Material%20Balance%20(????????????????)

1
Material Balance (????????????????)

• ????????????? ??????????????????????????
• ???? (System) ???? ????????????????????????
  ?????????????????????? (System Boundary)
  ??????????????????????????????

2
Quiz 6

• Antimony (Sb) is obtained by heating pulverized
  stibnite (Sb2S3) with scrap iron and drawing off
  the molten antimony from the bottom of the
  reaction vessel.
• Sb2S3 Fe ? 2 Sb 3 FeS
• Sppose that 0.600 kg of stibnite and 0.250 kg of
  iron turnings are heated together to give 0.200
  kg of Sb metal. Determine
• the limiting reactant
• the percentage of excess reactant
• the degree of completion
• the percen conversion based on
• the yield in kg Sb produced / kg Sb2S3 fed to the
  reactor.

3
??????? ????????

• ??????????????????????? ??????????????????????????
  ????????

?????????????????????????????????????????
Q, W
Q, W


-
-
mi
me
Q W DU DKE DPE D final state initial
state
Q W DH DKE DPE D Out In
4
???????????????????????

• ??????????????/???????
• ???????????????????????????

5
????????
?????????????????????????????? ?????.?.2551
?????????? ????????????????? 50,000 ??
??????? 75,000 ?? ???????? 22,000 ?? ????????????
19,000 ?? ????????????????????????????????????????
??? (???????????????????????????)
6
??????
???????????????????????????
???????????????? ???????????????
???????????????? - ????????????????
50,000 22,000 75,000 -19,000 ??/??
- 22,000 ??/?? ????????????????????????????
22,000 ??/?? Ans.
7
???????? ????????????????????????????????
?????????????????????????????? ?.?. 2552 ??????
??????? ??? ???
1. ????????????????????????? 8,000.00
2. ???????? 4500.00
3. ?????????? Prin.Chem.Eng 650.00
4. ?????????? 500.00
5. ????????????????? 915.00
6. ????????? 400.00
7. ?????????/?????????? 700.00
??? 8,000.00 -7665.00
???????????????????? 335.00
8
????????????????????????
???????????????????????????
?????????????????????????????
???????????????????????????
?????????????????????????
????????????????????
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????????????? (??????????????)
1. ?????? 2. ?????? 3. ???????????????????
(Component balance) 4. ???????????????????
5. ??????????? 6. ??????????? 7. ???????
(????????????)
10
????

• Unsteady State Process ???? Transient Process
  ?????????????????????????????????????????????
• Steady State Process ?????????????????????????????
  ?????????????? (???????????? ???????
  ????????????) ????????????????????????????????????
  ???????????????????????? ??????????????
  ???????????????????????????
• ??????????????????????????????????????????????????
  ???? ?????????????????????????????????? Steady
  State

