ce 630 solid-liquid extractioncolleges.jazanu.edu.sa/eng/documents/chelabsmanual… · ·...

Experiment Instructions

CE 630 Solid-Liquid Extraction

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Experiment Instructions

Please read and follow the safety regulations!

Publication-no.: 918.000 00 D 630 02 (A) DTP_15

CE 630 SOLID-LIQUID EXTRACTION

Author : Dipl.-Ing. Frank Jebavy

Table of Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Proper use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2 Unit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.1 General view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.2 Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.3 Process description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.4 Control cabinet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.4.1 Control elements and displays . . . . . . . . . . . . . . . . . . . . . . . 7

2.4.2 Indication of measured data . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4.3 System adjustment and regulation via software . . . . . . . . . . 8

2.5 Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.5.1 System requirements:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.5.2 Installation of software . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.5.3 Installation routine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.6 Starting up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.7 Care/Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.1 Risk of death or injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.2 Hazards to the unit and its function . . . . . . . . . . . . . . . . . . . . . . . . . 18

4 Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.1 General principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.2 Extraction agent requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.3 Factors influencing extraction performance. . . . . . . . . . . . . . . . . . . 24

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4.4 Nernst’s partition coefficient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.5 Operating methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.5.1 Cross flow method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.5.2 Uniflow method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.5.3 Counter flow method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.5.4 Comparison of methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

4.6 Calculations for extraction systems . . . . . . . . . . . . . . . . . . . . . . . . . 31

4.7 Assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

5 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.2 Experiment aims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.3 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.3.1 Creating the extraction material . . . . . . . . . . . . . . . . . . . . . 41

5.4 Extraction performance for discontinuous process . . . . . . . . . . . . . 42

5.4.1 Aim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

5.4.2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

5.4.3 Performing the experiment . . . . . . . . . . . . . . . . . . . . . . . . . 43

5.4.4 Evaluation of the experiment . . . . . . . . . . . . . . . . . . . . . . . 43

5.5 Influence of number of stages on extraction performance. . . . . . . . 44

5.5.1 Aim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

5.5.2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44



5.6 Influence of extraction agent temperature on extraction performance48

5.6.1 Aim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

5.6.2 Preparation for the Experiment: . . . . . . . . . . . . . . . . . . . . . 48



5.7 Influence of extraction agent flow rate on extraction performance . 52

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5.7.1 Aim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

5.7.2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52



6 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.1 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.2 Abbreviations and symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.2.1 Abbreviations used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.2.2 Symbols used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

6.3 Brief explanations of most important items . . . . . . . . . . . . . . . . . . . 61

6.4 Items supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

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1 Introduction

In numerous applications, extraction is a more effi-cient, selective and cost-effective alternative tocompeting separating methods such as distilla-tion, evaporation and diaphragm technology.

Applications of this method include obtaining oilfrom oil seeds or leaching of metal salts from ores.

The CE 630 Solid-Liquid Extraction experimen-tation stand separates solid mixtures usingsolid-liquid extraction (leaching). Solid-liquid ex-traction allows soluble components to be removedfrom solids using an extraction agent.

The range of experiments covers the following ar-eas:

– Familiarisation with the fundamental princi-ples of solid-liquid extraction

– Demonstration of solid-liquid extraction as acontinuous and discontinuous process

– Investigation of a single, two and three stageprocess

– Influence of extraction agent flow rate andtemperature on the extraction process

– Influence of extraction material mass flowand carousel speed on the extraction pro-cess

A PC is used to evaluate the results of the experi-ments. A detailed software operation manual is of-fered under online help. Select the "?" menu andthe Help option to open the online help.

1 Introduction 1


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1.1 Proper use

The unit can be used for training in the areas ofthermal processing and the field of apparatus con-struction. It is designed exclusively for training andis not suitable for industrial use.

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2 Unit description

2.1 General view

1 Spiral conveyor for extraction material 9 Process pump 2

2 Heating element and extraction material feed 10 Process pump 1

3 Carousel extractor 11 Extraction agent vessel

4 Carousel drive unit 12 Valves for selecting the mode

5 Extraction residue vessel 13 Control cabinet with controls

6 Extract vessel 14 Process schematic7 Exhaust pump for extract vessel8 Process pump 3

2 Unit description 3


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Fig. 2.1 CE 630 general view

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2.2 Function

The CE 630 unit works on the counter flow princi-ple, i.e. fresh extraction agent is fed to leached ex-traction material. With this operating method, theconcentration gradient is the driving force for themass transfer.

On the carousel extractor (Fig. 2.2), a feeder con-sisting of separate cells rotates slowly above aslotted base (2). The extraction material is continu-ously fed into the cells of the rotating feeder (4) bya spiral conveyor. Within the cells, the extractionmaterial is sprayed with extraction agent.

The leached extraction residue (3) falls into a de-signated vessel after a single revolution of thefeeder.

Valves allow single, two or three stage continuousoperation to be selected. Discontinuous mode ispossible with the carousel stopped.

Three pumps are available for delivering the ex-traction agent from the extraction agent vessel,and their speed can be individually adjusted foreach stage.

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Fig. 2.2 Example of a carousel extractor

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3

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The exhaust pump starts up automatically as soonas at least one of the three process pumps is tur-ned on and then conveys the extract into the desig-nated vessel.

The extraction agent temperature for the relevantstage can be adjusted and displayed using heaterswith PID controllers.

Each stage is equipped with conductivity sensorsto monitor the separation process. All measuredvalues can be displayed using software.

2.3 Process description

Three stage mode results in the following processdiagram (see Fig. 2.3 on the next page). A cell (1ststage) is sprayed with fresh extraction agent (distil-led water). The extraction material from this cell isthen discharged into a designated vessel.

