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You are here: Home / Process Engineering / Process Engineering / Food Engineering / BATCH SOLID-LIQUID EXTRACTION (SOXHLET) + BATCH DISTILLATION MP1035



Main characteristics of the pilot

  • Industrial instrumentation

  • Flow switch of the condenser cooling water for operators safety

  • Level and temperature switches to protect heating element

  • Borosilicate glass and stainless steel AISI 316L manufacturing

  • Rigid process pipes

  • Electrical heating

  • Variable reflux column head controlled by ATEX solenoid valve



Solid-liquid extraction is a semicontinuous process, coupling distillation with a “SOXHLET” type cartridge containing the solid product impregnated with an active principle (solute) to be extracted by dissolution in a heated solvent.

The distillation column generates solvent vapours which are condensed; this pure and heat solvent feeds into the cartridge containing the inert solid and the solute.

When the cartridge is full, the solution obtained (solvent and solute) empties out automatically by siphon action (leaching), then returns to the boiler where the solvent is once more brought to the boiling point. Leaching can also be caused by the continuous feeding of solvent or by successive manual drainings.

The solvent may also be fed in a single “pass” for infusion then the extract obtained is drained manually.


Teaching objectives


Study of the following experimental parameters :

  • Influence of solvent type.

  • Influence of residence time.

  • Influence of operating principle.

  • Study of column hydrodynamics.

  • Study of the separation of a binary or complex solution.


Calculations :

  • Mass balance.

  • Mass exchange coefficient calculation.

  • Heat balance.

  • Determination of number of theoretical plates (McCABE and THIELE, PONCHON and SAVARIT).

  • Determination of number of transfer units.


Technical specifications


  • Borosilicate glass boiler, electric heating, fitted with low level safety switch and high temperature safety switch.

  • Coolant for pressure drop measurement.

  • Borosilicate glass column in two pieces with “MULTIKNIT” type packing in AISI 316L stainless steel.

  • Two AISI 316L stainless steel plates, each fitted with a sampling valve and temperature plug.

  • Borosilicate glass column head, with temperature plug, fitted with a solenoid timer valve to control the reflux rate.

  • Vertical condenser, borosilicate glass body, AISI 316L stainless steel exchanger, single effet with baffles.

  • AISI 316L stainless steel distillate cooler.

  • Two borosilicate glass distillate receivers, each fitted with a drain valve in AISI 316L stainless steel.

  • “SOXHLET” type extraction cartridge, in borosilicate glass with fast opening lid and bag mounted on a AISI 316L stainless steel support.

  • Two polyethylene distillate collection tanks.

  • AISI 316L stainless steel connecting tubes for the process and reinforced PVC tube for cooling fluid.

  • Support framework with AISI 304L stainless steel tubes, aluminium connecting nuts and adjustable feet.



  • Cooling water feed to condenser fitted with variable area flowmeter with its adjusting valve and water flow switch to turn off heating in case of lack of cooling water.

  • Measurement of the column pressure drop by differential “U” type manometer.

  • IP55 command and control cabinet fitted with an emergency stop, operating buttons and the following interfaces:

  • Electronic timer controlling valve at the head of the column.

  • Boiler heating controller.

  • Two digital temperature indicators with seven Pt100 Ω type probes.


Dimensions and weight

1550 mm x 700 mm x 295 mm ~ 200 kg.


Essential requirements

230 V / 50 Hz / Single phase: 4 kW.

Cold water 20°C / 3 bar: 1 m³/h.