continuous rectification - kau...dep. of chemical & mat. engineering liquid-liquid extraction 3. add...

King Abdulaziz University

Faculty of Engineering, Rabigh

Dep. of Chemical & Mat. Engineering

Continuous Rectification

Procedure

1. Use caution avoid contacting hot surfaces.

2. Open cooling water inlet.

3. Set water flow rate at 150 - 200 L/h.

4. Turn main switch ON and turn controller setting to

"Local".

5. Open control software. On "Chart" tab, click

"Settings" and choose an appropriate path for

saving data.

6. Check the liquid level in the evaporator; if it's

below 6 L then

a) Prepare a mixture of 10-15 wt% ethanol in

distilled water.

b) If the evaporator temperature is less than

30 °C, pour directly to the evaporator.

c) Otherwise, add it to one of the feed tanks,

open the feed line valve and feed tank

bottom valve, and turn on the pump at

100%.

7. Turn on the heater at 100% (4000 W).

8. When column pressure drop starts to rise,

gradually reduce heater power to stabilize column

pressure drop of 30-40 mbar.

9. It is critical not to exceed about 45 mbar to avoid

reflux backup after the phase separator tank.

10. Keep reflux at 100% until steady state is achieved.

11. To estimate ethanol composition in the distillate

tank,

a) Clean, dry, and tare the volumetric flasks.

b) Fill the flask with sample.

c) Determine the density and temperature of

the sample, then estimate ethanol

composition from the provided density-

concentration tables.

d) Empty the flask back to the distillate tank

after measurement.

12. Columns can be operated at atmospheric and

vacuum modes with different

a) reflux ratios

b) feed preheating

c) numbers of plates (sieve plate column)

d) feed position (sieve plate column)

13. Corresponding concentration and temperature

profiles can be plotted.

14. Turn off heater and main power switch.

15. Close cooling water valves.

16. Return all collected samples and drain all tanks

into the feed tank (Tank VI).

Objectives

• Sieve plate and packed columns in batch, continuous

and vacuum modes with different

• reflux ratios

• numbers of plates (sieve plate column)

• feed position (sieve plate column)

• feed preheating

• Concentration, temperature profiles and number of

theoretical plates using the McCabe-Thiele diagram

Total Mass Balance

𝑚𝑆𝑡𝑎𝑟𝑡 = 𝑚𝑇.𝑝𝑟. +𝑚𝐵.𝑝𝑟. +𝑚𝐵.𝑝𝑟.,𝐸𝑣𝑎𝑝 +𝑚𝐸𝑛𝑑,𝐹𝑒𝑒𝑑

Ethanol Balance𝑚𝐸,𝑆𝑡𝑎𝑟𝑡 = 𝑚𝐸,𝑇.𝑝𝑟. +𝑚𝐸,𝐵.𝑝𝑟. +𝑚𝐸,𝐵.𝑝𝑟.,𝐸𝑣𝑎𝑝 +𝑚𝐸,𝐸𝑛𝑑,𝐹𝑒𝑒𝑑

𝑚𝐸,𝑇.𝑝𝑟. = 𝑚𝑇.𝑝𝑟. ∙ 𝜒𝐸,𝑇.𝑝𝑟.

Technical Data

Columns

• internal diameter: 50mm

• height: 780mm

Feed pump

• max. flow rate:

200mL/min

Water jet pump

• final vacuum: ~ 200mbar

Tanks

• feed: ~ 5L

• bottom product: ~ 4L

• top product: ~ 1.5L

• phase separation: ~ 0.5L

Heat transfer surfaces

• feed preheating/bottom

cooling: ~ 0.03m²

• top product condenser: ~

0.04m²

1. evaporator with column, 2. bottom heat exchanger, 3.

bottom product tank, 4. feed tank, 5. feed pump, 6. top

product tank, 7. feed, 8. reflux, 9. condenser, 10. phase

separation tank, 11. water jet pump, 12. solvent tank; F.

flow rate, L. level, P. pressure, PD. differential pressure,

T. temperature; dotted, blue line: cooling water




Solid-Liquid Extraction

6. Turn on heating element W1 and set solvent

temperature to 30 °C

7. The extraction material is sprayed throughout

the experiment (~30 to 45 min) and is not

replaced and obtain concentration development

in extract.

