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Index

Manufacture of 100 TPD of nano calcium carbonate i

Contents:

1. Material Balance01

2. Energy Balance..10

3. References..15

Index

Manufacture of 100 TPD of nano calcium carbonate ii

List of tables:

Table 1: Design Basis ..................................................................................................................... 1

Table 2: Specifications for reactant and product ............................................................................ 2

Table 3: List of streams used in process block diagram ................................................................. 2

Table 4: Properties of compounds involved ................................................................................... 4

Table 5 : Material flow across Crusher C001 ................................................................................. 5

Table 6: Material balance across Screener SC001 .......................................................................... 5

Table 7: Material balance across Reactor R001 (Input streams) .................................................... 6

Table 8: Material balance across Reactor R001 (Output streams) .................................................. 6

Table 9: Material balance across heat exchanger HX001 ............................................................... 6

Table 10: Material balance across Reactor R002 ........................................................................... 7

Table 11: Material balance across Screener SC002 ........................................................................ 7

Table 12 : Material balance across Reactor R003 (excluding streams 16 & 17) ............................ 8

Table 13: Material balance across filter F001................................................................................. 8

Table 14: Material balance across dryer D001 ............................................................................... 9

Table 15: List of specific heats at constant pressure ..................................................................... 11

Table 16: List of heat of reactions for different reactions ............................................................ 11

List of figures:

Figure 1: Process block diagram ................................................................................................................... 2

Index

Manufacture of 100 TPD of nano calcium carbonate 1

1. Material Balance

It is desired to produce 100 TPD of nano calcium carbonate powder. The product is produced in

continuous mode of operation. Purity of product is 98%.

Table 1: Design Basis

Production capacity 100 TPD

Operating hours 24 hours

Mode of operation Continuous

Purity 98%

The material balance are carried out across each equipment and shown in the tabular form.

Energy balances are done across equipments where heat is lost or provided.

Assumptions:

The value of specific heat does not change with temperature.

The value of heat of reaction does not change with temperature.

Reference temperature is 25.

Losses in Material and Energy during production are neglected.

All pressures are mentioned in atm unless specified.

All concentrations are on mole basis unless specified.

All streams, vessels and process units are assumed to be well mixed. Furthermore,

a steady state material and energy balance has been computed.

Index


Table 2: Specifications for reactant and product

(Reference: http://jnhongyuan8.en.alibaba.com/product/953750815-

218181311/Professional factory_Nano_Calcium_Carbonate.html)

Chemicals Reactant(%) Product(%)

CaCO3 96.5 98

MgCO3 3.5 2

Process block diagram:

1 2 3 7

4 9 10

5 6

8 11

12

13 15 18 19

14 16 17 20

21 22

23

Figure 1: Process block diagram

Table 3: List of streams used in process block diagram

STREAM

NO.

MATERIALS/UTILITIES

1 LIMESTONE

2 CRUSHED LIMESTONE

Vertical Shaft Lime Kiln

Hydrator

Crusher Screener

Screener Rotating

Packed Bed Filtration

Dryer

Heat

exchanger

Index


3 LIMESTONE FOR BURNING

4 IMPURITIES IN LIMESTONE LIKE MgCO3

5 NATURAL GAS

6 AIR

7 CARBON DIOXIDE AND AIR

8 CALCIUM OXIDE

9 COLD AIR

10 VENT AIR

11 CARBON DIOXIDE AND AIR

12 WATER

13 CALCIUM HYDROXIDE SLURRY

14 IMPURITIES LIKE Mg(OH)2

15 PURIFIED SLURRY

16 COLD WATER

17 WASTE WATER

18 PRECIPITATED CALCIUM CARBONATE

19 WATER(MOTHER LIQUOR)

20 CALCIUM CARBONATE(WET CAKE)

21 HOT AIR

22 VENT AIR

23 FINAL PRODUCT(NANO CaCO3)

Properties of reactants, intermediates and products:

The following tables summarizes the physical properties for the compounds involved

in the manufacture.

