heavy vibration in sulphur pit vent blower structure

Much more information about the measured vibration amplitude and frequency is needed for a variety of locations on the pit blower and piping.

Has the "rotating engineer" created a report of the measurements he has made, and what the "limits" are, and where the limits came from?

Sounds like you have a resonance problem. Typical problems with sulphur pumps is plate out onto the rotating element and the piping - particularly if the temperature drops at all. I imagine what has happened is that you have plate out (sulphur solidification) in the pipework and that has increased the mass so moving the natural frequency to near the run speed frequency of the pump or maybe even vane pass if running off BEP. I suggest you stop the pump for a minute or two and carry out a quick bump test on the affected pipework and structure to find out if you are seeing a natural frequency near pump speed.

Ron Frend

Hi Ron,
You understandably suggested "to find out if you are seeing a natural frequency near pump speed."
I don't think we know what the predominant vibration frequency(s) are yet.
Or anything else useful, really.

It also Looks like OP has not been back since the original post.

Oh well.