The two cells in front (2nd stage) are sprayed withthe extraction agent draining from the 1st stage.The two cells in front of the 2nd stage make up the3rd stage. In turn, they are sprayed with the extrac-tion agent draining from the 2nd stage.

The extraction material is thus extracted in sixcells. One cell is used to load material. One cell isused for emptying and one cell is free.

A steady state is reached after one revolution.Data acquisition only makes sense from the se-cond carousel revolution onwards.

The dwell time of the extraction material can be va-ried by adjusting the carousel speed.



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Components Measuring points

B1 Extraction agent vessel C1/T1Conductivity / temperature of fresh extraction agentStage I

B2 Extract vessel C2/T2Conductivity / temperature of extraction agent after1st stage Stage II

P1 Pump 1 (stage I) C3/T3Conductivity / temperature of extraction agent after2nd stage Stage III

W1 Heater 1 (stage I) C4/T4Conductivity / temperature of extraction agent after3rd stage

P2 Pump 2 (stage II) F Extraction agent flow rate Stage IW2 Heater 2 (stage II)

P3 Pump 3 (stage III) ValvesW3 Heater 3 (stage III) V1 Single stage - multi stage changeoverX1 Spiral conveyor V2 Two stage - three stage changeoverH1 Carousel extractor

B3 Extraction residue vessel I; II; III Stages



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Fig. 2.3 CE 630 process diagram

I II III

2.4 Control cabinet

2.4.1 Control elements and displays

1 Master switch

2 Speed adjuster for spiral conveyor X1

3 Forward (Feed)/reverse run switch for spiral conveyor X1

4 Speed adjuster for carousel extractor H1

5 On/off button for carousel extractor H1

6 On/off switch for heating elements W1, W2, W3

7 Speed adjuster for pump motors P1, P2, P3

8 On/off button for pump motors P1, P2, P3

9 Digital conductivity and temperature display C1 I [mS/cm][°C]

10 Digital conductivity and temperature display C2 after stage I [mS/cm][°C]

11 Digital conductivity and temperature display C3 after stage II [mS/cm][°C]

12 Digital conductivity and temperature display C4 after stage III [mS/cm][°C]

13 Digital flow display F before stage I [l/h]



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Fig. 2.4 Control cabinet

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2.4.2 Indication of measured data

The following measured data can be recorded(see Fig. 2.4).

– Temperature / conductivity of extractionagent before first wetting stage

– Temperature / conductivity of extractionagent before second wetting stage

– Temperature / conductivity of extractionagent before third wetting stage

– Temperature / conductivity of extractionagent after third wetting stage

– Volumetric flow rate of extraction agent befo-re first stage

2.4.3 System adjustment and regulation via software

The system is adjusted manually and regulated bythe software.

The speeds of the pumps, the spiral conveyor andthe carousel extractor can be continuously ad-justed. This is done using the adjusting knobs (7, 2and 4) on the control cabinet. A frequency con-verter integrated into the control cabinet regulatesthe set speeds using the frequency and keepsthem constant with different loads.

The spiral conveyor can be operated in two rota-tion directions. During normal operation the switch(3) to be rotated to the left and the extraction mate-rial is continuously fed into the cells of the rotatingfeeder.

In case of jammed particles of the extraction mate-rial inside spiral conveyor, the rotation direction tobe changed into reverse run to release the parti-cles out of spiral conveyor.



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For changing the rotation direction of the spiralconveyor, rotate switch (3) to the right for a shorttime.

NOTE

In case of changing the rotating direction of spiralconveyor, the switch (3, refer to fig. 2.4) at first tobe set onto zero position. After approx. 1s it can berotated into required direction.

Wetting is carried out in three stages in a counterflow. After each wetting step, the conductivity ofthe extraction agent is measured (9, 10, 11 and 12)to establish the saturation of the extraction agentwith the substance to be dissolved. In addition, thetemperature of the extraction agent can be in-creased using a heater (6).

Fault-free operation of the software is essential asif the software freezes, the heaters heat up to theirmaximum temperature (50°C).

The following variables must be adjusted manuallyon the experimentation stand:

– Speed of the feeder

– Speed of the screw for the spiral conveyor

– Delivery rate of pump 1





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The following variables must be regulated usingthe PC:

– Extraction agent temperature before first sta-ge

– Extraction agent temperature before secondstage

– Extraction agent temperature before thirdstage

NOTE

For safety, the temperature of the heater rods is li-mited.



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2.5 Software

The software permits investigation of the proces-ses occurring in solid-liquid extraction on a PC. Itincludes options for saving data and printing outclear diagrams and curves. This helps the user tounderstand the processes taking place as well asthe theoretical background.

2.5.1 System requirements:

• PC with Pentium IV

• 250 MB of available hard disk space

• CD-ROM drive

• Graphics resolution 1024 x 768, TrueColor

• USB connection 1.1

• Operating system Windows XP / 2000 / Vista

2.5.2 Installation of software

The following is needed for the installation:

– A fully operational PC, laptop or notebookwith USB port.

– G.U.N.T. - CD-ROM

NOTE

All components necessary to install and run theprogram are contained on the CD-ROM, suppliedby G.U.N.T. along with the CE630. No further aidsare necessary!



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After starting, the installation runs automatically.During the course of the installation, various pro-gram components are loaded onto the PC :

– LabVIEW®- runtime program for PCdata acquisition

– Driver routines for the “LabJack®” USBconverter

2.5.3 Installation routine

NOTE

The CE 630 unit must not yet be connected to thePC’s USB port while the program is being installed.Only after the software has been installed can theUSB hardware be connected.

– Boot the PC

– Load the G.U.N.T. CE 630 CD-ROM

– Start the installation program “Setup.exe” inthe folder “Installer”.

– Follow the installation procedure on thescreen.

