Filter Press_Report

Dec’ 2014

Overview of Filter Press | Nitesh Dattaram Kamerkar

ENERGY

ALTERNATIVE

INDIA , CHENNAI FILTER PRESS

. . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 1

FILTER PRESS

ENERGY ALTERNATIVES INDIA (EAI), CHENNAI

NEED FOR FILTER PRESSES

Filter presses are sometimes called "Plate-and-Frame Filters" which describes the

style of filters developed from the 1800's onwards. The majority of today's filters are

more correctly called "Membrane Plate Filters".

Many processes in the food, chemical or pharmaceutical industries make products that

are liquid-solid suspensions or slurries. These mixtures are a little like a runny mud or

Milk-shake. The solids in them do not dissolve in the liquid but are carried along in it.

Filter presses separate the solids from the liquids so that the useful part can be

processed or packaged.

Filter presses generally work in a "batch" manner. They are loaded with slurry before

completing a filtering cycle and producing a batch of solid filtered material, called the

filter "cake". The solid is removed, the press re-loaded with slurry and the batch cycle

repeated.

A filter press uses increased pressure to maximise the rate of filtration and produce a

final solid with a low water content. This is more efficient than filtration using a funnel

and paper which utilises the low pressure caused by the weight of liquid above the filter

paper.

WORKING PRINCIPLE OF FILTER PRESS

Filter press is simply a kind of machine, which performs Filtration & separation during its Press

operation.

A filter press consists of a series of chambers containing square or rectangular filter

plates supported in a frame. Once the filter chambers are loaded with slurry, the plates

are forced together with hydraulic rams that generate pressures typically in the region of

100 pounds per square inch (70,000kg per m2). For comparison, a car tyre would be

inflated to around 30 pounds per square inch.

Each plate is covered by a material or membrane that acts as the initial filter when the

press is in operation. As the solid filter cake builds up, the cake adds to the removal of

fine particles. The solution coming through the filter, called the filtrate, will be very pure.

If it is not wanted the filtrate can be drained away for safe disposal.

At the end of the compression, the solid filter cake can be removed. The whole process

Filter presses are extensively used in Food industry, because there are lots of things that

would not be very pleasant to eat if they were “lumpy”. For example vinegar, honey,

water, fruit juice, soft drinks, edible oil.

. . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 2

FILTER PRESS


is often computer controlled to make it automatic or semi-automatic.

**SOURCE: - http://www.putschusa.com

TYPICAL PROCESS SCHEMATICS

. . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 3

FILTER PRESS


STEPS INVOLVED IN FILTER PRESS PROCESSES ARE AS FOLLOWED:-

CLOSING OF THE PRESS

As the filter is completely empty, the moving head is activated by the jacks that clamps

the plates. The closing pressure is self-regulated through the filtration.

FILLING

During this short phase, the chamber is filled with the sludge or slurry to be filtered. The

filling time depends on the flow of the feed pump. For sludge of good filterability, it is best

to fill the filter quickly to avoid caking in the first chamber before the last ones are filled.

FILTRATION

Once the chambers are filled, further input of sludge increases the pressure from the

increasingly thicker layer of filtered sludge on the cloths. The filtration can then be

stopped manually, by a timer, or, more conveniently by a filtrate flow indicator

automatically when no more filtrate is passing through.

FILTER OPENING

The moving head is drawn back to disengage the first filtration chamber. The cake is

released by its own weight. A mechanized system pulls out the plates one by one, the

speed of which can be adjusted for the cake texture.

WASHING

Washing the cloth should be done every 15-30 runs. For mid or large units, this can be

done on the press itself using high pressure water sprays (80-100 bar). However, the

washing requirements will depend on the type of sludge.

SLUDGE OR SLURRY CONDITIONING

If unconditioned sludge is filtered through plate assembly, the filter cloth gets plugged.

Notwithstanding this, the fine particles can pass through and reduce solids recovery

efficiency. To reduce the medium blinding and to improve the filter cake structure

during filtration, the sludge is conditioned with suitable agents like polymer to neutralize

and flocculate the solids. The conditioning produces a rigid sludge with a porosity that

allows for effective water drainage.

** It is not always required or involved in Filtration process. It depends on type of Liquid-

Solid mixture. It is widely employed in Water Treatment Process.

. . . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 4

FILTER PRESS


CLASSIFICATIONS OF FILTER PRESS

PLATE & FRAME FILTER PRESS

Plate and frame filter press is the most fundamental design among all the other filter

presses, and majority nowadays refer it as “membrane filter plate”.

AUTOMATIC FILTER PRESS

It consists of larger plates and frames filter presses with mechanical “plate shifter”. The

function of the plate shifter is to move the plates and allow rapid discharge of the filter

cakes accumulated in between the plates. It also contains diaphragm compressor in the

filter plates which aids in optimizing the operating condition by further drying the filter

cakes.