Three stage - counter current - continuous

process

1. Synchronize speed of feeder and extractor

(material depth ~ 40mm per cell). The filling

hopper should be filled with a sufficient quantity

of extraction material.

2. Solvent flow rate should be > 6L/h.

Single stage process

1. Set valve position V1 and V2 to 1 stage.

2. Turn on process pump P1 and set solvent flow

rate 15.5 L/h.


temperature T1 at 30 °C.

Two stage process

1. Set valve position V1 and V2 to 2 stages.

2. Running 1 stage process settings, turn on and

adjust pump P2, turn on heating element W2

and set T2 at 30°C

Three stage process

1. Set valve position V1 and V2 to 3 stages.

2. Running 2 stage process, turn on and adjust

process pump P3.



Solvent temperature - extraction performance

1. Set according to the 1 stage experiment.

2. When concentration is no longer rising at

measuring point C4, set the solvent temperature

T1 to 30 °C.

3. When the concentration at C4 becomes constant

increase temperature T1 to 45 °C.

4. Obtain concentration development in extract at

different temperatures.

Solvent flow rate - extraction performance

1. Set according to the 1 stage experiment.

2. Turn on P1 and set solvent flow rate 8 L/h.



4. When concentration does not change at C4, set

flow rate to 11.5 L/h.

5. When the concentration at C4 becomes constant

increase flow rate up to 15.5 L/h.

6. Repeat by increasing solvent flow rate up.

7. Obtain concentration development in extract at

different solvent flow rate.

𝑀𝑎𝑠𝑠 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑜𝑓 𝑡ℎ𝑒 𝑒𝑥𝑡𝑟𝑎𝑐𝑡= 𝑐𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 × 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒

Objectives

• Solid-liquid extraction with 1, 2 and 3 stages (continuous and

batch)

• Effect of solvent flow rate, temperature, extraction material

feed rate and extractor revolving speed

Procedure

1. Set the master switch to “ON”.

2. Make sure that the push buttons for pumps, extractor and

material feeder are all OFF.

3. Make sure that the rocker switches for the heaters are at “0"

position.

4. Connect PC and the unit using USB cable and start the

software.

Extraction performance for single stage batch process

1. 70g of extraction material is weighed out and added to the cell

(this corresponds to material depth of approximately 40mm)

2. The extractor is turned using the speed adjuster until the cell is

centrally below the solvent feed for the 1st stage.

3. The extractor drive is then turned off.

4. Set the valve position V1 and V2 to 1 stage.

5. Turn on process pump P1 and set solvent flow rate 15.5 L/h.

Technical Data

Extractor

• 9 cells

• rotor diameter: ~ 200mm

• speed: ~0-9h-1

Spiral conveyor

• max. feed rate: ~ 20L/h

Peristaltic pumps

• max. flow rate: ~ 25L/h at

300min-1

Heaters

• power: ~330W

Tanks

• extraction material: ~ 5L

• extraction residue, solvent,

extract: each ~20L

B1. solvent tank, B2. extract tank, B3. extraction residue tank, P.

pump W. heater, H1. revolving extractor, X1. material feeder,

C1./C2./C3. stages conductivities, T1. fresh solvent temperature,

T2./T3./T4. stages temperatures, F. solvent flow rate, V1./V2./V3.

stage extraction valves




Liquid-Liquid Extraction

3. Add slowly 4500g of rapeseed oil to the feed

tank B5.

4. Circulate feed for 25min and stop P2.

5. Position 3-way ball valves for batch mode.

6. Open V30 and V4 for feed return.

7. Close V3 for solvent return.

8. Start solvent pump P1. If there are suction

problems, vent suction hose while opening V27

briefly.

9. Adjust solvent flow to about 80mL/ min using

V1.

10. Start P2 and set feed flow to about 800mL/min

using V2.

11. As the extraction column K1 fills up, close V30

as liquid starts to come out.