– Reboot the PC after the installation is finis-hed.

Once the software has been installed, the programcan be called up by selecting

“Start / All Programs / G.U.N.T. / CE 630"

in the menu. The first time the program is called up,a dialog box opens to specify the language.

NOTE

A detailed software operation manual is offeredunder online help. Select the "?" menu and theHelp option to open the online help.



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2.6 Starting up

Starting up is described step by step below.

– Check whether the extraction residue vessel(empty), extract vessel (empty) and extracti-on agent vessel - filled with approx. 18 l distil-led water - are installed.

– Fill the feed hopper on the extraction materialspiral conveyor with a sufficient quantity ofextraction material (e.g. 2 kg) and screw-inconnector to be connected on the side of thecontrol cabinet (Fig. 2.9).

– Select the mode and check the valve positionfor the number of stages (Fig. 2.8).

NOTE

The number of stages must also be entered in thesoftware.

– Connect the unit to the mains electricitysupply.

– Set the master switch to “ON”.

– Make sure that the push buttons for pumps,carousel extractor and spiral conveyor are allset to the “OFF” position. If so, the push but-tons are not lit.

– Make sure that the rocker switches for theheaters are set to the “0" position.In this switch position, the rocker switches

are not lit.

– Connect the PC and the unit using the USBcable (Fig. 2.10).

– Start the software.

The unit is ready to operate.



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Fig. 2.5 Valve position V1 and V2 setto 3 stages operating mode

Fig. 2.6 Spiral conveyor electricalconnection

Fig. 2.7 USB connection

2.7 Care/Maintenance

If there is a sharply fluctuating extraction agentflow rate and after every replacement of the ex-traction material, the extractor should be cleanedas the distilled water washes the debris and dustout of the extraction material and deposits it.

Cleaning the carousel extractor:

1. Before dismantling the spiral convey-or, the feed hopper should be emptiedand the screw-in connector removedfrom the connection on the control cabi-net. Then dismantle the empty spiralconveyor using the hexagon socketwrench supplied.

2. Open clamping arrangement of allthree temperature/conductivity sen-sors, unscrew transparent protectioncover with screw driver and place thesealongside the extractor on the work sur-face. The hose and cable connectionsremain in place.

3. Dismantle the feeder by unscrewingthe hexagon socket screw and liftingthe feeder upwards/

4. The slotted base is located below theremoved feeder. Remove extractionmaterial debris and dust into the extrac-tion residue aperture with a brush andremove any grains trapped in the slotswith a suitable tool.



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5. Unscrew the three wing screws onthe lower section of the extractor andthen lift off the slotted base using thethreaded rods. The walls of the cham-bers (see arrow) for the three extractionstages are transparent. If the extractoutlets become clogged while perfor-ming an experiment, the extract waterlevel rises.

NOTE

The experiment must be aborted immediately if theextract water level is so high that it overflows intothe chamber for the next stage.

6. Clear out the exposed chambers andfilters on the intake side extract outletsfor the individual stages with a vacuumcleaner and clean of extraction materialdebris and dust. Blow out the moisturewith compressed air or wipe with a dry,clean cloth.

7. The extractor is then re-assembled.The feeder must be placed onto theshaft and screwed on until it engages.

8. Screw in the hexagon socket screwby hand until the screw head is flushwith the screwing position (8). Then ful-ly tighten the screw by 1/4 turn with ahexagon socket wrench.

Further tightening of the hexagon so-cket screw results in an unwanted bra-king effect on the feeder duringoperation.



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3 Safety

Before using the unit, the instruction manual for experiments, in particu-lar the safety information, should be read carefully!Before starting experiments, all participants should be instructed aboutsafety and proper usage of the unit!

3.1 Risk of death or injury

WARNING

Reaching into the open control cabinet can re-sult in electric shocks

• Disconnect from the mains supply beforeopening

• Electrical work should only be performedby qualified electricians

• Protect control cabinet from splashedwater

WARNING

Dust can get into the eyes, the mouth or be in-haled when handling the extraction material.

• If dust gets into the eyes, rinse with plentyof clean water.

• After inhaling dust, inhale fresh air.

• If extraction material is swallowed, drinkplenty of clean water.

• Seek medical attention.

• The hazard and safety instructions des-cribed in the country-specific safety regu-lations must be observed exactly.

3 Safety 17


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• Wear appropriate protective glasses

• Wear appropriate protective gloves

• Wear appropriate respirator mask

3.2 Hazards to the unit and its function

NOTE

After completing individual experiments, clean theunit carefully and rinse all three stages with distil-led water.

NOTE

The extraction material may not come into contactwith other chemicals, to prevent unwanted chemi-cal reactions.

NOTE

To prevent the formation of algae and slime, onlyoperate the unit with distilled water.

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NOTE

This unit is only designed to be used with the ex-traction material we supply. The use of other che-micals is not recommended and is done at yourown risk.

NOTE

If an extraction agent flow rate of 6 l/h is not rea-ched, the heating rods are no longer activated bythe PC for safety reasons. The heaters are turnedoff.

NOTE

At extraction agent flow rates of more than 6 l/h,temperatures up to a maximum of 50°C can bereached. For safety reasons, the heaters are tur-ned off if the temperature of 50°C is exceeded.

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4 Theory

4.1 General principles

This manual does not replace textbooks. For fur-ther theoretical information refer to the currenttechnical literature.

Solid-liquid extraction involves dissolving solublecomponents out of solid mixtures using an extracti-on agent.

In the simplest form of this method, the extractionmaterial and the extraction agent are mixed well.The extraction agent and the dissolved usablesubstance are then removed and processed.

Processing of the extraction agent with dissolvedusable substance normally involves evaporation.The extraction agent is evaporated and the usablesubstance remains as a product. The extractionagent is condensed and can then be reused.