Index


Table 4: Properties of compounds involved

Sr.No. Component Molecular formula Molecular weight(kg/kmol)

1 Calcium carbonate CaCO3 100.0869

2 Calcium oxide CaO 56.0774

3 Calcium hydroxide Ca(OH)2 74.093

4 Carbon dioxide CO2 44

5 Magnesium carbonate MgCO3 84.3139

6 Magnesium oxide MgO 40.3

7 Magnesium hydroxide Mg(OH)2 58.32

8 Air - 28.84

9 Natural gas - 19

10 Water H2O 18.02

Basic calculations:

The basis for the problem statement is defined as 100 TPD of nano calcium carbonate.

Basis: 100 t/d = 100x1000/24 kg/hr = 4166.67 kg/hr = 4166.67/99.77 kmol/hr = 41.763 kmol/hr

As purity is 98%, CaCO3 = 0.98x4166.67 = 4083.33 kg/hr = 40.8 kmol/hr

Also impurities (MgCO3) in product = 0.02x4166.67 = 83.33 kg/hr = 0.99 kmol/hr

Reactions:

(A) CaCO3(s) CaO(s) + CO2(g)

(B) CaO(s) + H2O(l) Ca(OH)2 (aq.)

(C) Ca(OH)2(aq.) + CO2(g) CaCO3(s) + H2O(l)

As yield is 100%, as per reaction stoichiometry, Ca (OH)2 required = 41.763 kmol/hr = 3081.15

kg/hr and CO2 required = 41.763 kmol/hr = 1837.56 kg/hr. As yield of hydration is 96%, CaO

required = 41.763/0.99x0.96 = 44.037 kmol/hr = 2448.61 kg/hr. Also, yield of carbonation is

97%, limestone required = 45.398 kmol/hr = 4522.31 kg/hr. As some limestone is lost in

screening process, total raw material required = 4522.31/0.99 = 4567.99 kmol/hr = 45.893 kg/hr.

Index


1.1 Material balance across Crusher C001:

Assumption :

No material is lost in crushing process, the composition of inlet and outlet streams

are found and tabulated below.

Table 5 : Material flow across Crusher C001

Compound Input Output

Stream No. 1 2

kg/hr kmol/hr wt% kg/hr kmol/hr wt%

CaCO3 4408.11 44.04281 0.965 4408.11 44.043 0.965

MgCO3 159.88 1.85 0.035 159.88 1.85 0.035

Total 4567.99 45.89 1 4567.99 45.89 1

1.2 Material balance across Screener SC001:

Assumption:

1% loss of material during screening process.

Purity of raw material increases from 96.5% to 97%.

Table 6: Material balance across Screener SC001


Stream No. 2 3 4

kg/hr kmol/hr wt% kg/hr kmol/hr wt% kg/hr kmol/hr wt%

CaCO3 4408.11 44.043 0.965 4386.64 43.83 0.97 21.47 0.21 0.43

MgCO3 159.88 1.85 0.035 135.67 1.61 0.03 24.21 0.29 0.58

Total 4567.99 45.89 1 4522.31 45.398 1 45.68 0.50 1.00

1.3 Material balance across Reactor R001:

Assumption:

Conversion in the reactor to be 97%.

Outlet gas stream contains 50% air and 50% CO2.

Air: Natural gas to be 11 wt%.

Index


Table 7: Material balance across Reactor R001 (Input streams)

Compound Input

Stream No. 3 5 6


CaCO3 4386.64 43.83 0.97

MgCO3 135.67 1.61 0.03

Natural gas

193.76 10.2 1

Air

2131.4 73.9 1

Total 4522.31 45.40 1 193.76 10.2 1 2131.4 73.9 1

Table 8: Material balance across Reactor R001 (Output streams)

Compound Output

Stream No. 7 8


Air 1937.606 67.18467 0.5

CO2 1937.606 44.0365 0.5

CaO

2375.151 42.35487 0.97

MgO

73.45827 1.681635 0.03

Total 3875.212 106.4034 1 2448.609 44.037 1

1.4 Material balance across heat exchanger HX001:

The input to the heat exchanger is Stream No. 7 at 300oC. It is cooled to 100

oC

without change in composition.

