Simulation of a Plug Flow Reactor
Moderator: jasper
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arvind.prasad
- Posts: 54
- Joined: 02 December 2012, 14:39
Simulation of a Plug Flow Reactor
In the Plug Flow reactor Edit menu, under packings, and sub section empty bed we have a text box to enter the Wall dimension. I have gone through the help file but am not so sure, if the information to be supplied is the wall diameter or the wall thickness? How will wall thickness affect the calculations? Also, the wall diameter will always be equal to the reactor diameter for an empty bed. This information is already supplied in the edit> reactor > Reactor Diameter text box.
Re: Simulation of a Plug Flow Reactor
The label in front of the edit field is a bit too short and truncates the second word. I corrected the layout for the next update. The word is "wall roughness". It is parameter 'e' in the Colebrook equation:
http://cocosimulator.org/index_help.php ... US/pfr.htm
http://cocosimulator.org/index_help.php ... US/pfr.htm
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arvind.prasad
- Posts: 54
- Joined: 02 December 2012, 14:39
Re: Simulation of a Plug Flow Reactor
Dear Jasper,
The attached flowsheet is simulation of PFR for methanol synthesis from CO,CO2 and H2O. The wall heat transfer coefficient and tube heat transfer coefficient have been set to zero. On running the simulation, it is found that the enthalpyF balance is not zero. Can you explain this? I guess it should be zero.
The attached flowsheet is simulation of PFR for methanol synthesis from CO,CO2 and H2O. The wall heat transfer coefficient and tube heat transfer coefficient have been set to zero. On running the simulation, it is found that the enthalpyF balance is not zero. Can you explain this? I guess it should be zero.
- Attachments
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- methanol_yusup.fsd
- (61.91 KiB) Downloaded 1509 times
Re: Simulation of a Plug Flow Reactor
Thank you for reporting that. For the heat balance, the inert component flow was not taken into account for the d xi / dl term.
The issue is fixed now - fix is available via CUP. In your case it makes a big difference on the enthalpy balance.
The issue is fixed now - fix is available via CUP. In your case it makes a big difference on the enthalpy balance.
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arvind.prasad
- Posts: 54
- Joined: 02 December 2012, 14:39
Re: Simulation of a Plug Flow Reactor
Thanks for the update. Now it is working fine.
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arvind.prasad
- Posts: 54
- Joined: 02 December 2012, 14:39
Re: Simulation of a Plug Flow Reactor
Please find the attached flowsheet. I have connected the energy stream to the PFR, and selected tube heat duty option. The energy stream shows incorrect value of the heat to be removed from the reactor. Also the heat balance of the reactor shows that the reactor is working adiabatically.
- Attachments
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- methanol_yusup.fsd
- (64.65 KiB) Downloaded 1542 times
Re: Simulation of a Plug Flow Reactor
The answer looks correct to me.
Total enthalpyF in:
-5.93459e+08 W on feed.
Total enthalpyF out:
-6.24261e+08 W on product + 30.801896 MW on tube duty energy stream 12, = -5.93459e+08 W
The same 30.8 MW tube duty is reported in the last run report, and is taken into account in the energy balance when double clicking the unit.
Below is a table doing a first order integration of the heat transfer to the tubes using the temperature profile along the length (see Profiles report). Works out ok.
Total enthalpyF in:
-5.93459e+08 W on feed.
Total enthalpyF out:
-6.24261e+08 W on product + 30.801896 MW on tube duty energy stream 12, = -5.93459e+08 W
The same 30.8 MW tube duty is reported in the last run report, and is taken into account in the energy balance when double clicking the unit.
Below is a table doing a first order integration of the heat transfer to the tubes using the temperature profile along the length (see Profiles report). Works out ok.
Code: Select all
K 796 W/m2/K
T out 523.15 K
nTube 4801
dTube 0.0445 m
A tube 671.1839917 m2/m
Position Temperature dT dT(av) dH
m K K K W
0 498.15 -25
0.0726 500.8425576 -22.30744239 -23.65372119 -917467.6324
0.1452 503.328647 -19.82135296 -21.06439768 -817034.3644
0.2178 505.6288988 -17.52110117 -18.67122706 -724209.3684
0.2904 507.7616042 -15.38839582 -16.45474849 -638237.807
0.363 509.7429874 -13.40701255 -14.39770419 -558450.2948
0.4356 511.5874086 -11.5625914 -12.48480198 -484253.6875
0.5082 513.3075284 -9.842471581 -10.70253149 -415123.9522
0.5808 514.91464 -8.235360014 -9.038915797 -350596.5344
0.6534 516.418799 -6.731200996 -7.483280505 -290257.4014
0.726 517.8289632 -5.321036831 -6.026118914 -233737.8126
0.7986 519.1530708 -3.996929227 -4.658983029 -180710.0918
0.8712 520.3981953 -2.751804707 -3.374366967 -130883.1049
0.9438 521.5706226 -1.579377384 -2.165591045 -83997.76394
