Vacuum Operation

Operating below atmospheric pressure changes phase behavior. Liquids boil at lower temperatures. Dissolved gases release easier. Vacuum separation suits heat-sensitive materials, solvent recovery, and degassing applications where atmospheric pressure would cause decomposition or require excessive heating.

Separator Design

Horizontal or vertical vessel with vacuum-rated construction. Gas inlet or liquid feed, vapor space for disengagement, mist eliminator preventing carryover, vapor outlet to vacuum system, liquid outlet to downstream processing. Design prevents collapse under external atmospheric pressure.

Structural Requirements

External pressure creates compression loading opposite normal internal pressure. Vessel walls may need stiffening rings preventing collapse. Heavier construction than atmospheric vessels of same size. Design calculations per ASME Section VIII external pressure rules.

Operating Pressure

Vacuum ranges from slight (700 mmHg) to deep (10-50 mmHg absolute) depending on application. Vacuum distillation typically 50-100 mmHg. Degassing operations 100-300 mmHg. Design pressure includes full vacuum plus safety margin.

Material Selection

Carbon steel with external pressure rating. Stainless steel for corrosive services. Reinforcement rings or thicker walls provide external pressure resistance. Nozzles designed avoiding stress concentrations.

Applications

Vacuum distillation column overhead receivers, crude vacuum tower flash drums, solvent recovery vacuum systems, polymer degassing, chemical process vacuum separation, and any low-pressure separation application.

Vapor Handling

Vacuum pumps or steam ejectors maintain sub-atmospheric pressure. Non-condensables route to vacuum system. Condensable vapors may condense in separator or downstream equipment. Proper vacuum system sizing maintains operating pressure.

Level Control

Level instruments manage liquid inventory. Controllers coordinate with liquid withdrawal and feed rates. High-level protection prevents liquid carryover to vacuum system damaging pumps. Low-level alarm indicates feed problems.

Degassing Efficiency

Lower pressure enhances dissolved gas removal. Agitation or spray nozzles increase surface area accelerating degassing. Residence time allows gas evolution. Proper design achieves target dissolved gas levels.

Safety Considerations

Vacuum relief prevents excessive negative pressure if vacuum system fails. Atmospheric vents protect against collapse. Proper isolation procedures prevent vacuum exposure during maintenance. Design meets vacuum service safety requirements.

Construction Standards

Design per ASME Section VIII with external pressure calculations. Materials rated for vacuum service. Reinforcement per code requirements. Relief and vent sizing for vacuum protection. Complete documentation with structural analysis.

ERGIL vacuum separators provide reliable phase separation under sub-atmospheric pressure in refining, chemical, and specialty applications.