This kind of separator is different compared to the gravimetric separator, while S1 works by gravity force, S2 works by centrifugal force. The fluid moves very quickly creating a vortex inside the vessel. The fluid continues to spin and the particles of extract begin to separate moving toward the walls of the separator, sliding to bottom. This separator applies the Cyclonic Effect to separate fractions.The flow creates a cyclone inside this separator and all the compounds in the fluid are condensed along the internal walls of the vessel. The temperature of the walls determines which compound will be condensed.

With this operation, we can obtain the lighter solutes, and clean up the CO2. Our machines are equipped with 2 cyclonic separators, which are separator 2 (S2) and 3 (S3), because the first one (S1) is the gravimetric separator. S2 and S3 has got one important difference:

Separator 2 is heated, therefore the condensation point is high and light lipid-soluble compounds are collected here.

Separator 3 is cooled, therefore the condensation point is very low and water and light water-soluble compounds are collected here

This is the first Separator (S1). It applies the gravimetric effect to separate the extract in fractions. This separator is heated at set-point temperature.

When the mixture of CO2 and chemical compounds extracted are directed in this separation, the solvent’s temperature and pressure goes down thanks to a particular valve, which is called “Lamination Valve“. With this operation, the supercritical CO2 becomes a gas and it loses its solvent properties and so it releases the solutes that, for the gravity’s effect, fall down, in the bottom of the separator, ready to be collected.

In this separator the operator will collect all the heavier compounds, but to remove the lower compounds, water included, other operations of separation have to be conducted, with other separators.

We say that a liquid is in equilibrium with its gas when the same mass is exchanged from the gas to liquid and from liquid to gas. This happens continuously, and this point id strongly dependent on pressure and temperature. The change in temperature produces a change in the pressure, because, when high, more liquid CO2 turns in gas increasing pressure and when low more gaseous CO2 turns in liquid decreasing the pressure.

The pressure cannot give any information about the liquid CO2 level in the reservoir, but the pressure in a CO2 tank will be the same in the range from 0.1& to 100% of the liquid level inside! Therefore, a liquid level sensor is necessary to control the level. But the level is strongly dependent on the pressure and temperature inside the tank. So, to have a good control on the CO2 liquid level is mandatory to have a temperature control in the CO2 tank.

There are many point we can find the equilibrium points between gaseous CO2 and liquid CO2. All these point are situated along the CO2 Equilibrium curve. Choosing the best point is part of the system designing procedure, because it define the level of the liquid CO2 in the reservoir. As the CO2 condensing temperature at CO2 bottle pressure is about 14° C (57° F) , we chose this value to control the pressure in the reservoir. The control is fully automatic.

The Corilolis flow meter is basically a mass flow meter. It gives you exactly the mass of CO2 is delivered by the membrane pump, with at least three advantages if compared to traditional meters:

It has no moving parts. It works at full pressure at the outlet of the pump without compromising the suction flow or producing cavitation. It works with all the fluids status, gas, supercritical, liquid.

Because of its high pressure, no traditional meters are available for supercritical CO2. Of course this high performance technology is not cheap. Many system are not equipped with any flow meter to be more competitive in the price, but in this way, you will never be sure about how much and if the CO2 is really flowing in the circuit. Maybe is the expected flow or maybe nothing! Who can say it. Impossible to be sure. The Coriolis flow meter is essential to have the correct feedback and control the CO2 flow in the circuit. The full automation system detects the feedback from the flow meter and drive the motor to give exactly the expected kg/hr. This is irrelevant. As you can see in the pomp flow topic, lower and higher flow give less extract than optimal.

The condenser is essential in CO2 recirculation. The condenser is a piece of apparatus or equipment that can be used to condense, that is, to change the physical state of a substance from its gaseous to its liquid state. We use double pipe configuration in small systems (up to 48 liter) and shell and pipe configuration for industrial. We do not use plate exchanger as they clog easily and cannot resist to standard CO2 pressure.

The condenser is an important part of the extraction system as, without it, it cannot be possible to recirculate the CO2.

In fact, all along the process, CO2 continuously changes its status: first liquid, then supercritical, then gaseous and finally back liquid again. Here on the right see all the changes, step by step. Colors: Blue = Liquid CO2, Green = Supercritical CO2, Yellow = Gaseous CO2.

When the gaseous CO2 comes out from the separators, the CO2 is completely clean and can travel to the condenser and, after that, to the Reservoir, where the Liquid CO2 is stored, waiting to be pumped again in the circuit.

Quick opening cover design needs only one-eighth of a turn rotation for sealing. Ideal for high pressure operations requiring repetitive opening/closing. The “Clover Leaf” Closure Reactors provide maximum ease for quick opening or closing of the cover. The cover is simply inserted into the body and then rotated one-eighth of a turn. A safety locking pin is provided to insure that the cover is properly positioned and locked. One of the most difficult aspect is attaining continuous feed of the solids and continuous discharge at high pressure extraction vessels. Generally, the solid feed material is handled by using preloaded canisters. A quick opening closure that allows for rapid opening and closing is essential. Bolt closure is not safe and it takes a lot of time to open. On the other hand, cloverleaf cover opens in one second. If considered under the safety point of view, the cloverleaf cover offers three safety systems operating at the same time:

The static pin. When the lid is in close position the operator introduces the safety pin in the vessel hole. Remove the pin to rotate the lid.

The dynamic pin. When the pressure build up in the vessel, the cover moves up and the dynamic pin goes in the safety hole in the cloverleaf upper side. When the pressure is completely removed, the lid will go down clearing the dynamic pin. Now the lid can rotate to open.

The electronic sensors control the correct position of the lid. If the sensors are not perfectly aligned, the process cannot start.