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Core Separations has proven CO2 extraction system solutions to increase your throughput, lower your operating costs and deliver better quality extracts. We can estimate cost per gram of extract for your extraction requirements.  

You can review pilot-scale models details on our Systems page.  Photos of larger and industrial systems are also shown.

You can view the system schematic on this page to familiarize with details discussed here.

Ergonomic and easy to use system design, equipment features such as vessel loading/unloading, efficient product recovery and turnaround time to next batch are important for overall productivity and are addressed in our systems based on our extensive experience.  See below what sets our systems apart in SCF extraction field.

Flow

Mass of CO2 interacting with feedstock per unit of time (solvent to feed ratio) is one of the critical factors for achieving extraction efficiency. High CO2 flow rate capable systems are energy efficient and reduce extraction cycle times regardless of low, medium or high extraction pressure conditions. Labor and energy significantly contribute to extraction cost per batch. Reducing these costs is essential to lowering overall production costs and achieving higher extraction throughput per system. 

Accurate and repeatable COflow is maintained using feedback from a Coriolis mass flow meter to control pump’s speed to a setpoint.  Volumetric flow estimation based on pump’s capacity is meaningless for compressible fluids without density information.     

Pilot–scale systems (single or multi vessel configurations of 5L and 10L) are capable of CO2 flows of 24 Kg/hour (up to 400 grams/min) to 40 Kg/hour (667 grams/min), up to 350 bar and 150 deg. C. Flow is appropriately scaled for larger capacity extraction systems.  Co-solvent pump is available as an option on all systems. 

Pressure  and Temperature

Pumping system and pressure regulation are key components that work in tandem to ensure proper pressure conditions.

The pump’s unique features make it optimal for carbon dioxide delivery in high-pressure production systems. The pump employs piston-actuated diaphragm that isolates liquid carbon dioxide from possible contamination and is driven by frequency controlled high-efficiency motor.   The pump head is cooled to remove heat of compression for accurate and efficient flow delivery. No air is required for pump operation.

CO2 pump’s efficiency is directly related to CO2’s density entering the pump head. This is managed using cooling heat exchanger and chiller.  Precise flow control using a mass flow meter coupled with accurate automated back pressure regulator for pressure control eliminates flow irregularities or pressure pulsations that adversely effect extraction consistency.

Maintaining precise control of pressure and temperature conditions on high-pressure side for extraction and for extract collection in cyclone separators is important for product recovery and eliminating carryover. It is especially critical when using pressure and temperature gradients for fractionation in cyclone separators to enrich or concentrate extracts.

Heat exchangers in addition to appropriately sized and insulated tubing are very important to achieving extraction condition and to avoid plugging or extract precipitation in the tubing.

  • Sub-cooler: This cooler allows sub-cooling CO2 from the cylinder before pumping to avoid pump’s cavitation causes.
  • Pre-Heater:  heater allows heating the CO2 after the pump in a range of desired extraction temperatures.
  • Evaporator: this heater evaporates the CO2 just after depressurization to aid product recovery in cyclone separators.
  • Condenser: The condenser liquefies gaseous CO2 prior to recycling.

Fractionation and extract recovery

Systems’ post-depressurization fraction collection of extracts is unmatched in the industry.  Pressure and temperature gradient across cyclone separators during fraction collection gives more control including ability to trap water and volatiles in a cold trap before recycling CO2 back through the system.  Enriched or concentrated fractions substantially reduce downstream processing effort to recover desired compounds.

Flow stream exiting from automated back pressure and evaporator enters cyclonic separators designed to work at pressures of up to 200 bar. Separators allow efficient extract collection and enable CO2 recycling. Working at higher pressure in the separators minimizes solvent consumption, increases collection efficiency and limits plugging problems.  

The enthalpy required for the cyclonic separation comes from the evaporator and by heating the separators.   Extracts are manually collected (or automatically with option) from the separator’s bottom with a drain valve.  Cyclone separator’s efficient design and size reduces clean-up time between batches and cleaning can be automated in systems with co-solvent pump for “clean in place” recipe to recover residuals after an extraction. 

Operation and control system

Systems are computer-controlled with intuitive point and click graphical user interface (GUI). The control system employs microcontrollers and PID controllers for local control that are connected to computer.  Operator uses GUI process control software running on a PC to monitor and adjust process conditions.   System parameters such as flow rate, pressure, ramp rate, run time are controlled using the GUI.

Readings from flow, temperature and pressure sensors are clearly displayed and monitored for alarm conditions. The software alerts the user in case of an alarm and automatically stops the system if a critical alarm is triggered.   System also has indicator lights to show status of pumps, heaters and any faults.  An alarms view panel in the software has indication and acknowledgement of conditions.  Extraction recipes, alarm parameters, data logging, graphing of parameters is also edited, modified or saved using the GUI.

Quality and safety

Systems are designed for continuous production environments and are a result of over 30 years of experience in delivering SCF solutions worldwide for the most demanding applications. The systems are designed and manufactured in accordance with EU safety standards for machinery manufacturing. These standards encompass equipment and user safety. In particular, systems conform to the PED 2014/68/UE pertaining to pressure vessels and pressure equipment assemblies and with ASME standards, ASME VIII Div. 1 computational code for design and calculations of pressure vessels. The systems are certified to Pressure Equipment Directive of fluid group 1 in PED 97/23 when used with co-solvents. CSA certification is supplied as required.

  • A global hazard analysis is supplied with the system. All operation and safety documentation is supplied
  • Heat exchangers, vessels, separators are electrically heated. The system has precise control to reach set points fast and maintain them. Three probes are used for measurements – probe in the fluid, a probe in the vessel and redundant safety probe as required by safety standards
  • All pressure vessels and heating sources are protected with redundant pressure and temperature safeties
  • High pressure pump has a pressure switch
  • Pressure rupture discs and safety valves are used in the system for mechanical safety
  • Temperature cut-off switches for all heating elements
  • All wetted materials of construction are compatible and wear resistant to carbon dioxide and common solvents ethanol and methanol. 316 SS is used for pressure vessels and PTFE or EPDM for gaskets/seals
  • Tubing and components are insulated as required to minimize environmental losses, condensation and for safety as applicable
  • All sensors including flow, temperature and pressure are continuously monitored and have alarm set points in the control system

The system is compatible and certified for use of co-solvents (cf. fluid group 1 in PED 97/23). The system is not Ex proof certified as a standard option.