Hi
I have a mojonnier type carbocooler with flood type evaporator that has its surge drum just above the carbocooler. I use a Hansen 250psi relief valve on top of the surge drum for protection. In the past 5 months 3 of these valves have failed in the same fashion. They start leaking suddenly and keep open contionuously. Two things statrtle me. First, the pressure of the vessel never exceeds 200 psi, even with a hot sanitation carried out on the evaporator (at 65degC). Second, when we replace the bad relief valve, we find a lot of rust particled stuck between the valve and its seat.
What is the solution? The surge drum seems t be highly corroded. How to clean it? I have heard some suggestions about using water+oil, or white vinegar (I suppose this is acetic acid). Any suggestions? Will the location and orientation of the relief valve have any effect?