Hi all,
I'm currently facing a problem in simulating heterogeneous reactor with user-defined reaction kinetic expression. The reactor converts NO, CO, and H2O into NH3 and N2, hence it has two reactions (namely NTA_NH3 and NTA_N2, respectively). My intention is to parametrize the dimension and inlet flow rate of the reactor. Disclaimer: the pressure was expressed in kPa, hence it was divided by 1000.
As seen in the attached .fsd file, the simulation for the particular base case worked just fine. However, the parametrization didn't work at all. The main error is "NTA_N2: negative base in power", so I suppose there is something wrong with the rate expression of N2 formation, which I cannot find. What does this error message mean? And does anybody have an idea to solve this problem?
Thanks in advance.
Problem in simulating Heterogeneous Reactor
Moderator: jasper
-
- Posts: 7
- Joined: 14 October 2020, 13:49
Problem in simulating Heterogeneous Reactor
- Attachments
-
- rx_NO_CO_H2O_PtRutile_adiab_T_F_dimPar1_rct010_a.fsd
- (112.58 KiB) Downloaded 2399 times
Re: Problem in simulating Heterogeneous Reactor
If you apply the two conditions of the failed item to the actual case, 0.275 m diameter and 5.25 mol/s flow rate, you will see that the unit fails with the same message. At this point you can look at the profiles (appended), and you see that the Nitric oxide runs out. However your reaction rates do not appear to become zero at this point (there are additive terms in there, is that intended?); check your reaction. If this is as intended, you could perhaps attempt to continue using
instead of
Code: Select all
max(0,X("Nitric oxide"))
Code: Select all
X("Nitric oxide")
Code: Select all
Position Nitric oxide flow Carbon monoxide flow Water flow Ammonia flow Nitrogen flow Carbon dioxide flow Temperature Pressure Total flow Density Viscosity Superficial velocity r[NTA_N2] r[NTA_NH3] Enthalpy
m mol/s mol/s mol/s mol/s mol/s mol/s K Pa mol/s mol/m³ Pa s m/s mol/s/kg.cat mol/s/kg.cat J/mol
0 0.0315 0.07875 0.04725 0 0 0 573 101300 5.24475 21.2597406681 3.72339279547e-05 4.1534746098 1.51923088213e-06 2.45798132647e-06 5797.19704863
0.02 0.0314684768101 0.0786857971077 0.0472173211454 2.17861856654e-05 4.86829018705e-06 6.42028923302e-05 572.901776744 101055.446875 5.24471245243 21.2120617904 3.72292681529e-05 4.16278067589 2.617402184e-06 7.27520565017e-06 5795.15384713
0.04 0.0313881438379 0.0785099185946 0.0471217762917 8.54829838651e-05 1.31862053698e-05 0.000240081405371 572.894717242 100810.340371 5.24460858932 21.1608811339 3.72288381636e-05 4.17276632742 4.47478777906e-06 2.1158920085e-05 5795.08651377
0.06 0.0311986690584 0.078076769068 0.0468781043813 0.000247931869683 2.6698443058e-05 0.000673230931961 573.092169908 100564.60791 5.24435140375 21.1020316055 3.72378930055e-05 4.18419817914 6.878840028e-06 4.94907340768e-05 5799.45521996
0.08 0.0308400639976 0.0772371625965 0.0463970995265 0.000568600624866 4.56674568847e-05 0.00151283740351 573.607194287 100318.13729 5.24385143161 21.031412762 3.72616656489e-05 4.19784755191 9.1920829151e-06 8.67062037532e-05 5810.71711766
0.1 0.0302958807129 0.075948319757 0.0456524338486 0.00106504236911 6.95397578678e-05 0.002801680243 574.470622449 100070.786667 5.24308289669 20.9480190231 3.73015648926e-05 4.21394143531 1.10759489055e-05 0.000122282799272 5829.54685824
0.12 0.0295879433172 0.0742624838546 0.0446745322721 0.00171697573015 9.7542542677e-05 0.00448751614536 575.640911827 99822.415836 5.24207699386 20.8535356336 3.73556363302e-05 4.23222187801 1.25592744632e-05 0.000151338321042 5855.04906161
