Industrial Filtration : Industrial Filtration ~Group V~ : ~Group V~ Leader:
Ricafrente, Ma. Feberlie
Plaza, Lorie Ann
Villegas, Laery Rose
Arevalo, Arwin Contents : Contents 1. Introduction
2. Methods of Filtration
2.1. Gas Filtration
2.1.2. Bag Filter
2.1.3. Air Filter
By: Lorie Ann Plaza Slide 4: 2.2 Liquid Filtration
2.2.1. Cake Filters
220.127.116.11. Pressure Filter
18.104.22.168. Vacuum Filter
22.214.171.124. Centrifugal Filters
2.2.2. Clarifying Filters
3. Classification of Filtration
3.1. By driving force
3.2. By Filtration Mechanism
3.3. By Function
3.4. By Operating cycle
3.5. By nature of solid
By: Laery Rose Villegas Slide 5: 4. Filter Media
5. Filter Aid
6. Filtration Equipment
6.1. Gas Filter
6.1.1. Gravity filters
6.1.2. Sand filters
By: Arwin Arevallo Slide 6: 6.2 Pressure Filter
6.2.1. Filter Press
6.2.2. Plate and Frame Filter Press
6.2.3. Horizontal Tank-Rotating Leaf Filter
6.2.4. Horizontal Pressure Filter
6.2.5. Tube or Candle Filter
6.2.6. Vertical Tank or Vertical Leaf Filter
By: Ma. Feberlie M. Ricafrente Slide 7: 6.3 Vacuum Filter
6.3.1 Filter Drum
6.3.2 Rotary Drum Pre-coat Filter
6.3.3 Horizontal Belt Filter
6.3.4 Disc Filter
By: Laery Rose Villegas
7. Industries with Filtration System
8. Future Trends: Memcor CP Membrane Water Filter by Siemens Introduction : Introduction What is Filtration? : What is Filtration? Filtration is a unit operation in which a heterogeneous mixture with particles of solid are separated by a filter medium known as septum. The septum permits the flow of the fluid but retains the solid particles. Methods Of Filtration : Methods Of Filtration Gas Filtration
Liquid Filtration Methods of Filtration : Methods of Filtration Gas Filtration : Gas Filtration Types of Gas Filtration : Types of Gas Filtration Granular Bed Filter
Air Filter Granular Bed Filter : Granular Bed Filter Separators consist of beds of sand, carbon, or other particles which will trap the solid in a gas suspension that is passed through the bed. Bag Filter : Bag Filter -are bags of woven fabric, felt, or paper through which the gas is forced ; the solids are deposited on the wall of the bag. Air Filter : Air Filter -are light web of fibers, often coated with a viscous liquid, through an air containing a low concentrations of dust particles. Liquid Filtration : Liquid Filtration Liquid filtration occurs when a suspension of a solid in a liquid passes through a filter. That process takes place when the liquid is pulled through the filter by gravitational force or is forced through the filter by some applied pressure or by a pressure differential supplied by the existence of a vacuum. 2 Major Classes of Liquid Filters : 2 Major Classes of Liquid Filters Cake Filter
Clarifying Filter Cake Filter : Cake Filter A cake filter is formed by the substances that are retained in or on a filter (depending on whether a depth or a surface filter is used). The filter cake grows in the course of filtration, becomes "thicker" as particulate matter is being retained. With increasing layer thickness the flow resistance of the filter cake increases. After a certain time of use the filter cake has to be removed from the filter, e.g. by backflushing. If this is not accomplished, the filtration is disrupted because the flow resistance of the filter cake gets too high, thus too little of the mixture to be filtered can pass the filter cake and the filter plugs. Classes of Cake Filter : Classes of Cake Filter Pressure Filter
Centrifugal Filter Pressure Filter : Pressure Filter Are semi-continuous type machines that enter a wash and cake discharge mode at the end of the filtration cycle.
Super atmospheric pressure, or higher. Types of Pressure Filter : Types of Pressure Filter Filter Press
Plate and Frame Filter Press
Horizontal Pressure Filter
Tube or Candle Filter Slide 32: Horizontal Tank – Rotating Leaf Automatic Jet Spray Cleaning Filter Slide 34: Vertical Tank – Vertical Leaf Filter Vacuum Filter : Vacuum Filter Vacuum filtration is used primarily to collect a desired solid, for instance, the collection of crystals in a recrystallization procedure
Are those which operate with less than atmospheric pressure on the downstream side of the filter septum Types of Vacuum Filter : Types of Vacuum Filter Filter Drum
Rotary Drum Pre-coat Filter
Horizontal Belt Filter
Table Filter Slide 39: Filter Drum Slide 40: Rotary Drum Pre-coat Filter Slide 41: Top-Feed Filter Slide 42: Horizontal Belt Filter Slide 43: Table Filters Centrifugal Filter : Centrifugal Filter Centrifugal force causes the filtrate to flow through the cake and filter medium. Clarifying Filter : Clarifying Filter Is a pressure filter that employ a very fine filter medium, the pores of which are sufficiently small to prevent passage of particles of the size that must be removed.
