Wiped Film Evaporator and Vacuum Distillation

Superior Molecular Distillation Process For Liquid Separation and Chemical Purification

Pope Scientific designs and fabricates basic to complex systems using the Wiped Film Short Path Distillation Process for stills, evaporators and hybrid configurations that include fractional columns with wiped-film distillation units, centrifugal molecular distillation units, condensers, evaporation and processing vessels that meet our customer's application requirements, with superior results.

Short Path Distillation And Evaporation Process

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

Visit Knowledge Center For Additional Molecular Distallation Information.

Efficient thermal separation with minimum product decomposition and maximum product quality are results you can expect using this Wiped Film-Short Path process for distillation, evaporation, concentration, separation, purification or deodorization. The Wiped Film process offers far superior performance to flash evaporators, falling film stills, rotary evaporators and similar equipment, in any processing application where heat-sensitivity is a factor.

Thin Film Distillation and Wiped Film Evaporator

Pope Scientific Short Path/Wiped-Film Stills (WFS) and Wiped-Film Evaporators (WFE) successfully separate volatile from less volatile components for Oils, Fats, Chemicals, Polymers, Nutraceuticals, Fragrances, etc., with a gentle process utilizing the thin-film wiping action of feed liquid through a heated cylindrical vacuum chamber with high vacuum (i.e. vacuum distillation/evaporation).

Keys to the superiority of this process include:

  • Short residence time of the feed liquid
  • Significantly lowered temperature due to high vacuum capability, and
  • Optimal efficiency in mass and heat transfer

The brief (seconds) exposure of feed liquid to heated walls is due in part to the slotted wiper design which forces the liquid downward with strict control of residence time, film thickness, and flow characteristics.

High quality components, state-of-the-art fittings and materials, and total quality control during all phases of design, fabrication and testing result in processing equipment offering the highest performance possible.

Download Pope Scientific Wiped-Film Stills PDF. It is an introduction on the molecular background, brief operating description and includes molecular distillation unit applications.

 

 

Process Description - Wiped Film (Short Path) Distillation or Evaporation

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

Feed liquid is admitted into still under high vacuum, immediately spread into a very thin film and forced quickly down the evaporation surface. Heated walls (orange) and high vacuum (yellow) drive the more volatile components (distillate) to the closely positioned internal condenser as the less volatile components (residue) continue down the cylinder. The resulting fractions, thus separated, exit through individual discharge outlets. Depending on application, the desired product is either the distillate or the residue fraction. Small amounts of condensable low MW compounds collect in cold trap upstream of vacuum system. For high solvent loads, an optional external condenser may be installed immediately downstream of the still. (With external condenser incorporated, the internal condenser should be removed to provide a typical "WFE" or Wiped-Film Evaporator configuration.)

Pope adds superior design and construction to the basic wiped-film/short path still process. This has enabled Pope stills to sustain pressures down to one micron for molecular distillation.

  
Typical Applications

  • Biomaterial Concentration
  • Molecular Distillations Of Esters, Fatty Acids, Mono, Di, Omega 3 & Triglycerides
  • Vitamin, Nutraceutical, Essential Oil Isolation
  • Oil Deodorization
  • Water Removal - ppm Level
  • Solvent Recovery
  • Vacuum Distillation of Terpenes, Terpenoids
  • Chlorophyll, Phytosterols, Fat & Wax Removal, with clear distillate
  • Purification After Extraction, (supercritical CO2, butane, hydrocarbon, ethanol, etc.)
  • Concentration of Botanicals & Essential Oils
  • Fractional Distilling via Hybrid Technology
  • Improved Evaporation over Rotary Evaporators, Kugelrohr & Rotovap Apparatus

 

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

Delivering Results

The Best Solution for Your Application in Lab - Pilot Plant - Production Sizes

Separate, evaporate, concentrate or purify by using the superior process of short residence time, at a lower temperature, without degradation of your heat-sensitive material with the wiped-film technique. Examples of configurations for either distillation, evaporation or concentration are shown.

Our engineers work with you to provide the right size for the best results for your application. Standard lab scale stills are available in 2", 4" and 6" sizes with scale up models for pilot plants and processing scale. The key to the most efficent thermal technique is utilizing Pope's custom approach for your solution.

From lab scale to pilot plant to production scale, our custom configurations are ideally suited to your applications. A wide range of materials is offered for your custom configuration.