0.14 0.0287504905347 0.0722628137134 0.0435123146288 0.00249178739753 0.000128863171341 0.00648718628664 577.053108422 99572.9072348 5.24088345573 20.7504928509 3.74208400779e-05 4.25226984724 1.37610137095e-05 0.000173562760882 5885.819923
0.16 0.0278156127511 0.0700275548623 0.0422119337681 0.00335870804027 0.000162841690052 0.00872244513774 578.646355922 99322.1663903 5.23954909625 20.6412345649 3.7494331265e-05 4.27368959986 1.47781260737e-05 0.000190064985064 5920.54347323
0.18 0.0268096890771 0.0676213614563 0.0408116640772 0.0042922211812 0.000199046946343 0.0111286385437 580.370598932 99070.1169411 5.23811262128 20.5276695066 3.75737725603e-05 4.29615474099 1.56737455969e-05 0.000202038085987 5958.13675703
0.2 0.0257517214182 0.06509111096 0.0393393812361 0.00527374307403 0.000237269830354 0.01365888904 582.189760014 98816.7057653 5.23660211556 20.411166972 3.76574801538e-05 4.31943031861 1.64882394969e-05 0.000210460155476 5997.8190792
0.22 0.0246570377025 0.0624746576195 0.0378176116082 0.00628825615825 0.000277355146798 0.0162753423805 584.074742402 98561.8906104 5.23504026062 20.2928138248 3.77440991706e-05 4.34332658233 1.72457814668e-05 0.000216048641368 6038.96023915
0.24 0.0235379583795 0.0598024563219 0.0362644896334 0.00732367080806 0.000319187483489 0.0189475436781 586.002170214 98305.6391981 5.2334453063 20.1734662138 3.78325444217e-05 4.36769089511 1.79609068385e-05 0.000219332522888 6081.05333586
0.26 0.0224047088757 0.0570997976593 0.034695080475 0.00836994358049 0.000362675849014 0.0216502023407 587.952657523 98047.9269293 5.23183240878 20.053816187 3.79219195981e-05 4.3923963787 1.86419683188e-05 0.000220708656823 6123.67728689
0.28 0.0212657956997 0.0543877214379 0.0331219174299 0.00941871894398 0.00040774475526 0.0243622785621 589.910098648 97788.7365681 5.23021417683 19.9344216926 3.80114836414e-05 4.41733730926 1.92933359895e-05 0.000220483900911 6166.48155348
0.3 0.0201283546141 0.0516838621046 0.031555499182 0.0104629977758 0.000454325882175 0.0270661378954 591.861006406 97528.0568094 5.22860117745 19.815733801 3.81006194418e-05 4.44242482988 1.99166402743e-05 0.000218902933749 6209.17189123
0.32 0.0189984016153 0.049003061902 0.0300046519777 0.0114968959119 0.000502353313636 0.029746938098 593.794035272 97265.8814402 5.22700230282 19.6981168429 3.8188811168e-05 4.46758385831 2.05115147887e-05 0.000216166913118 6251.5001042
0.34 0.0178812643764 0.0463584248601 0.0284771521743 0.012515229114 0.000551755332152 0.0323915751399 595.699162515 97002.208114 5.225425401 19.5818788747 3.82756061594e-05 4.49274762319 2.10758966699e-05 0.000212446766403 6293.24629168
0.36 0.0167812377642 0.043760470313 0.0269792242391 0.0135138477374 0.000602459326657 0.034989529687 597.568340623 96737.0388748 5.22387676907 19.467253053 3.83606440873e-05 4.51786219741 2.16065783226e-05 0.000207890360279 6334.23323177
0.38 0.015702075606 0.0412183304362 0.0255162465204 0.0144891662165 0.000654381166224 0.0375316695638 599.394562457 96470.3782909 5.22236186951 19.3544308808 3.84436137203e-05 4.5428802328 2.20991172587e-05 0.000202628734205 6374.30606826
0.4 0.0146470715759 0.0387399455438 0.0240928656581 0.0154380867913 0.000707422893861 0.0400100544562 601.171708509 96202.2334044 5.22088544692 19.2435690496 3.85242455596e-05 4.56775995425 2.25479058412e-05 0.000196780142551 6413.32905451
0.42 0.0136189500854 0.0363317929989 0.0227128346037 0.0163581074943 0.00076147328758 0.0424182070011 602.894753129 95932.6137362 5.21945136547 19.1347845608 3.86023208136e-05 4.59246662976 2.29462751577e-05 0.000190451471988 6451.19015672
0.44 0.0126200260521 0.0339992737812 0.0213792394194 0.0172471709505 0.000816403576127 0.0447507262188 604.559461032 95661.5306954 5.21806284 19.0281660158 3.86776572389e-05 4.61697054578 2.32863969803e-05 0.000183740029014 6487.7944909
0.46 0.0116522405212 0.0317467916307 0.0200945427998 0.0181036353636 0.000872064135037 0.0470032083693 606.16231954 95388.9972914 5.21672248282 18.9237770178 3.87501057655e-05 4.6412465861 2.35592227711e-05 0.000176734157751 6523.06290981
0.48 0.010717170734 0.0295777705141 0.0188605914704 0.0189262695831 0.00092828191885 0.0491722294859 607.700519322 95115.027893 5.21543231371 18.8216578866 3.88195493563e-05 4.66527414488 2.37544024312e-05 0.000169513185637 6556.93164676
0.5 0.00981605743301 0.0274947213524 0.0176786556096 0.0197142268237 0.000984859949092 0.0512552786476 609.171902923 94839.6382271 5.21419379982 18.721828296 3.88859004441e-05 4.68903680854 2.38601577969e-05 0.000162147230426 6589.35124261
0.52 0.0089499074383 0.0254994759882 0.0165495602402 0.02046695707 0.0010415698233 0.0532505240118 610.574770324 94562.8447539 5.21300799457 18.6242939899 3.89490919499e-05 4.71252105266 2.3863135467e-05 0.00015469725383 6620.28233259
0.54 0.0081195322822 0.0235932747906 0.0154737341986 0.021184174431 0.00109814872083 0.0551567252094 611.907806966 94284.6646648 5.21187558963 18.5290495734 3.90090738953e-05 4.73571576061 2.37482932105e-05 0.000147214630014 6649.6941035
0.56 0.00732561304993 0.0217769145945 0.0144512932348 0.0218658017402 0.00115429468236 0.0569730854055 613.169962303 94005.1157878 5.21079700271 18.4360826234 3.90658078212e-05 4.75861139013 2.34988328668e-05 0.000139740749388 6677.56165719
0.58 0.00656874427211 0.0200508489794 0.0134820963975 0.0225119329651 0.00120966345884 0.0586991510206 614.360367059 93724.2164127 5.20977243709 18.3453764325 3.91192629885e-05 4.78119940826 2.30962396452e-05 0.000132306290056 6703.86421478
0.6 0.00584931371831 0.018414916384 0.012565594356 0.0231229343261 0.00126387805522 0.060335083616 615.478559082 93441.9856816 5.20880172046 18.2569035771 3.91694264878e-05 4.8034738952 2.25203620363e-05 0.000124928702357 6728.5900945
0.62 0.00516820921815 0.0168699747502 0.0117017572223 0.0236988257485 0.00131648459408 0.0618800252498 616.523157229 93158.4426111 5.20788527678 18.1706652094 3.92162435683e-05 4.8254221448 2.1750441811e-05 0.000117617390573 6751.70756753
0.64 0.00452576905797 0.0154154740868 0.0108896967192 0.0242401994173 0.00136701783978 0.0633345259132 617.493830594 92873.607542 5.20702268303 18.0866327792 3.92597062031e-05 4.84703861326 2.07653674647e-05 0.000110361213126 6773.20815448
0.66 0.00392284501885 0.0140519743174 0.0101291209888 0.0247472499042 0.0014149546159 0.0646980256826 618.389298753 92587.5011852 5.20621417053 18.0048070489 3.92997632021e-05 4.86831071988 1.95463486142e-05 0.000103137470509 6793.06262545
0.68 0.00336064455676 0.0127807808621 0.00942012799558 0.0252199118997 0.0014597238492 0.0659692191379 619.207627948 92300.1448726 5.2054604083 17.9252087387 3.93363336181e-05 4.88922086949 1.80805386845e-05 9.59084280872e-05 6811.22749081
0.7 0.00284019980721 0.011602670682 0.00876246256504 0.0256583555201 0.00150072441379 0.067147329318 619.947231536 92011.5609087 5.20476174231 17.8478493037 3.93693516207e-05 4.90975356558 1.63649407241e-05 8.86118955829e-05 6827.66704471
