CHE399

8/3/2019 CHE399

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Concentration

of Sugar byForwardOsmosis

By

Dianne Kate Pelon

Engelee Salvania

Giselle Anne Oliva

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Outline

Food and Beverages Industry

Common Methods used in Concentrationof Sugar

Evaporization /Crystallization

Osmosis

Significance of Study

Schematic Diagram of Forward OsmosisProcess

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Background of Study


Primarily concerned with the

production and distribution of

sugar-based products.

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Background of Study


These industries tend to generate wastestreams containing high concentrations ofsugar.

These solid wastes can be pressed toextract sucrose-rich liquor.

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Background of Study


Treating this concentrate is the limiting step

that increases the final cost of the product.

It would, therefore, be desirable to find a way

to concentrate or at least to pre-concentratethese sugar-rich solutions to save energy.

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Background of Study

Common Methods Used

Evaporation / Crystallization

Osmosis

Reverse Osmosis

Forward Osmosis

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Background of Study

Osmosis

A solvent is the base substance, where asolute is being dissolved and the result isthe solution.

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Evaporation /Crystallization

Crystallizationit may be defined as a process which

separates a pure solid in the form of itscrystals from a solution.

EvaporationProcess of separating any substance from

its solution by removing water.

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Reverse Osmosis Reverse osmosis is a separation process that

uses pressure to force a solvent through

a semi-permeable membrane that retains thesolute on one side and allows the pure solventto pass to the other side.

More formally, it is the process of forcing asolvent from a region of high solute

concentration through a membrane to aregion of low solute concentration byapplying a pressure in excess of the osmoticpressure.

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Forward Osmosis Uses the osmotic pressure gradient across the

membrane to produce a total flow of water through the membrane into the draw solution.

Driven by an osmotic pressure gradient,forward osmosis does not require directenergy input.

Forward osmosis is a low-resource water treatment technology that offers the

advantage of high rejection of a wide rangeof contaminants than traditional membraneprocesses.

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Factors Affecting the Rate ofOsmosis

Temperature - The higher the temperature,

the faster the movement of water molecules

across the semi permeable membrane.

Surface Area - The larger the surface area,

the more space for the molecules to move

easily across; the smaller the area, the more

restricted the movements of the molecules

and the slower the movement.

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Difference in Water Potential – The higher thedifference in water potential, the faster the

osmosis; for the lesser water molecules are inthe region of low concentration, more water molecules from the region of higher concentration can enter faster and easier.

Pressure – The more the pressure, the faster the molecules will move for they are beingpushed faster across a low concentration.

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Concentration gradient - The movementof osmosis is affected by the

concentration gradient; the lower theconcentration of the solute within asolvent, the faster osmosis will occur inthat solvent.

Light and dark – They are also factors ofosmosis; since the brighter the light, thefaster osmosis takes place.

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Objectives

To examine the use of FO as analternative for concentrating sugar.

Specifically, we need to investigate theuse of FO as a method for sucroseconcentration using a commerciallyavailable FO membrane and examine themembrane water flux performance as afunction of sucrose concentration.

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Schematic Diagram

Figure 1. Castello et al. 2009

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Forward Osmosis in

Desalination

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Advantages of FO

It operates at low or no hydraulicpressures

It has high rejection of a wide range ofcontaminants, and it may have a lower membrane fouling tendency thanpressure-driven membrane processes.

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Advantages of FO Because the only pressure involved in the FO

process is caused by the flow resistance in the

membrane module, the equipment used isvery simple and membrane support is less of aproblem.

Besides, for food and pharmaceuticalprocessing, FO has the benefit ofconcentrating the feed stream withoutrequiring high pressures or temperatures thatmay be damaging to the feed solution.

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