removal of the internals) including manways, nozzles, etc. and thickness measurements at noted areas of concern.

Inspect 70% of susceptible areas using (automated) ultrasonic scanning, manual ultrasonic measurements (using surface scanning), or profile radiography. Inspection of a smaller percentage area is acceptable if the corrosion mechanism is well understood, and susceptible areas known; lower coverage could still provide the level of confidence needed.

C (Fairly) Effective

Visual examination of at least 50% of suspect areas and spot ultrasonic thickness measurements at noted areas of concern.

Inspect 50% of susceptible areas1 using (automated) ultrasonic scanning, manual ultrasonic measurements (using suface scanning technique), or profile radiography.

D (Poorly) Effective

Any visual examination of less than 50% of suspect area.

Spot ultrasonic thickness measurements or profile radiography without areas being specified by a corrosion engineer or other knowledgeable specialist, e.g., fixed number of CMS with fixed CML configuration without area scanning of individual measurement points (MPs).

E Ineffective

N/A.

N/A.