A day-to-day example of solid-liquid extraction isthe preparation of coffee. Here, water (extractionagent) dissolves the colours and flavourings (usa-ble substance) out of the coffee powder (extractionmaterial, consisting of the solid carrier materialand the soluble components). Ideally, drinkablecoffee is obtained (extract) and the leached coffeepowder (extraction residue) remains in the coffeefilter.

In real processes, the solid carrier material alwaysstill contains a proportion of the usable substanceafter completion of the extraction process. In addi-tion, some of the extraction agent will still be ad-sorptively bonded to the solid carrier material.

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Solid-liquid extraction is mainly carried out as per-colation extraction and immersion extraction dis-continuously or, preferably, continuously.

• Percolation extraction:

The crushed and solubilised solid is passedthrough the extraction apparatus and sprayed withsolvent in stages. The solvent must flow effectivelythrough the solid.

Percolation extraction can only be used for extrac-tion materials that the extraction agent can flowthrough effectively when fed in. If the extractionmaterial has low permeability for the extractionagent, immersion extraction is recommended.

• Immersion extraction:

The solid is suspended in the solvent and extrac-ted. The subsequent phase separation takes placein decanters (used to decant liquid from thesediment).

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4.2 Extraction agent requirements

There is no universal extraction agent. The requi-red extraction agent must be identified specificallyfor the relevant extraction task. The extractionagent can either be identified experimentally usingsolution experiments or from the results of extracti-on tasks already investigated.

There are particular requirements of the extractionagent:

• Selectivity

It should only dissolve the usable substance,otherwise a subsequent separating methodis required to separate the usable substancefrom the extract

• Solubility

It should dissolve the usable substance asquickly as possible and dissolve the maxi-mum possible amount of usable substance

• Chemical reaction properties

It should not react chemically with the com-ponents of the extraction material

• Boiling properties

The boiling point of the extraction agentshould not be too high and the evaporationheat should be as low as possible, to ensureefficient recovery of the extraction agent

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4.3 Factors influencing extraction performance

Extraction performance is the amount of usablesubstance extracted per unit of time. It can be influ-enced by the following factors:

• Differences in concentration

The greater the difference in concentration ofthe usable substance in the extraction mate-rial and in the extraction agent, the greaterthe driving force when extracting. The differ-ence in concentration is increased by rapidlyremoving the dissolved extract from the sur-face of the extraction material and frequentlyreplacing the loaded extraction agent withfresh extraction agent.

• Extraction surface area

The surface of the extraction material is pro-portional to the extracted quantity of material.The extraction performance increases as theextraction surface area rises. In practice, thisis achieved by crushing the extractionmaterial.

• Diffusion resistance

The diffusion resistance depends on the sizeof the particles, the porosity and the penetra-bility of the extraction material for the extrac-tion agent. The diffusion resistance counte-ring the dissolving of the extraction materialshould be as low as possible.

• Temperature

The extraction performance is increased byhigher temperatures. Higher temperaturesincrease the thermal agitation, reducing theviscosity and thus accelerating the dissolvingof the usable substance.

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4.4 Nernst’s partition coefficient

If extraction agent and extraction material are wellmixed and left to react for a time, all of the usablesubstance is not dissolved out of the extractionmaterial. A residual amount of usable substancealways remains in the extraction material.

After a certain time, an equilibrium concentrationof usable substance in the extraction material andin the extraction agent is established. Nernst’s par-tition coefficient can be derived from thisequilibrium:

KY

XV �

KV: Nernst’s partition coefficient

Y: Concentration of usable substance inextraction agent

X: Concentration of usable substance inextraction material

The partition coefficient KV is a non-dimensionalcharacteristic number. It is different and specificfor every extraction agent / extraction material mix-ture. It provides information about the proportionsof usable substance contained in the extractionagent and in the extraction material after anextraction step.

For example, a partition coefficient of 9 means thatafter an extraction step, out of 100 kg of usablesubstance in the extraction material, 90 kg is nowdissolved in the extraction agent (nine parts out often) and 10 kg remains in the extraction material(one part).

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In order to be able to dissolve further usable sub-stance out of the extraction material, the loadedextraction agent must first be separated from theextraction material. New extraction agent can thenbe used in a second extraction step to dissolvemore usable substance out of the partially leachedextraction material. A new concentration equilibri-um will be established. This process must be re-peated until the required quantity of usablesubstance has been dissolved out of the extractionmaterial.

As the required quantity of usable substance ishardly ever dissolved out of the extraction materialin a single step in practice, a sequence of severalextraction steps needs to be carried out. The mosteffective method of carrying out multiple extrac-tions one after another using the same extractionmaterial is the counter flow method, as describedin the following sections.

4.5 Operating methods

The number of extraction steps needed to deliverthe desired separating results depends on variousfactors, including the chosen process. The possi-ble alternatives are:

– Cross flow method

– Uniflow method

– Counter flow method

The various methods of staged extraction deliverdifferent results with the same number of stages orrequire different quantities of extraction agent toachieve the same results.

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The description below is based on three extractionstages in each case.

4.5.1 Cross flow method

With the cross flow method, the extraction materialis sprayed with fresh extraction agent at each sta-ge (extraction stage 1, stage 2, stage 3). Freshextraction agent is mixed with more and more lea-ched extraction material. Figure 4.1 below showsthe cross flow method described schematically.

�mF Extraction material mass flow rate

XF Concentration of extraction materia

�mC Extraction agent mass flow rate

YC Concentration of extraction agent

�mE Extract mass flow rate

YE Concentration of extract

�mR Extraction residue mass flow rate

XR Concentration of extraction residue

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1. 2. 3.