The process by which unwanted solid materials are removed from a suspension in order to produce a very clear liquid. Classification of Filtration : Classification of Filtration By Driving Force
By Filtration Mechanism
By Operating Cycle
By Nature of Solids By Filtration Mechanism : By Filtration Mechanism Two models are generally considered and are the basis for the application of theory to the filtration process.
When the solids are stopped at the surface of the filter medium and pile upon one another to form a cake of increasing thickness, the separation is called cake filtration.
When solids are trapped within the pores or body of the medium , it is termed depth, filter-medium, or clarifying filtration. By Objective : By Objective The process goal of filtration may be dry solids (the cake is the product of value), clarified liquid (the filtrate is the product of value), or both. The former is achieved only in cake filtration, but clarification is accomplished in both filter-medium and cake operations. By Operating Cycle : By Operating Cycle Filtration may be intermittent (batch) or continuous. Batch filters may be operated with constant-pressure driving force, at constant rate, or in cycles that are variable with respect to both pressure and rate. By Nature of Solids : By Nature of Solids Thus filters usually are divided first into the two groups of either cake or clarifying equipment, then into groups of machines using the same kind of driving force, then further into batch and continuous classes. Filter Media : Filter Media Filter Media : Filter Media a solid sieve which traps the solid particles, with or without the aid of filter paper
a bed of granular material which retains the solid particles as it passes RESIDUEFILTERPAPER : RESIDUEFILTERPAPER Filter Media : Filter Media a solid sieve which traps the solid particles, with or without the aid of filter paper
a bed of granular material which retains the solid particles as it passes RESIDUE SAND GRAVELS : RESIDUE SAND GRAVELS Factors on Selecting a Filter Media : Factors on Selecting a Filter Media Acceptable resistance to mechanical wear
Good removal competence
Resistance to chemical attack.
Sufficient strength to support the filtering pressure.
Ability to discharge cake easily and cleanly.
Ability to plug slowly Types of Material of Filter Media : Types of Material of Filter Media Fabrics of Woven Fibers
Metal Fabrics or Screens
Pressed Felts and Cotton Batting
Rigid Porous Media
Granular Beds of Particulate Solids Fabrics of Woven Fibers : Fabrics of Woven Fibers For cake filtration these fabrics are the most common type of medium. Metal Fabrics or Screens : Metal Fabrics or Screens These are available in several types of weaves in nickel, copper, brass, bronze, aluminum, steel, stainless steel, and other alloys. Pressed Felts and Cotton Batting : Pressed Felts and Cotton Batting These materials are used to filtrate gelatinous particles from paints, spinning solutions, and other viscous liquids. Filter Paper : Filter Paper These papers come in a wide range of permeability, thickness, and strength. As a class of material, they have low strength, however, and require a perforated backup plate for support. Rigid Porous Media : Rigid Porous Media These are available in sheets or plates and tubes. Materials used include sintered stainless steel and other metals, graphite, aluminum oxide, silica, porcelain, and some plastics Polymer Membranes : Polymer Membranes These are used in filtration applications for fine-particle separations such as microfiltration and ultrafiltration Granular Beds of Particulate Solids : Granular Beds of Particulate Solids Beds of solids like sand or coal are used as a filter media to clarify water or chemical solutions containing small quantities of suspended particles. Filter Aid : Filter Aid Filter Aids : Filter Aids Use of filter aids is a technique frequently applied for filtrations in which problems of slow filtration. Filter Aid are used in two ways: : Filter Aid are used in two ways: The first is as a precoat to protect the filter media and guard the escape of small particles into the filtrate.
The second is filter aid is mixed with the prefilt slurry to trap the difficultly filterable particles in a permeable cake Diatomaceous Silica : Diatomaceous Silica This have a dry bulk density of 128 to 320 kg/m³ (8 to 20 lbs/ft³)
Contain particle mostly smaller than 50µm
Produce a cake with porosity in the range of 0.9 (volume of voids/total filter-cake volume)
The high porosity (compared with a porosity of 0.38 for randomly packed uniform spheres and 0.2 to 0.3 for a typical cake) is indicative of its filter-aid ability.
Different methods of processing the crude diatomite result in a series of filter aids having a wide range of permeability. Perlite : Perlite Perlite filter aids are somewhat lower in bulk density (48 to 96 kg/m³, or 3 to 6 lb/ft³) than diatomaceous silica and contain a higher fraction of particles in the 50- to 150-µm range.
It is also available in a number of grades of differing permeability and cost ,
the grades being roughly comparable to those of diatomaceous silica.
