manufacture of chlorine - caustic soda using electrolysis process (membrane cell) ...
TRANSCRIPT
![Page 1: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/1.jpg)
PROJECT TOPIC
MANUFACTURE OF CHLORINE–CAUSTIC
SODA USING ELECTROLYSIS PROCESS
BHARATI VIDYAPEETH COLLEGE OF ENGINEERING
CHEMICAL DEPARTMENTProf. R.K.Kulkarni
Presented by Ankush Gupta
![Page 2: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/2.jpg)
PROCESS FLOW DIAGRAM
Membrane Cell Process
![Page 3: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/3.jpg)
![Page 4: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/4.jpg)
MATERIAL BALANCE
![Page 5: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/5.jpg)
Basis : 1150 kg/hr NaOH , 1000 kg/hr Chlorine
2NaCl + 2H2O 2NaOH + H2 + Cl2
(58.5) (18) (40) (2) (70)
( 28.75) (28.75) (28.75) (14.375) (14.375) Kmoles/hr
(1681.8) (517.5) (1150) (28.75) (1006) kg/hr
• Sample calculationMoles = weight / molecular weight
For NaCl
Moles = 1150/40 28.75 Kmol/hr
NaCl required (Kg) = 28.75 * 58.5 1681.8 kg (1700 Kg/hr).
![Page 6: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/6.jpg)
Assumption : 1700 kg/hr of NaCl 20 kg/hr Na2Co3
• 15/100 x Feed =1700 Feed = 11333.33 Kg/hr.
OVERALL MATERIAL BALANCEFeed (F) + Na2Co3 = |Sludge|4 + |NaCl|311333.33 + 20 = |Sludge|4+ |NaCl|3………………………eqn(1)
MATERIAL BALANCE OF NaCl 1700 = 28%|NaCl|3 + 10%|Sludge|4170000 = 28|NaCl|3 + 10|Sludge|4…………………………….eqn(2)
On Solving Eqn(1) & eqn(2) we get|NaCl|3 = 3137.03 Kg/hr.|Sludge|4 = 8216.3 Kg/hr.
![Page 7: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/7.jpg)
For 55% efficiency of Caustic Soda &Cl2:
2NaCl + 2H2O = 2NaOH + H2 + Cl2
Mass flow(kg/hr) 878.36 270.25 330.28 8.256 289.01
Molecular Weight 58.5 18 40 2 70
Moles flow(Kmol/hr) 15.014 15.014 15.104 7.552 7.552
Moles flow(Kmol/hr) 8.257 8.257 8.257 4.153 4.153 (55%)
Sample Calculation: For NaOH : • Amount of NaCl entering a membrane cell = 28%|NaCl|3=28% (3137.03)=878.368kg/hrConverting into molar flow rate = 878.368/58.5=15.014 Kmol/hr
•By Stoichiometry , No of moles of NaCl = No of moles of NaOH = 15.014 Kmol/hr.But since we have for 55% efficiency for Membrane cell
• No of moles of NaOH = 55%(15.014)= 8.257 Kmol/hr.Therefore the amount of NaOH obtained= 8.257*40=330.28 Kg/hr
![Page 8: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/8.jpg)
OVERALL MATERIAL BALANCE OVER EVAPORATOR Aq. NaOH(35%NaOH) = Aq.NaOH(50% NaOH) + Water vapour 330.28 = 231.196 + 99.081
Calculation for amount of aq.NAOH obtained as a main product:• Pure NaOH out of aq. NaOH = 35% of (330.28) = 115.598 kg/hr• Water content in incoming aq. NaOH = 330.28 – 115.98 = 214.68 kg/hr
Amount of NaOH obtained after 50% concentration is• 50% of (aq. NaOH) = 115.598 kg/hr• Therefore aq. NaOH (50%) obtained as product = 231.196 kg/hr• Water content in obtained aq. NaOH (50%) = 231.196-115.598=115.598 kg/hr• Therefore Water Vapour = 214.68-115.98=99.082 kg/hr
![Page 9: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/9.jpg)
OVERALL MATERIAL BALANCE OVER DRYER:
Wet Cl2 + H2SO4(98% conc) = Dry Cl2 + H2SO4 (70% conc)289.019 + 98% of (25kg) = Dry Cl2 + H2SO4 (70%)
…….eqn1
MATERIAL BALANCE OF H2SO4 OVER DRYER:
Inlet H2SO4 (98%conc) = Outlet H2SO4 (70%conc) 98%(25) = 70% H2SO4
98x25 = 70% H2SO4
H2SO4 (70%) = 35 kg/hrSubstituting in …..eq1 Dry Cl2 = 278.519 kg/hr.