1.0164 522.6760135 -0.473986485 -1.026681934 -39822.37872
1.089 523.7192098 0.569209844 0.04761168 1846.735848
1.1616 524.7047913 1.55479127 1.062000557 41192.29818
1.2342 525.6364139 2.48641385 2.02060256 78374.02967
1.3068 526.51771 3.36770999 2.92706192 113533.2808
1.3794 527.3515812 4.201581158 3.784645574 146796.7676
1.452 528.1408239 4.990823929 4.596202544 178274.9966
1.5246 528.8879212 5.737921158 5.364372544 208070.3554
1.5972 529.5950348 6.445034782 6.09147797 236272.924
1.6698 530.2641369 7.114136869 6.779585826 262962.8761
1.7424 530.8969618 7.746961806 7.430549338 288212.0936
1.815 531.4949759 8.344975911 8.045968859 312082.6502
1.8876 532.0595278 8.909527765 8.627251838 334629.1373
1.9602 532.5917685 9.441768465 9.175648115 355900.0329
2.0328 533.0927237 9.942723741 9.692246103 375937.5538
2.1054 533.5633534 10.41335342 10.17803858 394780.2074
2.178 534.0045038 10.85450379 10.63392861 412463.0211
2.2506 534.4169621 11.26696208 11.06073294 429017.6746
2.3232 534.8014865 11.6514865 11.45922429 444474.1397
2.3958 535.15873 12.00872995 11.83010822 458859.7834
2.4684 535.489366 12.33936597 12.17404796 472200.3303
2.541 535.7939918 12.64399175 12.49167886 484520.4244
2.6136 536.0732089 12.92320887 12.78360031 495843.3143
2.6862 536.3276119 13.17761188 13.05041038 506192.1975
2.7588 536.5577931 13.40779308 13.29270248 515590.0914
2.8314 536.7643613 13.61436132 13.5110772 524060.2908
2.904 536.9479503 13.79795027 13.7061558 531626.893
2.9766 537.1092074 13.95920738 13.87857882 538314.7434
3.0492 537.248808 14.09880801 14.02900769 544149.4963
3.1218 537.3674482 14.21744819 14.1581281 549157.7481
3.1944 537.4658386 14.31583858 14.26664338 553366.7798
3.267 537.5447417 14.39474175 14.35529017 556805.1628
3.3396 537.6049326 14.45493264 14.4248372 559502.715
3.4122 537.6471754 14.49717536 14.476054 561489.2845
3.4848 537.6723091 14.52230907 14.50974221 562795.9645
3.5574 537.6811827 14.53118266 14.52674586 563455.4929
3.63 537.6745791 14.52457906 14.52788086 563499.5164
3.7026 537.653376 14.503376 14.51397753 562960.2415
3.7752 537.6184631 14.46846308 14.48591954 561871.9435
3.8478 537.5706712 14.42067122 14.44456715 560267.9896
3.9204 537.5108079 14.36080785 14.39073954 558180.1536
3.993 537.4397843 14.28978434 14.3252961 555641.7692
4.0656 537.3584611 14.20846107 14.24912271 552687.1973
4.1382 537.2675313 14.11753125 14.16299616 549346.5679
4.2108 537.1678809 14.01788094 14.0677061 545650.5088
4.2834 537.0603255 13.91032551 13.96410323 541632.0172
4.356 536.9455334 13.79553339 13.85292945 537319.8695
4.4286 536.8242391 13.67423909 13.73488624 532741.2739
4.5012 536.6971845 13.54718448 13.61071179 527924.8628
4.5738 536.5650238 13.41502379 13.48110413 522897.7119
4.6464 536.4283304 13.27833038 13.34667708 517683.6288
4.719 536.2877496 13.13774962 13.20804 512306.2493
4.7916 536.1438602 12.99386016 13.06580489 506789.3115
4.8642 535.9971414 12.84714142 12.92050079 501153.3352
4.9368 535.848117 12.69811698 12.7726292 495417.7727
5.0094 535.6972536 12.54725359 12.62268528 489601.8299
5.082 535.5449776 12.39497755 12.47111557 483722.8265
5.1546 535.3916845 12.24168454 12.31833104 477796.7037
5.2272 535.2377412 12.08774115 12.16471284 471838.2448
5.2998 535.0834857 11.93348567 12.01061341 465861.1201
5.3724 534.9292412 11.77924123 11.85636345 459878.1568
5.445 534.7752757 11.62527575 11.70225849 453900.8176
5.5176 534.6218343 11.47183435 11.54855505 447939.0523
5.5902 534.4691835 11.31918352 11.39550893 442002.7832
5.6628 534.3175117 11.16751175 11.24334763 436100.8337
5.7354 534.1669924 11.01699241 11.09225208 430240.2216
5.808 534.0178057 10.86780573 10.94239907 424427.8049
5.8806 533.8701112 10.7201112 10.79395847 418670.1718
5.9532 533.7240141 10.57401413 10.64706267 412972.4577
6.0258 533.5796206 10.42962058 10.50181735 407338.7618
6.0984 533.4370646 10.2870646 10.35834259 401773.7409
6.171 533.2964001 10.14640014 10.21673237 396281.041
6.2436 533.1576831 10.00768306 10.0770416 390862.7916
6.3162 533.0210022 9.871002183 9.93934262 385521.7987
6.3888 532.886392 9.736391986 9.803697085 380260.4537
6.4614 532.7538731 9.603873127 9.670132557 375079.8256
6.534 532.6234787 9.473478676 9.538675902 369980.9566
6.6066 532.4952439 9.345243934 9.409361305 364965.1726
6.6792 532.3691596 9.219159581 9.282201757 360032.9775
6.7518 532.2452234 9.095223442 9.157191512 355184.1482
6.8244 532.123475 8.973475044 9.034349243 350419.4093
6.897 532.0038844 8.85388438 8.913679712 345738.9454
6.9696 531.8864325 8.736432534 8.795158457 341141.8076
7.0422 531.7710912 8.621091233 8.678761884 336627.0809
7.1148 531.6578225 8.507822462 8.564456848 332193.4795
7.1874 531.5466666 8.396666587 8.452244525 327841.0491
7.26 531.4375735 8.28757351 8.342120049 323569.601
total 30793707.28
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arvind.prasad
- Posts: 54
- Joined: 02 December 2012, 14:39
Re: Simulation of a Plug Flow Reactor
Thanks for the clarification.
Regards
Regards