Diatomaceous silica will withstand slightly more extreme pH levels than perlite, and it is said to be somewhat less compressible. Industrial Applications : Industrial Applications Water and Sewage Treatment
Chemicals and Pharmaceuticals
Food and Drink
Papermaking Filtration Equipment : Filtration Equipment Pressure Filter : Pressure Filter Filter Press
Plate and Frame Filter Press
Horizontal Pressure Filter
Tube or Candle Filter Slide 76: ADVANTAGES:
Cakes are obtained with very low moisture content.
Pressure Filters are available in a wide level of automation from labor intensive operator controlled up to fully automatic machines.
Solutions may be polished to a high degree of clarity. DISADVANTAGES:
Cloth washing is difficult if it is 3mm thick.
The operator can hardly see the forming cake and is unable to carry out an inspection while the filter is in operation.
The internals are difficult to clean and this may be a problem with food grade applications. Filter Press : Filter Press Filterpresses
introduced in 1960’s
mainly for dewatering waste sludges.
labor intensive machines
not accepted in highly automated process industries.
The Filterpress design
consists of a head and follower that contain in between a pack of vertical rectangular plates.
The present day Filterpresses, , are equipped with by PLC's The main features of Filter Press are: : The main features of Filter Press are: Shuttle shifters that separate the plates one by one for cake discharge at a rate of 5-6 seconds per plate..
Shakers that subject the plate to vibrations and assist in discharging the cake.
Cloth showers with movable manifolds and high impact jets for intensive cloth washing. Special Features of Plates: : Special Features of Plates: Lower plate weight has reduced the downtime for shuttle shifting during the cake discharge mode.
Effective filtration area has gone up since with the largest available plates .
Typical membrane plates are shown in the photo. Plate and Frame Filtration : Plate and Frame Filtration Plate and frame filter presses are dewatering machines which utilize pressure (60-80 psi, typically) to remove the liquid from a liquid-solid slurry.
They are particularly suited for low solids or solids composed of fines.
Large plate and frame filter presses have mechanical "plate shifters", to move the plates, allowing the rapid discharge of the solids stuck in between them.
have the capability of blowing compressed air into the plate, to dry the cake, and to aid in it's discharge Slide 83: CGR PLATE RUBBER MEMBRANE PLATE CHAMBER PLATE PLATE AND FRAME PLATE Horizontal Plate Pressure Filter : Horizontal Plate Pressure Filter Horizontal Plate Pressure Filters were commonly applied to the fine chemical process industries such as antibiotics , pesticides or pigment to obtain a high product clarity.
Lately, they are used in heavier industries such as fertilizers or precious metals when the product is the cake and efficient washing and low moistures are required.
they are very well suited for handling flammable, toxic and corrosive materials since they are autoclaved and designed for hazardous environments when high pressure and safe operation are required
The filter structure consists of a stack of plates attached to a hollow shaft which are mounted inside a pressure vessel with each plate covered with a suitable filter medium Slide 88: Each circular plate in the stack is constructed with radial ribs that are welded to the bottom and support a horizontal coarse mesh screen which is covered with a finer woven metal screen or filter cloth to retain the cake. Slide 89: There are several applications, mainly in the pharmaceutical and paint industries, where special disposable filter paper is used to cover the plates on both sides so the filtration area is doubled. Slide 90: The vessels of Horizontal Plate Filters are, as opposed to Vertical Leaf Filter , always constructed vertically to accommodate the plates stack.
Two options for bottom design:
A conical bottom.
A dished bottom.
The selection depends largely on the cake discharge arrangement as discussed later.
The vessels at their bottoms are fitted with highly secured cake discharge openings to ensure safe sealing of the tank under pressure. Slide 91: Advantages
Simpler removal of plate stacks
Plates with the screens mounted on the topside, as opposed to two sided plates, provide good support for the forming cake and therefore are always used on applications with thick and heavy cakes. Disadvantages
High headroom is required for dismantling the entire plate stack.
The bearing of top and bottom driven filters is complex Vertical Pressure Leaf Filters : Vertical Pressure Leaf Filters Vertical Pressure Leaf Filters are quite similar to the Horizontal Plate Filters except for the orientation of the filter elements which are vertical rather than horizontal.
applied for the polishing slurries with very low solids content of 1-5% or for cake filtration with a solids concentration of 20-25%.
Also suited for handling flammable, toxic and corrosive materials since they are autoclaved and designed for hazardous environments when high pressure and safe operation are required.
The largest Leaf Filters in horizontal vessels have a filtration area of 300 m2 and vertical vessels 100 m2 both designed for an operating pressure of 6 bar Slide 94: There are two types of vessel configuration:
Advantages of the Vertical Leaf Filter:
when compared to the Horizontal Plate Filter is when cakes depart easily from the filtering medium. In such cases it is not necessary to incorporate means to assist discharge since gravity will release the cake and let it drop towards the discharge opening. For such cakes that do not discharge readily a special mechanism that vibrates the entire stack is incorporated and this will in most instances release the cake. Slide 96: Advantages
The cloth or woven mesh screens that cover the leaves of horizontal tanks may be accessed easily once the stack is pulled out of the vessel.
