Question

a hot stream is cooled by cooling water in a counter current heat exchanger propose a feedback control and sketch a schematic diagram

CONSULT APPENDIX WHERE APPROPRIATE shot stream is cooled by cooling water in a counter current heat exchanger ents as shown in Figure Q1. we, Te2 Heat exchanger Figure Q1. Heat exchanger It is desired to control the exit temperature (Tha) of the hot stream. All flow rates can be measured and manipulated. (a) Propose a feedback control method and sketch the schematic diagram. (5 marks) (b) Suggest a feedforward control method and sketch the schematic diagrarm (5 marks) (c) Construct block diagrams for both of your control configurations (10 marks) (d) Solve the following equation using Laplace Transform. df (t) dr (5 marks) Table Q1. Laplace transforms for various time-domain functions 5() (unit impulse) S(t) (unit step) t (ramp) df (t) sF(s)-f(0) dt -tib s(bs+1) S + (s+b,)(s+b2)

Answer 1

Tuy Cold out a) Cotd un Ta TIC Heat hot in Eachanger not aut TT fed back, cont rol Tun .cold un Heat hot un hot eut exchanger TIC TT ud fauoaid

distubane Pulata proces vauable smtullud nput fentoller fud backs Contoler ontte diuturbamct maripulatad pocuss vaukble contadled fed fawand contaleY

d) flt)- S(4) appy taptace /1.61-M] + 1 2 For g s 2 (1f 1 &S 4 2 fpiy Laplace nvee H)Flt)

fl+ SH) unit stap d t 1 - (+2fP 8 dt Bppy Laplace (558 nvorst 58 FH) = )= harmp Now Laplace oppy dt - Q . (011-(900513 fis) 83 (51f 4&s f (51t 4S2 apply vese FA) T6

News (HJP3 dt afply laplace (+1fp SFIS) FO)= FCS) erse FH