Technology Review: ZWAG Nutsche Filter for CBD Isolate Applications
For many years, the CBD industry fought archaic regulations and a lack of mass acceptance by consumers. This has all but changed recently thanks to improved legislation and a better understanding of the medicinal benefits.
This new resurgence has resulted in CBD isolate manufacturers facing the challenge of scaling their manufacturing capacity while ensuring consistent product cost and quality, workplace safety, and meeting regulations.
These manufacturing challenges can be met with technology that follow Current Good Manufacturing Practices (CGMPs) and Clean in Place (CIP) methodologies.
In the filtration process of making CBD Isolate, typically a vacuum Büchner funnel is utilized to pull the solvent and cannabinoid mixture through the filter – leaving behind the crystalline CBD. The crystalline CBD is then dried in a separate, stationary tray dryer. However, this process is inefficient to scale-up, resulting in production bottlenecks and safety concerns.
The ZWAG filter, an all-in-one Agitated Nutsche filter dryer offers manufacturers the ability to scale their production goals while maintaining CGMP compliance and full solvent containment. At the largest size, the ZWAG filter is able to crystallize, filter, wash and dry over 2,000kg of dry CBD isolate per batch with zero detectable residual solvent.
Cannabidiol (CBD) is a naturally occurring cannabinoid that has been cultivated to grow in high concentrations in hemp plants. In recent years this compound has shown preliminary evidence as a useful treatment in many ailments and continues to grow in usage.
While CBD comes in various forms that can contain other cannabinoids, terpenes, and THC, its purest form is CBD Isolate. During the isolate production process, the CBD extract is refined to strip away all impurities and photocannabinoids, including THC, resulting in a final product that is a 99% pure, odorless, and tasteless crystalline powder. This powder is easily able to be mixed with oils, supplements, gums, and extracts with a high degree of dosage and purity certainty. Additionally, this isolate can be used as a building block to synthesize other minor cannabinoids.
Production of CBD Isolate
To produce CBD isolate, CBD must first be extracted from the hemp. This follows well-known crude CBD extraction processes. Post extraction the CBD concentrate is still full of plant material so further purification is required (Figure 1 Stage 1). First a filtration & winterization stage removes fats, lipids, proteins, and residual biomass from a chilled mixture (Figure 1 Stage 2).
After winterization, the CBD oil is further purified using a fractional distillation that helps recover extraction and/or winterization solvent while also removing other undesirable compounds such as chlorophyll and terpenes. The product of distillation is a clear, refined oil containing CBD and other minor cannabinoids (Figure 1 Stage 3).
Figure 1: Block flow diagram for the refining of a pure CBD Isolate
The crystallization and isolation processes are used to further separate CBD from other minor cannabinoids. To begin crystallization, the CBD oil is dissolved in a non-polar solvent in a reactor. Typically, pentane is the non-polar solvent of choice, but other examples include hexane or heptane. The temperature of this solution is gradually cooled until precipitation begins to occur. Temperature and agitation speed are both reduced until the solution is fully crystallized (Figure 1 Stage 4).
In the final stage of producing a pure CBD isolate, the slurry containing CBD crystals must be filtered, washed, and dried (Figure 1 Stage 5). The filtration stage separates the CBD crystals from the mother liquor. The crystals should be washed with ice cold non-polar pentane, to remove impurities contained in the mother liquor from the surface of the isolate. The isolate is soluble in pentane so care should be taken that the use of wash liquor is minimized to prevent isolate loss. Finally, all residual pentane is dried from the crystals down to PPM levels prior to downstream packaging.
Agitated Nutsche Filter Dryers: The All-In-One Solution