![Page 10: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/10.jpg)
ENERGY BALANCE
![Page 11: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/11.jpg)
STEAM REQUIREMENT FOR HEATING BRINE
m = mass flow rate of Aq NaCl in kg/hrCP = specific heat capacity of Aq NaCl At 60OCΔT = Temperature Difference λ = latent Heat of evaporization in kJ/kg m1 = Flow rate of steam kJ/hr
mcPΔT = m1 λ
3137.03 x 3.274 (333-298) = m x 2358.40 m1 = 151.186 kJ/hr
![Page 12: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/12.jpg)
ENERGY BALANCE OVER MEMBRANE CELL
Assumption Datum temperature = 25oC
INLET STREAM
OUTLET STREAM
MATERIAL NAME
SPECIFIC HEAT AT 60oC FLOW RATES kg/hr
H2O 4.185 kJ/kgK 270.252
Aq.NacL solution
3.247 kJ/kgK 876.368
MATERIAL NAME SPECIFIC HEAT AT 80oC FLOW RATES kg/hr
Hydrogen (g) 14.43 kJ/kgK 8.256
Chlorine (l) 0.48 kJ/kgK 289.019
NaoH (35% by wt) 3.594 kJ/kgK 330.28
Depleted brine 3.247 kJ/kgK 521.065
![Page 13: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/13.jpg)
• INPUT STREAM Material mcPΔT Aq .NaCl 876.368 x 3.247x (333-298) = 99594.84 kJ/hr H2O 270.252 x 4.185 x (333-298) = 39585.16 kJ/hr
TOTAL HEAT INPUT = 99594.84 + 39585.16 = 139180 kJ/hr
• OUTPUT STREAMMaterial mcPΔT Hydrogen (g) 8.256 x 14.43 x (353-298) = 6552.37 kJ/hrChlorine (l) 0.48 x 289.019 x(353-298) = 4855.51 kJ/hr Aq.NaoH 3.594 x 330. 28 x (353-298) = 41545.92 kJ/hr Depleted Brine 3.247 x 521. 065 x (353-298)= 59216.43 kJ/hr
TOTAL HEAT OUTPUT = 6552.37 + 4855.51 + 41545.92 + 59216.43 = 112170.23 kJ/hr
2Na (s) + 2H2O 2NaOH + H2O ΔH = -368.4 kJ/gmNa
Depleted brine = 526.064 kg/hr (50% by wt of NaCl)0.5 x 526.064 x -368.4 = - 96900.98 J/hr
![Page 14: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/14.jpg)
MATERIAL NAME
SPECIFIC HEAT AT 80oC FLOW RATES kg/hr
Aq.NaoH 35% by wt
3.594 kJ/kgK 330.28
MATERIAL NAME SPECIFIC HEAT AT 110oC FLOW RATES kg/hr
50 % Caustic soda 3.564 kJ/kgK 231.196
INLET STREAM
OUTLET STREAM
MATERIAL NAME Latent Heat AT 110oC FLOW RATES kg/hr
Steam 2231.86 kJ/kg 94.127
ENERGY BALANCE OVER EVAPORATOR
![Page 15: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/15.jpg)
• INPUT STREAM Material mcPΔT Aq .NAOH 330.28 x 3.594 x (353-298) = 65286.44 kJ/hr
TOTAL HEAT INPUT = 65286.44 kJ/hr
• OUTPUT STREAMMaterial mcPΔT Aq.NaoH (50% by wt) 231.196 x 3.564 x (383-298) = 45319.03 kJ/hr Material mλ Water vapour (g) 94.127 x 2231.86 = 210078.28 kJ/hr
TOTAL HEAT OUTPUT = 45319.03 + 210078.28 = 255397.31 kJ/hr
![Page 16: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/16.jpg)
MATERIAL NAME
SPECIFIC HEAT FLOW RATES kg/hr
Wet chlorine 0.48 kJ/kgK 289.019
H2SO4 (98% by wt)
1.465 kJ/kgK 10
MATERIAL NAME
SPECIFIC HEAT FLOW RATES kg/hr
Dry chlorine 0.48 kJ/kgK 285.019
H2SO4 (70% by wt)
2.177 kJ/kgK 14
INLET STREAM
OUTLET STREAM
ENERGY BALANCE OVER DRYER
![Page 17: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/17.jpg)
• INPUT STREAM Material mcPΔT Wet Chlorine 289.019 x 0.48 x (353-298) = 7630.10kJ/hr
TOTAL HEAT INPUT = 7630.10 kJ/hr
• OUTPUT STREAMMaterial mcPΔT Dry Chlorine (l) 285.019 x 0.48 x (343-298) = 6156.41 kJ/hr H2SO4 70% 14 x 2.177 x (303-298) = 152.39 kJ/hr
TOTAL HEAT OUTPUT = 6156.41 + 152.39 = 6308.8 kJ/hr
![Page 18: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/18.jpg)
% conversion NaCl = (Reacted moles / Total no moles) x 100
= {(878.36 – 261.032)/878.36} x 100= 70.28 %
%Yield = (NaoH moles Formed /Reacted moles of NaCl) x 100
= {(115.598/ 40) / (617.328/58.5) } x 100 = 27.37 %
![Page 19: MANUFACTURE OF CHLORINE - CAUSTIC SODA USING ELECTROLYSIS PROCESS (MEMBRANE CELL) * CORRECTION NEEDED](https://reader033.vdocument.in/reader033/viewer/2022061507/55ba2302bb61eb8d4c8b46e1/html5/thumbnails/19.jpg)
REFERENCES1 ) Subrata Basu , Swapan Kumar Mukhopadhyay , Amitava Gangopadhyay
and Sujata G. Dastidar “International Research Journal of Environment Sciences Characteristic Change of Effluent from a Chlor-alkali Industry of India due to Process Modification” 2013.
2) S.Koter.A.Warszawski “Polish Journal of Environmental Studies Electro- membrane Processes in Environment Protection” (2000)
3) Yohannes Kiros and Martin Bursell “International Journal Electrochemistry Science Low Energy Consumption in Chlor-alkali Cells Using Oxygen Reduction Electrodes (2008)”
4) Rezaee, J. Derayat, S.B. Mortazavi,Y. Yamini and M.T. Jafarzadeh “American Journal of Environmental Sciences Removal of Mercury from Chlor-alkali Industry Wastewater using Acetobacter xylinum Cellulose(2005)”
5) Dryden’s outlines of chemical technology (2012)