RECESSED PLATE FILTER PRESS

Recessed plates are made up of polypropylene squares with concave depression and a

hole in the center. Two plates join together to form a chamber to pressurize the slurry and

squeeze the filtrate out through the filter cloth lining in the chamber. However there are

disadvantages to this method such as longer cloth changing time, unable to

accommodate filter papers as well as the possibility of forming uneven cake.

FILTER PRESS

PLATE & FRAME FILTER PRESS

OR

MEMBRANE FILTER PLATE PRESS

AUTOMATIC FILTER PRESS

RECESSED PLATE FILTER PRESS

. . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 5

FILTER PRESS


SIGNIFICANT INDUSTRIES IN WHICH FILTER PRESSES ARE USED

EXTENSIVELY

PIGMENTS & DYE MANUFACTURING

Corrosive environment, elevated temperatures and often volatile atmospheres demand

suitable Filtration and Separation method. Over last few decades, Conventional devices

such as drum Filters & Centrifuges have been successfully replaced by Filter Presses.

Typical Applications are:-

Titan Dioxide (TIO2) {finishing/ desalting & waste/ neutralization }

Caustic Solutions

Acids

Coatings

FOOD & AGRICULTURE

Filter Presses are the standard for applications in the sugar industry as a Juice Purification

Systems. The robust and high performance design as well as the high degree of

automation makes these filters the ideal choice for many applications in this market.


Wine and Juices

Beer

Edible oils

“Green Energies” (Bio- ethanol)

Animal waste

Sugar & sweeteners processes

CHEMICAL / PETROCHEMICAL

The presence of contaminants in the petrochemical manufacturing process can have a

direct impact on the quality of the material produced. Therefore, Chemical/

Petrochemical Industries require large capacities filter presses with fully automatic

operation.


Calcium Carbonate (CaCO3)

Barium sulphate (Completion fluid)

Silicates (product & waste)

Polymers (Fibers)

Brine Solutions (Coolant recovery)

. . . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 6

FILTER PRESS


RECYCLING & ENVIRONMENT

A major environmental problem, issues arises due to hazardous waste released by

numerous industries all across the world. Due to current strict Global environmental

Policies, filter presses are also contributing significantly in this segment.


Stone processing (cutting, polishing & gravel washing applications)

Plastic fibers (Carpet recycling)

Power plants (Flue Gas Desulphurization, FGD)

Industrial waste

Chemical waste

PHARMACEUTICAL & BIOTECH

Demand for precisely controlled processes and clean environments in Pharmaceutical &

Biotech industries can be met with Filter Press Systems.


Yeast

Bio solids

Seaweed

Blood plasma

Enzymes

PULP & PAPER

Although centrifuges are the preferred choice of dewatering equipment in this industry,

Filter Press Systems have proven to provide superior results in regard to solid capture rate,

final moisture content and salt removal (cake washing).


Green liquor (Soda Recovery)

Coatings waste treatment

MINING & MINERALS

Large capacity Filter Presses for harsh environments with their innovative cake discharge

system is an economic choice for this industry. There is a huge demand for large

capacity filter presses.

. . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 7

FILTER PRESS



Mineral concentrates

Flotation slurries

Coal

Clays (Kaolin, Bentonite, Ceramics)

RECENT INNOVATIONS IN FILTER PRESSES

Filter Presses for Sludge Treatment 1

Filter press performance depends on type of Sludge which is going to be filtered. To

obtain higher efficiency & better performance in Filter Presses to treat all kind of

Sludge some conditioning agents are added on filter paper or filter cloth. So, there is

a lot of research & development going on around the globe for developing best

suited & economical Conditioning Agent or Flocculants. Diatomaceous Earth (DE), Fly

Ash are most commonly used Bulking Agents and Ferric Chloride, Alum, Lime,

Polyelectrolyte(polymer) are most commonly used Conditioning Agents.

Types of Sludge are:-

Hydrophilic organic sludge: Inorganic conditioning is often recommended to

enable satisfactory cake release due to minimal adherence to filter cloth.

Hydrophilic inorganic sludge: The filter press generally requires the addition of

lime only.

Hydrophobic inorganic sludge: It is very dense and ideal for the filter press. It is

dewatered without any preliminary conditioning.

Oily sludge: The filter press can be used to treat sludge containing light oils, the

presence of grease can sometimes impair the smooth running of the filter; clothes

have to be degreased at frequent intervals.

The filter cloths are woven fabrics using monofilament or multifilament synthetic fibers

or a combination of both. The most commonly used materials are polypropylene,

polyester, and nylon.

1 http://www.lenntech.com/library/sludge/presses/filter-press.htm

http://www.lenntech.com/library/sludge/presses/filter-press.htm

. . . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 8

FILTER PRESS


Candle Filter Technology 2

Candle Filters are installed for clarification and recovery applications from liquids with

low solids content from 5% to less than 1% solids and even down to trace amounts.

AUTOMATIC PROCESS CYCLE:-

Filling: The slurry feed enters the bottom of the filter vessel.

