Desorption Process

Rich solvent from absorber enters column near top. Reboiler heat vaporizes absorbed components and solvent. Rising vapor strips dissolved gases from descending liquid. Regenerated lean solvent exits bottom returning to absorber. Overhead vapor contains stripped components routing to disposal or recovery.

Column Design

Vertical vessel with rich solvent inlet, stripping section with trays or packing, reboiler at bottom providing heat and vapor, overhead condenser if needed, lean solvent outlet, stripped gas outlet, and temperature controls. Height provides stripping stages for target regeneration level.

Operating Principle

Heat reduces solubility releasing absorbed components from liquid. Vapor flow strips dissolved gases from solvent. Temperature and pressure selected balancing regeneration efficiency versus energy consumption and solvent stability. Lower pressure enhances stripping but increases vacuum system costs.

Reboiler Types

Kettle reboilers for simple operation. Thermosiphon circulation reduces fouling. Forced circulation handles difficult services. Steam heating most common though hot oil used for high temperatures. Reboiler duty major operating cost requiring optimization.

Material Selection

Stainless steel resists corrosion from hot regenerated solvent and acid gases. Carbon steel with corrosion allowance for mild services. Special alloys for severe conditions. Materials withstand reboiler temperatures typically 110-150C for amine systems.

Applications

Amine regenerator releasing H2S and CO2 from sweetening solvent, glycol regenerator removing water from dehydration solvent, solvent recovery stripping absorbed organics, activated carbon regeneration, and any system requiring solvent regeneration through thermal stripping.

Energy Optimization

Reboiler duty directly impacts operating costs. Heat integration with absorber reduces energy. Lean-rich exchanger preheats rich solvent using lean solvent heat. Split-flow configurations save energy. Optimization balances capital versus operating expenses.

Overhead System

Total condenser returns stripped components as liquid for further processing. Partial condenser allows gas separation. Reflux section above feed enhances volatile separation from solvent. System design depends on stripped component handling requirements.

Solvent Quality

Regeneration level affects absorber performance. Insufficient stripping reduces absorption capacity. Excessive heat degrades solvent. Temperature control critical maintaining solvent quality. Monitoring ensures proper regeneration without degradation.

Pressure Control

Column pressure affects stripping efficiency and solvent stability. Lower pressure enhances desorption but may require vacuum. Atmospheric operation simplest. Pressure selection balances performance versus complexity and cost.

Construction Standards

Design per ASME Section VIII for operating pressure and temperature. Materials for corrosive stripped gases and hot solvent. Reboiler and condenser sizing per process requirements. Complete documentation with heat and material balance.

ERGIL desorption columns provide efficient solvent regeneration through thermal stripping enabling continuous operation in gas treating and recovery systems.