Extraction

1. Increase solvent flow ~400mL/min by V1.

2. Open V3 to have feed flow ~ 800mL/min.

3. Maintain phase boundary at 1/2 of the extraction

column height by adjusting V3.

4. After every 20min, measure density by taking

samples from V21.

5. Empty sample into B1 after measurement. After

180min of extraction time, stop pumps P1 & P2.

6. Close V1-V4 and open V30.

7. Open V3 to route solvent back to B1.

8. Close V3 as soon as the phase boundary reaches

the base of the extraction column.

9. Collect feed from the extraction column into the

measuring beaker by opening V28 and then

V29.

10. Drain measuring beaker into B5.

11. Calculate the efficiency of extraction.

Distillation

1. Pour 4000g of extract into flask D1.

2. Turn the main switch to "1".

3. Slowly open valve V11 (ambient pressure).

Move heating zone switch to "3".

4. Switch on heating mantle H1.

5. Release controller TIC1 and set SP at 95°C.

6. Open cold water inflow to W1 well before

boiling starts.

7. Bring the residue in D1 to boiling point.

8. Ensure that the level in D1 is sufficient.

9. Interrupt distillation as soon as the vapour

temperature T2 reaches the value of 98°C.

10. Switch off H1, close water supply to W1 and

turn main switch to "0“.

11. Calculate the efficiency of distillation.

Cleaning

Rinse dirty components and lines with warm water,

detergent and methylated spirits.

Objectives

• Separation of a liquid mixture by liquid-liquid extraction in

counterflow operation

• Enrichment of extract by distillation (continuous or batch

mode)

• Mass balances, effect of feed flow rates on the extraction

efficiency

Procedure for Batch Operation

1. Pour 5000g tap water into solvent tank B1.

2. Pour 500g of ethanol into feed tank B5.

3. Close V2 in the feed inflow and start P2.

Technical Data

Extraction column

• diameter: 40mm,

• height: 1.5m

Distillation

• diameter: 30mm,

• height: 415mm

• heater power : 1200W

Tanks

• feed and raffinate: 30L each

• solvent & extract:15L each

• top product (distill.):15L

• bottom tank (distill.): 5L

Feed pump

• max. flow rate: 1L/min

• max. head: 80m Solvent

Pump

• max. flow rate: 1.2L/min

• max. head: 10m

Water jet pump

• final vacuum: ~ 200mbar

1. extraction column, 2. three-way valves, 3. water jet pump, 4.

solvent pump, 5. solvent tank, 6. top product tank (distillation), 7.

extract tank, 8. condenser with cooling water connection, 9.

distillation column, 10. feed pump, 11. feed tank, 12. raffinate

tank, F. flow rate, P. pressure, T. temperature, L. level

Experimental conditions

Extraction of ethanol from rapeseed oil with water

• Mass fraction of ethanol in the feed: 10%

• Equal masses of feed and solvent: each 5000g

• Extraction time: 180min

• Solvent flow: 400mL/min




Tray Drier

Theory Immediately after contact between the drying media

(wet solid) and the drying medium (hot air), the

solid temperature adjusts until it reaches a steady

state. If the solid is initially very wet the surface is

essentially covered in a thin film of liquid which is

considered to be unbound moisture. The solid

temperature and the rate of drying may increase or

decrease to reach the steady state condition. At

steady state, the temperature of the wet solid surface

is the wet bulb temperature of the drying medium.

Temperatures within the drying solid also tend to

equal the wet bulb temperature of the air. However,

lag between the movement of mass and heat result in

some deviation. Once the media temperatures reach

the wet bulb temperature of the air, the temperatures

of the media and air become stable and the drying

rate remains constant. This is the “constant rate

drying”. The moisture is transported to the surface

of the media by capillary forces and drying is

limited only by the rate at which the heat is

supplied. This period ends when the solid reaches

the critical moisture content. The surface film of

moisture over the solid has been reduced by

evaporation to a point where any further drying

causes dry spots to appear on the solid

surface. Beyond the critical moisture content the

surface temperature of the solid rises and the drying

rate falls off rapidly. This is the “falling rate” period

and can last for a significantly longer time than the

constant rate period. This holds true even though the

moisture removal may be less. The drying rate

approaches zero as the moisture content reaches

equilibrium. This is the lowest moisture content

obtainable with the solid under the drying conditions

used

Experiment:

To produce a drying and a drying rate curve for a

wet solid being dried with air of fixed temperature

and humidity.