Fig. 4.1 Cross flow method

� ,m XF F� ,m YC C � 0 � ,m YC C � 0 � ,m YC C � 0

� ,m YE E1 1� ,m YE E2 2

� ,m XRa Ra

St.St.St.

� ,m YE E3 3

4.5.2 Uniflow method

First extraction step (Stage 1)

Extraction material and extraction agent movecontinuously in a uniflow (Fig. 4.2). In the firststage, fresh extraction material is mixed with freshextraction agent.

Second extraction step (Stage 2)

From here, the slightly loaded extraction agent isfed onwards and brought back into contact with ex-traction material, which contains slightly lower pro-portions of usable substance. The extraction agentis loaded further, but not by as much as before.

Third extraction step(Stage 3)

In the third and final extraction step, the extractionagent - now already loaded to a large extent - is incontact with leached extraction material. The lar-gely loaded extraction agent is hardly loaded withany additional usable substance.

This method enables multiple extraction steps tobe carried out with the same extraction agent.

The loaded extraction agent is brought into contactwith increasingly small quantities of usable sub-stance from the increasingly leached extractionmaterial (for legend refer to Fig. 4.1).

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1. 2. 3.

Fig. 4.2 Uniflow method

� ,m XF F

� ,m XRa Ra� ,m YE E3 3

� ,m YE E2 2� ,m YE E1 1

� ,m YC C � 0

St. St. St.

4.5.3 Counter flow method

First extraction step (Stage 3)

Extraction material and extraction agent movecontinuously in a counter flow (see Fig. 4.3 and4.4). Leached extraction material from the secondstage is mixed with fresh extraction agent in thethird stage. This fresh extraction agent dissolvessmall quantities of usable substance out of the al-ready leached extraction material.

Second extraction step (Stage 2)

From the third stage, the slightly loaded extractionagent is brought back into contact with extractionmaterial from the first stage, which contains slight-ly higher proportions of usable substance than thatfrom the second stage. This further loads theextraction agent.

Third extraction step (Stage 1)

In the third and final extraction step, the extractionagent from the second stage - now already loadedto a great extent - meets fresh extraction materialand becomes loaded with more usable substance.This method enables multiple extraction steps tobe carried out with the same extraction agent (forlegend refer to Fig. 4.1).

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1. 2. 3.

Fig. 4.3 Counter flow method

� ,m XF F� ,m YC C � 0

� ,m YE E1 1� ,m YE E2 2

� ,m YE E3 3� ,m XRa Ra

St. St. St.

1 Extract outlet A Liquid path (extract)

2 Extraction residue B Solid path (extraction material)

3 Extraction agent inlet X Usable substance content in extraction material

4 Extraction material feed Y Usable substance content in extraction agent

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Fig. 4.4 Illustration of counter flow principle on carousel extractor

4.5.4 Comparison of methods

The counter flow method generally represents theoptimum option. Compared to the uniflow method,a considerably higher proportion of usable sub-stance is transferred from the extraction materialinto the extraction agent. The concentration gra-dient (see section 4.3) as the driving force for themass transfer is utilised more effectively with thecounter flow method.

The cross flow method results in even higheryields. However, compared to the counter flow me-thod it requires the use of much more freshsolvent.

4.6 Calculations for extraction systems

To determine the theoretical number of stages in atriangular diagram, simplifications are assumed. Agenuine equilibrium is not established. The bon-ding of the usable substance in the capillaries, atthe inner and outer surfaces differs greatly and de-pends on the solid properties (e.g. porosity) andthe disintegration (crushing) of the extractionmaterial.

The following assumptions are made in a simpli-fied model of the transfer of usable substance:

The extraction agent penetrates the extractionmaterial effectively. The component to be dissol-ved is absorbed by the extraction agent up to thepoint of equilibrium and then replaced by fresh ex-traction agent. Part of the extraction agent remainsadsorptively bonded to the extraction material af-ter the solid-liquid separation. If the extraction ma-terial (initial solid (F)) does not contain any extracti-on agent, the extraction process can berepresented in the triangular diagram:

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Conodes (angle dividing line):

In equilibrium, the ratio of B to C must be equal inthe extraction residue and in the extract. This me-ans that the conodes must be rays through point A.It must be assumed that extraction agent must beabsorbed in A.

Extract:

The extract points are on the BC side, as A is inso-luble in C.

Extraction residue:

If A is completely insoluble in C, the extraction resi-due concentrations lie on a line that starts at F andends on the AC side. This line can be parallel to theBC side.

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A C

B

E

XA

XB

XC

R

F

Fig. 4.5 Extraction process in triangular diagram

Usable substance

Conodes

Extract branch

(Extraction agent)(Extraction material)

Extractionresidue branch

In these cases, as much extraction agent must beabsorbed in the extraction material as the amountof usable substance that is transferred to the ex-tract as the sum must be

m m constB C� � .

so that the concentration remains.

Xm

m m mconstA

A

A B C

��

� .

This can be assumed in many cases. Otherwise,there are variations from the parallels to BC that donot have to be straight lines.

