1. Filtration2. Microfiltration3. Ultrafiltration4. Reverse osmosis (hyperfiltration)

Upon completion of the topic the students are able to :

1. Explain filtration process and membrane filtration2. Citing examples of filtration equipments and membrane

filtration equipments3. Understanding the mechanisms and processes of

filtration and membrane filtration and able to perform simple input-output analysis

Fellows P. J. 2000.

Bab 6 : Separation and concentration of food components (Cold separation & concentrat’)

Earle. R.L. 1983.Bab 10 : Mechanical Separation

References :

Filtration Sieving Centrifugal Separation

Sedimentation

1.Filtration 2.Microfiltration3.Ultrafiltration4.Reverse osmosis

(hyperfiltration)

I. Filtration (Conventional Filtration)

Filtration is the removal of insoluble solids from a suspension (or ‘feed slurry’) by passing it through a porous material (or ‘filter medium’). The resulting liquor is termed the ‘filtrate’ and the separated solids are the ‘filter cake’.

The rate of filtration is expressed as follows:

Reverse osmosis (RO) (or ‘hyperfiltration’) and ultrafiltration (UF) are both unit operations in which water and some solutes in a solution are selectively removed through a semi-permeable membrane.

Pressure Filters:

1. Vacuum filtration

2. Plate-and-frame filter press

Video Filter press minyak

Video Filter press animasi

3. Rotary drum filter

The filter press has relatively low capital costs, high flexibility for different foods, it is reliable and easily maintained. It is widely used for the production of apple juice and cider and vegetable oils

3. Rotary drum filter

Plott t/(V/A) vs (V/A) ?

Slope ?

Intercept ?

Equation ?

Plott t/(V/A) vs (V/A)

slope 0.0265

intercept 1.6

II. Membran ProcessUnit operations in which water and some solutes in a solution are selectively removed through a semi-permeable membrane.

Suspended particles

Macro molecules

Salt, sugar molecules

WATER

Size separation capabilities of different membrane systems.

Size separation capabilities of different membrane systems.

The advantages of membrane concentration over concentration by evaporation are:

1.the food is not heated, and there is therefore negligible loss of volatiles or changes to nutritional or eating quality2.in contrast with boiling, membrane concentration does not involve a change in phase and therefore uses energy more efficiently3.simple installation with lower labour and operating costs4.no requirement for steam boilers.

The main limitations of membrane concentration are:

1.variation in the product flow rate when changes occur in the concentration of feed liquor2.higher capital costs than evaporation3.a maximum concentration to 30% total solids4.fouling of the membranes (deposition of polymers), which reduces the operating time between membrane cleaning.

III. Microfiltrasi (MF).

MF separates dispersed particles such as colloids, fat globules or cells, and may therefore be thought of as falling between UF and conventional filtration

Penjernihan minyak goreng dgn Microfiltrasi (MF):

Membran Microfiltrasi

IV. Ultrafiltrasi (UF).

Ultrafiltrasi (UF).

UF is used to separate macromolecules. UF membranes have a higher porosity than RO, but smaller than MF, retain only large molecules (for example proteins or colloids).MF : 0.1 s/d 2 mikronUF : 0.01 s/d 0.1 mikronRO : 0.001 s/d 0.0003 mikron

Most for Concentrate milk prior to the manufacture of dairy products, to concentrate whey to 20% solids or selectively to remove lactose and salts (1). higher product yield and nutritional value, (2). simpler standardisation of the solids content, (3). lower rennet consumption and easier processing).

Other applications include:1.concentration of sucrose and tomato paste2.treatment of still effluents in the brewing and distilling industries3.separation and concentration of enzymes, other proteins or pectin4.removal of protein hazes from honey and syrups5.treatment of process water to remove bacteria and contaminants (greater than 0.003 m in diameter)

Large scale Reverse Osmosis (RO).

V. Reverse Osmosis (RO).

Reverse osmosis is used to separate water from low-molecular-weight solutes (for example salts, monosaccharides and aroma compounds), which have a high osmotic pressure. A high pressure (4000–8000 10*3 Pa), five to ten times that used in UF is therefore necessary to overcome this (hence the term reverse osmosis).

APPLICATION:

1. concentration of whey from cheese manufacture, 2. concentrate and purify fruit juices, enzymes, fermentation

liquors and vegetable oils3. to concentrate wheat starch, citric acid, egg white, milk,

coffee, syrups, natural extracts and flavours4. to clarify wine and beer5. to demineralise and purify water from boreholes or rivers or

by desalination of sea water.

Spiral cartridge membrane: (a) components; (b) schematic flow diagram.

Reverse Osmosis (RO) membrane

RO Membrane structures: (a) asymmetrical membrane cross-section; (b) symmetrical membrane cross-section; (c) hollow-fibre asymmetrical membrane cross-section; (d) flat sheetasymmetrical membrane cross-section.

Perbandingan antara ukuran pori-pori membran Reverse Osmosis (RO) dengan ukuran rambut manusia

Karakteristik Berbagai jenis membran RO dan UF

Laboratory scale Reverse Osmosis (RO) membrane

Tubular membrane.

pre-treatment for reverse osmosis membranes to prevent fouling by suspended organic materials and colloidal materials using MF and UF.

MF – Carbon Filter – UF series for preliminary filtration

Laboratory scale Reverse Osmosis (RO).

Large scale Reverse Osmosis (RO).

Fruit juice containing 9% w/w solids is pre-concentrated at 35ºC by reverse osmosis, prior to concentration in an evaporator. If the operating pressure is 4000 kPa and the mass transfer coefficient is 6.3 10*-3 kg m*-2 h*-1 kPa*-1, calculate the area of membrane required to remove 5 t of permeate in an 8 h shift. (Assume that sucrose forms the majority of the solids in the juice and the universal gas constant is 8.314 kPa m*-3 mol*-1 K*-1). MW sucrose = 342

Required flux: 5 ton dalam 8 jam

1.Fellows P. J. 2000. Food Processing Technology: Principles and Practice. Second Edition. CRC Press, Boca Raton.

2.Earle. R.L. Unit Operations in Food Processing. 1983. Pergamon Press

3.Brennan, J.G. Food Processing Handbook. 2000. Elsevier Publ. Co., Ltd. N.Y.

4.Singh, R.P. and D.R. Heldman, 2001. Introduction to Food Engineering, 3rd Edition, Academic Press.