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(No Transcript)
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????????????? Steady State ????????????????????
?????????????????????? (1) ???????????????????
? ?????????????????????? (2) ???????? (1) ???
(2) ?????????????????????????????????????????
?????????????????????? ?????????????????????????
???
13
????????
?????????????????? ??????????????????????????????
??? (Thickener) ??????????????????????
?????????????????????? ????????????? Steady State
???????????????????? 100 kg ??????????????????????
??
14
Basis ?????????? 100 kg ??? Steady State
????????????? ???????????? ?????????? 100 kg
????????? 70 kg
??? W kg W 100 70 30 kg
???????????????????????????? 30 kg
Ans
15
??????????????????? ???????????????? 1. ??????
????????????? ? ????????? ????????????????????????
????? streamline 2. ???? Basis 3. Set ????? 4.
???????? 5. ?????????
16
????????????????????????????????
Differential balance
Integral balance
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???????????????????????????? ??????????
Differential balance ?????????????????? ???????
?????????????????????????????????????? (??/??)
Integral balance ????????????????????????????
2 ???? ????????? kg ?? ???? ??????? ????????????
????????????????????? ???? Generation 0
??? Consumption 0 ??????????????? Steady -
state Accumulation 0
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???????? ???????????? 300 lb ??? C 24.0 lb ??
reactor ??? 600F ????????????????????????????
???????????????? Reactor ???????? 1. ?????? C,
O2 ????????????????????? reactor 2. ???????????
C ??? O ???????????????? reactor 3. ???????????
???????????????? reactor
O2 21 N2 79
19
Basis ????? 300 lb (???? C 24.0
lb)     ???????? 2.17 8.17 10.34 lb
mol
??????????? O2 300 lb air 1 lb mol air 21 lb mol O2
??????????? O2 29.0 lb air 100 lb mol air
??????????? O2 2.17 lb mol
??????????? N2 300 lb air 1 lb mol air 79 lb mol N2
??????????? N2 29.0 lb air 100 lb mol air
??????????? N2 8.17 lb mol
??????????? C 24.0 lb C 1 lb mol C
??????????? C 12.0 lb C
??????????? C 2.00 lb mol
20
C O2 ?
CO2 ???????? (lb mol) 2.00 2.17 0 ???????(lb
mol) 0 0.17 2.00
Component IN IN OUT OUT
Component lb lb mol lb lb mol
C 24.0 2.00 0 0
O2 69.5 2.17 5.5 0.17
N2 230.5 8.17 230.5 8.17
CO2 0 0 88.0 2.00
Total 324 12.34 324 10.34
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???????????????????? 1. N2 ??????????????????????
???????????????????????????????????????? Inert
???????????????????? (Impurities)
????????????????? ????????????????????????????????
???????? Reactor ??????????????????????? 2.
?????????????????????? ?????????????????? Reactor
?????????????????????????????????????? Reactor
??????????????????????????????????????????????????
?????? Reactor ????
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3. ???????????????????????????????????????????????
???????? ????????????????????? ???? ?????????????
O ??? O2 , H ??? H2 ??????? ????????????????????
? ????? ???????????????????? ?????????????????????
????????? ????????????????????????????????????????
???????????????????????????????????
??????????????????????????????????????????????????
????????????????????????????????
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3. ???????????????????????????????????????????????
???????? ????????????????????? ???? ?????????????
O ??? O2 , H ??? H2 ??????? ????????????????????
? ????? ???????????????????? ?????????????????????
????????? ????????????????????????????????????????
???????????????????????????????????
??????????????????????????????????????????????????
????????????????????????????????
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????????????????????? ??????????? C ???????
??????????? C ??????
2.00 lb mol ??????????? O ???????
??????????? O ??????
4.34 lb mol
????? ???? ???? ???? ??? ??? ???
????? C (lb mol) CO2 (lb mol ) O2 (lb mol) C (lb mol) CO2 (lb mol) O2 (lb mol)
C 2.00 0 0 0 2.00 0
O 0 0 22.17 4.34 0 22 4 0.172 0.34
25
????????????????????? ??????????? C
??????? ??????????? C ??????
24.0 lb ??????????? O
??????? ??????????? O ??????
138.9 128 10.9
????? ???? ???? ???? ??? ??? ???
????? C (lb) CO2 (lb) O2 (lb) C (lb) CO2 (lb) O2 (lb)
C 24 0 0 0 24 0
O 0 0 22.1732 138.9 0 2232 128 0.17232 10.9
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???????????????????????? Accumulation In Out
Generation - Consumption C balance 0 C in
C out Generation Consumption 0 2.00
lb mol C out 0 2.00 lb mol C out 2.00
- 2.00 0 O2 balance 0 O2 in O2 out
Generation Consumption 0 2.17 lb mol
O2 out 0 2.00 lb mol O2 out 2.17 -
2.00 lb mol 0.17 lb mol
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???????????????????????? Accumulation In Out
Generation - Consumption C balance 0 C in
C out Generation Consumption 0 2.00
lb mol C out 0 2.00 lb mol C out 2.00
- 2.00 0 O2 balance 0 O2 in O2 out
Generation Consumption 0 2.17 lb mol
O2 out 0 2.00 lb mol O2 out 2.17 -
2.00 lb mol 0.17 lb mol
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CO2 balance 0 CO2 in O2 out
Generation Consumption 0 0
CO2 out 2.00 lb mol 0 CO2 out
2.00 lb mol N2 balance N2 in N2 out
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???????? ?????? 1000 kg/h ?? Benzene (B) ???
Toluene (T) ??????????????????????????????????? B
??????? 50 ??? T ??????? 50
?????????????????????? 2 ???? ?????? (Top Stream)
?? B 450 kg/h ???????????????? 475 kg T/h
?????????????????? Steadystate
???????????????????? ???????? flowrate
??????????
