1 Exercise 3 From Fujio Kida, JGC Co. All cases –Write on where throughput manipulator (TPM) is located –Is the system consistent? If “yes”, is it local-consistent? If “no” propose a fix You should use the “consistency rules” (mass balance regulation) to justify your answers For difficult problems, Kida recommends to write down the equations and see if there is any solution, for example, using the Maxima software –See subdirectory Kida-software Six articles on Plantwide process control in “Chemical Engineering” (Tokyo) (In Japanese)

2 5. OK? Note: CV here means ”control valve” (so it is actually the MV).

3 6. OK? Assumption for pumps: Flow (W1) is not fixed but depends on pressure difference (P2-P1)

4 8. OK?

5 9. OK? Where is production set?

6 10. OK? Where is production set?

7 11. OK? Where is production set?

8 13. OK? (Where is production set?

9 16. OK?

OK? Cooling of side stream from distillation column (“liquid pumparound”). Liquid is send back again to same place so behaves as closed system.

OK?

OK? How would you reconfigure if you want max. production and “Acid Gas” is bottleneck?

OK?

EXTRA Consistent? Note: CV here means ”control valve” (so it is actually the MV).

OK?

OK?

17 (Case-A) P8 by CV9: (as shown in flowsheet) –(A-1) Is it consistent? –(A-2) How can P5 be controlled without becoming inconsistent? (By which CVi?) –(A-3) Is it possible to implement an additional Flow Controller (FC) on W2, W3 or WR? and which valve (CV) can be employed without becoming inconsistent ? –(A-4) How can P4 be controlled without becoming inconsistent? (Case-B) P8 by CV8: (instead of by CV9, see Fig. 24B): Same questions! 24. OK? See next pages for identical problem, but with gas. Note: CV here means ”control valve” (so it is actually the MV). Assume a fixed pump power (or compressor power) Justify all your answers. Kida has a price for the best solution

18 24A

19 24B