Sugar Plant Clarification House Capacity Calculation | Sugar Mill
- 1 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%.
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
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
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.
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.
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
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
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
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
6. Lime station
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
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 2/3rd for juice sulphitation and 1/3rd for syrup sulphitation.
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%.
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
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.
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
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
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.
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%
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