Counter flow extraction

Overall result

� � � � �

, ,m m m m mF C E R e M� � � �1


�mC Extraction agent mass flow rate

�

,mR e Extraction residue mass flow rate

�mE1 Extract mass flow rate

�mM Total mass flow rate

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1 2 e

�

,mR 1�

,mR 2�

,mR e�1

�

,mE 2�

,mE 3�

,mE e

�mF

�

,mE 1

�

,mR e

�mC

Component result:

� � � �

, , , ,m x m y m y m xF F C C E E R e R e� � � � � � �1 1

Percentage extraction yield:

��

��

�

�1 100

x

xR e

F

,

Determination of pole point:

� � � � �

, ,m m m m mF E R e C P� � � �1

Assumption:

xR,A = Constant.; The extraction residue branch isa parallel to the side BC

Stage determination process:

– Plotting the parallels to BC through F (ex-traction residue branch)

– Representation of overall result

(If E1 is unknown, the position of the mixing pointmust be calculated using the lever rule)

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A C

B

E

R

F

1

E2

1M

E3

E4

R2

R3

R4

Re

(Usable substance)

Pol

Extraction residue branch

(Extraction material) ( Extraction agent)

Extract branch

– Plotting of the pole point (plot E F1 sections

and extend CRe to the intersection)

– Ray from A to E1; R1 lies at the intersectionwith the straight lines FRe

– Ray from pole point through R1 to BC side;the intersection is E2

– Ray from A to E2; Intersection on the straightlines FRe is R2

This algorithm should be carried out until Re is rea-ched or the value falls below it. The number of co-nodes plotted corresponds to the theoretical num-ber of stages.

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4.7 Assessment

The concentration of the carrier material withusable substance is determined by weighing theunloaded and loaded carrier material.

xm m

mF ��1 2

1

xF Concentration of carrier material

m1 Loaded carrier material

m2 Unloaded carrier material

To determine the extraction material flow thecontent of two cells must be weighed and dividedby the dwell time. (Using the bulk density is too im-precise for the small cells.)

�mm

F ��


m Content of two cells with extractionmaterial

� Dwell time

The mass flow rate of the extraction agent de-pends on the adjustable volumetric flow rate andthe density.

�

�m VC C� ��

�mC Extraction agent mass flow rate�VC Extraction agent volumetric flow rate

� Extraction agent density

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Specifying a phase relationship

��

�

mm

F

C

depends on the wetting properties and the masstransfer rates. This can only be tested experimen-tally.

The extract substance flow is calculated from thetotal quantity of extract collected and the dwelltime.

�

,mm

EE ges

1 ��

�mE1 Extract mass flow rate

�mEges Total quantity collected

� Dwell time

The extract concentration YE and the concentra-tions between the stages are determined by mea-suring the conductivity.

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5 Experiments

5.1 Introduction

The following sections describe experiments thatcan be performed with this unit. The selection ofexperiments makes no claims of completeness butis intended to be used as a stimulus for your ownexperiments.

The measured results listed should not be viewedas reference or calibration values for all conditions.Depending on the construction of the individualcomponents, experimental skills and environmen-tal conditions, deviations may occur in theexperiments.

5.2 Experiment aims

The aim of performing the experiments is to sepa-rate potassium hydrogen carbonate using distilledwater from an aluminium oxide / potassium hydro-gen carbonate solid mixture using solid-liquidextraction.

For example, the influence of

– the process method (continuous or disconti-nuous)

– the mode (one, two and three stage)

– the extraction agent flow rate

– the extraction agent temperature

on the mass transfer per unit of time arepresented.

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5.3 Preparation

To compare the results of different series of exper-iments with one another, because of the variety ofsetting options on the unit, it is necessary to useonly a limited number of basic settings.

For this reason, the person leading the experimentshould define these basic settings before perfor-ming the experiment and determine the associa-ted unit settings experimentally and record them inwriting.

For example, to set the extraction material flow,the speed of the spiral conveyor and the carouselshould be synchronised using the relevant speedadjusters (see Fig. 2.4, page ) so that a materialdepth of approx. 40 mm per cell is achieved.

The resulting extraction material weight per cell isdetermined by collecting the extraction material atthe extraction residue aperture with a separatevessel and weighing it. The carousel speed is de-termined using a stopwatch by measuring the timerequired for one revolution of the feeder with thissetting.

We recommend that the following settings are defi-ned before performing the experiment and thatonly one setting is varied per experiment to identifyits influence on the transfer of usable substance:

• Spiral conveyor speed

• Carousel speed

• Extraction material flow

• Mode (one, two or three stage)

• Extraction agent flow rate

• Extraction agent temperature

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5.3.1 Creating the extraction material

To prepare the extraction material (solid mixture),the aluminium oxide must be hydrated in a potassi-um hydrogen carbonate solution and then dried asdescribed below.

Step 1

Add 10 l distilled water and 600 g potassium hydro-gen carbonate, for example, to a sufficiently largevessel and mix until the salt is completely dissol-ved in the distilled water.

Step 2

Approx. 4 kg of aluminium oxide grains are thenadded to the solution described above. The grainsshould be completely immersed in the solution, i.e.at least 2 cm below the surface of the solvent, andleft for around 24 hours.

Step 3

The excess residual solution is then shaken off.The aluminium oxide / potassium hydrogen carbo-nate solid mixture (extract material) created canbe dried in the ambient air (e.g. on a baking tray) orin an oven if required.

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5.4 Extraction performance for discontinuous process

In this experiment, extraction material is sprayedwith unloaded extraction agent. The cell in the fee-der below the extraction agent feed for the 1st sta-ge is first filled with extraction material. The extrac-tion material is sprayed throughout the duration ofthe experiment and is not replaced.

5.4.1 Aim

This experiment is intended to investigate the influ-ence of a discontinuous process method on the ex-traction performance. The change in concentra-tion of the extract resulting from the mass transferYE , at measuring point C4, is observed over a cer-tain period of time and the figures determined bythe PC are plotted in a diagram.

5.4.2 Preparation

Set up as described in section 2.6, page 13.

• For example, 70g of extraction material isweighed out and added to the cell (this corre-sponds to an approximate material depth of40 mm).

• To achieve uniform spraying, the carouselextractor is turned using the speed adjusteruntil the cell is positioned centrally below theextraction agent feed for the 1st stage. Thecarousel drive is then turned off.

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5.4.3 Performing the experiment

Set the valve position V1 and V2 to 1 stage.

