6 replies to this topic

[cyclop2509]

a picture of the pfd and the reaction kinetics have been added to this post.

 

i am trying to make the simulation produce more ammonia. as seen in the figure i have 19000 mol of hydrogen circulating in the stream, and nitrogen can be added from the N2 stream as needed. as seen in the kinetics of the reaction, ammonia in the feed slows down the reaction in a significant way. i tried multiplying the reactors, with cooling/heating in between, and even flashing the streams in between to get rid of the amonnia in the feed streams to the 2nd and above reactors. the feed enters the stream in 15000 pascal and 230 celcius degrees. i get a 85% conversion, but that is only when the feed streams contains 22 times more hydrogen then nitrogen, and the conversion is based on the nitrogen. I also tried having a duty exit stream from the reactor because it is an exothermic reaction, and that doesnt help either. i tried virtually cleaning the recycle stream completely from ammonia, which i think should result in great conversion.. but that doesnt help either..

any tips maybe? cause if 19000 mol of hydrogen are in the streams, alot more ammonia can be produced.

 

the reaction is:

1/2N2 +3/2H2 = NH3

 

the kinetics:

 Screen Shot 2013-12-09 at 1.50.15 PM.png   12.92KB   6 downloads

the pfd:

 Screen Shot 2013-12-09 at 1.45.39 PM.png   113.62KB   4 downloads

[thorium90]

If you like, you can post your hysys file here.

Did you try using another method to calculate your reactor? Like excel?

Edited by thorium90, 09 December 2013 - 08:00 AM.

[curious_cat]

 

 

the feed enters the stream in 15000 pascal and 230 celcius degrees. 

 

15000 Pa? Are you sure? Sounds like a low pressure. 

[cyclop2509]

i used 25000 and 30000 and still not a great increase...

[cyclop2509]

and i have uploaded the file if anyone wants to take a look ill be more than happy to listen to some tips...

 

 444.usc.zip   272.02KB   36 downloads

 

 

as you can see its an entire plans that produces ammonia and methanol from methane and nitrogen

[curious_cat]

i used 25000 and 30000 and still not a great increase...

 

I think you have some severe unit confusion going on. 

 

30000 Pa abs is still below atmospheric pressure. You do realize that, right? 

[cyclop2509]

its kpa.... 250-300bar...