Consultation about price setting in TEA

[zasddsgg]

Hello, in the process, stream stra is the chemical stream needed for the reactor R (stream stra only contains chemical a), stream strb is the stream only contains component a recovered by the recycling section, I did not recycle it back to the reactor R, but only as an outlet stream. When calculating TEA, the following two setting methods get different MPSP (I use the TEA calculation method of cellulosic model), may I ask which setting method is right? Assume that the price of component a is 17, the initial input of stream stra is 500, and the quality difference of component a between stream stra and stream strb is 300, that is, the net consumption of component a is 300.

The first method: Let BioSTEAM automatically subtract the cost of stream strb. The code is as follows:

Stream stra = bst.Stream(‘stra’, a=500, price=17)
Stream strb = bst.Stream(‘strb’, price=17)

The second method: The price of component a in stream stra is set according to the net consumption of a. The code is as follows:

Stream stra = bst.Stream(‘stra’, a=500, price=17*300/500)
Stream strb = bst.Stream(‘strb’, price=0)

[zasddsgg]

Hello, I have added the following picture to illustrate the problem. Since the MESP obtained by the above two methods is quite different, I am not sure which method is correct. Could I trouble you take some time to have a look. Thanks again for your help.

Or does the strb have to be recycled to reactor R (as shown in the following picture) for the calculated MESP to be correct? Is it possible for strb to flow without recirculating back to reactor R as in the two methods a and b above? Is this calculation of the MESP correct?

I tried to recycle stream strb to the reactor R (as shown in the figure below), then the makeup amount of component a was 300 kg/h (obtained by adding specifications), the stra flow rate was still 500 kg/h, and the code of the stream set was as follows. The MESP obtained by this way was completely different from the MESP obtained by the second method above. May I ask you which method of MESP obtained is correct?

Stream makeup= bst.Stream(‘makeup, a=1, price=17) # only contain chemical a
Stream strb = bst.Stream(‘strb’)
Stream stra = bst.Stream(‘stra’)