Short Path Distillation

Short path distillation gets its name from the distance in which the vapor stream is condensed. In this case, the evaporator wall generates the vapors as the feed moves by gravity, while being agitated and distributed evenly, down the evaporator wall. The vapor stream travels a "short path" directly to the condenser which is located within the evaporator chamber. Since the vapor stream is immediated condensed, the short path distillation process precludes the vapor from forming vapor pressure. This allows ultimate pressures of 0.001 mbar to be attained. This also allows heat sensitive materials to undergo purification at much lower temperatures preventing degradation. It also allows for very high ambient equivalent temperatures to be achieved. Short path distillation in a plant setting is a continuous process.

short path evaporator

All UIC Short Path evaporators are comprised of five main assemblies:
  1. An evaporator body constructed of glass or stainless steel depending upon their size
  2. Roller/Wiper film distribution system
  3. Motor with variable speed drive for the roller wiper system
  4. Internal condenser with side-mounted vacuum connection
  5. Collections trays with drain lines for distillate and residue

What is the maximum practical Vacuum achievable in a Distillation System?
Distillation MethodVacuum Potential
(mm Hg)
AEBP PotentialComment
Batch w/Condenser50465C / 870FLong holding period (at OBP)
Single tray
Fractional Column20500C / 933FLow AEBP
Multiple trays possible
Good separation
Packed Column20500C / 933FLow AEBP
Single tray device
Good separation
Wiped Film Evaporator1585C / 1085FMedium AEBP
External Condenser
Single tray device
Short Path Evaporator0.001740C / 1365FVery High AEBP
Internal Condenser
Single tray device