Mechanically simple since there are no complex sealing glands or bearings. Disadvantages
High headroom is required for dismantling the leaves on vertical vessels.
Large floor space is required for discharging the cake on horizontal vessels.
The emptying of the vessel in between cake filtration, washing and drying requires close monitoring of the pressure inside the vessel to ensure that the cake holds on to the candles. Candle filter : Candle filter Candle Filters are, as all pressure filters, operating on a batch cycle and may be seen in process lines handling titanium dioxide, flue gas, brine clarification, red mud, china clay, fine chemicals and many other applications that require efficient low moisture cake filtration or high degree of polishing.
Candle Filters are also used for thickening to produce a concentrated flowable slurry by partial removal of the liquid phase as filtrate.
Candle Filters may operate on very short cycle times taking advantage of the high filtration rates whilst the cakes are still thin.
One of the features of Candle Filters when used for thickening is their clear filtrate since gravity Thickeners, in analogy, produce overflows which always contain a certain amount of fine suspended solids Slide 99: The Candle Filter consists of three major components:
The filtering elements
The cake discharge mechanism
All these components may be constructed from exotic materials of construction and heated to meet the process requirements There are two types of vessel configuration: : There are two types of vessel configuration: Vessels with conical bottom for cake filtration and polishing.
Vessels with dished bottom for slurry thickening. Slide 102: Advantages
Excellent cake discharge.
Adapts readily to slurry thickening.
Minimum floor space.
Mechanically simple since there are no complex sealing glands or bearings. Disadvantages
High headroom is required for dismantling the filtering elements.
The emptying of the vessel in between cake filtration, washing and drying requires close monitoring of the pressure inside the vessel to ensure that the cake holds on to the candles. Vacuum Filter : Vacuum Filter Vacuum filtration is used primarily to collect a desired solid, for instance, the collection of crystals in a recrystallization procedure
Are those which operate with less than atmospheric pressure on the downstream side of the filter septum Vacuum Filter : Vacuum Filter Filter Drum
Rotary Drum Pre-Coat Filter
Horizontal Belt Filter
Table Filter Procedure for Vacuum Filtration : Procedure for Vacuum Filtration Assemble the apparatus
Wet the paper with a small amount of the solvent to be used in the filtration. Turn on the vacuum source.
Filter the solution
Rinse the solids. Assemble the Apparatus : Assemble the Apparatus Wet the paper with a small amount of the solvent to be used in the filtration. Turn on the vacuum source : Wet the paper with a small amount of the solvent to be used in the filtration. Turn on the vacuum source Filter the solution : Filter the solution Rinse the solids : Rinse the solids Filter Drum : Filter Drum Basically cylindrical in shape designed to carry the filter medium which is attached to its surface. The inner surface is divided into rows of cells to which a vacuum can be applied or shut off in sequence as the drum rotates.
The drums are two types:
deep cell and pipe Discharged Modes : Discharged Modes Scraper Knife
Pre-Coat with Shave-Off Knife Rotary Drum Pre-Coat Filter : Rotary Drum Pre-Coat Filter The Rotary Drum Pre-coat Filter is used to polish solutions having traces of contaminating insoluble. To polish the solution the drum deck is pre-coated with a medium of a known permeability and particle size that retains the fines and produces a clear filtrate. Materials Used to Form the Precoat Bed : Materials Used to Form the Precoat Bed Diatomaceous Earth
Special Ground Bed Operational Sequence : Operational Sequence Precoating
Polishing Horizontal Belt Filter : Horizontal Belt Filter Horizontal Belt Filters are, in broad
terms, the most commonly used
vacuum filters in the industry due to
flexibility of operation
adaptation to corrosive slurries
suitability to handle large throughputs Subassemblies : Subassemblies Belt
Vacuum Box and Wear Belts
Vacuum Box Lowering Mechanism
Feed and Wash Boxes
Cake Discharge End
Belt Supporting Deck
Cloth Tracking Mechanism Operational Sequence : Operational Sequence Cloudy port recycle or sedimentation pool
Final drying Table Filter : Table Filter The Table Filters belong to the top feed group, introduced in the early 40's and were rather small and of a simple design.
Their main limitation was at the discharge zone since the cake was contained in a fixed rim and special sealing arrangements had to be provided in order to avoid the spillage of brine at the table's circumference. Industrial Applications : Industrial Applications Water and Sewage Treatment
Chemicals and Pharmaceuticals
Food and Drink
Papermaking Future Trends : Future Trends ~End~ : ~End~