Claus unit incinerators

[RogerH]

Dear all
We have recently started a discussion on ocygen analysers located in incinerators (thermal oxiders) at the tail end of sulphur units(claus).
In this location the licensor have decided that an oxygen analyser in the incinerator is not needed.

From the previous plants I have been at the (other) licensors have installed oxygen analysers in the incinerator flue gas like done in any other fired furnace. I got experience from two other "majors".
I haven't given this much throught and found as a "natural" component in the design. We did always run the oxygen in the 6-8 vol% level in order to be able to take a swing. Particularly when the rich amine flash drum entrained substantial amounts of hydrocarbons and this ended up in the tail end of the claus as fuel (semi-combusted) to the incinerator.

Wonder if any of you out there have any views on this, i.e. if an oxygen analyser is needed or one can do without it. Personally I dont feel really comfortable running an incinerator at a uncontrolled, too low level in this application.

What is the views of others/you?

 

[MLX2000]

Roger,

As far as I am concerned this licensor must be replaced ASAP. In fact, we have added a second O2 analyser in our SRU tail gas incinerator. This incinerator must be shut down if there is no reliable O2 analyser working. This is basic safety. Who wants to run combustion solely on feedforward information

Regards,

MLX2000

 

[JLSeagull]

I don't know that the sulfur incinerator is significantly different than another process incinerator or heater. The operating company can easily justify an oxygen analyzer or other instrumentation that is not required by a licensor. The cost of an oxygen analyzer is around $20k. I assume that the incinerator cost would require several zeros after the $20k. In the event of a heater incident, the remaining costs could be much higher still.

 

[chemicalengineerthai]

1) why licensor say no need;
-Due to that place always last location for monitoring not for control. SRU air requirement alway over size/ & high margin for air flow. especially when run lower S load
- SRU unit always has exessive air/O2 exess by its nature.
-may be SRU design has 1 train spare
-Incinerator will require another huge air to burn the remaining HC substance
-Always damage/short life for online analyser/poor reading, high O&M cost compaare to the benefit

2) What we can do- if for monitoring purpose ( automatic on line analyser can be deleted but the proper flue gas sampling shall be available & test weekly and monitor the trend.

3) I have experience withboth unit which had/ not had on-line analyser, work no proplem, one thing I have is I always do material balance /prediction from feed/unit capacity & maintain air flow to SRU is adequate