Sugar Factory Clarification Section Capacity Requirement Calculations

Sugar Plant Clarification House Capacity Calculation | Sugar Mill

Here discussed about sugar mill capacity calculation for the Clarification section like pumps, juice reaction tank, lime and sulphur requirement, juice clarifier, vacuum filters … etc.

1. Raw Juice Pump

Raw juice pump is also called Mixed juice pump or screened juice pump.

Screen juice % cane vary from 100 to 120% depend upon the type of juice extraction system like milling or diffuser

In Milling plant raw juice % cane having 100 to 105%

In diffuser plant raw juice % cane having 110 to 120%.

Example:

Crushing Rate    –  230 TCH  ( 5000 TCD / 22 = 230 TCH )

Juice % cane      – 105%

Juice Density      – 1.06 gm/ml

Raw Juice Pump capacity = 230 x 105% / 1.06 = 228 M³/hr

Generally pump capacity consider 20% extra on requirement.

So 228 x 120% = 273 M³/hr

2. Screen Juice tank or Raw Juice tank

Screen Juice tank capacity consider as per retention time on same. It required minimum 8 to 10 minutes retention time

Example:

Juice Quantity  –  228 m³/hr  = 228/60 = 3.8 m³/min.

Screen Juice tank capacity = 3.8 x 8 = 30 M³ = 300 HL

3. Phosphoric Acid Dosing Tank and its pump

Phophoric Acid Dosing require as per properties of raw juice. The maximum dosing consider 100 to 200 PPM on juice quantity

Example

Juice quantity                     = 230 T/hr

Phosphoric acid                 = 150 PPM

P2 O5 % in given H3PO4 = 85%

Quantity of phosphoric acid = 230 x 150 ppm / 0.85 = 40.6 Kg/hr

Holding volume required = 40.6 x 8 hrs = 325 Kg   ≈ 0.5  M³

This capacity applicable without dilution of chemical. If dilution require the capacity to be increased as per dilution ratio. The pump capacity also consider as per the dilution factor.

Phosphoric Acid (H3 PO4 ) Dosing in Sugar Industry | Online Calculator

4. Juice Heaters

In sugar process juice heating carryout in three stages – Raw juice heating, Treated juice heating and clear juice heating

Raw juice heating       –  From 30 ⁰C to 75 ⁰C

Treated Juice heating –  From 73 ⁰C to 102 ⁰C

Clear juice heating      – From 95 ⁰C to 102 ⁰C

Design aspects of Juice Heater

1. Properties of heating media ( Steam / Vapour / hot water )
2. Temperature and velocity of Juice
3. Efficient removal of condensate water  & non-condensable gases.
4. Heat transfer coefficient
5. Less retention time of juice in Juice heater.

Best steam economy option for Raw Juice Heating in sugar industry

Juice heating purpose used three types of heaters –  shell and tube multipass tubular juice heater, Direct contact heaters and Plate heat exchanger.

To find the heating surface of shell and tube & plate type heaters used the formula

Heat received by heated media(juice) = Heat rejected by heating media( vapour/hot water)

M x Cp x ΔT = K x S x ΔTm

ΔTm = LMTD = Log Mean Temperature Difference

ΔTinlet = Ti – ti ( Co current Flow)

ΔT outlet = To – to (Co current Flow)

Here “Ti” and “To” are heating media inlet and outlet temperatures &

” ti”  and “to” are juice inlet and outlet temperatures.

