Temperature Control for CBD/THC Extraction and Distillation
The legalization of hemp-derived CBD and marijuana-derived THC across many US states and Canada has boosted growth in the extraction and distillation equipment market. Manufacturers of these machines have decades of experience refining processes. They originally developed extraction and distillation techniques for various organic compounds, chemicals, and beverages. However, hemp and marijuana have unique properties. Processors and original equipment manufacturers (OEMs) continue to fine-tune methods for extracting and purifying CBD and THC.
Many different extraction and distillation methods exist. Each has benefits and some drawbacks. However, all require careful control of temperature, pressure or vacuum, throughput volume, and solvent feed rate during extraction.
Extraction Process – Key Temperature Control Considerations
Currently, common extraction methods use CO2, butane, propane, or ethanol. The extraction agent cools down to as low as -80°C (-176°F). Then, pressure liquefies it. A chiller achieves this cooling, either as a standard or custom unit tailored for specific temperature profiles.
Commercial systems often use a jacketed vessel for extraction. A temperature control unit (TCU) circulates water, oil, or other liquids in the jacket. This circulation maintains steady vessel wall and extraction chamber temperatures.
Precise temperature control is essential throughout extraction. Controlling chamber temperature closely affects the final product’s quality and traits. Furthermore, producers need consistent control from batch to batch. Controlling temperature within 0.275°C (0.5°F) ensures product consistency.
Effects of Temperature Variations
Increasing extraction temperature can reduce terpenoid concentration and risk denaturing CBD/THC. It may also increase wax/resin extraction, resulting in more volume but lower quality. Conversely, lowering temperature tends to increase oil concentration and reduce wax content.
Because of these effects, producers must use equipment with precise and repeatable temperature control. Demand exists for variations in extraction products. Thus, chilling equipment and TCUs with high precision and closed-loop controls play a vital role.
Winterization and Decarboxylation Steps
After extraction, processors obtain “crude extract” containing 55-75% cannabinoids. Some processors sell it as-is, but most refine it further.
Winterization cools the extract to about -20°C (-4°F) in a chiller-driven jacketed vessel. This step precipitates unwanted elements. After filtering, the oil retains cannabinoids, chlorophyll, and terpenes.
Decarboxylation activates CBD/THC by heating the extract. This step releases the carboxyl ring group (COOH). Producers may perform decarboxylation before or after winterization.
Distillation Process – Temperature Control Essentials
Distillation completes the purification by separating remaining elements. Even after winterization, up to 40% of the feedstock may still contain impurities. For ethanol extraction, ethanol must evaporate separately.
Similar to extraction, distillation requires careful control of temperature, pressure, and feed rates. These factors ensure high-quality final products with optimal characteristics.
Equipment and Process Details
Wiped film molecular short-path stills are common distillation units. The oil feedstock enters a jacketed vessel heated by an oil-circulating TCU. Temperatures can reach up to 343°C (650°F), though typical distillation occurs between 130-180°C (266-356°F).
Inside, a wiper spreads the feedstock as a thin film on the evaporation chamber wall. Volatile terpenes evaporate and collect in a separate vessel. Meanwhile, CBD/THC vapors condense in a cooler TCU-controlled condenser (60-70°C / 140-158°F).
The final step removes solvents in a cold trap cooled by a chiller.
Integrated Removal of Heavy Residues
Some OEMs design wiped film stills to remove heavier materials during distillation. Chlorophyll, waxes, and other residues descend the vessel walls and collect separately.
Final Purification – Crystallization
Producers may separate THC from CBD via crystallization. A reactor vessel mixes feedstock and solvent, then slowly chills from 60°C to -20°C. This forms a slurry, which goes to a jacketed filter dryer. The dryer uses a circulating hot oil unit to maintain temperature.
This process yields CBD or THC crystals with purities exceeding 98%.
Temperature Control Equipment Specifications
Chillers
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Capacity from 1 to 60 tons; custom sizes available
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Variable speed reduces energy use up to 50%
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Operating range from -18°C to 27°C (0°F to 80°F)
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Accurate closed-loop control to 0.275°C (0.5°F)
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Data logging with remote monitoring
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Industry 4.0 ready
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Durable heat exchanger materials and low maintenance
Temperature Control Units (TCUs)
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Water circulating TCUs operate up to 149°C (300°F)
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Pumps range from ¾ to 7 ½ HP, 25 to 150 GPM
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Heaters range from 9 to 144 KW (low watt density)
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Oil units reach up to 343°C (650°F)
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Pump capacities from 10 to 150 GPM
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Heating only or heating/cooling combinations available
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Dual circuit TCU/chiller options