Re: [dwsim-users] reactor application - ethyl acetate
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Re: [dwsim-users] reactor application - ethyl acetate
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From: Hector P. <hpe...@gm...> - 2016-04-27 04:07:21
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Hi Daniel, Thanks for sending the file along with the updated build! I actually went through the file and included the reverse reaction by adjusting the Reverse Order exponents (the Aspen Plus video has both forward and reverse reactions). I also dropped the conversion on the Conversion reactor (to~70%) and set the equilibrium constant (for the Equilibrium Reactor) to be k_forward/k_reverse (ratio of rate constants). My numbers are now very close, if not the same as the ASPEN simulation video. One thing I did run into is that the reactor dimensions for the PFR and CSTR in the aspen video create errors in DWSIM. I had to decrease the PFR length because it gave me a warning about the pressure drop being too high. The CSTR volume also had to be decreased because it gave me a mass balance error. Do you know why the aspen dimensions don't work? This could perhaps be a lack of feasibility check on the ASPEN side. Also, what is "Volume Delta (Relative)" on the PFR specs? One other thing I checked was the CSTR duty (compared to the ASPEN video) and found the DWSIM value to be about 6 times lower than the ASPEN value (perhaps something having to do with the smaller volume used in DWSIM?). Thanks once again. I am really liking this simulator. It seems easier to use than aspen. Hector D. Perez On Tue, Apr 26, 2016 at 7:11 PM, Daniel Wagner <dan...@gm...> wrote: > Hi Hector, > > By following the Aspen Plus video I was able to make it work, there is no > reverse reaction. Also, there was a bug in the PFR pressure drop > calculation, you'll have to use an updated build. Download it from this > link and unpack the files in DWSIM's installation directory: > https://sourceforge.net/projects/dwsim/files/DWSIM/DWSIM%203.7/Build5960.rar/download > > Also, I forgot to tell you that, for kinetic reactions, every compound in > the reaction must be present even if in a small amount, i.e. 0.000001. 0 > will give you an error. > > You can also try the updated simulation file, I've added the equilibrium > reactor as well. > > Regards > Daniel > > > 2016-04-26 18:17 GMT-04:00 Hector Perez <hpe...@gm...>: > >> Hi Daniel, >> >> >> >> For kinetic reactions, what are the units on the activation energy? (same >> units as those specified for the molar entropy?). I included the DO and RO >> exponents as well as the base compound and now get a new error on the CSTR: >> “An error occurred during the mass balance calculation. Check reaction >> kinetics data and reactor sizing information as well.” >> >> >> >> The PFR gives me the error: “One or more flash specification values are >> invalid. Please check the associated UO or Material Stream for incorrect >> specifications or miscalculated values. >> >> >> >> Thank you, I really appreciate your assistance. >> >> >> >> Hector D. Perez >> >> >> >> *From: *Daniel Wagner <dan...@gm...> >> *Sent: *Tuesday, April 26, 2016 3:59 PM >> *To: *Hector Perez <hpe...@gm...> >> *Cc: *dws...@li... >> *Subject: *Re: [dwsim-users] reactor application - ethyl acetate >> >> >> >> For the existing reactions, you've missed the compound concentrations' >> direct and reverse order exponents. You also didn't define the base >> compound, which should be the main reactant. >> >> >> >> For the conversion and equilibrium reactors, you must define the >> corresponding reactions. Kinetic reactions only work with the PFR and the >> CSTR. >> >> >> >> 2016-04-26 16:43 GMT-04:00 Hector Perez <hpe...@gm...>: >> >> Hi, >> >> >> >> I am trying to replicate the following ASPEN tutorial to set up the >> liquid reaction for ethyl acetate formation from ethanol and acetic acid >> using different types of reactors: >> >> >> >> https://www.youtube.com/watch?v=_DOdlUDI-kI >> >> >> >> Unfortunately, only the Gibbs reactor yielded any result with a ethyl >> acetate flow that was 12 kmol/hr lower than the ASPEN simulation. The only >> differences I can see is that the ASPEN simulation uses the NRTL-hoc, >> whereas my simulation uses NRTL. >> >> >> >> The conversion reactor had zero conversion and both the PFR and CSTR >> reactors gave the error: "The given key was not present in the dictionary." >> I'm not sure what this means. I tried different thermodynamic models >> besides NRTL with no avail. >> >> >> >> I will send my simulation file attached. >> >> >> >> I would really appreciate any light on the matter. >> >> >> >> Obrigado! >> >> >> >> >> Hector D. Perez >> >> Chemical Engineering Consultant >> >> >> >> >> >> ------------------------------------------------------------------------------ >> Find and fix application performance issues faster with Applications >> Manager >> Applications Manager provides deep performance insights into multiple >> tiers of >> your business applications. It resolves application problems quickly and >> reduces your MTTR. Get your free trial! >> https://ad.doubleclick.net/ddm/clk/302982198;130105516;z >> _______________________________________________ >> Dwsim-users mailing list >> Dws...@li... >> https://lists.sourceforge.net/lists/listinfo/dwsim-users >> >> >> >> >> > > |
