Once again Murphy has thrown down a challenge. Our sulfur pit offgas eductor flow had been tapering off for a few weeks so we pulled the educotr for an inspection. We had about 1% wear in the eductor measurements, but found the steam jacketed eductor and steam jacketed piping to have a build up of a dark, foreign material. Lab analysis of the material found it to be ~26% Carbon and 12% Sulfur and 12% Iron plus cats and dogs. This is on a 200LTPD sulfur unit that only burns clean acid gas from the amine units. We have had no indication of pit fires in this unit. Does anyone have any idea of a source for such a high level of carbon in a sulfur pit. Granted we are drawing ambient air into the pit for sweeping, but it is hard to imagine enough carbon in the air to foul the eductor. It makes me think maybe we sooted the furnace with some hydrocarbon, but shouldn’t that have laid down in the converter beds rather than in the sulfur pit? As far as I know, we aren’t seeing any increase in pressure drop across the SRU. Any thoughts or prior experiences??