Start-up (Pre-Heating & Zeroing load cells):

1.Make sure the unit is switched off and remove the

three drying trays from the UOP8-MKII and set

aside.

2.Turn on the UOP8-MKII tray drier using the main

switch on the drier and also by clicking the “power

on” button (so that it appears as button) on the

Armsoft software.

3.Adjust the fan speed and louvre as required to

achieve an inlet air velocity of 0.6m/s.

4.Note the temperature of T1 on the mimic diagram

and enter this temperature as the ambient air

temperature by clicking on the button on the mimic

diagram.

5.Open the heater PID () and set to automatic with a

set point of 55°C. Be aware that you must choose

the option Automatic from the PID menu. Check

that the preheat temperature sensor rises then

stabilises approximately at the set point

temperature.

Moisture Content & Time

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0 5 10 15 20 25 30 35 40 45 47

Time (min)

X

Design of the device




Evaporator

Summary:Evaporation is a process used to concentrate

aqueous solutions. It involves removing volatile

solvent from an aqueous solution consisting of non-

volatile solute by vaporization, in a vessel known as

evaporator. Evaporation process begins with a

liquid product and ends up with a more

concentrated liquid as the main product. In some

special cases, the evaporated, volatile component is

the main product, for example in water desalination

the vapors obtained by the evaporation process are

condensed and used for drinking purposes.

Similarly the water that contains minerals is

evaporated to obtain solid free water which can

then be used in boilers, and for other special

requirements. In all these cases the condensed water

is the desired product. The use of multiple effect

evaporators to increase progressively the

concentration of a feed solution is widely adopted

in the process industries. Evaporation is one of the

principal methods used in the chemical industry to

concentrate aqueous solutions.

This industrial equipment is usually large and

complex so the Armfield evaporator has been

specially designed to be of manageable scale in a

student laboratory, while retaining the essential

features of its industrial counterparts. Particular

attention has been paid to the number and variety of

experiments possible using the various evaporator

modules available. Comprehensive exercises using

Rising Film or Falling Film with Single Effect and

Double Effect with various feed permutations can

all be achieved. Connection to a computer greatly

enhances the capability of the equipment with the

data logging, data processing, help texts and control

exercises included in the software package.TheoryThe equipment used for experimentation is

ARMFIELD RISING FILM EVAPORATOR

STEAM UOP20-X-STM. The heating medium is

steam which is provided by a steam generator

associated with the evaporation unit. The schematic

of the experimental set up is shown in Fig. 1. The

experimental unit is a floor standing tubular frame

work for an evaporation system. It can be arranged

as rising or falling film with single or double effect

evaporation system. The unit is provided with full

set of instrumentation. Thermocouples are available

at twelve different points to measure the temperature

of the product and heating fluid. The unit also

comprises of a feed pump, vacuum pump, condenser,

condensate vessel, temperature control feed

preheater of 2kW and collection tanks.





Filterability Index

Unit DescriptionThe filterability index unit is used for

demonstrating the filtering process through a

porous media. It enables a water quality test to be

made on a suspension to be filtered through sand

or similar granular media. This unit utilizes a bed

of granular material, normally sand, which can be

chosen by the student to suit his own purposes.

The measurements taken with this unit enable a

filterability index to be calculated which has

significance in deep bed filter performance.

The unit is a bench-top unit composed of a feeding

tank, where the initial solution of water with solids

in suspension is placed. During the normal

operation, the tank is communicated with the sand

filter upper part, through a pipe of 10 mm

diameter. The filter lower part is communicated

with the flowmeter. A regulation valve located at

the flowmeter allows to change the flow which

passes through the filter. The fluid pressure is

obtained by means of the gravity, because the

feeding tank is placed in high. The pressure is

measured by a manometer. The filter cartridge is

easily removable, so it allows to study the

difference between different media, both in

compositions and in mesh. This unit, in addition to

students teaching and training, also can be used in

routine control at water purification works, or at

water treatment works which employ tertiary

filtration.