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Basis ??????? 1000 kg / h ???? 1 hr. Overall
balance F D B Benzene balance 0.50 F
450 kg/hr q2 0.50 (1000) 450 q2
q2 50 kg
B/hr Toluene balance 0.50 F q1 475
kg/hr 0.50 (1000) q1 475
q2 25 kg B/hr. ????????????????
?? In Out 1000 (450 25) (475
50) 1000 1000
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???????? ?????? 1000 kg/h ?? Benzene (B) ???
Toluene (T) ??????????????????????????????????? B
??????? 50 ??? T ??????? 50
?????????????????????? 2 ???? ?????? (Top Stream)
?? B 450 kg/h ???????????????? 475 kg T/h
?????????????????? Steadystate
???????????????????? ???????? flowrate
??????????
32
???????? Batch mixing process
33
Basis A 200 g, B 150 g ??? x ???? mass
fraction ??? MeOH ????? C Overall balance C
200 150 350 g CH3OH balance 200(0.4)
0.7(150) x (350) 80 105 x
(350) x 185 / 350 0.5286
?????????????????? H2O balance In Out
0.6(200) 0.3(150) (1-0.5286)(350) 165 1
65
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??????????????????????????? ??????????????????????
??? 1. ???????????????????????????????????
?????????????????????????? ???????????? flowchart
??????????????????????????????????????????????????
???? Flowchart ????????????????????????????????
??????????? Box ???? Symbol ??? Process Unit
(Reactor, Mixer, Dryer, ) ?????????????
?????????????????????????????????????? Input ???
Output Stream ????????????????????????????????????
??????????????????? ????? Box ???? ????? ?????
??????????????????????? ??????????????????????????
?? ????????????????????????????????????????
???????????????????????????????????????????
?????????????????????????????????????? Stream
??????????????????????????????????????????????????
???? Stream ???????? F ??? Feed , T
?????????????? ??????? ??????????????????
??????????????????????? ??????????? ?????????
(Data-base) ??????????? ??????????????????????????
?
35
2. ??????? Basis ?????? flowrate ????????????
Process ?????? Basis ??????????????
????????????????????????????????????? Stream
?????? Basis ?????????? flowrate ???????????? 1
???? 100 ????????????????????????? 3.
??????????????????????????????????????????????????
???? Flowchart ???????????????????????????????
??????????????????????????????????????? Component
balance ??????????????????????????
???????????????????????? ????????????????????????
??????????? ??????????????????????????????????????
???????? (??????????????????????????? L)
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2. ??????? Basis ?????? flowrate ????????????
Process ?????? Basis ??????????????
????????????????????????????????????? Stream
?????? Basis ?????????? flowrate ???????????? 1
???? 100 ????????????????????????? 3.
??????????????????????????????????????????????????
???? Flowchart ???????????????????????????????
??????????????????????????????????????? Component
balance ??????????????????????????
???????????????????????? ????????????????????????
??????????? ??????????????????????????????????????
???????? (??????????????????????????? L)
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4. ????? ???????? 5. ????????? ?????????????
?????????????????????????????????
???????????????????? Redundant equation (????
total mass balance) ??????????????????????????????
??????????? ??????????????????
????????????????? ???????????????????????
38
??????? ???????????????????? ?????????????????????
??? 4 ????? ??????
???????? 4 ????? 3 unknown ???????
????????????? ??????????
0.25 NaCl 0.35 KCl 0.55 H2O 0.30 ------(1)
0.35 NaCl 0.20 KCl 0.40 H2O 0.30 ------(2)
0.40 NaCl 0.45 KCl 0.05 H2O 0.40 ------(3)
1.00 NaCl 1.00 KCl 1.00 H2O 1.00 ------(4)
??? ???????????????????? 3 ????????
???????????????? unknown ???????????? 4
????????????????? ?????????????????????????? 1
??? 3 ??????????? ???????????????????
39
???????? Determine the Number of Degree of
Freedom ??????????????????????
???????????????????????????? D ????????
??????????????????????????????????????????????????
? ????????????????????????????????????????????????
??
40
????????? ????????????? ????????????? Degree of
Freedom ?????????????????????????
???????????????????????????????????????????????
??????????????????????????????????????????????????
??? 100 ???? ???????????????????????????????????
????????????????????????????????????
????????????????????????????
Stream ?????????????????????????????????? ??????????????????????????????????
A 2 A, ?H2SO4
B 3 B, ?H2SO4 , ?HNO3 ???? B, ?H2SO4, ?H2O
C 2 C, ?HNO3 ???? C, ?H2O
D 2 ?H2SO4 , ?HNO3 ???? ?HNO3, ?H2O???? ?H2SO4 , ?H2O
Total 9
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???????? ????????? Alcohol ???? ?????????????????
?? Alcohol ???????????? Bottom Product
??????????????????????? ??????????????????????????
?????????
42
Basis F 1000 kg ??????????????????????
?EtOH , ?H2O ????? B ????????? B, ????????? 2
?????????????????????????????????? 2 ?????
?????????????????????????????????? overall
balance F D B 1000 kg 100 kg
B B 900 kg B F D
D 1 F 1000 100 kg
D 10 F 10 100 kg
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kg feed in - kg distillate out kg bottom product out
EtOH 0.10(1000) - (0.60)(100) 40
H2O 0.90(1000) - (0.40)(100) 860
900
Composition ????? B
kg by mass
EtOH 40 4.4
H2O 860 95.6
900 100.0
????????????????? Total Balance ?????? B
900 kg ?????? EtOH 40 kg ??? B ??????????????
???????? 900 40 kg 860
kg ??????????????????????? ?????????????????????
??????????????? ??????????????????????
44
Homework

• 7.12
• 7.13
• 7.14