Three-Stage Compression

Large ammonia systems use three stages achieving high discharge pressure for synthesis or refrigeration. Each intercooling step condenses ammonia requiring separation. Third-stage separator provides final liquid removal ensuring dry gas enters final compression stage.

Separator Configuration

Vertical knockout drum before third-stage suction. Compact design with gas inlet, liquid sump, mist eliminator, gas outlet to compressor, drain system, and safety shutdown. Minimal liquid volume expected but critical to remove.

Operating Pressure

Third-stage suction pressure typically 8-15 bar for refrigeration, higher for synthesis applications. Design accommodates interstage conditions with safety margin. Heavier construction than lower pressure stages.

Liquid Sources

Residual condensate from incomplete second-stage separation. Additional condensation from temperature variations. Minimal quantities but must remove preventing mechanical damage to high-pressure cylinders operating at maximum stress.

Material Selection

Carbon steel with ammonia-resistant specifications. Compact vessel construction. Mist eliminator captures fine droplets. Design handles thermal cycling and ammonia phase behavior at operating conditions.

Safety Priority

High-level shutdown directly interlocked with compressor emergency stop. Redundant level instruments provide fail-safe protection. Fast valve closure prevents liquid reaching cylinders. Critical protection for most expensive compression stage.

Applications

Multi-stage ammonia refrigeration in large cold storage, ice manufacturing plants, ammonia synthesis compression trains, and industrial refrigeration requiring high discharge pressure. Third stage operates at highest mechanical stress needing absolute liquid protection.

Separation Efficiency

Removes free liquids and mist ensuring bone-dry gas to third stage. Wire mesh captures submicron droplets. Combined efficiency exceeds 99%. Minimal pressure drop preserves suction conditions for efficient compression.

Liquid Recovery

Collected ammonia drains to intermediate pressure or recovery system. Liquid volumes small but recovery prevents losses. Drain coordination with overall ammonia inventory management.

Construction Standards

Design per ASME Section VIII for operating pressure. IIAR compliance for ammonia refrigeration. Safety systems per compressor requirements. Complete documentation with interlocking diagrams.

ERGIL third-stage suction separators provide final liquid protection ensuring safe reliable operation of high-pressure ammonia compression equipment.