Process Control HW 10 Help Session

Kevin SiggardTierra Duffield

10.1

• Assumptions– Pressure drop is negligible (given in problem

statement)– Constant Pressure and Temperature– Flow is incompressible– The density of the air is unaffected by the Chlorine

concentration

10.1

10.1

10.1

10.1

• Would this be acceptable if this were a carbon monoxide leak?– NO• It takes a very short amount of time for an abundant

supply of carbon monoxide to saturate the blood stream• ∴ 1.72 minutes is unacceptable and possibly deadly

11.1

• See Fig. 11.8 for a standard block diagram• The only change that must be made to Fig.

11.8 is to add one more disturbance variable because the problem statement tells us to treat both the feed flow rate and the feed composition xf as disturbance variables

11.1 (Fig. 11.8)

Gm

Km Gc Gv Gp

Gd

Ysp E P UYsp

Ym

Yu Y

Yd

D

11.1 (Fig. 11.8 adapted)D1

Gd1

Gm

Km Gc Gv GpYsp E P UYsp

Ym

Yu Y

Yd2

Gd2D2

Yd1

11.3. P only controller for a stirred-tank heater control system part a)

11.3 part b)

11.3 part b)

11.3 part c)

11.3 part c)

Typo in 11.4

Apparently, there are typos in problem statement. Specifically use

and

11.4 part a)

Gm

Km Gc G_IP Gv GpC’3sp(s) E(s) P’(s)

P’T(s)C’3sp(s)

C’3m (s)

Q’2(s)C’3(s)X2

GdC ‘2 (s)

X1

C’3 (s)

lb solute/ft^3

ma ma ma psiGal/min

lb solute/ft^3ma

lb solute/ft^3

11.4 part b)

11.4 part b)

11.4 part b)

11.4 part b)

11.4 part c)

• The trick for deciding if the PI controller needs to be retuned is determining whether or not the suggested change affects the block transfer function. If the block transfer function changes, then you will need to retune.

11.4 part c)

11.5 part a)

11.5 part b) and c)

11.5 part d) and e)

e) – The system is under damped so it will oscillate.

11.7

11.7

11.7