Consultation about price setting in TEA

a) Hello, in the process (as in the following picture), 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.
Since the ```MESP``` obtained by the ```following two methods``` is quite different, I am not sure which method is correct.

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)
```

b) In addition, the above two methods also seem to have an impact on the results of global sensitivity analysis (```Spearman results```), and the important factors obtained by the two methods are different (The following figure is an example). In the Spearman results of the first method, the impact of Stream stra's price on MESP is more important, while the second method is not so important. May I ask you which result is correct?

The issue names no file or test. Start by tracing the cellulosic model's TEA calculation and Stream price handling, then compare the two `stra`/`strb` setups and their Spearman results. Done means documenting which setup is correct and explaining the differing sensitivity outcomes.

Written by the indexing model from the issue text.