The company DEVEX Verfahrenstechnik in Warendorf has taken a decisive step in the direction of extracting cannabis oil with the development of the CryoEXS plant. This makes it possible to extract cannabis oil from hemp and then filter it, connect an ethanol retrieval system, and then refine it in a final step by deploying decarboxylation that transforms the acid content of the oil. Sven Wildförster, the managing partner of DEVEX Verfahrenstechnik is certain, “As far as we are aware, this makes us the only supplier of such a very economical complete system in the world.“ Sliding gate valves and aseptic seat valves from Schubert & Salzer provide the highest degree of control precision – even within the sensitive cryogenic temperature range. There is an increasing global demand for cannabis oil, especially the cannabinoid CBD. This non-psychoactive ingredient in the cannabis oil has antispasmodic, anti-inflammatory and anxiolytic effects in addition to it being effective against nausea. This is the reason why the demand is especially increasing on a global scale in the oncological pain therapy and as a food supplement. Cannabis oil manufacturers are provided with a special benefit by DEVEX Verfahrenstechnik with its plant as it uses cryogenic ethanol as an extracting agent. This cryogenic temperature process ensures that the extraction is very gentle and productive. The ethanol also runs through a closed and therefore economical cycle. An ethanol recovery system is also integrated in the plant that at the same time ensures that the residual ethanol content in the remaining biomass is kept to a minimum.

Cryogenic temperatures pose a challenge to control valves

The operating of control valves under cryogenic temperatures places the highest demands on the technology. This showed the distinctive advantages provided by valve solutions from Schubert & Salzer. Even the standard sliding gate valve can be used within a temperature range of – 60°C and + 350°C. “The cooling circuit in our cannabis extraction plant runs in a cryogenic temperature range of max. – 50°C,“ says Sven Wildförster. “This is where we make successful use of sliding gate valves from Schubert & Salzer. We use a refrigerant to cool the ethanol down to the required temperature so as to achieve the best possible result in the extraction. Finding suitable control and shut-off valves was not easy. The sliding gate valve was just the solution we needed as the temperature-controlled regulation is fundamentally dependant on the controlling precision of the sliding gate valve. It is down to these valves that we are able to achieve a very precise cryogenic temperature. We are also able to benefit from both the sliding gate valves and the aseptic valves from Schubert & Salzer that we also use as they have a design that meet our needs. They are narrow and compact in addition to them being easy to install and operate.“ DEVEX Verfahrenstechnik supplies the cannabis extraction plant to customers around the globe. This is where the sliding gate valves display additional excellent benefits such as their low weight, the easy installation and operation, and the simple maintenance. Mr Wildföster on this subject, “We mainly deliver our plants to the place of installation in the form of pre-assembled units, this being accompanied by our engineers. The compactness of the sliding gate valves is an advantage during the installation but not only that: these control valves can be easily maintained by the plant operator after completion of the commissioning, it also being possible to adapt them to the changing process parameters. As we normally fit our plants with sliding gate valves with a size of DN50, the benefit gained by the compactness and the low weight is not quite so striking, but I do not want to miss them, nevertheless. Especially as this makes it much easier for our customers to maintain and service their plants.“

It gets even colder

Sliding gate valves with an optional body extension are available in a cryogenic temperature version of max. – 200°C that can be used for the high precision controlling of liquid nitrogen or oxygen, for example. The maximum control stroke of a sliding gate valve also only amounts to 9 mm here. Not only does thisshort stroke provide short actuating paths and switching times, sliding gate valves are able to achieve opening and closing times of 100 ms for the full stroke with a resolution of 0.1% of the stroke position even when subjected to cryogenic temperatures. Not only do these high dynamics improve the control quality, they also form the basis for control loops with very short reaction times. The special design that comprises two slotted discs that slide against each other and thereby seal against each other, make sliding gate valves one of the few fittings that combine a very high degree of control precision with almost no leakage. The central throttle device organ – the slotted discs that slide against each other – are also hardly affected by wear so that a long lifetime can even be achieved under extreme conditions.

Safe control even in ex-zones