Some practical some practical possibilities of unit

1) Study of the filtration operation principles

2) Flowmeter calibration

3) Flow through permeable layers

4) Practice of sand filter cleaning

5) Filtration procedure

6)Calculation of Filterability Index from

measurements taken

7) Deep bed filtration of suspensions with

different particle layers





Plate and Frame Filter Press

Unit Description

Arrangment of filter plates in frame filter press

Fundamental principles

Cake filtration is a mixture of surface and deep bed

filtration.

The progress of filtration develops dynamically.

Metallic cloth or needle felting is used as the filter

material, in some cases covered with a fine textile

cloth. To support this, perforated plates or sieves

are placed underneath.

The suspension fed onto the initially clean filter

material first of all flows almost completely through

the filter material with only the largest solid

particles being retained. More and more solid

particles are gradually deposited on the filter

material, creating a filter cake that becomes

increasingly thick.

The actual filtration only occurs when a sufficiently

thick filter cake has formed. For the suspension to

pass through this filter cake, there must be a

pressure difference between the feed side and the

filtrate outlet side. This can be generated by:

– Hydrostatic pressure

– Creation of excess pressure on the

suspension side (pressure filtration)

– Creation of a vacuum on the filtrate side

(vacuum filtration)

Above a certain filter cake thickness, it must be

removed. However, a residual layer is left behind

so that there is no unclarified initial filtrate.

Cake filtration




Venturi Scrubber System

Introduction

The SOLTEQ Venturi Scrubber System (Model: AP02) is designed and manufactured to a standard with emphasis on ease

of use and operational safety for introduction of air pollution control by using venturi scrubber system to Chemical

Engineering students. It consists mainly of transparent cylindrical venturi scrubber, a separation chamber, a water

recirculation chamber, a powder-feeder system, an air blower, an outlet dust filter, and air flow meter.

The venturi scrubber system is made of a durable clear PVC with throat diameter of 32 mm and both convergence and

divergence diameter of 101.6 mm. The separation chamber is also made of durable clear PVC with dimension of 0.6 m

diameter and 2 m height. The chamber has a rectangular tangential inlet at the bottom of the venturi chamber. A mist

eliminator is located at the top section of the chamber to prevent any water droplets from escaping. The water recirculation

tank consists of a water tank, water pump, digital flow meter, pressure transmitter and a needle valve.

An air blower installed at the outlet is capable of drawing 222 m3/hr of air through the system. The air velocity is set by

adjusting the speed of the blower which is controlled by an inverter. With the aid of a pneumatic vibrator, a valve is

installed below the feed container to control the amount of dust particles sample introduced into the system. A pressure

regulator is used to regulate the pneumatic vibrator.

Three digital differential pressure transmitters have been installed for measuring pressure drops across the bag house,

venturi meter, and air flow rate. Student will demonstrate venturi scrubber operations by varying several parameters such

as liquid to gas (L/G) ratio to estimate its effect on separation efficiency and verify the theoretical relationship between

total pressure drop and air inlet velocity

Section Description of Venturi

Scrubber

Schematic diagram of the Venturi Scrubber System




Flow through Particle Layers

10. After filling the filter, carefully slide the

filter crown on to the glass tube until its

front end makes contact with the crown.

11. Ensure that the O-rings are correctly seated

in order to protect them against damage.

12. After assembling the filter, install it back in

its holder and tighten the knurled screws

again.

13. De-aerate hoses by opening both discharge

valves and rinse the hoses with water until

they are completely free of air bubbles.

14. Then close both discharge valves

simultaneously.

15. Establish the hose connections for the inlet,

outlet and pressure distributor.

