The effluent air leaving solvent recovery contains an equilibrium concentration of solvent in the range of 50-70% by weight, dependent upon vapour temperature. The purpose of the mineral oil system is to absorb the residual solvent out of this effluent air stream to less than 1% by weight of solvent before it is safely discharged to atmosphere. The solvent absorption takes place into cool mineral oil. After absorbing the solvent, the cool mineral oil is heated and then the solvent is steam stripped out of the mineral oil under vacuum. The hot, stripped mineral oil is then cooled and circulated back for absorption, forming a closed loop mineral oil system.

Optimised Solvent Vapour Absorbing Efficiency

  • Only 5-20 g/m3 of solvent left in effluent air
  • 8-10 meter tall packing section for optimised oil/vapour contact
  • Stainless steel pall ring packing for optimised oil/vapour contact
  • Cool 20°C vapour entering minimizes packed column loading
  • Cool 23°C mineral oil entering maximizes absorbtion of solvent
  • Only 0.1% M&V in mineral oil entering Solvent Vapour Absorber
  • Only 2% M&V in mineral oil leaving Solvent Vapour Absorber

Optimised Mineral Oil Stripping Efficiency

  • Mineral Oil Stripper under vacuum to minimize solvent in recirculated mineral oil
  • 2-stage Mineral Oil Stripper with flash section plus packed column section
  • Entrainment separator to minimize mineral oil losses and contamination of edible oil
  • Mineral Oil Stripper under vacuum to eliminate water draining required with atmospheric systems

Minimized Solvent Losses During Upsets

  • Final Vent Cooler with chilled water minimizes remaining solvent in vapour stream, even during an upset vapour load
  • Ample recirculated mineral oil flow rate allows for much higher absorbtion rates during an upset vapour load