ALLARD ENGINEERING SERVICES
Bubble Caps: AES has designed a distribution cap for activated carbon adsorption vessels that has superior flow control without the risk of damaging the column walls from impinging carbon. The caps were first installed at Bald Mountain Process Area No. 2 in 1998 as part of an improvement project for the adsorption train. The cascading carbon column hydraulics were analyzed and a more efficient baffle plate was installed including the AES designed bubble cap. The columns were operating around 600 gpm with combined gold/silver loadings of ~150 opt. After installation of the baffle plate the flow-rate increased to 1,270 gpm with average carbon loadings of over 300 opt and a peak loading of 494 opt. Additional recommendations were made to bring the column set to 1,400 gpm.
The original caps were assembled out of PVC pipe fittings. Now the AES bubble cap is injection molded from polypropylene. These caps have recently been installed in both the Relief Canyon ADR and the Quartzite Cascading Columns and are available through AES.