Amine Gas Sweetening & Acid Gas Removal Calculator
Circulation rate sizing, rich/lean loading, contactor column diameter, and regenerator reboiler steam duty.
1. Sour Feed Gas Stream
2. Amine Solvent Chemistry
3. Reboiler & Tower Hydraulics
Amine Plant Hydraulic & Thermal Performance
Process & Reaction Enthalpy Telemetry
Amine Gas Sweetening & Regeneration Closed-Loop Simulator
Interactive flowsheet: High-pressure contactor tower, rich amine flash tank, lean/rich plate heat exchanger, regenerator stripper column with reboiler steam loop, and overhead acid gas discharge.
5 Fatal Traps & Industrial Engineering Pitfalls
1. Heavy Hydrocarbon Condensation & Severe Amine Foaming
Lean amine enters the top of the contactor typically at 45 to 50 deg C. If lean amine temperature drops below the hydrocarbon dew point of the feed gas (or if inlet gas is cooler than lean amine by less than 5 deg C), retrograde hydrocarbon condensation occurs inside the tower. Liquid pentanes, hexanes, and aromatics form a separate immiscible phase with aqueous amine, reducing surface tension and creating violent foaming. The contactor liquid level collapses into the overhead scrubber within 15 minutes.
2. Over-Loading Rich Amine & Flashing Carbon Steel Erosion
In an effort to minimize circulation pump power, plant engineers sometimes reduce amine flow, allowing rich loading to rise above 0.48 mol/mol. Dissolved CO2 forms aggressive un-neutralized carbonic acid ($H_2CO_3$), and rich amine flashing across the bottom level control valve liberates high-velocity acid gas bubbles. The combined mechanical cavitation and chemical attack strips the iron sulfide protective patina off carbon steel piping, resulting in pipe wall thinning and catastrophic leaks at elbows and tees.
3. Heat-Stable Salts (HSS) Accumulation & Corrosion Runaway
When sour gas contains traces of oxygen, sulfur dioxide, or cyanides, irreversibly bound Heat-Stable Amine Salts (HSS: formates, acetates, oxalates, and thiosulfates) accumulate in the closed loop. HSS cannot be regenerated by reboiler steam. Once HSS exceeds 6% to 8% of total amine concentration, active absorption capacity degrades while solution conductivity surges, driving aggressive galvanic corrosion across regenerator bundle tubes and cross-exchangers.
4. Iron Sulfide Particulate Sludge Choking Structured Packing
Corrosion throughout sour gas systems generates sub-micron iron sulfide ($FeS$) black particles. Without continuous slipstream mechanical filtration (100% full-flow 10-micron cartridge filters plus a 10% to 20% slipstream activated carbon bed), black FeS sludge accumulates in the narrow corrugated channels of structured packing. Liquid distribution channels plug, inducing maldistribution, localized dry spots, and severe weeping that drops H2S removal efficiency.
5. Reboiler Skin Temperature Thermal Decomposition (>150 deg C)
MDEA begins thermal degradation at skin temperatures exceeding 150 deg C (300 deg F), breaking down into corrosive secondary amines, diamines, and volatile organic acids. If reboiler heating utilizes high-pressure steam (>5 barg) or thermal oil with tube-wall skin temperatures above 155 deg C, thermal cracking accelerates exponentially. Plant operators must limit motive steam pressure to 2.5 to 3.5 barg and verify high-velocity circulation across reboiler tubes to prevent localized stagnation hot spots.
Gas Sweetening Material & Energy Balance Equations
The total molar rate of acid gas absorbed ($dot{n}_{AG}$, kmol/h) is determined from sour feed gas rate ($dot{V}_{std}$) and molar fractions:
The required lean amine volumetric circulation rate ($L_{amine}$) is governed by net working loading:
Where $M_{amine}$ is molecular weight ($119.16$ for MDEA, $105.14$ for DEA, $61.08$ for MEA).
The Regenerator Reboiler Thermal Duty ($dot{Q}_{reb}$) combines sensible liquid heating, chemical bond desorption enthalpy, and overhead stripping steam generation: