38957201 Material Balance
14
Material Balance Pre-heater: Input to the pre-heater:(Unit ratios are obtained from literature) The n-butane rich gas has to be heated to the reaction temperature before being sent into the reactor. Composition of the n-butane rich gas is, Hydrogen = 4 moles = 4*2 = 8 kg/hr Oxygen = 2 moles = 2*32 = 64kg/hr Nitrogen = 8 moles = 8*28 = 224 kg/hr Butane = 57.4 moles = 57.4*58.12 = 3336.088 kg/hr Water = 28.6 moles = 28.6* 18 = 514.8 Total input to the pre-heater = 4146.888 kg/hr Output from the pre-heater: No reaction takes place in the pre-heater, hence the output is, Hydrogen = 4 moles = 4*2 = 8 kg/hr Oxygen = 2 moles = 2*32 = 64kg/hr Nitrogen = 8 moles
description
hi
Transcript of 38957201 Material Balance
Material Balance
Pre-heater:
Input to the pre-heater:(Unit ratios are obtained from literature)
The n-butane rich gas has to be heated to the reaction temperature before being sent into
the reactor.
Composition of the n-butane rich gas is,
Hydrogen = 4 moles
= 4*2 = 8 kg/hr
Oxygen = 2 moles
= 2*32 = 64kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Butane = 57.4 moles
= 57.4*58.12 = 3336.088 kg/hr
Water = 28.6 moles
= 28.6* 18 = 514.8
Total input to the pre-heater = 4146.888 kg/hr
Output from the pre-heater:
No reaction takes place in the pre-heater, hence the output is,
Hydrogen = 4 moles
= 4*2 = 8 kg/hr
Oxygen = 2 moles
= 2*32 = 64kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Butane = 57.4 moles
= 57.4*58.12 = 3336.088 kg/hr
Water = 28.6 moles
= 28.6* 18 = 514.8
Total output from the pre-heater = 4146.888 kg/hr
Stream Input (kg/hr) Output (kg/hr)
Hydrogen 8 8
Oxygen 64 64
Nitrogen 224 224
Butane 3336.088 3336.088
Water 514.8 514.8
Total 4146.888 4146.888
Dehydrogenator:
Reactions:
C4H10 → CH2=CH.CH=CH2 + 2CH2 + 2H2;
C4H10 → C4H8 + H2
In the dehydrogenator, the above two reactions takes place, the n- butane rich gas may
get partially converted to butadiene and butene’s. the probability of butadiene formation is very
less compared to the formation of butane.
Assumptions:
Reaction 1: Conversion of butane to butadiene is 10%.
Reaction 2: Conversion of butane to butene is 80%.
Input to the Dehydrogenator:
Hydrogen = 4 moles
= 4*2 = 8 kg/hr
Oxygen = 2 moles
= 2*32 = 64kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Butane = 57.4 moles
= 57.4*58.12 = 3336.088 kg/hr
Water = 28.6 moles
= 28.6* 18 = 514.8
Total input to the Dehydrogenator = 4146.888 kg/hr
Output from the Dehydrogenator:
Conversion of butane takes place. Output from the dehydrogenator is,
Hydrogen = 61.4 moles
= 61.4*2 = 122.8 kg/hr
Oxygen = 2 moles
= 2*32 = 64 kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Butane = 3336.088 - (3336.088*0.1) - (3336.088*0.8)
= 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Water = 28.6 moles
= 28.6*18 = 514.8 kg/hr
Butene = 3336.088*0.8
= 45.92 moles
= 45.92*56.11 = 2576.571 kg/hr
1,3- butadiene = 3336.088*0.1
= 5.74 moles
= 5.74*54.09 = 310.4766 kg/hr
Total output from Dehydrogenator = 4146.257 kg/hr
Stream Input (kg/hr) Ouput (kg/hr)
Hydrogen 8 122.8
Oxygen 64 64
Nitrogen 224 224
Butane 3336.088 333.6088
Water 514.8 514.8
Butene 0 2576.571
1,3-butadiene 0 310.4766
Total 4146.888 4146.257
Oxydehydrogenator:
Reactions:
C4H8 → CH2=CH.CH=CH2 + H2
In the oxy-dehydrogenator, butene is converted to 1,3-butadiene. The conversion in the
reactor is 90%. Additional oxygen is supplied to carry out the reaction.