16. Pressures drop (∆𝑝) is calculated from the difference in heights of water columns (∆ℎ)in the two glass tubes

∆𝑝 = 𝜌 𝑔 ∆ℎDeposited layers (Fixed beds)

Darcy’s equation

𝑄 =∆𝑝𝐴

𝐿𝑅ߟwhere 𝐴 is flow area, 𝑄 is volumetric flow rate, 𝑅 is hydraulic resistance and ߟ𝐿 is dynamic viscosity

Carman-Kozeny modified Darcy equation as

𝑄 =∆𝑝𝐴𝜀3𝑑𝑝

2

𝐿ߟ 1 − 𝜀 2𝐻𝐾where 𝑑𝑝 is particle size, 𝐻 is bed height and 𝐾

is material constant.

Fluidized beds

∆𝑝 = 𝐻 1 − 𝜀 𝜌𝑝 − 𝜌𝐿where 𝜀 is the bed voidage, 𝜌𝑝 is apparent

density of particles and 𝜌𝐿 is the density of the fluid

𝑅𝑒 = 42.86 1 − 𝜀 1 + 3.11 × 10−4𝐴𝑟𝜀3

1 − 𝜀 2− 1

𝐴𝑟 =𝑔𝑑𝑝

3 𝜌𝑝 − 𝜌𝐿

𝜈2𝜌𝐿where 𝐴𝑟 is Archimedes number, 𝜈 is the kinematic viscosity and 𝑔 is the gravity acceleration

17. Drain the system of water and disconnect the

manometers.

18. Remove the particle layers from the filter.

Objectives

• Flow properties of deposited layers and fluidized beds

comprising of different granular materials, sizes and layer

heights

• Verification of Carman-Kozeny equation

• Onset of fluidization

Procedure

1. Fill a measurement beaker with 20 mL (𝑉𝐿) of water. 2. Fill the measurement beaker with particles until a water

layer is no longer visible.

3. Read the total volume of deposit and water (𝑉𝐿 + 𝑉𝑆). 4. Determine the porosity (𝜀)

𝜀 =𝑉𝐿

𝑉𝐿 + 𝑉𝑆5. Position the device on a flat surface in the vicinity of a

drain and water connection.

6. Loose and remove the knurled screws on the filter crown.

7. Detach the hoses of manometer from the filter crown and

base.

8. Withdraw filter out of its holder and detach filter crown

from the filter tube by hand.

9. Place the filter base and glass tube on a level surface and

fill the filter with particles until the required particle

deposition height has been attained. Read the height from

the mounted scale.

Technical Data

Test tanks

• length: 510mm

• inside diameter: ~ 37mm

Filter medium

• thickness:2mm

• material: sintered metal

Expansion tank

• capacity: ~ 4500mL

Fixed bed (A) and fluidized beds (B): 1. tube (particle layer), 2.

valve (flow rate), 3. inlet, 4. outlet, 5. expansion tank; P. pressure, F.

flow rate




Depth Filtration

IntroductionThe CE 579 unit is part of the 2E – ENERGY & ENVIRONMENT product area.

ENERGY

The ENERGY product area includes units involved with regenerative energies. Examples of these are photovoltaics, solar heat

and water power.

ENVIRONMENT

Harmful substances are transferred and converted in the hydrosphere (water), the atmosphere (air) and the pedosphere (soil).

Water, soil and air are referred to as environmental compartments and are linked together by the global water cycle. In addition,

the ENVIRONMENT area includes training on the topic of waste. The CE 579 is part of the water training area. This training

area covers the most important basic processes in water treatment. The basic processes can be divided into three groups The

choice of processes depends on the properties

of the substances to be removed from the water. Mechanical processes are used to remove insoluble substances (solids). By

contrast, dissolved substances can be removed using biological or physical/chemical processes. If the dissolved substances are

biodegradable, biological processes are used. On the other hand, if the dissolved

substances are not biodegradable, physical/ chemical processes are used. Filtration is a mechanical process that is very

commonly used in water treatment. In terms of filtration, we can differentiate between:

• Surface filtration

• Depth filtration

Sand Filter

continuous rectification - kau...dep. of chemical & mat. engineering liquid-liquid extraction 3. add...

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