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(2011) Question 82 What are your preferred process and catalyst options to maximize LCO yield? Among the options, please discuss the ramifications of lowering the riser outlet temperature by 40-50 F on the heat balance, including suggestions on how to best utilize any excess air blower capacity at the lower riser temperature.

One way to increase refinery distillate yield if there is not an O2 or regenerator temperature limit is to increase the upstream distillation efficiency to minimize the amount of 700 F minus boiling point material to the FCC. Reducing lighter material in the VGO reduces the crackability of the feed. The typical results of this are lowering the API gravity and the aniline point while slightly increasing the VGO tail, sulfur and Conradson carbon number.
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(2011) Question 83: What are your recommended practices and categories for benchmarking FCC units? Include as appropriate, process performance, reliability, capital efficiency and operations.

Valero participates in the Solomon survey that benchmarks the refinery process units for energy and reliability. Independent to that commercial survey, we have benchmarked our FCC’s on a yield basis using a constant pricing model, accounting for the feed quality differences. The results of the yield benchmarking are used to identify underperforming assets for potential capital improvements.
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(2011) Question 84: What is the typical flash point for your slurry oil product? Can a flash point of 200 F or higher be achieved with steam stripping the main fractionator bottoms? What are your storage temperature guidelines? What lower explosion limit (LEL) and H2S levels are found in the tank vapor space?

This topic of slurry oil flash point and control has been a recent discussion topic at our FCC units. Collective inputs indicate the range of flash points temperatures are from 140degF to 220degF.
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(2011) Question 85: How often do you clean the FCC slurry exchangers?

For us, as I'm sure for it is for others, minimizing FCC slurry exchanger cleaning has been a continuous improvement effort for quite some time. As a result we have implemented best practices in the areas of slurry circuit and fractionator operations and design. Through these efforts we have some units that only need to clean during cycle ending turnarounds.
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