4 replies to this topic

[cyclop2509]

the assignment concerns a given plant that produces ammonia and methanol from methane air and nitrogen.

the given plant is losing money and should be made profitable by making as many efficient changes as possible. Now ive tried alot of things, but all the changes ive made are either losing money or saving negligible amounts compared to the gross annual lost. is there something great that im not seeing here? a picture of the pfd is attached and a text that explains a bit more about the plant and the kintetics, costs and the assignment as well. If you guys have some tips id be delighted.

 

 

 

 

 

 

 

 Project_Tender_2014_v1.pdf   937.15KB   18 downloads

 

 

 

 

 1422947_10201766309252894_1770823332_n.jpg   85.05KB   4 downloads

[curious_cat]

What have you tried so far? 

 

Sounds like a nice assignment. I'd start by evaluating the existing flowsheet, as given. Which are the highest cost items? Where are you losing most raw materials. etc. 

 

Some features that leap at me are the pressures of the synthesis loop. Use the kinetic expressions provided and play around. My hunch is the reaction conditions / recycle is going to be key. 

 

Heat integration is another obvious cost reduction but a second order effect. 

Edited by curious_cat, 26 November 2013 - 11:50 AM.

[cyclop2509]

basically i tried changing the streams, by playing around, and trying to make more product, which is the hydrogen in the first reactor. ive managed to do so, but because i need a splitter (probably modeled as an absorber), cause the reaction in the second reactor is slowed down by the concentration of hydrogen, and i want to remove it between the two reactors, it gets pretty expansive as well.... i played around with some other reactions according to the kinetics they have, so ill get more wanted product. but havent managed nothing major yet, ill see what more i can do thank you! ill be happy for some more tips!

[curious_cat]

Another way to attack this is to study existing technology in use. See what their operating T P recycle etc. are. That might give you a hint. 

 

If most plants are using a 100 bar pressure and your flowsheet only 10 bar might be worth drilling deeper into. 

[cyclop2509]

i tried to add a recycle stream that recycles the methane and water in the product stream. so more hydrogen will be produced as it is the product for all the other operations. now, i have a problems with converging.... what do i do? cause i spent ages and it wont converge....