PAN SECTION CAPACITY CALCULATION

 

Capacity Calculation of Pan Section in Sugar Industry | Boiling House Capacity

Sugar crystallization process takes place in pan section of sugar plant. The equipment supply tanks, Batch/continuous pans, condensers, molasses conditioners, spray pond, crystallizers fall under pan section.

Capacity of Batch/Continuous pans

The boiling times considered for A, B & C massecuites are 4 hours, 6hours and 8 hours respectively . For refinery massecuite,2 to 3 hours is considered.

Example:

Crushing Capacity of the plant = 230 TCH

“A” massecuite%cane = 25 to 30%

“B” massecuite%cane = 12 to 13%

“C” massecuite%cane = 6 to 8%

” A” Massecuite Quantity = 230 x 30% = 69 T/hr = 1656 T/day

” B” Massecuite Quantity = 230 x 13% = 30 T/hr = 720 T/day

” C” Massecuite Quantity = 230 x 8% = 18.5 T/hr = 444 T/day

While considering batch pans with 60 Ton capacity each

Massecuite	Boiling Hours	No. of strikes per day per pan	Quantity of massecuite per strike in Ton	No. of pans required
A	4	24 hours/4 = 6	1656/6 = 276	276/60 ≈ 5 nos.
B	6	24 hours/6 = 4	720/4 = 180	180/60 = 3 nos.
C	8	24 hours/8 = 3	444/3 = 148	148/60 ≈ 3 nos.

While considering Continuous pans for all massecuiteboilings

For continuous pans, 10% to 20% extra capacity is to be considered.

From the above

For ” A” Continuous Pan  =  69 T/hr x 110%    ≈  76 T/hr

For ” B” Continuous Pan   = 30 T/hr x 120%    ≈ 35 T/hr

For ” C” Continuous Pan   = 18.5 T/hr  x 120%  ≈ 22 T/hr

Grain and Molasses ratio for A, B & C massecuites is generally taken as follows ( It depends on grain size and purity of material)

“A” Grain to Liquor (syrup/melt/AL) ratio – 1 : 1 to 2

“B”  Grain to Liquor (A heavy) ratio   – 1 : 2 to 3

“C”  Grain to Liquor (B heavy/ C light) ratio   – 1 : 3 to 4

 

 

 

 

B massecuite purity online calculation sheet | Sugar Technology

C massecuite final purity calculation |Grain Quantity requirement for C CVP

Massecuite	Boiling Hours	No. of strikes per day per pan	Quantity of grain required in Ton	Quantity of massecuite per strike in Ton	No. of pans required
A Grain	4	24/4 = 6	1656/2 = 828	828/6 = 138	138/60 = 2.3 (70T x 2 nos.)
B Grain	6	24/6 = 4	720/3 = 240	240/4 = 60	60/60 = 1 no.
C Grain	8	24/8 = 3	444/4 = 111	111/3 = 148	37/60 ≈ 1 no.

Thumb rules for finding the capacities of batch/continuous pans

Note: It is not accurate capacity but it gives approximate value instantly

Batch pans

“A” Batch pan capacity in Ton – TCD x 0.06 ( Ex: 5000 x 0.06 = 300 T )

“B” Batch pan capacity in Ton – TCD x 0.04 ( Ex: 5000 x 0.04 = 160 T )

“C” Batch pan capacity in Ton – TCD x 0.03 ( Ex: 5000 x 0.03 = 150 T )

Continuous pans

“A” Continuous pan capacity in Ton – TCD x 0.014 ( Ex: 5000 x 0.015 = 75 T/hr )

“B” Continuous pan capacity in Ton – TCD x 0.006 ( Ex: 5000 x 0.006 = 30 T /hr)

“C” Continuous pan capacity in Ton – TCD x 0.004 ( Ex: 5000 x 0.004 = 20 T /hr)

“A” Grain pan capacity in Ton – TCD x 0.025 ( Ex: 5000 x 0.025 = 125 T )

“B” Grain pan capacity in Ton – TCD x 0.01 ( Ex: 5000 x 0.01 = 50 T )

“C” Grain pan capacity in Ton – TCD x 0.01 ( Ex: 5000 x 0.01 = 50 T )

Low Grade Massecuite Treatment in Sugar Crystallization Process

Sugar Seed Slurry Requirement Calculation for B and C massecuite

Types of Graining Techniques in sugar crystallization process | Pan Boiling

Pan Supply Tanks

“A” massecuite feeding liquor (syryp/melt/A light) consider minimum 2 hours retention time