0.72 0.00236324005086 0.0105204994389 0.00815725107828 0.0260618298446 0.00153746712971 0.0682295005611 620.605165088 91721.7734968 5.2041197881 17.7727803066 3.93986903307e-05 4.92988334743 1.4414872374e-05 8.11821141466e-05 6842.31551733
0.74 0.00193163330714 0.00953716419448 0.00760552257762 0.026429648845 0.00156936100136 0.0692128358055 621.178262369 91430.8072561 5.20353616573 17.7000598433 3.94242124035e-05 4.94958256915 1.22736126207e-05 7.35374391946e-05 6855.1024682
0.76 0.00154716947767 0.00865603605974 0.00710885827235 0.0267607583819 0.00159603814766 0.0700939639403 621.663423037 91138.6887127 5.20301282428 17.6297446985 3.94457833308e-05 4.96882388695 1.0018692477e-05 6.56090221323e-05 6865.95864938
0.78 0.00121113295842 0.00788022956115 0.00666908829302 0.0270539383681 0.00161746641418 0.0708697704388 622.0583777 90845.4464726 5.20255162603 17.5618690166 3.9463305729e-05 4.98758598292 7.76314640423e-06 5.73676160518e-05 6874.83274997
0.8 0.000925589991255 0.00721467411381 0.00628907581284 0.0273072800216 0.00163356707104 0.0715353258862 622.359399782 90551.1105098 5.2021555129 17.4965092013 3.94766163648e-05 5.00583640333 5.65935217979e-06 4.89000132029e-05 6881.64145369
0.82 0.000690308979803 0.00666023628956 0.00596991900004 0.0275200512301 0.0016448219725 0.0720897637104 622.566889422 90255.7115708 5.20182510118 17.4336267302 3.94857366069e-05 5.02357318762 3.85147744007e-06 4.04209443833e-05 6886.3919098
0.84 0.000503297079945 0.00621455050737 0.00571124511771 0.027692500485 0.00165210329498 0.0725354494926 622.684423706 89959.2808026 5.20155914598 17.3730969606 3.94908295453e-05 5.04081812943 2.43934325066e-06 3.22942560181e-05 6889.16106507
0.86 0.000359558615509 0.00586816985622 0.00550860293099 0.0278275952761 0.00165642513163 0.0728818301438 622.721187082 89661.8461383 5.20135218195 17.3146422683 3.94923082152e-05 5.05763481991 1.4393439073e-06 2.49067249006e-05 6890.14980247
0.88 0.000252742528597 0.00560842272533 0.00535567188701 0.0279295493054 0.00165885616042 0.0731415772747 622.688890884 89363.4320648 5.20119681988 17.2579195868 3.94906979417e-05 5.07410649812 7.97190993156e-07 1.85888652247e-05 6889.61498061
0.9 0.000175351430273 0.00541895675136 0.00524359701136 0.0280042658892 0.0016601934177 0.0733310432486 622.601494519 89064.056642 5.20108340775 17.2025279848 3.94866236361e-05 5.09033396513 4.18196292266e-07 1.34767170306e-05 6887.86374126
0.92 0.000120639940945 0.00528454889435 0.00516390064368 0.028057396801 0.00166098370648 0.0734654511056 622.471613023 88763.7323427 5.20100292109 17.148108098 3.94806495465e-05 5.10640922575 2.10608582623e-07 9.55350356707e-06 6885.17400582
0.94 8.2152894123e-05 0.00518979793091 0.00510763672706 0.0280949060787 0.00166147259101 0.0735602020691 622.311406116 88462.4650651 5.20094616829 17.0943164177 3.94733190962e-05 5.1224219649 1.0202557342e-07 6.62965996503e-06 6881.81416201
0.96 5.53671967321e-05 0.00512371849235 0.00506834298589 0.0281211019062 0.00166176752598 0.0736262815077 622.129420561 88160.2564086 5.20090657961 17.0409117003 3.94650141027e-05 5.1384360713 4.77440938119e-08 4.51438942546e-06 6877.97297063
0.98 3.60638669888e-05 0.00507599974409 0.00503992756738 0.0281400455185 0.00166194738468 0.0736740002559 621.93362793 87857.1047005 5.20087798434 16.9876705547 3.94560907517e-05 5.15451212987 2.06800629962e-08 2.95398366088e-06 6873.82652725
1 2.22318354157e-05 0.00504157369388 0.00501933354874 0.0281537748643 0.00166199872759 0.0737084263061 621.72785169 87553.0050186 5.20085733898 16.9344844651 3.94467197573e-05 5.1706803666 7.96901659589e-09 1.8213534967e-06 6869.45937848
