4 replies to this topic

[ny177]

I am simulating a process flow sheet in aspen plus, in which i have 3 feed stream, f1, f2 ,f3 and rgibbs reactor, 

I want to control the flow of f2 and f3 using temperature of rgibbs. the control of flow is as follows 1) start with f2 only when temperature of rgibbs reach to 1000 degree C stop f2 and start f3 until rgibbs temperature reach to 700 degree C. at 700 C start f2 stop f3 until temperature of rgibbs reaches to 1000 C. i want to repeat above steps for 6 iteration.

[Pilesar]

The narrative is difficult for me to follow exactly. Is this steady state or dynamic simulation? Assuming you are using steady state simulation, if I were doing something like this, I would first consider using a different reactor for each scenario with a controller on each. Simulators are a calculation tool and I am not too concerned if my model does not look exactly like the process flow sheet.

[ny177]

Thank you for your reply sorry if I am not able to make my question clear, 

I will try to articulate my question properly properly.

 

1) Rgibbs reactor operating as adiabatic system with 3 feed stream, f1, f2 and f3. 

2) reaction of f1 and f2 is exothermic reaction and reaction of f1 and f2 is endothermic reaction.

3)  f1 is continuous flow but  f2 and f3 are controlled on the basis of temperature of reactor.

4) at the start of simulation  f2 is kept on and f3 is kept off. f1 is always on.

4) In the starting reaction in rgibbs take place between f1 and f2 so due to exothermic nature the temperature of the reactor increases. i want to control the flow of the f2 such         that it cut off when temperature of the reactor goes to 1000 degree C. and at the same time f3 gets turn on.

5) now in the reactor reaction between f1 and f3 take place which is a endothermic reaction due to which temperature of the reactor decreases. I want to control the flow of f3         such that it cut off when temperature of the reactor goes to 700 degree C and at the same time f2 gets turn on.

 

 

hope you understand the problem now. 

 

I want to do steady state simulation Is it possible in steady state simulation? if possible you can tell me how to do in aspen dynamic simulation, I will be grateful. 

[Pilesar]

If you are reaching steady state at each step, then model each step independently in a separate reactor of your model. You can take the outlet of one reactor and feed it to the next to simulate 'steps.' Adjust the feed stream flows to get the temperatures you are targeting. Formulate the questions you want the simulation to answer before you build a model in order to know what must be modeled. Rgibbs reactors give a final steady-state result. If your process is not reaching steady state, then you may need to go beyond a steady state model. I recommend you do not attempt a dynamic model in AspenPlus yourself until you have much simulation experience. From your description, I think steady state modeling will be sufficient.

[ny177]

thank you very much for your valuable suggestion @Pilesar