“B” massecuite feeding liquor (A Heavy) consider minimum 3 hours retention time

“C” massecuite feeding liquor ( B heavy/ C light) consider minimum 4 hours retention time

Example:

Crushing Capacity of the plant = 230 TCH

Syrup % cane – 25 to 30%

Melt % cane  – 12 to 14%

A light %cane- 2 to 3%

A heavy%cane- 12 to 15%

B heavy%cane – 6 to 7%

C light%cane – 2 to 3%

Syrup + melt + A light = 43% (average) = 230 x 43% ≈ 100 T/hr

High grade massecuite supply tanks capacity = 100 x 2 hours = 200 / 1.25(density) = 160 M³ = 1600 HL

A heavy molasses quantity = 230 x 15% = 34.5 T/hr

A heavy supply tanks capacity = 34.5 x 3 hours = 103.5 / 1.3(density) ≈  80 M³ = 800 HL

B heavy + C light molasses quantity = 230 x 10% = 23 T/hr

A heavy supply tanks capacity =23 x 4 hours = 92 / 1.3(density) ≈  70 M³ = 700 HL

Thumb rules for finding the capacities of supply tanks in pan section

High grade massecuite feed materials ( Syrup + melt + A light ) supply tanks capacity in HL = TCH x ( 7 to 8)

Low grade massecuite feed materials ( A Heavy + B heavy + C light ) supply tanks capacity in HL = TCH x ( 7 to 8)

Molasses Conditioners capacity

For its capacity, consider extra 10 to 20% on molasses production

Example:

Crushing Capacity of the plant = 230 TCH

A heavy%cane- 12 to 15%

B heavy%cane – 6 to 7%

C light%cane – 3 to 4%

A heavy molasses quantity = 230 x 15% = 34.5 T/hr

A heavy molasses conditioner capacity = 34.5 x 110% = 38 T/hr

B heavy  molasses quantity = 230 x 7% = 16.1 T/hr

B heavy molasses conditioner capacity = 16.1 x 110% = 18 T/hr

C light molasses quantity = 230 x 4% = 9.2  T/hr

C Light molasses conditioner capacity = 9.2 x 110% = 11 T/hr

Capacity calculation of crystallizers

Crystallizers are used for cooling and holding of the massecuite. Air cooled type crystallizers are used for high grade massecuites, receiving crystallizers of continuous pans and for seed  crystallizer. Water cooled crystallizers are used for low grade massecuites for proper cooling and better exhaustion.

A – Massecuite –  ( 2 hours cooling purpose + 2 hours curing purpose) –  Air cooled

B – Massecuite – ( 6 to 8 hours cooling purpose + 3 hours curing purpose) –  Air cooled + water cooled

C – Massecuite  –  ( 20 to 24 hours cooling purpose + 4 hours curing purpose) –  Air cooled + water cooled

Each crystallizer capacity should be 10 to 15%  more than the existing pan capacity.

For example, if a 60 T (42 m³) pan is considered, then  the capacity of crystallizer can be taken as 70 T (48 m³).

For an air cooled type crystallizers is considered for “C’ massecuite then cooling time can go upto 72 hours. So, proper design of cooling elements used in crystallizers enables the cooling time to come down to 18 to 24 hours.

Application of Crystallizers in Sugar Industry | Crystallizer Capacity Calculation

Example:

Crushing Capacity of the plant = 230 TCH

“A” massecuite%cane = 25 to 30%

“B” massecuite%cane = 12 to 13%

“C” massecuite%cane = 6 to 8%

” A” Massecuite Quantity = 230 x 30% = 69 T/hr

” B” Massecuite Quantity = 230 x 13% = 30 T/hr

” C” Massecuite Quantity = 230 x 8% = 18.5 T/hr

Crystallizer capacity for “A” massecuite

Quantity of  “A” massecuite  for (2+2) hrs = 69 x 4 =  276 Tons ≈ 300 Ton

Total volume of  “A” crystallizers  = 300 /1.45 = 206 M³ = 2060 HL ( sp.gr =1.45 )

So total capacity split is into number of crystallizers and each crystallizer shall have 10 to 15%  more  capacity than that of the pan. Generally, total capacity of “A” massecuite crystallizers are made equal to total capacity of “A” pans.

