I would strongly recommend not installing the radar gauge on the tank manway containing hot resid and in the presence of nitrogen. The risks are high due to the possiblity of resid ignition on loss of nitrogen flow or intrusion of air. In addition, the nitrogen poses a suffocation risk to workers.
A more prudent path would be to consider installing a gamma level detection device, which can be done without shutting down the feed surge tank or opening it while in service.
Best regards – Mitch Moloney
