teknik bioseparasi - everything at once · mempelajari ruang lingkup teknik bioseparasi dan teknik...

Teknik BioseparasiDina WahyuGenap/ Feb 2014

OutlineChemical Reaction Engineering

Pendahuluanmempelajari ruang lingkup teknik bioseparasi dan teknik “cel disruption”

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Teknik Pemisahan Secara Fisika 1

Koagulasi dan flokulasi Mengetahui teknik pemisahan dengan cara koagulasi dan flokulasi

Teknik Pemisahan Secara Fisika 2Mempelajari teknik pemisahan sedimentasi

Teknik Pemisahan Secara Fisika 3 Mempelajari teknik filtrasi pada bioseparasi

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5

3

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Teknik Pemisahan Secara Fisika 1Mempelajari teknik sentrifugasi pada bioseparasi

Koagulasi dan flokulasi Mengetahui teknik pemisahan dengan cara koagulasi dan flokulasi

Adsorpsi Proses adsorpsi pada cairan dan gas, serta pengetahuan bahan adsorpsi

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Adsorpsi 2Kinetika Adsorpsi, Isotherm Adsorption7

Chap.4 Sedimentation

• Equation of motion

Sedimentation , also known as settling, may be defined as the removal of solid particles from a suspension by settling under gravity.

• Equation of motion• Equilibrium sedimentation• Sedimentation coefficient• Equivalent time• Production centrifuge• Production centrifuge• Ultracentrifugation• Sedimentation at low acceleration

Bioprocess Overview

Intra-CellularProductExtra-Cellular

Product

Upstream Processing

Chemical/Enzymatic/

Solid-liquidSeparation

Concentration

ProductCell Disruption

Centrifugation/Sedimentation,Extraction, Filtration

Evaporation, Ultrafiltration,Adsorption, Precipitation

Chemical/Enzymatic/Mechanical/Physical

Purification

Formulation

Final Product

Chromatography

Crystallisation, freeze drying,Spray drying, sterile filtration

Basic Biotechnology, 2nd Ed, Ch 9

Sedimentation• This is the separation of a liquid from particles suspended in the

liquid• A particle, falling from rest, accelerates under the force of gravity

The drag force increases so the acceleration decreases• The drag force increases so the acceleration decreases(liquid viscosity is important here)

• Acceleration eventually becomes zero – the terminal velocity is reached

• Terminal velocity is reached quickly, e.g. a 100 m particle in water reaches 2 mm/s in 1.5 ms

• Upward velocity of liquid must be less than terminal velocity for • Upward velocity of liquid must be less than terminal velocity for sedimentation to work

• We must know the terminal velocity!

Sedimentation Tank

GRAVITATIONAL SEDIMENTATION• Sedimentation uses gravitational forces to separate

particulate material from fluid streams. The particles are usually solid, but they can be small • The particles are usually solid, but they can be small liquid droplets, and the fluid can be either a liquid or a gas.

• Sedimentation is very often used in the food industry for separating dirt and debris from incoming raw material, crystals from their mother liquor and dust or product particles from air streams.liquor and dust or product particles from air streams.

Applications of settling and sedimentation:

* Removal of solids from liquid sewage wastes

* Settling of crystals from the mother liquor

* Separation of liquid-liquid mixture from a solvent-extraction stage in a settler

* Settling of solid food particles from a liquid * Settling of solid food particles from a liquid food

Example

Continuous sedimentation plantContinuous sedimentation plant Cyclon separatorCyclon separator

For a rigid particle of mass m moving in a fluid, there are three forces acting on the body:

(1) Gravity force, Fg, acting downward

THEORY OF PARTICLE MOVEMENT THROUGH A FLUID

(1) Gravity force, Fg, acting downward

(2) Buoyant force, Fb, acting upward

ssb

gmgVF

where r = density of the liquid

mgFg

where r = density of the liquid

rs = density of the solid particle

Vs = volume of the particle

For a rigid particle of mass m moving in a fluid, there are three forces acting on the body:


(3) Drag force, FD, acting in opposite direction to the (3) Drag force, FD, acting in opposite direction to the particle motion

2

2

DD

vACF

where CD = the drag coefficient

A = the projected area of the particle

The resultant force equals the force due to acceleration.

2

2

D

vAC

gmmg

dt

dvm

s

The falling of the body consists of two periods:

(1) The period of accelerated fall

The initial acceleration period is usually very short,


The initial acceleration period is usually very short, of the order of a tenth of a second or so.

