How To Properly Clean Supercritical CO₂ Equipment?

Supercritical carbon dioxide equipment is environmentally friendly, highly efficient, and selective, making it widely used in the food, pharmaceutical, and cosmetic industries. Proper cleaning of this equipment is crucial for maintaining extraction efficiency, product purity, and equipment lifespan. So, how should this type of equipment be cleaned?

Residues can clog pipelines and reduce extraction efficiency. Cross-contamination between different product batches may affect quality. Long-term residue buildup can also wear down seals and corrode pipelines. Regular cleaning ensures compliance with industry regulations and production standards.

Operators should wear pressure-resistant gloves, safety goggles, and protective clothing. Respirators should be used when necessary. The workspace must be well-ventilated, and a carbon dioxide concentration monitor should be available. Ensure that the pressure relief valve and emergency shut-off device are functioning properly.

Prepare supercritical carbon dioxide as the primary cleaning medium, along with food-grade or pharmaceutical-grade solvents (such as ethanol) for stubborn residues. Tools should include non-abrasive brushes, sponge pads, and dedicated pipeline cleaning tools. Disassembly tools and spare seals should also be ready.

Shut down the equipment and disconnect the power. Close the carbon dioxide supply valve and depressurize the system to atmospheric pressure. Disconnect all pipelines and seal the open ports. For new equipment or units that have been idle for an extended period, perform three cleaning cycles with pure ethanol, followed by purging with supercritical carbon dioxide to remove any remaining solvent.

1.Component Disassembly
Disassemble parts such as the separator, filter, extraction vessel liner, and seals according to the manual. Precision components should be stored separately and handled with care.

2.Supercritical Carbon Dioxide Rinsing
Load the components into the cleaning vessel. Raise the temperature to 31–150°C and increase the pressure to 7–30 MPa to achieve supercritical carbon dioxide. Begin with static cleaning for 1–2 hours, followed by dynamic cleaning for 2–4 hours, using the high diffusivity of the fluid to flush away residues.

3.Treatment of Stubborn Residues
For difficult-to-remove residues, soak components in a solvent such as ethanol for 1–2 hours, gently brushing if needed. After solvent cleaning, purge the system again with supercritical carbon dioxide to ensure complete solvent removal.

4.Component Inspection and Repair
Inspect seals for wear or aging and replace them if necessary. Replace clogged filter elements. Check the inner surfaces of pipelines and vessels for scratches or corrosion. Use cleanliness test paper to verify that no residues remain.

5.Reassembly and Testing
Reassemble all components according to their markings, ensuring tight and secure connections. Perform a leak test by introducing carbon dioxide and holding the pressure for 30 minutes. Once no leaks are detected, run the equipment under no-load conditions while monitoring pressure, temperature, and other parameters until stable operation is confirmed.

Temperature and pressure influence cleaning effectiveness; typical recommendations are 40–60°C and 15–25 MPa. Flow rate is usually maintained at 5–10 L/min. Light contamination may require 2–3 hours of cleaning, while heavy contamination may need 4–6 hours. For polar contaminants, adding up to 5% ethanol can improve cleaning efficiency, provided the system is thoroughly purged afterward.

Never disassemble equipment under pressure-always depressurize fully first. Maintain adequate ventilation to prevent carbon dioxide accumulation. Keep all ignition sources away during solvent cleaning. Operators must receive appropriate training.

Equipment used frequently should be cleaned weekly; moderate-use systems may be cleaned every two weeks. Always perform a thorough cleaning before extended shutdowns. Keep records of cleaning parameters and part replacements, and conduct a full system inspection annually.

Pharmaceutical Industry: Use pharmaceutical-grade solvents and perform microbiological testing after cleaning to meet GMP standards. Automated cleaning systems are recommended for consistency.

Food Industry: Prefer pure carbon dioxide cleaning to avoid solvent residues. For equipment processing coffee or oils, cleaning temperatures may be increased to 50–60°C.

Cosmetics Industry: Focus on removing pigments and fragrance residues. Seals made of food-grade silicone are recommended for better compatibility.

Following these cleaning practices helps ensure reliable equipment performance and consistent product quality. Always refer to the equipment manual and adapt procedures to specific operating conditions.

https://www.landerlee.com/supercritical-co2-cbd-extraction-device/ .If you have any questions or needs in this area, or if your friends or partners require assistance, please feel free to contact us.