Table 9: Material balance across heat exchanger HX001


Stream No. 7 11


Air 1937.606 67.18467 0.5 1937.606 67.18467 0.5

CO2 1937.606 44.0365 0.5 1937.606 44.0365 0.5

Total 3875.212 106.4034 1 3875.212 106.4034 1


Assumption:


Index


Table 10: Material balance across Reactor R002


Stream No. 8 12 13


CaO 2375.15 42.355 0.97

MgO 73.46 1.682 0.03

H2O

792.66 44.04 1

Ca(OH)2

3018.91 40.75 0.97

Mg(OH)2

93.37 1.53 0.03

Total 2448.61 44.04 1 792.66 44.04 1 3112.28 42.28 1

1.6 Material balance across Screener SC002:

Assumption:

1% loss of material during screening process.

Purity of slurry increases from 97% to 98%.

Table 11: Material balance across Screener SC002


Stream No. 13 14 15


Ca(OH)2 3018.91 40.75 0.97 2.46 0.033 0.079 3016.45 40.712 0.98

Mg(OH)2 93.37 1.53 0.03 28.7 0.49 0.921 64.7 1.11 0.02

Total 3112.28 42.28 1 31.123 0.523 1 3081.16 41.763 1


Assumption:


Index


Table 12 : Material balance across Reactor R003 (excluding streams 16 & 17)


Stream No. 15 11 18


Ca(OH)2 3016.453 40.72 0.98 Mg(OH)2 64.70431 1.11 0.02 H2O

751.73 41.763 0.153

CaCO3

4083.34 40.8 0.83

MgCO3

83.33 0.99 0.017

Air

1937.61 67.185 0.7 CO2

1937.61 44.04 0.3

Total 3081.158 41.763 1 3875.22 106.4 1 4918.4 83.55 1

1.8 Material balance across filter F001:

Assumption:

Around 50% of moisture is removed.

Table 13: Material balance across filter F001


Stream No. 18 19 20


CaCO3 4083.34 40.8 0.83

4083.34 40.8 0.89

MgCO3 83.33 0.99 0.017

83.33 0.99 0.018

H2O 751.73 41.763 0.153 375.87 20.88 1 375.87 20.88 0.083

Total 4918.4 83.55 1 375.87 20.88 1 4542.54 62.67 1

1.9 Material balance across dryer D001:

Assumption:

Around 97% of moisture is removed in dryer.

Index


Table 14: Material balance across dryer D001


Stream No. 20 23 24


CaCO3 4083.34 40.8 0.89

4083.34 40.8 0.98

MgCO3 83.33 0.99 0.018

83.33 0.99 0.02

H2O 375.87 20.88 0.083 364.6 20.26 1 11.28 0.63 0.0027

Total 4542.54 62.67 1 364.6 20.26 1 4166.67 41.763 1

Energy balance


2. Energy Balance

All the quantities are expressed in kJ/hr, if not specified. For the energy balances applied to

reactors:

General equation: At Steady state operation,

Heat in + Heat generated = Heat out + Heat transferred to heat transfer fluid.

Heat in or Heat out is evaluated as )( refpi TTCM i

Basic Assumption:

All equipments are perfectly insulated from the surroundings and thus, energy lost

to the surroundings is neglected.

Specific heat is independent of temperature.

T1= Temperature of stream 1 and similar notation for other stream.

H1= Enthalpy of stream 1 and similar notation for other stream.

Reference temperature is 25.

T1= T2 =T3=T4=T19=T23= 300C.

T5= 11500C, T6= 1000C.

T7= 3000C, T11=T22= 1000C.

T9=150C, T10= 2000C.

T13=T14=T15= 650C.

T16= 50C, T17= 370C.

T18= 200C.

T21= 1100C.

