Flash Process

Hot lean amine leaves the regenerator at 115-125°C and 5-15 psig containing residual dissolved gases. Flash tank operates at atmospheric or slight vacuum allowing these gases to vaporize and separate. Gas exits overhead to vent or recovery while degassed liquid flows to pumps and heat exchangers without vapor lock or cavitation risks.

Vessel Configuration

Vertical or horizontal drum with hot amine inlet, vapor space for gas disengagement, vapor outlet to disposal, liquid outlet to amine pumps, and level control. Internal baffles reduce velocity promoting separation. Simple atmospheric or low-pressure operation needs minimal instrumentation compared to high-pressure regenerator equipment.

Gas Recovery

Flash vapor contains mainly CO₂ with some hydrocarbons and water. Low H₂S content allows atmospheric venting in many cases. Some facilities compress flash gas for fuel use. Others route it to flare. Vapor handling depends on composition and environmental permits.

Design Pressure

Tank operates near atmospheric, designed for full vacuum to 15 psig. Vacuum protection prevents collapse if downstream pumps create suction with vapor outlet blocked. Relief valves guard against pressure buildup. Simple low-pressure construction reduces cost versus rated pressure vessels.

Material Selection

Carbon steel with corrosion inhibitors works for most amine service. Stainless steel for high acid gas loading or elevated temperatures. Tank interior sees less corrosion than regenerator since amine temperature drops and dilution occurs. Atmospheric operation avoids high-pressure material requirements.

Operating Benefits

Removes 60-80% of dissolved gases reducing pump NPSH requirements and eliminating vapor binding. Degassed amine improves lean/rich heat exchanger performance by preventing vapor formation on hot side. Lower dissolved gas content means better treating capacity when amine returns to contactor.

Control Integration

Level transmitter controls amine flow to pumps maintaining inventory. High level prevents overflow to vapor line. Low level protects pumps from gas ingestion. Temperature monitoring tracks flash efficiency. Simple level-based control integrates with amine circulation system.

Applications

Natural gas sweetening units after amine regeneration, refinery hydrogen purification systems, syngas treating plants, and any amine system where dissolved gas removal improves operation. Particularly important in high-pressure contactors where gas solubility increases.

Performance Impact

Eliminates pump cavitation issues common when pumping hot amine with dissolved gases. Reduces rich/lean exchanger fouling from vapor formation. Improves contactor efficiency by reducing inert gas loading in lean amine. Simple addition with significant operational benefits.

Construction Standards

Atmospheric tank design per API 650 or low-pressure vessel per ASME Section VIII. Materials suitable for hot amine service. Vent sizing prevents vacuum or overpressure. Complete documentation with flash calculations and material specifications.

ERGIL lean amine flash tanks improve gas treating reliability by removing dissolved gases protecting pumps and heat exchangers in amine circulation systems.