Input to the oxy-dehydrogenator:
Hydrogen = 61.4 moles
= 61.4*2 = 122.8 kg/hr
Oxygen = 2 moles
= 2*32 = 64 kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Water = 28.6 moles
= 28.6*18 = 514.8 kg/hr
Butene = 45.92 moles
= 45.92*56.11 = 2576.571 kg/hr
1,3- butadiene = 5.74 moles
= 5.74*54.09 = 310.4766 kg/hr
Oxygen(additional) = 5 moles
= 5*32 =160 kg/hr
Total input to oxy-dehydrogenator = 4306.257 kg/hr
Output from the oxy-dehydrogenator:
Hydrogen = 122.8 + (2576.571*0.9)
= 102.728 moles
= 102.728*2 = 205.456 kg/hr
Oxygen = 7 moles
= 7*32 = 224 kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Water = 28.6 moles
= 28.6*18 = 514.8 kg/hr
Butene = 2576.571 – (2576.571*0.9)
= 4.592 moles
= 4.592*56.11= 257.6571 kg/hr
1,3-butadiene = 310.4766 + (2576.571*0.9)
= 47.068 moles
= 47.068*54.09 = 2545.908 kg/hr
Total output from oxy-dehydrogenator = 4305.43 kg/hr
Stream Input (kg/hr) Output (kg/hr)
Hydrogen 122.8 205.456
Oxygen 64 224
Nitrogen 224 224
Butane 333.6088 333.6088
Water 514.8 514.8
Butene 2576.571 257.6571
1,3-butadiene 310.4766 2545.908
Oxygen (additional) 160 0
Total 4306.257 4305.43
Condenser:
The output gases from the reactor will be at a higher temperature. The temperature must
be reduced to be sent into the absorber. Hence the output is sent into a condenser.
Input to the condenser:
Hydrogen = 102.728 moles
= 102.728*2 = 205.456 kg/hr
Oxygen = 7 moles
= 7*32 = 224 kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Water = 28.6 moles
= 28.6*18 = 514.8 kg/hr
Butene = 4.592 moles
= 4.592*56.11= 257.6571 kg/hr
1,3-butadiene = 47.068 moles
= 47.068*54.09 = 2545.908 kg/hr
Total input to condenser = 4305.4299 kg/hr
Output from the condenser:
Hydrogen = 102.728 moles
= 102.728*2 = 205.456 kg/hr
Oxygen = 7 moles
= 7*32 = 224 kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Water = 28.6 moles
= 28.6*18 = 514.8 kg/hr
Butene = 4.592 moles
= 4,592*56.11= 257.6571 kg/hr
1,3-butadiene = 47.068 moles
= 47.068*54.09 = 2545.908 kg/hr
Total output from condenser = 4305.4299 kg/hr
Stream Input (kg/hr) Output (kg/hr)
Hydrogen 205.456 205.456
Oxygen 224 224
Nitrogen 224 224
Butane 333.6088 333.6088
Water 514.8 514.8
Butene 257.6571 257.6571
1,3-butadiene 2545.908 2545.908
Total 4305.43 4305.43
Absorber 1:
The butadiene so formed contains high volatile components like hydrogen, oxygen, etc.
they have to be removed. Hence the product from the oxy-dehydrogenator is sent into a absorber.
The solvent used in the removal of these high volatile gases is N-Methylpyrrolidone. The solvent
absorbs butane, butene and 1,3-butadiene.
