Distillation Equipment

Short Path Distillation Unit

Mechotech designs and manufactures turnkey short path distillation units — also called molecular distillation units — that separate and purify heat-sensitive or high-boiling compounds under high vacuum. Unlike conventional distillation, which relies on differences in boiling point, short path distillation exploits the short mean free path of vapour molecules: the heated evaporator and the condenser sit only a short distance apart, so evaporating molecules travel straight to the condenser with minimal residence time and thermal stress. This gentle, low-temperature route is used to refine essential oils, remove terpenes, and purify high-value botanical actives to isolate and crystal grade for the nutraceutical, pharmaceutical, food, flavour and fragrance industries.

A Mechotech short path unit spreads the feed as a thin film across a heated evaporator wall using rotating wiper/scraper blades, then evaporates the target molecules under deep vacuum. Because the internal condenser is placed close to the evaporator surface, vapour crosses the short path almost without collisions and condenses immediately — giving very short residence time and protecting delicate, high-boiling compounds from degradation. Units are built in high-grade borosilicate glass for laboratory and pilot work, or in stainless steel 304 / 316 for industrial production, and can be supplied as single- or two-stage systems with a cold trap, magnetically-coupled scraper seal, configurable feed and heating, and PLC/touchscreen control. It integrates directly downstream of Mechotech's SCFE and solvent-extraction lines, taking winterised crude through to a purified distillate or crystal isolate.

Process Flow

Technical Specifications

Technology	Short-path / molecular distillation
Working Principle	Mean-free-path separation of vapour under high vacuum
Construction	Borosilicate glass (lab/pilot) or SS 304 / SS 316 (industrial)
Evaporation Area	Configured to requirement — bench to industrial
System Vacuum	Deep vacuum, down to ~0.001 mbar (configurable)
Operating Temperature	Low-temperature, configured to the target compound
Wiper / Scraper	PTFE wiped-film with magnetically-coupled drive seal
Stages	Single- or two-stage (configurable)
Feed Mode	Knob valve / peristaltic / gear pump (configurable)
Heating	Electric heating belt or jacketed medium (configurable)
Cold Trap	Standard
Automation	PLC / touchscreen control (configurable)
Output	Purified distillate, isolate or crystal-grade fraction

Plant Capacities

Scale	Evaporation Area	Scale / Usage	Configuration	Handling Capacity
Laboratory / bench	up to ~0.1 m²	R&D, formulation, sampling	Borosilicate glass, single-stage	up to ~5 L/h
Pilot	~0.1–0.25 m²	Process development & scale-up	Glass or SS 304 / 316, single or two-stage	~5–15 L/h
Small production	~0.25–0.5 m²	Small-batch / specialty	SS 304 / 316, single or two-stage	~15–25 L/h
Production	~0.5–1.5 m²	Continuous production	SS 304 / 316, two-stage	configured to requirement
Industrial	>1.5 m²	High-throughput continuous	SS 304 / 316, two-stage / train	configured to requirement

Short-path, wiped-film and molecular distillation units are sized by evaporation area; the wiper drive, internal/external condenser, cold trap, vacuum system, feed and heating are scaled to each unit. Handling capacity depends on the feed material and throughput — larger and custom sizes on request.

Manufacturing Process

Feed Charging & Degassing

The crude extract is charged to a jacketed feed tank; light volatiles and residual moisture are flashed off under vacuum before distillation.

Thin-Film Formation

Metered feed is spread into a thin, continuously renewed film across the heated evaporator wall by rotating wiper/scraper blades for rapid, even evaporation.

Low-Temperature Evaporation

Under high vacuum the target molecules evaporate gently at reduced temperature, with very short residence time on the hot surface.

Short-Path Transit

Vapour travels the short distance to the closely-spaced internal condenser almost without molecular collisions, minimising thermal exposure.

Condensation & Collection

The distillate condenses on the internal condenser and is collected, while the non-volatile residue is discharged separately.

Fraction Separation

Single- or two-stage operation separates light and heavy fractions — for example stripping terpenes, capturing the target active, and rejecting heavies.

Cold Trap & Vacuum Protection

A cold trap protects the vacuum system while purified cuts are collected to the required specification.

Applications

Essential-oil refining and terpene removal / decolourisation
Purification of botanical actives to isolate and crystal grade
Refinement of winterised SCFE / solvent crude oils
Vitamin and tocopherol concentration
Omega-3 and fatty-acid ethyl-ester concentration
Monoglyceride, emulsifier and fatty-acid distillation
Flavour and fragrance material purification
Heat-sensitive, high-boiling and high-value compound purification

Key Features

Gentle Low-Temperature Separation
High vacuum lowers the effective boiling temperature, protecting heat-sensitive and high-value compounds from thermal degradation.
Short Path, Short Residence Time
The closely-spaced internal condenser gives molecules a short, collision-free path and very brief exposure to heat.
Wiped-Film Evaporation
PTFE wiper blades form a thin, continuously renewed film for fast evaporation and strong resistance to fouling and scaling.
Single or Two-Stage Fractionation
One- or two-stage configurations separate light and heavy fractions in a single pass for higher purity.
Glass or Stainless-Steel Build
High-grade borosilicate glass for lab/pilot scale, or SS 304 / SS 316 for industrial production, with a magnetically-coupled scraper seal.
Integrates with the Extraction Line
Slots in downstream of Mechotech's SCFE and solvent-extraction plants to take crude through to purified distillate or crystal isolate, under PLC/touchscreen control.

Frequently Asked Questions

What is short path (molecular) distillation?

It is a high-vacuum distillation method in which the heated evaporator and the condenser are placed only a short distance apart. Instead of relying on boiling-point differences, it uses the short mean free path of vapour molecules, so they travel straight from the evaporator to the condenser with very short residence time — ideal for heat-sensitive and high-boiling substances.

How is it different from conventional distillation?

Conventional distillation separates by boiling point at or near atmospheric pressure, exposing the product to higher temperature for longer. Short path distillation works under deep vacuum with a thin wiped film and a very short vapour path, so it separates gently at much lower temperature and minimal thermal stress.

Why use it for heat-sensitive or high-boiling compounds?

The combination of high vacuum, low temperature and short residence time lets you distil compounds that would otherwise degrade — such as botanical actives, vitamins, fatty-acid concentrates and fine fragrance materials — while preserving purity and colour.

What can a short path unit purify?

Essential oils (including terpene removal), winterised SCFE or solvent crude oils, botanical actives purified to isolate/crystal grade, vitamins and tocopherols, omega-3 concentrates, monoglycerides and flavour/fragrance materials.

Glass or stainless steel — which should I choose?

High-grade borosilicate glass suits laboratory and pilot work where visibility helps optimise conditions; stainless steel 304 / 316 gives better heat transfer, throughput and durability for industrial production. Mechotech supplies both.

What vacuum and temperature does it run at?

It operates under deep vacuum — down to around 0.001 mbar — at a low temperature set to the target compound. Vacuum level, temperature, evaporation area and stage count are all configured to the application.

Does Mechotech supply it turnkey and integrated with extraction?

Yes. Mechotech is a turnkey short path distillation unit manufacturer and can integrate it downstream of its SCFE and solvent-extraction plants, delivering design, manufacture, installation, commissioning and support as one system.

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Short Path Distillation Unit