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PLANT DESIGN FOR SULFURIC ACID MANUFACTURE
CHU492 PROJECT Harshadul Faseem.P Minas. VP Muhammed Dhanish
Guide: Dr.Lity Alen Varghese
CONTENTS
• Objective• Process• Plan• Mass balance• Further steps
OBJECTIVES
• Design a plant for manufacturing sulfuric acid with a capacity of 1000 tones/day of 98% sulfuric acid
• Optimization of processes
• Maximize the heat recovery
• Reduce the emission of sulfur dioxide
PROCESS• Lead chamber process• Contact process
• Single absorption• Double absorption (DCDA)
Among these the DCDA process is the most modern process which has got increased yield and reduces stack emission of SO2
The DCDA process• Raw Materials
• Molten Sulfur• Air• Water
• Reactions
Process Flow Chart
PLAN• The whole project has been divided to seven
different stagesStage Work
1 Identification of the best process
2 Mass balance and heat balance of the selected process
3 Design of heat transfer equipments (two heat exchangers, two waste heat boilers)
4 Design of mass transfer equipments ( two absorption columns and drying tower)
5 Design of four stage catalytic converter and burner
6 Selection transport equipments (pumps and blower)
7 Optimization and cost analysis
MASS BALANCE
• Assumption• Complete burning of S in the burner• 99.8 % conversion of SO2 to SO3 in the reactor
• Overall absorption of SO3 in the process is 100%• 40% excess oxygen is provided • Humidity of entering air is 65% at 300 C
Simplified flowchart for mass balance
Dryer
Burner
Reactor Absorption column
Absorption column
Tank 1 Tank 2Molten sulfur
Calculation• Product = 1000 tones/day of 98% H2SO4
• Taking basis of 1hr operation • Primary estimations:
SUBSTANCE AMOUNT (kmole)
Final product :H2So4 416.67
Equivalent SO3 required 416.67
So2 needed (SO3/0.998) 417.502
O2 required 626.25
O2 supplied (40% excess) 876.75
Total amount of dry air 4175.01
N2 present 3298.26
Moisture present 110.98
Drying tower
2141.23 kmole98% H2SO4
2251 kmole97% H2SO4
4285.99 kmoleMoist air DRYER
4175.013 kmoleDry air
The Burner
BURNER3298.26 kmole N2
876.75 kmole O2
417.502 kmoleMolten sulfur
417.502kmole SO2
459.248 kmole O2
3298.26 kmole N2
Reactor (4 stage catalytic converter)
Stage % conversion1 74.02 18.43 4.34 3.1Overall conversion
99.8
417.502kmole SO2
459.248 kmole O2
3298.26 kmole N2
13.778 kmole SO2
257.385 kmole O2
403.724 kmoleSO3
3298.26 kmole N2
First three stages
Inter-pass absorber
Absorber 1
13.778 kmole SO2
257.385 kmole O2
403.724 kmoleSO3
3298.26 kmole N2
13.778 kmole SO2
257.385 kmole O2
158.01 kmoleSO3
3298.26 kmole N2
2450.718 kmole98 wt% H2SO4
2450.718 kmole100 % H2SO4
Reactor (fourth stage)
13.778 kmole SO2
257.385 kmole O2
158.01 kmoleSO3
3298.26 kmole N2
0.835 kmole SO2
250.91 kmole O2
170.95 kmoleSO3
3298.26 kmole N2
Final absorber
Absorber 2
0.835 kmole SO2
250.91 kmole O2
170.95 kmoleSO3
3298.26 kmole N2
0.835 kmole SO2
250.91 kmole O2
3298.26 kmole N2
1709.6 kmole98 wt% H2SO4
1709.6 kmole100 % H2SO4
Final absorber circulating tank
Tank 2
1709.6 kmole100 % H2SO4
1709.6kmole98 wt% H2SO4
189.95 kmole98 wt% H2SO4
189.95 kmolewater
Inter pass absorber circulating tank
Tank 12251 kmole97% H2SO4
2141.23 kmole98% H2SO4
462.25 kmole98% H2SO4
2450.718 kmole100 % H2SO4
2450.718 kmole98 wt% H2SO4
189.95 kmole98 wt% H2SO4
161.32 kmolewater
FURTHER STEPS
• Energy balance• Equipment design and selection• Optimization and cost analysis
Reference
THANK YOU