Filtration: The slurry is pumped under pressure into the vessel. Cake will deposit on the

outside of the candle; the separated filtrate will flow through the filtrate pipe and

the registers. This process continues to a maximum pressure drop, the maximum cake

thickness, or the minimum flow.

Washing: Displacement washing or recirculation washing.

Drying: Blowing gas, steam or “shock” drying.

Heel Filtration: The liquid remaining in the vessel cone after filtration or washing is

completely filtered.

Cake Discharge: Gas flows through the register pipes, and down the filtrate pipe. The

filter media gently expands allowing for cake discharge. Alternatively, the cake can

be discharged as a slurry.

Sock Cleaning after Cake Discharge: If necessary, sock cleaning is accomplished by

filling and circulating cleaning fluids while blowing gas in the reverse direction to the

filtration direction, which creates a turbulent mixture or a quasi-ultrasonic

cleaning effect.

2 http://www.bhs-filtration.com/products/candle_filter.aspx

Candle Filter

http://www.bhs-filtration.com/products/candle_filter.aspx

. . . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 9

FILTER PRESS


Candle Filter Technology is Modular in nature that means we can implement this

technology in small Bottle-size vessel. In which an upside-down candle, screwed inside

that Bottle-size vessel.

Energy efficient Membrane Filter Press 3

From energy use and technology gap audit studies in various chemical industries in

Ahmedabad chemical cluster, below mentioned things are identified:

Energy efficiency improvement opportunities

Environment and safety improvement of workers

Design flaws in the conventional filter press

Operational & maintenance practices in conventional filter press

The drying cost is one of the major costs in the overall production process of chemicals, in

typical chemical industry. Apart from the energy cost, drying time is one of the major

time consuming area in overall production process of chemicals, in typical chemical

industry the drying time would be around 72 hours per batch. The existing installed

conventional dryer takes 72 hours for processing one batch. If combined with a

membrane filter press the drying time is reduced to 49 hours per batch. This not only

saves energy consumed by the dryer, through reduced hot air consumption for hot air

generator but also enhances the productivity of the dryer as the drying process

becomes faster process.

3 www.bee-india.nic.in – Detailed Project Report (DPR) on Membrane Filter Press, DPR No. AMD/CHM/MFP/07

http://www.bee-india.nic.in/

. . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 10

FILTER PRESS


Advantages of replacing the conventional filter press with Energy Efficient membrane

filter press are:

Reduction in load on HAG and hence wood consumption

Improved productivity

Improved working environment

Faster filter press process, it leads to energy savings

Improves the efficiency of the unit

Reduction of deforestation and GHGs emissions

COMPARISON BETWEEN CONVENTIONAL & MEMBRANE FILTER PRESS

Sr. No. Details Conventional Filter Press Energy Efficient Membrane Filter Press

1 Drying time in Dryer due to caking More Less

2 Load on Hot Air Generator (HAG) More

Less

3 Environment pollution High (partial combustion & more fuel consumption)

Low ( Complete combustion & less fuel consumption)

4 Caking Time High Low

5 Operational Cost ( due to compressed air usage)

High Low

6 Heat Losses High Low

From the above table it is clear that Energy efficient membrane filter press has significant

advantages in Energy, Environmental, Economic & safety aspects over the conventional filter

press. It is therefore, justifiable to install energy efficient membrane filter press in place of

conventional filter press.

. . . . . . . . . . . . . . . . . . . . . . . . . . P a g e | 11

FILTER PRESS


Detailed Technology Assessment Report (from Detailed Energy Audit Report on Membrane

Filter Press done by BEE at Chemical SME Cluster, Ahmedabad, Gujarat, India.)

Sr. No.

Parameter Units Value

1 Drying time in conventional filter press hrs/batch 72.00

2 Drying time in new membrane filter press hrs/batch 49.00

3 Volume processed per batch litre 1280.00

4 Wood consumption in HAG (Hot Air Generator)

Kg/hr 70.00

5 Wood consumption in HAG with conventional filter press

Kg/batch 5040.00

6 Wood consumption in HAG with membrane filter press

Kg/batch 3430.00

7 Specific fuel consumption for conventional filter press (@ 1280 Litre/batch )

Kg/litre 3.94

8 Specific fuel consumption for membrane filter press (@ 1280 Litre/batch )

Kg/litre 2.68

9 Savings in specific fuel consumption Kg/litre 1.26

10 Annual operating batches Nos. 150.00

11 Annual production capacity @ 1280 Litre/Batch

Litre/annum 192000.00

12 Wood energy saved per annum tonnes/annum 241.50

13 Average fuel cost /tonne 3000.00

14 Total monetary saving ( in Lakh) 7.26

15 Total investment required ( in Lakh) 24.20

16 Simple payback period Years 3.33

Filter Press_Report

Documents

filter presses filter

filter press processes

filter chambers

filter paper

initial filter

solid filter cake

process filter presses

chennai filter pressp