APC Residue Silo

The Air Pollution Control Residue Silo has over a period of time lost capacity due to a build-up of material around the inside of the cone and partway up the sides, following the November 2008 shutdown it was noted this had become more of a problem, perhaps caused by the silo trace-heating being switched off for many days during the shutdown.

In order to ensure the silo could provide enough capacity during the festive period it was decided to clean the silo, this took place on December xxx .
For the cleaning to be possible an additional access port was required to be installed into the top of the silo (600mm²) this was done by GOL engineers.
A window of 12 hours was allocated for the cleaning to be completed. During this period the plant remained operational the FGT recirculation and filter hoppers were used as a buffer. Additional boiler rapping (cleaning) was undertaken prior to and suspended while the silo cleaning was undertaken.
The silo was emptied as far as possible early on the morning of the clean. A tanker was positioned under the silo discharge for the duration of the cleaning.

The silo cleaning was undertaken by Intech Environmental using a Giro-whip this consists of brass chains (whips) attached to a pneumatically driven motor lowered into the silo on an articulated arm.

The cleaning was undertaken and all equipment returned to service within the allocated time period, the result of the clean was particularly good (see photo below) all reside was removed.