Visual cells

One of the main challenges of developing new products or processes is the lack of basic information on the behavior of the systems under operating conditions. Well because it is worked with little studied compounds or because the conditions are not the usual ones, it is difficult to find in the bibliographic bases data on the balance of phases, solubilities or reaction kinetics.

Visual cells are high-tech devices specifically designed and constructed to study solubility, equilibrium and reaction kinetics under carefully controlled conditions. By use of a view chamber, formation of different fluid or solid phases may be detected, such as precipitates or gas bubbles in a liquid.

High Pressure Processes group disposes of three visual cells for analysis of different systems.

This high pressure view chamber is desinged for observation of pahse behaviour and reactions and elevated temperature and pressure.

Basically, a cylindrical internal volume is filled with a fluid or a fluid mixture. This mixture is agitated via a magnetically coupled agitator. A manual operated magnetic lift allow to place a solid sample inside the cell view chamber after being thermostated and pressurizied via a sluice (lock hopper) system. Two further ports allow fluid supply, sampling and pressure detection. Two cylindrical sapphire windows that are allocated opposite to each other allow visualization of main part of the internal volume.

This high pressure view cells disposes of the following compounds:

  • support frame
  • view chamber: internal volume approx. 30 ml, sapphire windows with sight diameter of 18 mm, graphite seals, magnetic coupled agitator, magnetic sample lift, electrical heating jacket (1.5 kW) and protection cover with ventilator.
  • two manual pressure generators
  • pressure indications, analogous, display in MPa and psi above atmospheric pressure (0.1 – 40 MPa)
  • safety valve 320 bar
  • high pressure valves 1/8″ and high pressure tubing 1/8″ and 1/4″
  • monochrom Camera, 1/2″ and zoom
  • LED light source
  • Digital pressure and temperature recording unit for two pressure sensors and two thermocouples (NiCr-Ni thermocouple).

All parts of the equipment subjeted to high temperature and pressure are made of inconel whereas the surrounding fittings and valves are from SS 316. Maxima operating temperature and pressure are 500 ºC and 30 MPa, althought specific parts of the device as the magnetic lift and the agitator should not be into contact with temperatures higher than 300 ºC. To ensure that operation pressure does not reach values higher than 30 MPa, a safety valve is connected to the view chamber which fully opens at 32 MPa.

 It was designed and constructed by Eurotechnica.

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This visual cell allows the observation of phases behaviour at high pressures and temperatures.

The apparatus is composed by a stainless steel cylinder, in the interior of which is housed the substance that is going to be studied and a piston moved by an hydraulic manual Niquel alloy piston pump. Besides the cylinder, the visual cells is composed by: 24 mm diameter quartz crystal window, PTFE joint, analogic pressure indicator, high pressure 1/8″ valve and high pressure 1/8″ conexion tubing.  To ensure a correct mixing, the cell disposes also of a magenetic stirrer. Inside the cell, the stirrer is hermetically sealed to avoid leaks and variations of the pressure.

This horizontal visual cell has a variable volume between 40 and 70 mL.  Maxima operation temperature is 200 ºC and maxima pressure is 200 bar. To avoid security risk in case that system pressure increases close to maxima bearable presssure the system disposes of a bursting disc fixed at 250 bar.

Visual cell disposes also of a lamp to illuminate one end of the view cell and a camcorder to capture images of inside the cell and displayed on the computer screen, avoiding direct viewing through the windows. It was constructed by Eurotechnica.

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This visual cell allows the observation of phases behaviour at high pressures and temperatures.

The apparatus is composed by a stainless steel cylinder, in the interior of which is housed the substance that is going to be studied and a piston moved by an hydraulic manual piston pump. The cylinder has 5 perforations: two for the sapphire windows located in oposite sides of the cylinder, one for the pressure transductor, one for the thermopar for temperature measuremente and the last one, that could be used to introduce a fluid inside the cell. Also, a magnetic stirrer can be introduced to enhace mixture inside the cell.

Inner volume of the cell is variable, can reach values between 11 and 25 mL. Maximum operating temperature is 200 ºC and maximum pressure is 50 MPa. The internal temperature of the cell was controlled by a PID temperature controller (OMRON E5GN) acting over an electrical jacket. The temperature was measured with a K type thermocouple with an accuracy of 1.5 K. The pressure was measured with a membrane relative pressure meter DESIN TPR 18/V2, with an accuracy of 0.2% span (0-400 bar) (accuracy 0.8 bar).

Visual cell disposes also of a lamp to illuminate one end of the view cell and a camcorder to capture images of inside the cell and displayed on the computer screen, avoiding direct viewing through the windows.

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