Input to the Absorber 1:
Hydrogen = 102.728 moles
= 102.728*2 = 205.456 kg/hr
Oxygen = 7 moles
= 7*32 = 224 kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Water = 28.6 moles
= 28.6*18 = 514.8 kg/hr
Butene = 4.592 moles
= 4,592*56.11= 257.6571 kg/hr
1,3-butadiene = 47.068 moles
= 47.068*54.09 = 2545.908 kg/hr
N-Methylpyrrolidone = 55.5 moles
= 55.5*99.13 = 5501.715 kg/hr
Total input to absorber 1 = 9807.145 kg/hr
Output from absorber 1:
Top product:
Hydrogen = 102.728 moles
= 102.728*2 = 205.456 kg/hr
Oxygen = 7 moles
= 7*32 = 224 kg/hr
Nitrogen = 8 moles
= 8*28 = 224 kg/hr
Water = 28.6 moles
= 28.6*18 = 514.8 kg/hr
Butene = 0.04592 moles
= 0.04592*56.11 = 2.576571 kg/hr
Total output from top product = 1170.833 kg/hr
Bottom product:
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Butene = 4.54608 moles
= 4.54608*56.11 = 255.0805 kg/hr
1,3-butadiene = 47.068 moles
= 47.068*54.09 = 2545.908 kg/hr
N-Methylpyrrolidone = 55.5 moles
= 55.5*99.13 = 5501.715 kg/hr
Total output from bottom product = 8636.312 kg/hr
Total output from absorber 1 = 9807.145 kg/hr
Stream Input (kg/hr) Output (kg/hr)
Top product Bottom product
Hydrogen 205.456 205.456 0
Oxygen 224 224 0
Nitrogen 224 224 0
Butane 333.6088 0 333.6088
Water 514.8 514.8 0
Butene 257.6571 2.576571 255.0805
1,3-butadiene 2545.908 0 2545.908
N-Methylpyrrolidone 5501.715 0 5501.715
Total 9807.145 1170.833 8636.312
Stripper 1:
Input to stripper 1:
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Butene = 4.54608 moles
= 4.54608*56.11 = 255.0805 kg/hr
1,3-butadiene = 47.068 moles
= 47.068*54.09 = 2545.908 kg/hr
N-Methylpyrrolidone = 55.5 moles
= 55.5*99.13 = 5501.715 kg/hr
Total input to stripper 1 = 8636.312 kg/hr
Output from stripper 1:
Top product:
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Butene = 4.54608 moles
= 4.54608*56.11 = 255.0805 kg/hr
1,3-butadiene = 47.068 moles
= 47.068*54.09 = 2545.908 kg/hr
Total output from top product = 3134.5973 kg/hr
Bottom product:
N-Methylpyrrolidone = 55.5 moles
= 55.5*99.13 = 5501.715 kg/hr
Total output from bottom product = 5501.715 kg/hr
Total output from stripper 1 = 8636.312 kg/hr
Stream Input (kg/hr) Output (kg/hr)
Top product Bottom product
Butane 333.6088 333.6088 0
Butene 255.0805 255.0805 0
1,3-butadiene 2545.908 2545.908 0
N-Methylpyrrolidone 5501.715 0 5501.715
Total 8636.312 3134.5973 5501.715
Absorber 2:
1,3-butadiene has to be separated from the top product from stripper 1. So absorber 2 is
made use of to absorb 1,3-butadiene using sulfolane as a solvent.
Input to absorber 2:
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Butene = 4.54608 moles
= 4.54608*56.11 = 255.0805 kg/hr
1,3-butadiene = 47.068 moles
= 47.068*54.09 = 2545.908 kg/hr
Sulfolane = 50 moles
= 50*120.17 = 6008.5 kg/hr
Total input to absorber 2 = 9143.097 kg/hr
Output from absorber 2:
Top product:
Butane = 5.74 moles
= 5.74*58.12 = 333.6088 kg/hr
Butene = 4.54608 moles
= 4.54608*56.11 = 255.0805 kg/hr
1,3-butadiene = .001*47.068 = 0.047068 moles
= .047068*54.09 = 2.545908 kg/hr
Total output from top product = 359.3852 kg/hr
Bottom product:
1,3-butadiene = 47.068 – 0.047068 = 47.02093 moles
= 2543.362 kg/hr
Sulfolane = 50 moles
= 50*120.17 = 6008.5 kg/hr
Total output from bottom product = 8551.862 kg/hr
Total output from absorber 2 = 8911.247 kg/hr
Stream Input (kg/hr) Output (kg/hr)
Top product Bottom product
Butene 255.0805 255.0805 0
Butane 333.6088 333.6088 0
1,3-butadiene 2545.908 2.545908 2543.362
Sulfolane 6008.5 0 6008.5
Total 9143.097 591.2353 8551.862
Stripper 2:
Input to stripper 2:
1,3-butadiene = 47.068 – 0.047068 = 47.02093 moles
= 2543.362 kg/hr
Sulfolane = 50 moles
= 50*120.17 = 6008.5 kg/hr
Total input to stripper 2 = 8551.862 kg/hr
Output from stripper 2:
Top product:
1,3-butadiene = 47.068 – 0.047068 = 47.02093 moles
= 2543.362 kg/hr
Bottom product:
Sulfolane = 50 moles
= 50*120.17 = 6008.5 kg/hr
Total output from stripper = 8551.862 kg/hr
Stream Input (kg/hr) Output (kg/hr)
Top product Bottom product
1,3-butadiene 2543.362 2543.362 0
Sulfolane 6008.5 0 6008.5
Total 8551.862 2543.362 6008.5