The following settings are suggested:

Turn on process pump P1:

Extraction agent flow rate 15.5 l/h

Turn on heating element W1:

Extraction agent temperature 30 °C

5.4.4 Evaluation of the experiment

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Fig. 5.1 Concentration development of usable substance in extract for discontinuous process

Time in s

Con

cent

ratio

nY

Ein

g/ll

T1 = 30 °C

The variables calculated by the PC are shown in the following diagram.

After an initially high yield of usable substance, this becomes very low after ashort period. The consumption of unloaded extraction agent is high relative tothe yield. The method used corresponds to the cross flow method.

5.5 Influence of number of stages on extraction performance

In this experiment, the extraction material and ex-traction agent are continuously moved in a counterflow with different numbers of stages. When themaximum yield of usable substance in the firststage is reached, i.e. the average concentrationYE1m (see process diagram) no longer rises, thesecond stage is set up and continued until the av-erage concentration YE2m is constant again. Thethird stage is then set up and continued until themaximum usable substance yield is reached - av-erage concentration value YE3m is constant.

5.5.1 Aim

To investigate the influence of the number ofstages on the extraction performance with thecounter flow method. The change in concentrationof the extract resulting from the mass transfer YE1 ,YE2 , YE3 at measuring point C4, is observed over acertain period of time and the figures determinedby the PC are plotted in a diagram.

5.5.2 Preparation


Preparation for the Experiment:

• Synchronise the speed of the spiral conveyorand the carousel extractor so that a materialdepth of approximately 40 mm per cell isachieved.

• The filling hopper should be filled with a suffi-cient quantity of extraction material.

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Single stage process






Extraction agent temperature T1 30 °C

NOTE

The speed of the pumps P2 and P3 must be adjus-ted during the experiment in such a way that as fewair bubbles as possible occur in the relevant intakelines (2, 3). If the number of air bubbles increases,the relevant pump speed must be reduced usingthe speed adjusting knob (Fig. 2.4, page 7). Duringthe experiment, the extract liquid level must be ob-served through the window (1) of the extract cham-bers in the lower section of the extractor. If the li-quid level rises, the pump speeds P2 and P3 mustbe reduced. If this does not help, the carousel ex-tract must be cleaned as described in section 2.8.

Two stage process:

Set the valve position V1 and V2 to 2 stages.


Settings from the previous experiment(single stage process) are retained.

Turn on and adjust process pump P2



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1

2

3

Three stage process:

Set the valve position V1 and V2 to 3 stages.


Settings from the previous experiments (singlestage and two stage process) are retained.

Turn on and adjust process pump P3




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Fig. 5.2 Concentration development of usable substance in extract for single stage process

Con

cent

ratio

nY

E1

ing/

l

Time in s

The variables calculated by the PC are shown in the following diagrams. A com-parison of the measured variables (see Fig. 5.2, 5.3 and 5.4) indicates that asthe number of stages increases, the yield of usable substance rises asexpected. With the counter flow method used here, the concentration gradientas the driving force for the mass transfer is most effectively used in three stagemode.

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Fig. 5.3 Concentration development of usable substance in extract for two stage process

Con

cent

ratio

nY

E2

ing/

l

Time in s

Fig. 5.4 Concentration development of usable substance in extract for three stage process

Time in s

Con

cent

ratio

nY

E3

ing/

l

5.6 Influence of extraction agent temperature on extraction performance

In this experiment, with a continuous process, ex-traction material is sprayed with unloaded extracti-on agent at different temperatures in single stagemode. Temperatures up to a maximum of 50°Ccan be reached depending on the extraction agentflow rate.

5.6.1 Aim

To investigate the influence of the extraction agenttemperature on the extraction performance. Thechange in concentration of the extract resultingfrom the mass transfer YE1, at measuring point C4,is observed over a certain period of time and thefigures determined by the PC are plotted in a dia-gram.

5.6.2 Preparation for the Experiment:











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Observe concentration YE1, at measuring pointC4. When the concentration is no longer rising, setthe next temperature up.




Observe concentration YE1, at measuring pointC4. When the concentration is no longer rising, setthe next temperature up.





The variables calculated by the PC are shown inthe following diagrams.

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Fig. 5.5 Concentration development of usable substance in extract at extraction agent temperature 25°C

Con

cent

ratio

nY

E1

ing/

l

Time in s

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Con

cent

ratio

nY

Ein

g/l

Time in s


Time in s

Con

cent

ratio

nY

Ein

g/l

Diagrams 5.5 to 5.7 show the measured extractconcentrations YE1, at measuring point C4.

The arithmetical averages calculated for the mea-sured concentrations YE1, at measuring point C4are as follows:

Once a constant operating state can be identified,the following variables are averaged in the follo-wing time spans:Fig. 5.5: Time span 800 s ... 1240 s

Average concentration YE1m at 25°C 0.85 g/l

Fig. 5.6: Time span 0 s ... 1000s


Fig. 5.7: Time span 0 s ... 900 s


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The extraction performance does not increase significantly with higherextraction agent temperatures and demonstrates asymptotic behaviour.

5.7 Influence of extraction agent flow rate on extraction performance

In this experiment, with a continuous process, ex-traction material is sprayed with unloaded extracti-on agent at different flow rates in single stagemode.

5.7.1 Aim

To investigate the influence of the extraction agentflow rate on the extraction performance. Thechange in concentration of the extract resultingfrom the transfer of usable substance YE1, at mea-suring point C4, is observed over a certain periodof time and the figures determined by the PC areplotted in a diagram.

5.7.2 Preparation




• The extraction agent flow rate should not fallbelow 6 l/h (see section 3.2).

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Extraction agent flow rate 8 l/h



Observe concentration YE1. When the concentra-tion is no longer rising, set the next extractionagent flow rate up.


