Q&A

Question 16: In your experience, are there documented cases of organic chlorides coming in with certain crudes? If so, what is their impact on hydrotreating units?

In researching this question with our corrosion experts, they identified this as a mature issue that has been well documented in NACE publications and international symposiums. These papers identify multiple cases of organic chlorides coming in with specific crude oils.

Question 24: For a hydrocracker with a debutanizer/stabilizer column, what corrosion issues do refineries experience in the feed and/or overhead systems? What have you done to mitigate the corrosion? What are your key considerations in optimizing these parameters

This answer assumes that the Debutanizer column is the first fractionation column design. In such columns, corrosion of the column bottoms, bottom outlet piping, reboiler tubes, fractionator feed heater tubes and the downstream fractionator is possible due to poor stripping of H2S.

Question 42: What are your best practices to minimize catalyst carry over to the main column on start up?

Catalyst loss events experienced while bringing the FCC online after a shutdown are troublesome as they can add significant cost and delay to the startup. Because the main air blower is run close to design conditions throughout the startup, losses are more frequently observed from the reactor side.

Question 29: How are crudes with high filterable solids crude managed to mitigate their impact on the operation? What levels of solids do you see and how are they measured?

Several major refiners have begun to use a water wash step at the end of the D4807 test to determine the actual non-water-soluble filterable solids. This method is more reflective of actual solids contained in the crude.

Question 83: What is your experience with regenerator cyclone refractory hex steel failure due to oxidation/corrosion? Do you observe a relationship between these failures and feed sulfur content or refractory type?

The other mode of failure can be the erosion of the CFN holding flanges and cone, which could potentially result in leaking flue gas and catalyst to atmosphere. In either case, a shutdown may be needed if expander blade deposits and expander vibration become unmanageable or the CFN boxes kept on eroding.

Question 34: What strategies (operational, technological, logistical) do you consider for slurry streams that will not meet the IMO specifications?

What strategies (operational, technological, logistical) do you consider for slurry streams that will not meet the IMO specifications?

Question 2: What are the operating constraints in co-processing coker naphtha in a ULSD (ultra-low sulfur diesel) and/or a gas oil hydrotreater unit?

There are some constraints relative to processing coker naphtha. I have outlined a few of them on the slide. Key with coker naphtha are the changes in the process chemistry that occur starting, perhaps, with the dilution of the hydrogen partial pressure due to the vaporization of the naphtha.

Question 37: What is the impact of CO (carbon monoxide) and/or CO2 (carbon dioxide) on noble metal catalyst performance?

CO and CO2are poisons for noble metal catalysts, with CO being a very strong poison. Contamination level as low as 50 to 100 ppm can result in significant and permanent loss of activity. CO should be limited to less than 10 ppm. In our experience, units which achieve long cycles (10 years plus) typically have CO levels less than 5 ppm.

Question 6: Do LTOs contain higher concentrations of nitrogen? If so, how has this higher concentration effected gasoline processing units?

The LTOs generally do not contain a higher concentration of nitrogen. LTOs are typically characterized as light, sweet, low-sulfur, low-nitrogen crudes. For example, the Eagle Ford and the Bakken nitrogen typically contains less than 2 ppm. Nonetheless, the gasoline processing units are impacted when refineries process higher percentage of the LTOs because of the crudes.

Question 7: What are your typical precious metal recoveries from reforming catalysts? What factors impact this?

BILL KOSTKA (AXENS NORTH AMERICA)
Reported platinum recoveries from reforming catalyst following commercial utilization have typically ranged between 90 and 100 wt% and have rarely been less than 80 wt%. The magnitude of this range is both frustrating and at least somewhat explainable.

How one

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