(2) The period of constant velocity fall

Set 0dt

dvand solve the above equation for v.

02

2

v

ACgm

mgdt

dvm D

AC

mgvv

Ds

sg

)(2

* vg is called the free settling velocity or terminal velocity.

02

ACmgdt

m Ds

Brownian motion: the random motion imparted to the particle by collisions between the molecules of the fluidsurrounding the particle and the particle.


* If the particles are quite small, Brownian motion is present.

This movement of the particles in random directions tends to suppress the effect of gravity.

Settling of the particles may occur more slowly or not at all.

* At particle sizes of a few micrometers, the Brownian effect becomes appreciable and at sizes of less than 0.1 mm, the effect predominates.


0.1 mm, the effect predominates.

In very small particles, application of centrifugal force helps reduce the effect of Brownian motion.

To capture particles in a solution having density gradient.

Application: determining the density of the solute or suspended particle.

ISOPYCNIC (SAME-DENSITY) SEDIMENTATION

suspended particle.

* There are three methods for establishing conditions for isopycnic sedimentation:

(1) Layer solutions of decreasing density, starting at the bottom of the tube.

(2) Centrifuge the solution containing a density-forming solute (such as CsCl) at extremely high speed.

(3) Use the gradient mixing method.

* Methods for establishing conditions for isopycnic sedimentation (continued)

(3) Use the gradient mixing method.

Produce an outflow with a linear solute gradient.

The most widely used method.


The most widely used method.

QQ/2

Q

tV

CCQCtC 0,12

0,1 2

)()(


tV

CtC0

0,1 2)(

where C1,0 = initial solute concentration in the mixed chamber

C, Q

C2

C2 = solute concentration in the non-mixed chamber(constant)

Q = outflow rate from the mixed chamber

V0 = initial volume in each vessel

Separation of solid particles into several size fractionsbased upon the settling velocities in a medium.

DIFFERENTIAL SETTLING (or CLASSIFICATION)

INCLINED SEDIMENTATION Particle-free overflow

exits the upper end, and particle-rich suspension leaves in the underflow.

Rapid removal of high density solids can be achieved.

The particles need to settle only a distance

leaves in the underflow.

settle only a distance of order b (compared with a distance of order L in a vertical settler).

INCLINED SEDIMENTATION (2/2)

Applications:

(1) Continuously (or batchwise) harvest supernatant from supernatant from particle (cell)-laden broth.

(2) Concentrate (batchwise) the particulate fraction.

(3) Perform a binary particle classification by particle classification by size.

Scaleup of inclined settlers:increasing the area for settling.

References• Separation Processes in the Food and Biotechnology Industries.

Woodhead Publishing. Retrieved November 30, 2003 from Knovel Chemistry and Chemical Engineering Database.

• Transport Processes and Separation Process Principles. Christie John Geankoplis. 2003. Prentice Hall.

Solid-Liquid Separation in Water Treatment

3/14/2014water treatment24

These settling types are demonstrated in a batch settling test as illustrated below:

The height of the interface (between the clarified zone and the zone settling zone) versus time is plotted in the figure below to determine the "zone settling velocity"(ZSV). Velocity of this interface is steady after some induction period but changes with time as compression begins. The slope of the steady interface subsidence rate represents zone settling velocity. rate represents zone settling velocity.

Initial suspended solids concentration has a significant effect on the ZSV because the higher the suspended solids concentration the more difficult it is to pass water through the pore spaces in the settling matrix. (The only way a matrix can settle is if the water below it is allowed to pass upward through the matrix). A typical relationship between initial suspended solids and ZSV is shown here.shown here.

Factors affecting zone settling velocity:

1. Suspended solids concentration2. Depth of settling column (or tank)3. Stirring ( 0.5 – 2 rpm to prevent “arching”)4. Temperature5. Polymer addition ( affects matrix structure)

Design of Zone Settling Tanks

Two important functions of these sedimentation tanks are : clarification and thickening.

For a continuous flow clarifier, operated at steady-state, mass flow of suspended solids can schematically represented as follows:

Activated Sludge Mass Balance over Settler



Weir Details

LAMELLA SETTLING TANKS:Shortening the settling distance

Pipe


Pipebundlesalso used

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teknik bioseparasi - everything at once · mempelajari ruang lingkup teknik bioseparasi dan teknik...

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