Cp values of various materials used and heat of reactions at reaction temperature are tabulated:

Energy balance


Table 15: List of specific heats at constant pressure

(Reference: Wagman D.D., et.al., 1982)

Sr.No. Component Cp (J/gmol-K)

1 Ca(OH)2 87.5

2 CaO 42

3 CaCO3 83.5

4 MgO 37.2

5 Mg(OH)2 77

6 MgCO3 75.5

7 CO2 37.1

8 H2O 75.327

9 Air 28.84

10 Natural gas 44.46

Table 16: List of heat of reactions for different reactions

Sr.No. Reaction Heat of reaction[Hrxn] (kJ/mol)

1 CaCO3 CaO + CO2 .Calcination 167.5

2 CaO + H2O Ca(OH)2 Hydration -81.484

3 Ca(OH)2+ CO2 CaCO3 + H2OCarbonation -96.391

Energy balance


2.1. Energy balance across Reactor R001:

H3 + H5 + H6 + Hrxn = H7 + H8

Enthalpy of stream 3 = H3 = Hcaco3 + Hmgco3 = (mCp (T-Tref))caco3 + (mCp(T-Tref))mgco3

= 43.34x83.5x (303.15-298.15) + 1.61x75.5x (303.15-298.15) = 18906.8 kJ/hr.

Similarly, H5 = 193.71x2.34x (1423.15-298.15) = 510075.8325 kJ/hr.

H6 = 159852.75 kJ/hr, H7 = 982125.1413 kJ/hr.

Hrxn = moles of product x H0rxn = 167.5x44.037 = 7376.1975 kJ/hr.

H8 = 42.3549x42x (T-298.15) + 1.682x37.2x (T-298.15)

Solving, we get, T8 = 383.15K = 1100

C.

2.2. Energy balance across heat exchanger HX001:

H7 + H9 = H10 + H11

982125.1413 + mair x28.84x(293.15-303.15) = mair x28.84x(473.15-303.15) + 95824.5

Solving, we get, mair = 151.35 kmol/hr.


H8 + H12 + Hrxn = H13

156524.3071 + 44.0365x75.327 (T-298.15) + (-96.391x40.745) = 184149.9765

Solving, we get, T12 = 34.510C.

Energy balance



H11 + H15 + H16 + Hrxn = H17 + H18

H11 = 28.84x151.35x150 = 654740.1 kJ/hr.

H15 = 40.717x87.5x40 + 1.11x77x40 = 145928.3 kJ/hr.

H16 = mH2O x (278.15-298.15) x 75.327

Hrxn = 96.391x41.7628 = -4025.56 kJ/hr.

H17 = mH2O x 2259.81

H18 = 41.7628x75.327x(293.15-298.15) + 40.798x83.5x(293.15-298.15) + 0.99x75.5x(-5)

Solving, we get, mH2O = 61.2744 kmol/hr = 1102.94 kJ/hr.

2.5. Energy balance across filter F001:

H18 = H19 + H20

-33135.4672 = 20.88 x 75.327 x (303.15-298.15) + 40.8 x 83.5 x (T-298.15) +

20.88 x 75.327 x (T-298.15) + 0.99 x 75.5 x (T-298.15)

Solving, we get, T20 = 26.890C.

2.6. Energy balance across dryer D001:

H20 + H21 + Hvap = H22 + H23

Latent heat of water = 2260.33 kJ/kg. So, heat required to evaporate 364.6 kg of water =

2260.33kJ/kg x 364.6 kg/hr = 824091.45 kJ/hr = Hvap

Energy balance


H20 = 11172.35475 kJ/hr

H21 = mair x 28.84 x (393.15-298.15)

H22 = mair x 28.84 x (373.15-298.15)

H23 = 17642.67423 kJ/hr

Solving, we get, mair = 28.35 kmol/hr = 817.62 kJ/hr.

References


References:

Chase. M.W., et.al., JANAF Thermochemical Tables, Third Edition,J. Phys. Chem. Ref.

Data.14, 1985.

Chen Jian-Feng., et.al., Synthesis of Nanoparticles with Novel Technology: High-

Gravity Reactive Precipitation, Ind.Eng.Chem.Res.39,2000, 948-954.

Feng.B., et.al., Effect of various factors on the particle size of calcium carbonate formed

in a precipitation process, Materials Science and Engineering A 445-446, 2007, 170-179.

Kemperl.J.,et.al., Precipitation of calcium carbonate from hydrated lime of variable

reactivity, granulation and optical properties, Int. J. Miner. Process. 93, 2009, 8488.

Wagman. D.D., et.al., The NBS Tables of Chemical of Chemical Thermodynamic

Properties, J. Phys. Chem. Ref. Data.11, 1982.

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