Vanadium and iron poisoning can have an especially devastating effect on FCC catalyst performance. Vanadium attacks the Y-zeolite in the base catalyst causing permanent destruction and consequent loss in activity and coke selectivity. Whereas iron, at added levels from just +0.3 wt%, forms a glassy/nodular shell on the catalyst surface which seals off the catalyst interior prohibiting hydrocarbon diffusion into and out of the catalyst particle. CAT-AID traps vanadium and iron (and other feed contaminants) thereby protecting the base catalyst from their detrimental effects. In addition, these contaminant metals promote undesired dehydrogenation reactions which when left uncontrolled increase the hydrogen yield and delta coke. CAT-AID traps and passivates vanadium and iron thereby decreasing the hydrogen (relieving wet gas compressor constraints) and delta coke (lowering the regenerator temperature and increased catalyst circulation).
SOx is well known to compete with vanadium for metal trapping sites, rendering most so-called vanadium traps ineffective in the real world. As part of the fundamental design of CAT-AID it’s metals trapping component is protected by sites designed to capture SOx and preserve them for the function they are intended to perform – trapping metals. As a consequence, CAT-AID also acts as a SOx capturing agent. Use of CAT-AID decreases caustic consumption in units running with wet gas scrubbers.
With the use of CAT-AID refiners will experience decreased fresh catalyst addition requirements and often eliminate the need for flushing equilibrium catalyst additions. CAT-AID provides the refiner with a “delta coke credit” that may be used to increased unit severity, feed rate, and/or increase resid processing.