Distillation is a very common process used in various industries. It’s even used in the cannabis and hemp industry to extract the major cannabinoids CBD and THC. While there are numerous techniques to execute the process of distillation, two particular methods stand out – short path and simple distillation. However, not many understand the difference between them. So, what is short-path distillation vs simple distillation?

These are two distinctive methods of distillation employed for separating compounds based on their physical properties, like boiling point, melting point, crystallization, etc.

Understanding the distinctive characteristics of short paths and simple distillation is critical for making an informed decision and choosing the right method for achieving a desired end product. That’s why, in this article, we’ll explain everything you need to know regarding these techniques and the main differences between them.

Short Path Distillation vs Simple Distillation

Understanding simple distillation

Simple distillation is a single-stage distillation process where a liquid mixture is boiled, resulting in vapor condensing. It’s able to separate a mixture of components with large gaps between boiling points, making it one of the most common and useful methods of distillation. Simple distillation is employed to purify a solvent that has a solute dissolved in it. For example, if we take salt water, through this process, salt will be left behind in the flask while the water will be purified.

Furthermore, the separation process of simple distillation can be divided into four main steps:

Heating
Evaporation
Condensation
Collection

The process begins with a flask, or still pot, containing the mixture of liquids. The flask is then heated until the compound with the lowest boiling point starts to evaporate, leaving behind the component with a higher boiling point, which will remain in the flask for a longer time. Once the compound evaporates and rises up, it’s sent through a condenser, where it is chilled and liquified to collect as a separate compound.

The process is repeated until the two necessary compounds are separated.

Understanding short-path distillation

The short path method of distillation, also referred to as fractional distillation, uses an advanced process that includes minimal residence time, high vacuum, and a short distillation path. It works by separating out multiple desirable and undesirable compounds by heating them to a temperature at which one or more fractions of the liquid will vaporize.

During the short-path process, a boiling flask is used to heat crude oil, and the oil is agitated with a magnetic stirrer. The compounds are separated in the oil using heat until they transform into vapor. The vaporized compounds rise up and then are chilled back to a liquid using a condensing coil. As the temperature rises, a new compound fraction is evaporated, re-condensed, and then goes into a receiving flask.

Cannabis oil compounds are separated into three different “fractions”, collected at the different temperature points in the distillation process. This includes:

Main fraction - containing THC and CBD cannabinoids
Heads fraction - containing terpenes and other high volatiles
Tails fraction - containing other high boiling point cannabinoids

Understanding short-path distillation — Source: shutterstock.com / Photo Contributor: Quality Stock Arts

The Main Differences Between Short Path Distillation and Simple Distillation

1. Distillation techniques

Simple distillation is a process that separates a mixture of components with large gaps between boiling points, generally at least 122°F (50°C). It uses a simple apparatus with two flasks and a container. Unlike short path distillation, there is no long column, but a smaller temperature difference is still between the top and bottom corners.

On the other hand, short-path distillation separates mixtures with relatively close boiling points, which makes it great for making THC distillates. It utilizes a complex apparatus with a fractionating column. This element is a long condenser that does not distribute the heat evenly, making it hotter below and cooler on the top.

2. Efficiency and purity

Short path distillation typically outperforms simple distillation due to the pressure vacuum it implements, which significantly helps speed up the process. This also aids in the efficiency of yield, minimizing the loss of volatile components, resulting in exceptional levels of purity.

Simple distillation is commonly used to purify relatively pure liquids, separating organic solvents from solutions to remove mineral impurities. While this method is perfect for separating components with distinct boiling points, it may not be as effective and precise as short-path distillation.

3. Complexity and equipment

The experimental setup of simple distillation is generally more straightforward than short-path distillation. Typically, it consists of a simple apparatus, having two flasks and a container, making it easy to use and relatively cost-effective.

On the contrary, short-path distillation often requires specialized equipment, resulting in a complex apparatus and a fractionating column. This includes:

Condensers
Chilling units
Heating equipment for evaporation
Vacuum pump and gauge
Receiving vessel

The intricate design and precise setup engineering lead to a greater initial setup cost for short-path distillation.

4. Advantages and disadvantages

Comparing short path distillation and simple distillation, you’ll run into several pros and cons both methods exhibit.

Simple distillation cannot be used for separating two liquids with a small gap between boiling temperatures, where, in such cases, short path distillation is employed. This method is a widely used technique, especially in the energy and transport sector, as it effectively separates even the most complex mixtures. Additionally, it’s able to produce a higher purity distillate with minimal decomposition when compared to simple distillation.

However, simple distillation is one of the most straightforward processes, offering a suitable and effective solution when separating mixtures containing non-volatile solutes. Additionally, due to the ease of use and simple apparatus, this process is less energy-intensive and offers minimal operating costs when compared to short-path distillation.

The Main Differences Between Short Path Distillation and Simple Distillation — Source: shutterstock.com / Photo Contributor: SD_FlowerPower

Conclusion

In conclusion, comparing short-path distillation vs simple distillation is essential for choosing the most suitable technique to achieve optimal separation efficiency and product purity. While simple distillation remains a fundamental method for separating solutions with distinctive boiling points, short-path distillation excels in precision and sophistication when dealing with mixtures with relatively close boiling points.

These two methods have distinctive characteristics in various factors, including the distillation process, efficiency and purity, complexity, and equipment used. Both provide exceptional advantages but also have several limitations. That’s why understanding their characteristics is vital for manufacturers to optimize distillation and ensure the quality of final products.

Hopefully, this article has helped you gain a better insight into short path and simple distillation.

Short-Path Distillation vs Simple Distillation