Dear all
I think the thermoeconomic analysis of attached paper is not correct...
Can someone please help me? (see pages 293 and 299 as I have highlighted)
Article On thermoeconomic analysis of a single-effect mechanical vap...
water cost before pump: 55.66$/h
water cost after pump: 94.21$/h (????????????????)
Other pumps at this analysis do not increase the cost very more but this pump increase the cost approximately 40$/h
With calculation I find 55.9559 $/h for output:
inlet water cost+electricity cost*pump power+fix rate cost=55.66+0.09*2.81+0.043=55.9559
Regards
https://www.sciencedirect.com/search?qs=paper%27s%20analysis%20about%20thermoeconomic&show=25&sortBy=relevance
Dear Md. Washim Akram
Thanks a lot, but I can search the web
I only want to know the reason of the abnormal increase of the cost at the attached paper
Steffen Schmid
Thanks for your interest in my work!
Th cost reported finally is correct as I have done the same procedure in many other papers. The difference you are getting is because of not considering blow down (rejected brine cost and post treatment chemical cost) . If you add it n the final term you will get exactly the same value. It is not mentioned in the formula but it is obvious that the blow down cost will directly affect the final product cost so it should be added.
Hope you find the answer.
regards
Dear Muhammad Ahmad
Thank you very much for your answer and kindness.
I would be very grateful if you guide me about my two final questions about your paper:
Cost balance equations from the calculated value (Table 8 and 9) have some conflicts. Did you consider any other assumptions?
For example for inlet pump:
C0+WFP*Celect+ZFP=C1
C0=4.6
C1=5.3
So "WFP*Celect+ZFP" must be C1-C0=0.7
but by calculating with the paper data: WFP*Celect+ZFP=3.52*0.09+0.051=0.3678
and 0.3678 is not equal to 0.7?Why?
By calculation other cost balance equations for other instruments, this conflict occurs. Did you consider any other assumption?
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And also the exergy destruction for the compressor is 5.38 (table 4)
According to table 3 actual work of compressor is 623 (Wa=623)
So we can find Ws=Wa-Exdestroyed=623-5.38=617.62kW
And the compressor efficiency is obtained: eta= Ws/Wa=617.62/623=0.99
But the compressor efficiency in the paper is 0.8??
Thank you very much
Regards,
Schmid
Dear Muhammad Ahmad
Addition of the above points, I can't understand why your SEC has a maximum point? Other papers (like attached file for EL-Dessouki) have not reported it until now...
You write this:
For this reason, you write "An increase in SEC occurs because of higher compression ratio required to execute high-temperature operations. After certain temperature, the effect of a decrease in specific volume of the vapors dominates hence reducing the SEC"
But in all of the MVR and MVC papers the effect of specific volume has dominant effect.
( I also test it with EES)
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