Still Versions

Wiped-Film Molecular (Short-Path) Still
The molecular distillation design is selected for when the distillate is of high boiling point and/or extremely heat sensitive. High vacuum (to 0.001 torr) and a close proximity internal condenser are utilized.

Wiped-Film Evaporator (WFE)
The evaporator design is selected where there is a significant percentage of moderate or low boiling distillate. Medium vacuum (to 0.1 torr) and a high surface area external condenser are utilized.

Hybrid Still
Hybrid designs combine WFE and Fractional Column technology, for simplicity when separating materials that have close boiling points.

TYPICAL FLOW RATES FOR A WIPED-FILM STILL CONFIGURATION
Based on Equipment Size
Diameter (inches) Surface Area (sq. feet) Surface Area (sq. meters) Typical Flow Rates (kg/hr), Application Dependent
2 0.35 0.033 0.1 - 3
4 1.16 0.108 1.0 - 20
6 2.35 0.218 2.0 - 40
9 5.30 0.49 10 - 100
12 10.50 0.98 20 - 200
20 25.00 2.32 50 - 450
20 37.50 3.48 80 - 700

 

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

 

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

 

Applications

  • Pharmaceutical
  • Biomaterial Concentration
  • Polymer Devolatilization
  • Molecular Distillations Of Esters, Fatty Acids, Mono, Di, & Triglycerides
  • Residue Removal / Decolorization
  • Vitamin, Nutraceutical, Essential Oil Isolation
  • Wax Fractionation
  • Oil Deodorization
  • PCB, Insecticide Removal
  • Water Removal - ppm Level
  • Flavor Purification
  • Solvent Recovery
  • Vacuum Distillation of Terpenes, Terpenoids
  • Chlorophyll, Phytosterols, Fat & Wax Removal, with clear distillate
  • Purification After Extraction, (supercritical CO2, butane, hydrocarbon, ethanol, etc.)
  • Concentration of Botanicals & Essential Oils
  • Fractional Distilling via Hybrid Technology
  • Improved Evaporation over Rotary Evaporators, Kugelrohr & Rotovap Apparatus
  • Many Other Specialties

Examples

2" Lab Size Standard

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

Basic 2" molecular glass lab still, No. electric heater. Also available in stainless steel.

4'' Combination Still/ Evaporators

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

Portable semi-pilot plant utilizes standard glass components on a custom support structure. Designed for versatility.


6" Pharmaceutical Evaporator

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

Utilized for production of high purity final intermediates. Hastelloy C-276 construction. Explosion proof for Class I, Group D, Div. I environment.

6" Two-Stage Molecular System

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

The unit, as pictured, is completely self-contained (including full instrumentation) and ready for evaporation and/or molecular distillation operation by itself, or in combination with existing processes. Continuous, single or two-stage modes, may be selected. The 2.36 sq. ft (0.22 sq. m) 316 stainless steel still bodies (glass or Hastelloy also available) allow feed rates from 10 to 30 liters/hour, depending upon the application. Vacuum levels from 300 torr to better than 0.001 torr, and temperatures from ambient to350 degrees Celsius are possible.


6" Biomaterial Concentrator/Evaporator

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

Fully explosion-proof 316L stainless steel system for concentration of delicate synthetic peptides after HPLC purification processing. Such systems typically replace rotary evaporators as processes are scaled up.

12" Molecular Distillation Plant

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

Single stage 12" (1 sq. M Surface Area) molecular still pilot plant. Removal of light componenets from vegetable oil reaction application.


20" Molecular Still System

Molecular Distillation | Wiped Film Evaporator | Vacuum Distillation

Molecular Still Unit System shown incorporates jacketed 20" still body with 2.3 sq. m surface area, plus baffle type degasser stages. Equipped for high vacuum (to 0.001 torr) and high temperature (to 350°C), this unit is capable of a wide variety of applications.

   

 

Process & Instrument Diagram

 

Definition of Molecular Distillation:

  1. Distillation that is carried out under a high vacuum in an apparatus so designed as to permit molecules escaping from the warm liquid to reach the cooled surface of the condenser before colliding with other molecules and consequently returning to the liquid and that is used in the purification of substances of low volatility.
  2. Vacuum distillation in which the molecules of the distillate reach the condenser before colliding with one another.
  3. Distillation in which a substance is heated under vacuum, the pressure being so low that no intermolecular collisions can occur before condensation

 

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Technology to Labs, Pilot Plants, &
Production Processing Worldwide For 50 Years

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