If using the vapour as a heating media then Ti = To = Tv ( since latent heat only transfer from vapour to juice)

This equation can be simplified as

Example:

Crushing rate = 230 TCH  and juice % cane = 105%

S = Heat transfer surface area in m²
M = Quantity of material to be heating or cooling =  241500 kg/hr
Cp = Specific heat of material  = 0.92 Kcal/kg/^oC
K = Overall heat transfer Coefficient  = 510 Kcal/m²/hr/^oC
Tv = Vapour temperatures = 85 ^oC
ti = juice inlet temperature = 50 ^oC
to = juice outlet temperature = 70 ^oC

Now from the above formula Heating surface = 360 m²

For more information go through the below links

Shell and Tube Multipass Heat Exchanger Design | Tubular juice heater

Direct Contact Heater (DCH) Design Calculation with Online Calculator

Plate Heat Exchanger Working | PHE Application in Sugar Industry Process

Some approximate values in juice heaters capacity calculation

Velocity in tubular juice heaters – 1.7 to 1.8 m/sec

Every 10 ^oC juice temperature rising required steam = 1.8 % on cane

Steam required for juice heating station – 12 to 15% on cane

Head loss in tubular juice heaters = 12 to 16 mwc

Head loss in plate type heaters = 10 to 12 mwc

5. Juice reaction Vessel

The holding volume of the reaction vessel maintained 7 to 8 minutes

Juice coloumn height should be maintained  2.0 to 2.4 metres

Treated juice receiving tank – It is consider 50 to 60% on reaction vessel holding volume

Example:

Crushing rate = 230 TCH  and juice % cane = 120% (including mud juice)

Juice flow rate =276 T/hr = 276/1.06 = 260 m³ /hr ( 1.06 Density of juice)

Holding volume of the reaction vessel = 260 x 7 / 60 = 30 M³ = 300 HL

Treated juice receiving vessel capacity = 300/2 = 150 HL

Treated juice pump –  Generally pump capacity consider 20% extra on requirement.

So 260 x 120% = 320 M³/hr

For more details go through the below link

Juice Defecator and Juice Sulphitor Design Criteria | Online Calculator

6. Lime station

Requirement of lime depend upon the process like defecation or sulphitation.

Lime station capacity consider 2 to 3 time more then our requirement. (preparation of lime will be twice or thrice per day only)

• In sulphitation process lime%cane – 0.16 to 0.22
• In Defication process lime%cane – 0.12 to 0.15
• So depend upon the lime requirement we calculate capacity of lime station
• For capacity of milk of lime (MOL) storage tanks purpose considered minimum 8 hours holding volume
• Lime pump capacity –  100% extra on actual requirement of MOL

Example:

Crushing rate = 210 TCH and lime%cane = 0.2

Lime requirement = 210 x 0.2% = 420 kg/hr

Lime station capacity = 420x 3 = 1260 kg/hr  ≈ 1200 Kg/hr

So lime elevator, lime slaker, lime classifier and grit separator shall be installed to suit 1200 kg/hr lime.

Consider 8º Baume or 14.4 Brix  ( 1 Baume = 1.8 brix )

For the preparation of lime solution, the water requirement is 12.5 kg / kg of lime at 8º Be

MOL requirement = 420 x (12.5+1) = 5670 Liters/hr  ≈ 6 M³/hr

Hence the MOL storage tank capacity requirement = 6 x 8 = 48 m³ = 500 HL  ( 2 nos. –  250 HL )

MOL pump capacity =  6 x 2 =12 M³/hr

7. Sulphur Station

Sulphur requirement – 0.05 to 0.08 % on cane. Out of the total requirement of the sulphur consider 2/3^rd for juice sulphitation and 1/3^rd for syrup sulphitation.

Sulphur Melter | Sulphur Melting process in sugar processing industry

Air requirement for SO₂ gas generation

Sulphur dioxide (SO2) is a gas resulting from the combustion of sulphur and oxygen

S + O₂ SO₂

Hence, 1 kg of sulphur requires 1 kg of oxygen, the reaction releases 2,217 Kcal per kg of sulphur

So theoretical quantity of air required 4.3 times the weight of sulphur ( Air contains 23.15% of oxygen by weight).
Practically for complete combustion of sulphur  to be proved 100% excess air, a weight of air equal to 8 to 9 times the weight of sulphur.

Generally, 12- 16% SO₂ gas is obtained, or an average of 14%.

