FOAMSTOP low catalyst impact antifoam reduced silicon carryover from coker by 78%
A refiner was treating their coker with BPR45000 antifoam that was contributing 3,500 lb (1,588 kg) of silicon per year carryover to downstream units. The refiner was experiencing an increase in the silicon content of incoming crudes, resulting in rapid contamination of their downstream catalysts. They agreed to trial FOAMSTOP™ low catalyst impact (LCI) antifoam to address the problem. This patented product contains a proprietary agent that is more thermally stable than conventional silicone oils. A temporary tote injection system was installed to allow feeding of the trial antifoam and provide ease of switching back to the old antifoam if needed.
FOAMSTOP antifoam from Baker Hughes, a GE company (BHGE), was trialed over 32 coke drum cycles to compare to a previous run of 32 cycles using BPR45000 antifoam. Fresh feed and furnace charge rates were similar for each case. The trial run had a slightly higher charge rate, 21.3 over 19.8 MBPD, which contributed to a slightly reduced cycle time of the coker. The amount of silicon added to the drum by the antifoam was reduced by 68%, from 0.95 to 0.30 lb (0.43 to 0.14 kg) of silicon per MBPD.
Samples of coker naphtha were taken during the drum cycle for the base case and the trial case. When using BPR45000 antifoam, the silicon concentration in the naphtha samples was 19 ppm Si. When using FOAMSTOP antifoam, the silicon concentration was 6 ppm, confirming that the contamination of coker naphtha with silicon was lower when using FOAMSTOP LCI antifoam.
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