1.02 1.36502415702e-05 0.0050200693742 0.00500641082292 0.0281623900149 0.00166198194924 0.0737299306258 621.512501087 87247.9518165 5.20084443303 16.8813387302 3.94369193295e-05 5.18694580178 3.02603823101e-09 1.11372643643e-06 6864.88048775
1.04 9.45759380735e-06 0.00500954138055 0.00500007547702 0.0281666135788 0.00166196649116 0.0737404586195 621.289190955 86941.9388815 5.20083811314 16.8281859809 3.94267616213e-05 5.20332273196 1.45483504129e-09 7.65725593975e-07 6860.12545208
1.06 7.18865260163e-06 0.00500389178023 0.00499669481791 0.0281688673515 0.00166197407539 0.0737461082198 621.062583404 86634.9592123 5.2008347249 16.7748968537 3.94164550833e-05 5.21984882354 8.39655764934e-10 5.76627521023e-07 6855.29728619
1.08 4.82368635672e-06 0.00499802405663 0.00499319206056 0.0281712025231 0.00166198897273 0.0737519759434 620.836506143 86327.0036938 5.20083120724 16.7213654639 3.94061708994e-05 5.23655598413 3.77712610848e-10 3.83340811111e-07 6850.48061158
1.1 2.46436356138e-06 0.00499214662135 0.00498967394807 0.0281735479314 0.00166199592996 0.0737578533786 620.610771184 86018.0613332 5.20082768217 16.6675946035 3.9395900643e-05 5.25344593006 9.84920562686e-11 1.94012748174e-07 6845.67129855
1.12 6.42342336405e-07 0.00498759441132 0.00498694375927 0.0281753680573 0.00166199687764 0.0737624055887 620.384371261 85708.1209691 5.20082495104 16.6136089171 3.93855992363e-05 5.27051416033 6.68039482845e-12 5.00711903698e-08 6840.84708742
1.14 -1.71808006266e-08 0.0049859498191 0.00498595869019 0.02817602477 0.00166199828285 0.0737640501809 620.156124375 85397.1722204 0 0 0 0 0 0 0
Re: Problem in simulating Heterogeneous Reactor
Re-checking your expression, it does go to zero in case X[nitric oxide] goes to zero - it is the only term in the numerator.
The negative rate of nitric oxide however is within integration tolerance. Perhaps try the solution with max(0, ... ) to avoid the negative value.
The negative rate of nitric oxide however is within integration tolerance. Perhaps try the solution with max(0, ... ) to avoid the negative value.
-
- Posts: 7
- Joined: 14 October 2020, 13:49
Re: Problem in simulating Heterogeneous Reactor
Thank you for the reply, Jasper. I tried with max(0, X[nitric oxide]) and max(0, X[carbon monoxide]), both being the terms in the numerator, it didn't work (the same negative rate error message). Heck I tried as far as making the entire rate equations with max(0, ...) and it still failed the same way, which is really strange and doesn't make sense.jasper wrote:Re-checking your expression, it does go to zero in case X[nitric oxide] goes to zero - it is the only term in the numerator.
The negative rate of nitric oxide however is within integration tolerance. Perhaps try the solution with max(0, ... ) to avoid the negative value.
I checked the NO value for D = 0.3 m, flow rate 6 mol/s, the value of NO does turn negative and hence the simulation failed to continue (see attached Excel spreadsheet). This is one hell of a weird code bug.
- Attachments
-
- Book2.xlsx
- (11.8 KiB) Downloaded 2399 times
Re: Problem in simulating Heterogeneous Reactor
Works for me if I just change X("Nitric oxide") into max(0,X("Nitric oxide")) in both reaction terms (2x each).
Re: Problem in simulating Heterogeneous Reactor
that in fact makes all runs work:
-
- Posts: 7
- Joined: 14 October 2020, 13:49
Re: Problem in simulating Heterogeneous Reactor
Yeah now it's working. Thanks a lot!jasper wrote:that in fact makes all runs work:
Re: Problem in simulating Heterogeneous Reactor
Glad to hear it.