MTBE RECOVERY
View: Process Flow Diagram
View: Simulation Results
This example presents the solution of the recovery of MTBE (methyl tert-butyl ether) from a process stream, probably the product of a synthesis reactor.
The recovery is performed using a distillation column with 32 theoretical trays a total condenser and a reboiler.
MTBE is recovered as bottom product.
The
feed composition is as follows :
|
No |
Component |
Molar Fraction |
Molar flow rate, kmol/h |
|
1 |
PROPENE |
0.037096 |
52.895 |
|
2 |
PROPANE |
0.028077 |
40.035 |
|
3 |
ISOBUTANE |
0.311174 |
443.703 |
|
4 |
ISOBUTENE |
0.002784 |
3.969 |
|
5 |
1-BUTENE |
0.109363 |
155.941 |
|
6 |
1,3-BUTADIENE |
0.001915 |
2.731 |
|
7 |
BUTANE |
0.137990 |
196.760 |
|
8 |
TRANS-2-BUTENE |
0.127419 |
181.687 |
|
9 |
CIS-2-BUTENE |
0.085243 |
121.548 |
|
10 |
METHANOL |
0.045195 |
64.444 |
|
11 |
ISOPENTANE |
0.010520 |
15.001 |
|
12 |
METHYL TERTBUTYL ETH |
0.102358 |
145.952 |
|
13 |
TERT-BUTYL ALCOHOL |
0.000175 |
0.249 |
|
14 |
TERT-AMYL ETHER |
0.000690 |
0.984 |
The column is constrained with two performance specifications:
· Reflux ratio .at 0.8
· MTBE recovery equal to 99.8 %
Thermodynamic methods
In this case the UNIFAC method is selected for the calculation of liquid activity coefficients. Vapor and liquid fugacities are calculated using the IDEAL method. The same method is used for enthalpy calculation.
Results
The column is easily solved using 12 iterations. Column profile, product compositions and reflux data are given.
*** UNIT 1 - 'C2 ' - ' DISTILLATION COLUMN ' ***
--- Feed Streams --- - Product Streams -
'S1 ' 'S2 '
'S3 '
1) * OPERATING CONDITIONS *
*** OUTLET LIQUID *** *** OUTLET VAPOR ***
* Tray * Temperature * Pressure * -Molar Rate- -Weight Rate- -Molar Rate- -Weight Rate-
°C bar kmol/h kg/h kmol/h kg/h
CON 56.17 8.00 2302.6 126971. 0.0000 0.00000
1 63.29 8.35 1042.9 58901.3 2302.6 126971.
2 65.37 8.38 1040.0 59464.6 2322.2 129441.
3 66.72 8.41 1030.8 59537.1 2319.3 130004.
4 67.96 8.45 1017.4 59397.6 2310.0 130077.
5 69.28 8.48 999.70 59111.2 2296.6 129937.
6 70.81 8.51 976.10 58645.6 2278.9 129651.
7 72.69 8.54 943.98 57924.5 2255.3 129186.
8 75.14 8.57 901.57 56900.0 2223.2 128466.
9 78.33 8.61 852.19 55720.2 2180.8 127442.
10 82.16 8.64 806.31 54774.3 2131.4 126263.
11 86.03 8.67 773.68 54338.9 2085.6 125317.
12 89.19 8.70 755.16 54308.1 2052.9 124881.
13 91.36 8.73 747.26 54525.2 2034.4 124849.
14 93.50 8.76 1880.4 138885. 1953.3 121082.
15 118.57 8.80 1930.0 158963. 1733.7 125944.
16 133.36 8.83 2051.0 176755. 1783.4 146022.
17 138.94 8.86 2115.7 185102. 1904.4 163815.
18 140.83 8.89 2136.5 187828. 1969.1 172161.
19 141.55 8.92 2144.8 188858. 1989.9 174887.
20 141.92 8.96 2148.7 189318. 1998.1 175917.
21 142.17 8.99 2151.2 189582. 2002.1 176377.
22 142.39 9.02 2153.1 189771. 2004.5 176641.
23 142.58 9.05 2154.7 189927. 2006.4 176830.
24 142.78 9.08 2156.2 190066. 2008.0 176986.
25 142.96 9.12 2157.6 190196. 2009.5 177125.
26 143.15 9.15 2158.9 190319. 2010.9 177255.
27 143.33 9.18 2160.2 190440. 2012.2 177378.
28 143.52 9.21 2161.6 190564. 2013.6 177499.
29 143.71 9.24 2163.0 190699. 2014.9 177623.
30 143.90 9.27 2164.8 190863. 2016.4 177758.
31 144.10 9.31 2167.1 191090. 2018.1 177922.
32 144.32 9.34 2170.8 191460. 2020.5 178149.
REB 144.58 9.37 146.65 12941.0 2024.2 178519.