Capacity of  “B” massecuite Crystallizer

Quantity of “B” massecuite for (7+3) hrs = 30 x 10 = 300 Tons

Total volume of  “B” crystallizers  = 300 /1.5 = 200 M³ = 2000 HL ( sp.gr =1.5 )

The total capacity is split into water cooled and air cooled crystallizers in the ratio of 7 : 3 or 8 : 2

Crystallizer capacity for “C” massecuite

Quantity of “C” massecuite for (24 +4) hrs = 18.5 x 28 = 518 Tons  ≈ 550 Ton

Total volume of  “C” crystallizers  = 550 /1.5 = 370 M³ = 3700 HL ( sp.gr =1.5 )

The total capacity is split into water cooled and air cooled crystallizers in the ratio of 8 : 1

Vertical Crystalliser Design Calculation for Sugar Massecuite Cooling

Concepts of Vertical Crystallizer  in Sugar Plant | Mono Vertical Crystallizer

Vacuum crystallizers :

The capacity of  Vacuum crystallizer for A, B & C massecuites should be equal to the capacity of existing batch pans used for grain/footings of the massecuite. usually, one crystallizer per massecuite is considered.

Capacity of condenser

Coefficients  of Evaporation rate for batch pans depend on the purity of material and hydro-static head of the massecuite. Hence, if the massecuite level increases in pan then evaporation rate will be decreased.

As per Mr. E.Hugot, the evaporation rates in kg/m² /hr  are as follows

	Initial	Final
Footing Pan	85	17
A-Masseccutie	71	32
B-Masseccutie	46	11
C-Masseccuite	36	17

For the purpose of condenser capacity calculations, batch pan evaporation rates are to be considered between 50 to 60 in kg/m² /hr and for continuous pans between 20 to 30 kg/m² /hr

Average evaporation rate in Batch Pans

A massecuite  – 60  kg/m² /hr ,

B massecuite  – 55 kg/m² /hr &

Cmassecuite – 50 kg/m² /hr

Average evaporation rate in Continuous pans

A massecuite  – 30  kg/m² /hr ,

B massecuite  – 25 kg/m² /hr &

C massecuite – 20 kg/m² /hr

Example:

If the heating surfaces of a 60 MT batch pan is 282 m², then the condenser capacity required is

282 m² x 50 kg/m² /hr  = 14100 kg/hr ≈ 14.1 T/hr

If the heating surfaces of a 35 MT/hr continuous pan is 650  m² , then the condenser capacity required is

650 m² x 25 kg/m² /hr  = 16200 kg/hr ≈ 16 T/hr

Injection water System and Condensers

The vapour condensation quantity is that of vapour from pan section and evaporator last effect.

Vapour produced from pan section = 18 to 25% on cane  ( For back-end refinery plants, it goes upto 28% on cane)

Vapour produced from last effect evaporator body = 5 to 8 % on cane

Water required for condensing the vapour calculated on the basis of cooling water ratio.

 = Total heat of the vapour = 621 Kcal/kg @ 55 ⁰C

Definitions in Steam Properties and Online Steam Table For Saturated steam

To = Condenser outlet warm water temperature in ⁰C

Ti = Condenser inlet cold water temperature in ⁰C

Example:

Crushing Capacity of the plant = 230 TCH

To = Condenser outlet warm water temperature = 47  ⁰C

Ti = Condenser inlet cold water temperature = 36 ⁰C

So, Total vapour quantity for condensing = 230 x 33% = 80 T/hr

Cooling water ratio = (621 – 47) / (47 – 36) = 52.2 T/hr

i.e,  52.2 tons of water is required for One ton of vapour.

Total water required for condenser =  80 x 52.2 = 4176 T/hr

Condenser System for vacuum creation and their types with design criteria

Injection water pump capacity

Operating Injection water pump capacity = 4000 M³/hr

Installed Injection water pump capacity = 50 % more than the requirement = 4000 x 150% = 6000 M³/hr

( Split the total capacity  into 2 x 50% capacity of the pumps and 1 x 50% as a standby)

Spray pond capacity

Theoretically,  750 kg/hr of warm water requires 1 m² of area of spray pond.

As per the latest trends of designs, 900 to 1000kg/hr of warm water requires 1 m² area of spray pond.

Spray Pond area required = 4000M3/hr / 900 kg/hr

= 4000 x 1000 / 900 = 4444 m² ≈ 4500 m²