Process pump P1:




Process pump P1:




Process pump P1:


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The variables calculated by the PC are shown inthe following diagrams.

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Fig. 5.8 Concentration development of usable substance in extract at extraction agent flow rate 8 l/h

Con

cent

ratio

nY

E1

ing/

l

Time in s

Fig. 5.9 Concentration development of usable substance in extract at extraction agent flow rate 11.5 l/h

Con

cent

ratio

nY

E1

ing/

l

Time in s

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Con

cent

ratio

nY

E1

ing/

l

Time in s


Con

cent

ratio

nY

E1

ing/

l

Time in s

Diagrams 5.8 to 5.11 show the measured extractconcentrations YE1.

The product of the measured extract concentra-tion YE1 and the selected extraction agent flow rate�Vc gives the usable substance mass flow rate �mE .

�

�m Y VE E C� �1

Results from diagram 5.8:

Extraction agent flow rate �Vc 8 l/h

Average concentration YE1m 1.74 g/l

Extract mass flow rate �mE 14 g/h


Extraction agent flow rate �Vc 11.5 l/h


Extract mass flow rate �mE 16.1 g/h




Extract mass flow rate �mE 17 g/h




Extract mass flow rate �mE 19.5 g/h

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Comparing the calculated mass flow rates provides the result that as the extrac-tion agent flow rate rises, the yield of usable substance increases. However, theconcentration is reduced.

6 Appendix

6.1 Technical data

Overall dimensions

L x W x H 880 × 700 × 1740 mm

Weight Approx. 160 kg

Carousel

Number of cells 9

Diameter Approx. 200 mm

Speed Approx. 0 ... 9 h-1

Motor power consumption Approx. 0.9 W

Spiral conveyor

Pump Capacity Approx. 0 ... 20 l/h

Motor power consumption Approx. 4.0 W

Hose pump

Number 3 St

Max. capacity Approx. 25 l/h

at 300 rpm and hose 4.8 x 1.6 mm

Heater

Number 3 St

Power consumption (each) approx.330W

Tanks

Extraction material Approx. 5 l

Extraction residue Approx. 20 l

Extraction agent Approx. 20 l

Extract Approx. 20 l

6 Appendix 57


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Measuring ranges

Flow rate 0.025 ... 0.5 l/min

Conductivity 0 ... 20 mS/cm

Temperature 0 ... 50 °C

Power supply

Single phase 230 V, 50 Hz

Optional alternatives, see rating plate

58 6 Appendix


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6.2 Abbreviations and symbols

6.2.1 Abbreviations used

A Liquid path (extract)

B Solid path (extraction material)

B1 Extraction agent vessel

B2 Extract vessel

B3 Extraction residue vessel

T1 Temperatureof fresh extraction agent

T2 Temperatureof extraction agent after 1st stage

T3 Temperatureof extraction agent after 2nd stage

T4 Temperatureof extraction agent after 3rd stage

F Extraction agent flow rate before Stage I

H1 Carousel extractor

P1 Pump 1 (stage I)

P2 Pump 2 (stage II)

P3 Pump 3 (stage III)

V1 Single stage - multi stage changeover

V2 Two stage - three stage changeover

W1 Heater 1 (stage I)

W2 Heater 2 (stage II)

W3 Heater 3 (stage III)

X Concentration of usable substance inextraction material

X1 Spiral conveyor

Y Concentration of usable substance inextraction agent

I; II; III Stages

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6.2.2 Symbols used

KV: Nernst’s partition coefficient

m mass g, kg

�mC Extraction agent mass flow rate g/s

�mE Extract mass flow rate g/s

�mEges Total mass flow rate g/s

�mF Extraction material mass flow rate g/s

�mM Total mass flow rate g/s

�mR Extraction residue mass flow rate g/s�VC Extraction agent volumetric flow rate ltr/h

XF Concentration of extraction materia g/kg

XR Concentration of extraction residue g/kg

YC Concentration of extraction agent g/ltr

YE Concentration of extract g/ltr

� Extraction agent density kg/ltr

phase relationship

� Dwell time s

60 6 Appendix


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6.3 Brief explanations of most important items

Concentration gradient:

The concentration gradient as the driving force forthe mass transfer.

Counter flow method:

Extraction material and extraction agent movecontinuously in a counter flow

Cross flow method:

With the cross flow method, the extraction materialis sprayed with fresh extraction agent at eachstage

Extraction material:

Consisting of the solid carrier material and the sol-uble components

Extraction agent:

An extraction agent dissolves usable substanceout of the extraction material.

Solid-liquid extraction:

Solid-liquid extraction involves dissolving solublecomponents out of solid mixtures using an extrac-tion agent.

Uniflow method:

Extraction material and extraction agent movecontinuously in a uniflow.

Usable substance:

Soluble component in extraction material.

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6.4 Items supplied

1 x experimentation stand

1 x CD with software

1 x Aluminium oxide

1 x Potassium hydrogen carbonate

1 x USB cable

1 x Hexagon socket wrench

1 x Screw driver

1 x Instruction manual

62 6 Appendix


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Index

BBoiling properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Ccarousel extractor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Chemical reaction properties . . . . . . . . . . . . . . . . . . . . . . 23counter flow method . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29cross flow method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

DDifferences in concentration . . . . . . . . . . . . . . . . . . . . . . 24Diffusion resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24dwell time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Eextraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4extraction agent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21extraction material . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5, 21extraction residue . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4, 21extraction steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Extraction surface area . . . . . . . . . . . . . . . . . . . . . . . . . . 24

IImmersion extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Installation of software . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

PPercolation extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . 22process diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Rrotating feeder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

SSelectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23setting options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Solid-liquid extraction. . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Solubility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

TTemperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24triangular diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Uuniflow method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28usable substance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

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