Washing Tank

8/11/2019 Washing Tank

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ROTARY WASHER

DESIGN DESCRIPTION

Rotary washer is to be used for the washing of rice straws. It consists of an impeller or

an agitator. Impellers or agitators are used to enhance the washing of a material. Most washing

tanks, as well as the impellers or agitators are made of stainless steel to adapt to wide varieties

and quantities of materials.

DESIGN SELECTION

Steel rotary washer with an agitator is selected because it is suited to wash the rice

straw without damage. It has an ellipsoidal head and hemispherical bottom is selected to

eliminate sharp corners or regions into which fluid currents would not penetrate.

DATA AND ASSUMPTIONS

1. The feed rate of fresh rice straw is 126.93 kg per batch

2. The water flow rate to the tank is 7.61606 kg per batch

3. Density of rice straw is 162.03 kg/m3

4. Density of water is 1000 kg/m3

DESIGN CONSIDERATION

1. Height to diameter ratio of the tank: 2:1 (Perrys Chemical Engineering Handbook 8 th

Edition)

2. Corrosion resistance: 1/16 in (Process Equipment Design by Hesse)3. Joint Efficiency: 80% (Process Equipment Design by Hesse)

4. Filling Capacity: 80% (Process Equipment Design by Hesse)

5. Factor of Safety: 1.2 (The Mechanical Design Process by Ullman. 2ndEdition p. 316)

DESIGN REQUIREMENTS

1. Tank volume

2. Tank diameter

3. Tank height

4. Thickness of the shell

5. Thickness of the head and bottom6. Agitator dimensions

7. Power requirements


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DESIGN CALCULATIONS

1. Tank Volume

Where:

For 1.2 factor of safety (20%):

For 80% filling capacity:


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2. Tank Diameter

Since H = 2D;

3. Tank Height

Height of the cylinder:

Height of ellipsoidal head:

Height of hemispherical bottom:


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Total Tank Height:

4. Shell Thickness

Where:

For maximum allowable working pressure:

Where:


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For maximum allowable tensile stress:

Converting to Pa;

Computing for shell thickness:

(

)

5. Thickness of Head and Bottom

Thickness for ellipsoidal head:

Thickness for the hemispherical bottom:

Where:

Computing for head thickness:

0.0005 m


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Computing for bottom thickness:

0.0025 m


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SPECIFICATIONS

ROTARY WASHER

IdentificationItem: Rotary Washer

Number of RequiredUnits:

1

Materials Handled: Rice StrawsFunction: To remove the dirt in rice straws

Materials ofConstruction:

Stainless Steel

Design Data

Parameters Proposed Design Existing Design

Capacity

Tank volume

Tank diameter

Tank height

Shell thickness

Ellipsoidal headthickness

Hemispherical bottomthickness

Agitator Dimensions

ClearancePower requirement

Source


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DESIGN CONFIGURATIONS


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TRAY DRYER

DESIGN DESCRIPTION

Tray dryers are also called shelf, cabinet, or compartment dryers. The material to be

dried may be a lumpy solid or a pasty solid and is spread uniformly on a metal tray. Trays are

removable and loaded in trucks. Steam-heated air is recirculated by a fan over and parallel to

the surface of the trays.

DESIGN SELECTION

Tray dryer is the simplest of the dryers and is useful when the production rate is small.

Tray dryer is flexible and can dry almost anything. It is typically used in batch process.


1. The mass of entering feed is ______ kg/batch

2. The density of rice straws is 162.03 kg/m3

DESIGN CONSIDERATIONS

1. Depth of every tray: 4 cm (Chemical Process Equipment Selection and Design by Walas

p. 248)

2. Distance between trays: 43 cm (Chemical Process Equipment Selection and Design by

Walas p. 248)

3. Dimension of tray: 85 cm x 96 cm x 4 cm (Chemical Process Equipment Selection and

Design by Walas p. 248)4. Rows of tray: 4 rows

5. Cross velocity of air: 3.5 m/sec (Unit Operations of Chemical Engineering by McCabe.

6thEdition p. 795)

6. Material of Construction: Stainless Steel 304 (Stainless Steel 300 Series.

http://goo.gl/mU7FMf)

7. Insulation used: Fiber glass (Tray Dyer Insulator. http://goo.gl/K4qkXL)


9. Power per truck in the dryer: 1.1 kw (Perrys ChE Handbook. 6thEdition sec 20-22)

DESIGN REQUIREMENTS

1. Capacity

2. Number of Trays

3. Dimension

4. Area

5. Mass Loading

6. Power Requirement


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DESIGN CALCULATIONS

SPECIFICATIONS

TRAY DRYER

IdentificationItem: Tray Dryer


1

Materials Handled: Washed Raw MaterialFunction: To remove the moisture content absorbed by rice straws


Stainless Steel

Design Data


Number of Trays

Tray Dimension

Dryer Dimension

Dryer Area

Mass Loading

Power Requirement

Others

Source


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PLATE AND FRAME FILTER PRESS 1

DESING DESCRIPTION

A filter press contains a set of plates designed to provide a series of chambers or

compartments in which solids may collect. The plates are covered with a filter medium. Plates

and frames sit vertically in a metal rack, with cloth covering the face of each plate.

