A liquid in an industrial process must be heated with a heat exchanger through which steam passes. The exit temperature of the liquid is controlled by adjusting the rate of flow of steam through the heat exchanger with the control valve. An open-loop test was performed in which the steam pressure was suddenly changed from 15 to 18 psi above atmospheric pressure. The exit temperature data are shown in the following table. Use the
Time (min) Temperature ( I)
0........................................156
1........................................157
2........................................159
3........................................162
4........................................167
5........................................172
6........................................175
7........................................179
8........................................181
9........................................182
10.......................................183
11.......................................184
12.......................................184