Removal of Insolubles(Filtration)

Filtrationremoval of solid particles from a fluid by passing the fluid through a filtering medium or septum, on which

the solids are deposited

• Air Filter• Liquid Filter (water purifier)

MicroorganismInsoluble fermentation broth

Soluble brothvs

Equipment

Laboratory Scale

vacuum

Filter paper

Large Scale

Plate and Frame Horizontal Plate

Vertical Leaf Candle Type

Equipment

Continuous Rotary Vacuum Filter

Microfiltration(membrane separation)

Continuous Rotary Vacuum Filter

Filter Press (Pressure Filter)

40 ~ 150 lb/in2

ΔP

Canvas

Feed

Frame FramePlatePlateCanvas Canvas Canvas

Liquid(filtrate)

Wet Cake

Filter Press Operation

i. Feed inputii. Filtrate flow stops or sudden

increase in filtration pressureiii. Wash liquid inputiv. Air blowing (steam blowing)v. Open press and scraping off of

solids

Automation Materials(SUS, PP--)

Operating Variables

• vacuum• wash/spray water

Darcy’s Law

l

Pk

flow rate through a porous bed

where: ν – velocity of the liquidk – constant (Darcy’s law permeability of the bed)ΔP – pressure drop across the bed of thickness lμ – viscosity of the liquid

Holds only when:Reynold No

51

d

where: d – particle size or pore diameterρ – liquid densityε – void fraction in the cake

[1]

[2]

Filtration: Theory

For batch filtration

dt

dV

A

1 where: V – total volume of filtrate

A – filter area

CM RRk

l where: RM – resistance of the filter medium

RC – resistance of the accumulated mass

CM RR

P

dt

dV

A

1

[3]

[4]

[5]

Incompressible Cakes

areafilter

volumefiltratethicknesscake

Therefore, cake resistance RC

A

VRC 0

where: α – specific cake resistanceρ0 – mass of cake solids per volume of filtrateΑ : dimension – length/mass

[6]

Substitution of Eq. 6 into Eq. 5

MRAV

P

dt

dV

A

0

1

[7]

Initial condition 00 Vt [8]

Integration of Eq. 7 yields

BA

VK

P

R

A

V

PV

At M

20 [9]

A plot of (At/V) vs (V/A) should be linear. The slope K is a function of ΔP and of the cake properties.

If medium resistance RM is insignificant, then

2

0

2

A

V

Pt

[10]

Compressible Cakes

SP ' Assume!

Figure 1. Cake resistance versus pressure drop.

Example 2.3-1) Streptomyces Filtration from an Erythromycine Broth

Filtration time(sec)

Volume of fil-trate(L)

5 0.040

10 0.055

20 0.080

30 0.095

Q. Determine specific cake resistance α, medium resistance RM.

A=0.1 ft2

μ=1.1 cP∆P=20 in. of mercuryρ=0.015kg dry cake/L

sol.) Darcy’s law:

in. in.∴α=2.4 X 1011 cm/ g

∴RM=0

(V/A) vs. (At/V) plot → y-intercept= 0

Example 2.3-2) Filtration of Beer Containing Protease

Q.1 How long will it take to filter beer at 50 psi? 2 How long will it take at half this pressure drop?

Filtering 3000 L with 15 frames(each of area 3520 cm2)RM is negligible.Total pressure drop(∆P)= 65 psi

* Compressible cake* With funnel 5 cm,filtering 100 cm3 of beer in 24 min* s=2/3

& ∵ compressible cake

0

∴

psi

min psi1/3 /cm3

( R∵ M is negligible.)

psi1/3

Q.1 How long will it take to filter beer at 50 psi?

psi

Q.2 How long will it take at half this pressure drop?

psi

∆P= 25 psi

Example 2.3-3) Filtration of Incompressible Steroid Crystals

Weight of crystals 62 g

Pressure of filtration 15 psi

Filter diameter 5.08 cm

Cake depth 12.5 cm

Cake volume 253.3 cm3

Filtration time 163 min

*Assumption: - Cake is incompressible. - Feed pump: 10 psi - filtrate is raised against the equivalent of 15 ft head.

Q.1 Predict the number of frames needed. 2 Estimate time required to filter a 63 kg batch of steroid.

inin

Q.1 Predict the number of frames needed.

The number of frames needed is 18 frames.

Q.2 Estimate time required to filter a 63 kg batch of steroid.

psi

psi

psi

psi

psi

psi

in2

Purification of the IgG antibody by affinity cross-flow filtration

2011. 10. 5.Danim Yun

24

IgG & cross-flow filtration

Antibodies are proteins made by the immune system to destroy foreign invaders. There are five major types of antibodies: immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin E (IgE) and immunglobulin D (IgD). An IgG antibody helps to battle bacterial and viral infections.

Protein A

IgG

25

Crystalline bacterial cell surface layers (S-layers)

Identical subunits and functional groups show same position and orientation on each S-layer subunit

-> crystalline matrix has a nanometer range.-> using for immobilization of Protein A

Steep rejection curves cut-off; 45,000

After crosslinking the S-layer protein with glutaraldehyde, carboxyl groups from acidic amino acids were activated with carbodiimide and used for immobilization of Protein A

26

cross-flow filtration system

27

Results from affinity cross-flow filtration experiments

Albumin and minor amounts of nonadsorbed IgG

IgG-human albumin mixture

Eluted IgG fraction

28

Thank you