In this process, two chemical streams are mixed together in a reactor vessel. The ensuing chemical reaction is exothermic (heat-producing) and must be cooled by a water cooling system to prevent overheating of the vessel and piping. A temperature transmitter (TT) senses the reaction product temperature and sends a 4-20 mA signal to a temperature indicating controller (TIC). The controller then sends a 4-20 mA control signal to the temperature valve (TV) to throttle cooling water flow:
Suppose something fails in the control valve mechanism to make it incapable of opening further than 80%. From 0% to 80% position, however, the valve responds normally.
Describe in detail the effect this fault will have on the performance of the cooling system.
There will be no effect on the performance of this cooling system, except in circumstances where the controller tries to open the valve further than 80%. In those cases, the process temperature will exceed setpoint.