In our Copper smelter based sulfuric acid plat faces sulphur carryover from furnace and find sulphure deposition in gas cleaning plant,Wet ESP and drying tower,.....However we maintain 4 to 5% oxygen at furnace outlet gas,There is huge sulphur deposition witnessed sometimes which coated over all wet elecrostatic precipitated and performance of the wet ESP are paralised which resulted damaging downstream of the equipments.
Please advice me to overcome this issue.

I was down at Southern Copper Ilo Smelter last year and they were just cleaning up their wet gas cleaning system from a sulphur carryover situation. These incidents can cause unexpected downtime and costs. I seem to remember that they don't have an oxygen analyzer on the off-gas but I am uncertain about that. An oxygen analyzer in that service is difficult to keep on-line and reading accurately.

There may be some comfort in knowing that you are not the only one to have this problem.

If your analyzer is working properly, it may be that there may be channelling in the gas stream so that you are not measuring the true oxygen concentration. Maybe a CFD analysis of your off-gas system may reveal some problem areas and provide recommendations for a better location for your analyzer.

I was thinking if a sulphur analyzer might be useful in this situation, the kind they use in the sulphur recovery industry (Claus plants).

The key is being able to detect when conditions in the furnace deviate to the point where sulphur carryover is likely. You can then adjust the operation of the furnace before sulphur plugs up the wet gas cleaning system.

Douglas