DESIGN SELECTION

The filter press has long been the most common filtering device throughout the chemical

industry. It is used in batch processes and is simple to operate, very versatile and flexible in

operation, and can be used at high pressures and has a high resistance.


1. Mass flow rate of the slurry

2. Mass flow rate of the cake

3. Mass of the filtrate

4. Density of the filtrate

5. Density of the cake

6. Feed temperature


1. Operating pressure: 6.5 atm (Unit Operations of Chemical Engineering by McCabe. 6th

Edition p. 994)2. Plate thickness: 1 in (Unit Operations of Chemical Engineering by McCabe. 6thEdition p.

993)

3. Frame thickness: 4 in (Unit Operations of Chemical Engineering by McCabe. 6thEdition

p. 993)

4. Filter Medium:

5. Plate size: 42 in x 42 in (Unit Operations of Chemical Engineering by McCabe. 6th

Edition p. 993)

6. Time of filtration: 30 mins (based on the experimentation)

7. Time of washing:


9. Filter Resistance:

10. Cake Resistance:

DESIGN REQUIREMENTS

1. Filter rate

2. Plate area

3. Frame dimension


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4. Number of frames

5. Mass of wash water

6. Power requirement

DESIGN CALCULATIONS


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SPECIFICATIONS


IdentificationItem: Plate and Frame Filter Press


1

Materials Handled: Slurry from CyclodehydrationFunction: Filters the slurry to recover the filtrate after cyclodehydration


Carbon Steel and Rubber

Design Data


Filter Rate

Plate Area

Frame Dimension

Number of Frames

Mass of Wash Water

Pressure Head

Power Requirement

Accessories

Source


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ROTARY KNIFE MILL

DESIGN DESCRIPTION

Rotary knife mill has rotor and stator to continuously shear and crush materials with the

rotating cutter blade and stationary knife like scissors. Screen fixed along the lower semicircular

controls the size of the product

DESIGN SELECTION

Rotary knife mill is commonly used for the size reduction of most biomass feedstock. It is

robust and has a simple structure. The particle size is controlled by the size of the sieve

installed on the milling machine.


1. The amount of feed entering the rotary knife mill is

2. The desired particle of the product is 0.250 mm (60 mesh)


1. Number of rotating cutter blades: 5 (Biomass Size Reduction.http://goo.gl/VvKhgM)

2. Number of stationary knives: 4 (Biomass Size Reduction.http://goo.gl/VvKhgM)

3. Rotor diameter:

4. Cutter blade diameter:

5. Rotary knife chamber height:

6. Factor of Safety:7. Work Index:

DESIGN REQUIREMENTS

1. Capacity

2. Rotor size

3. Floor space requirement


DESIGN CALCULATIONS
http://goo.gl/VvKhgMhttp://goo.gl/VvKhgMhttp://goo.gl/VvKhgMhttp://goo.gl/VvKhgM


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SPECIFICATIONS

ROTARY KNIFE MILL

IdentificationItem: Rotary Knife Mill


1

Materials Handled: Rice StrawsFunction: To reduce the size of the rice straws


Stainless Steel

Design Data


Capacity

Height

Diameter

Rotor size

Number of cutterblades

Number of stationaryknives

Knife size

Floor spacerequirement

Product size

Power requirement

Accessory

Source


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DESING DESCRIPTION

A filter press contains a set of plates designed to provide a series of chambers or

compartments in which solids may collect. The plates are covered with a filter medium. Plates

and frames sit vertically in a metal rack, with cloth covering the face of each plate.

DESIGN SELECTION

The filter press has long been the most common filtering device throughout the chemical

industry. It is used in batch processes and is simple to operate, very versatile and flexible in

operation, and can be used at high pressures and has a high resistance.


1. Mass flow rate of the slurry

7. Mass flow rate of the cake

8. Mass of the filtrate

9. Density of the filtrate

10. Density of the cake

11. Feed temperature


1. Operating pressure: 6.5 atm (Unit Operations of Chemical Engineering by McCabe. 6th

Edition p. 994)2. Plate thickness: 1 in (Unit Operations of Chemical Engineering by McCabe. 6thEdition p.

993)

3. Frame thickness: 4 in (Unit Operations of Chemical Engineering by McCabe. 6thEdition

p. 993)

4. Filter Medium:

5. Plate size: 42 in x 42 in (Unit Operations of Chemical Engineering by McCabe. 6th

Edition p. 993)

6. Time of filtration: 30 mins (based on the experimentation)

7. Time of washing:


9. Filter Resistance:

10. Cake Resistance:

DESIGN REQUIREMENTS

1. Filter rate

2. Plate area

3. Frame dimension


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4. Number of frames

5. Mass of wash water


DESIGN CALCULATIONS


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SPECIFICATIONS


IdentificationItem: Plate and Frame Filter Press


1

Materials Handled: Slurry from CyclodehydrationFunction: Filters the slurry to recover the filtrate after cyclodehydration


Carbon Steel and Rubber

Design Data


Filter Rate

Plate Area

Frame Dimension

Number of Frames

Mass of Wash Water

Pressure Head

Power Requirement

Accessories

Source


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Washing Tank