- HEATER/COOLERS -
1 - Condenser -11329.767 Mcal/h
2 - Reboiler 11216.857 Mcal/h
- PRODUCT STREAMS -
Stream 'S2 ', LIQUID draw-off from condenser
Flow rate, molar 1279.248 kmol/h - weight 70539.538 kg/h
Stream 'S3 ', LIQUID draw-off from reboiler
Flow rate, molar 146.652 kmol/h - weight 12940.954 kg/h
- FEED STREAMS -
Stream 'S1 ', Feed on tray 14
Flow rate, molar 1425.900 kmol/h - weight 83480.486 kg/h
- REFLUX DATA -
Molar rate 1023.397 kmol/h Weight rate 56431.528 kg/h
Ratios with respect to OVERHEAD product(s)
Molar 0.8000 Weight 0.8000
Ratios with respect to TOTAL FEED
Molar 0.7177 Weight 0.6760
2) * PRODUCT STREAMS *
* Stream 'S2 ', LIQUID draw-off from condenser
- Temperature 56.169 °C - Pressure 8.0000 bar
* No * Component * -Molar Rate- -Mol Fr- - Weight Rate- -Wt Fr-
1 PROPENE 52.895 0.041348 2225.819 0.031554
2 PROPANE 40.035 0.031296 1765.554 0.025029
3 ISOBUTANE 443.703 0.346847 25788.033 0.365583
4 ISOBUTENE 3.969 0.003103 222.691 0.003157
5 1-BUTENE 155.940 0.121900 8749.353 0.124035
6 1,3-BUTADIENE 2.731 0.002135 147.704 0.002094
7 BUTANE 196.760 0.153809 11435.717 0.162118
8 TRANS-2-BUTENE 181.687 0.142027 10194.103 0.144516
9 CIS-2-BUTENE 121.548 0.095015 6819.822 0.096681
10 METHANOL 64.444 0.050376 2064.777 0.029271
11 ISOPENTANE 15.001 0.011726 1082.303 0.015343
12 METHYL TERTBUTYL ETH 0.290 0.000227 25.606 0.000363
13 TERT-BUTYL ALCOHOL 0.244 0.000190 18.058 0.000256
14 TERT-AMYL ETHER 0.000 0.000000 0.000 0.000000
---------------------------------------------------------------------------------
* TOTAL * 1279.248 1.000000 70539.538 1.000000
kmol/h kg/h
* Stream 'S3 ', LIQUID draw-off from reboiler
- Temperature 144.584 °C - Pressure 9.3700 bar
* No * Component * -Molar Rate- -Mol Fr- - Weight Rate- -Wt Fr-
1 PROPENE 0.000 0.000000 0.000 0.000000
2 PROPANE 0.000 0.000000 0.000 0.000000
3 ISOBUTANE 0.000 0.000000 0.000 0.000000
4 ISOBUTENE 0.000 0.000000 0.000 0.000000
5 1-BUTENE 0.000 0.000000 0.000 0.000000
6 1,3-BUTADIENE 0.000 0.000000 0.000 0.000000
7 BUTANE 0.000 0.000000 0.000 0.000000
8 TRANS-2-BUTENE 0.000 0.000000 0.000 0.000000
9 CIS-2-BUTENE 0.000 0.000000 0.000 0.000000
10 METHANOL 0.000 0.000000 0.000 0.000000
11 ISOPENTANE 0.000 0.000000 0.000 0.000000
12 METHYL TERTBUTYL ETH 145.662 0.993248 12839.944 0.992195
13 TERT-BUTYL ALCOHOL 0.006 0.000040 0.435 0.000034
14 TERT-AMYL ETHER 0.984 0.006712 100.575 0.007772
---------------------------------------------------------------------------------
* TOTAL * 146.652 1.000000 12940.954 1.000000
kmol/h kg/h
<<XPKEYINP_BEG>> LINKEDPFD
<XPSIM> ...generated by XpsimWin v.1.06 ...
*
RUN ID=PROB-07 USER=STAFF PROBLEM='MTBE SEPARATION'
DESC MTBE RECOVERY COLUMN
DESC APPLICATION TEST CASE
DIMENSION INPUT MET PRES=BAR
*
*
System Data
*
*
CHEMCOMP PRLN / C3 / IC4 / IBTE / BUT1 / 13BD / NC4 / BTT2 / BTC2 / +
MEOH / IC5 / MTBE / TBA / TAME
THERMSET UID=SET1
METHODS AL=UNIFAC FV=IDEAL FL=IDEAL HS=IDEAL
*
*
Flowsheet Data
*
*
*
COLUMN UID=C2
PARA TRAY=32 CON REB NITER=20
FEED STR=S1 TRAY=14
DRAWOFF STR=S2 TRAY=0 PHASE=LIQ
DRAWOFF STR=S3 TRAY=33 PHASE=LIQ RATE(VAR)=158.8
PROFILE TRAY=0 LIQ=1100 TEMP=54.5 PRES=8 / TRAY=1 PRES=8.35 / TRAY=33 +
TEMP=149 PRES=9.37
HEAT TRAY=0 VAR
HEAT TRAY=33 VAR
SPEC RATE=0.998 RATIO STR=S3 REFSTR=S1 COMP=MTBE
SPEC RRATIO=0.8
<DISABLE>
SPEC RATE=0.8 RATIO STR=LNET:1 REFSTR=S2
</DISABLE>
PRINT TRACE=PART STREAM=1
*
STREAM=S1 TEMP=71.1 PRES=10.35 RATE=1425.9 NORM XBASIS=M
COMP PRLN:116.61 / C3:88.26 / IC4:978.17 / IBTE:8.75 / BUT1:343.78 / +
13BD:6.02 / NC4:433.77 / BTT2:400.54 / BTC2:267.96 / MEOH:142.07 / +
IC5:33.07 / MTBE:321.76 / TBA:0.55 / TAME:2.17
*
*
END