Example:

Crushing rate = 210 TCH  and sulphur %cane = 0.1

Sulphur required = 210 x 0.1 = 210 Kg/hr

For juice sulphitation = 210 x 2/3 = 140 kg/hr &

For syrup sulphitation = 210 x 1/ 3 = 70 kg/hr

Sulphur bunners capacity should be minimum 140 kg/hr for juice side and 70 kg/hr for syrup side sulphitation.

Air blowers capacity required 1250 M³/hr (140 x 9 ) for juice side sulphur bunner and 650 (70 x 9) M³/hr for syrup side sulphitation.

8. Juice Clarifier

Clarifier or subsider is a vessel into which the juice to be settled is fed uniformly and continuously, The clear juice obtained is similarly withdrawn from the upper part of the subsider in an equally uniform and continuous manner, as also are the muds from the lower portion.

Most commonly 3 types of clarifiers used in sugar plant

Rapi-Dorr 444
Graver clarifier
Short retention clarifier

The capacity of the clarifier for Rapi- Dorr and graver consider retention time 2.5 to 3 hours. For short retention time clarifier consider the retention time 40 to 50 minutes.

Example:

Crushing rate = 210 TCH  and juice %cane = 120%, calculate the capacity of Rapi-Dorr

Juice flow rate = 210 x 120% = 252 T/hr = 252 / 1.06 = 238 M³/hr

Holding volume of the clarifier = V = 238 x 2.5 = 595 M³

According to mud setting rate the height of the each compartment maintained as 5 feet each then total height of the clarifier is 20 feet ( 4 compartments x 5 feet)

Dia of the clarifier = D & height = H = 6.096 m

V = 0.785 x D² x H

D = 11.150 metres

According to standard sizes of Rapi-dorr 444 as follow as

Size                                Volume

18 Feet x 20 Feet     –  133 M³
20 Feet x 20 Feet     –  164 M³
22 Feet x 20 Feet     –   199 M³
24 Feet x 20 Feet     –   237 M³
26 Feet x 20 Feet     –   278 M³
28 Feet x 20 Feet     –   322 M³
30 Feet x 20 Feet     –   370 M³
32 Feet x 20 Feet     –   421 M³
34 Feet x 20 Feet    –   474 M³
36 Feet x 20 Feet    –   533 M³

Clarifiers Flash tank design formulas with online calculation

Flocculants Used in Sugar Processing | Flocculant Dosing Calculation

Clear juice pump capacity – Generally pump capacity consider 20% extra on requirement.

So 238 x 120% = 285 ≈ 300 M³/hr

9. Vacuum Filters

Vacuum filters capacity required – 0.6 to 0.7 m²/TCH

Filter cake production – 60 to 120 kg/ m²/hr

Mud Pump capacity- 20 to 25 % on raw juice

Filter Juice pump     – 15 to 20% on raw juice

Bagacillo required   – 4 to 8 kg per TCH

Cake wash water     –  100 to 150% on filter cake quantity or 4 to 6% on cane

Bagacillo Blower     – Calculate on the basis of 6.25 m³ of air will be required per kg of bagacillo.

Example:

Rotary vacuum filter Equipment capacity calculation

10. Syrup Sulphitor

The holding volume of the syrup sulphitor maintained 12 to 15 minutes

Juice coloumn height should be maintained  1.5 to 1.8 metres

Syrup % cane consider around 25%

Example:

Crushing rate = 230 TCH  and syrup %cane = 25%,

Syrup Quantity   – 230 x 25% = 57.50 T/hr = 57.50 / 1.2 = 48 M3/hr ( Specific volume of syrup ≈ 1.2 )

Holding volume of the syrup sulphitor = 48 x 12 / 60 = 9.6 M³ ≈ 100 HL

Thumb rule for syrup sulphitor capacity  in HL = TCD x 2%

Syrup pump capacity – Generally pump capacity consider 20% extra on requirement.

So 48 x 120% = 57.6 m³ ≈ 60 m³/hr

11. Syrup Clarification

Syrup Clarification Design for Plantation white sugar manufacturing

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