Filtration
The Filtration process is the separation of solids from a suspension in a liquid by means of a porous medium or screen. Filtration is a basic manufacturing process in the chemical-manufacturing industry and is also employed for treatment of sewage, remove of wax from lubricant oils
Mechanism of filtration
In the laboratory, filtration is often carried out using a form of Buchner funnel, and the liquid is sucked through the thin layer of particles using a source of vacuum. In even simpler cases the suspension is poured into a conical funnel fitted with a filter paper.
Figure 1 Buchner funnel
In the industrial equivalent, difficulties are encountered in the mechanical handling of much larger quantities of suspension and solids. A thicker layer of solids has to form and, in order to achieve a high rate of passage of liquid through the solids, higher pressures are needed. A typical filtration Figure ( 2 ) which shows the filter medium, in this case a cloth, its support and the layer of solids, or filter cake, which has already formed.
Figure 2 Filtration
In Fig. (2) , the cake gradually builds upon the medium and the resistance to flow progressively increases. During the initial period of flow, particles are deposited in the surface layers of the cloth to form the true filtering medium.
The liquid to be filtered is called the slurry ( suspension) ; the liquid passed by the filter is called the filtrate; and the solid material remaining on the filter is known as the filter cake .
The rate of filtration depends on:
(a) The pressure drop from the feed to the far side of the filter medium.
(b) The area of the filtering surface.
(c) The viscosity of the filtrate.
(d) The resistance of the filter cake.
(e) The resistance of the filter medium
The filter medium
The filter medium is a porous medium capable to passing liquid through ,while retaining solid
place without the medium and the overall performance of the filtration system depend on properties of filter medium .
The properties of filter medium:
1. Mechanically strong
2. Resistant to the corrosive action of the fluid
3. Offer as little resistance as possible to the flow of filtrate.
4. Cheap in cost
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
الرجوع الى لوحة التحكم
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