Q&A

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.

(2019) Question 45: What are your options to maximize light cycle oil from the FCCU (e.g. operating conditions, feedstock, recycle, equipment, catalyst, etc.)?  What are the typical unit constraints?  What projects have been considered at your facility to capture the increased value of diesel?

There are multiple ways to maximize light cycle oil from the FCC including reducing conversion, reformulating the fresh catalyst, utilizing additives, and adjusting fractionation.

(2019) Question 46: How often do you perform steam optimization in the FCC reactor? What process response and benefits do you typically see from performing "step tests" to feed nozzle, lift, and stripping steam flow rates?

How often do you perform steam optimization in the FCC reactor? What process response and benefits do you typically see from performing "step tests" to feed nozzle, lift, and stripping steam flow rates?

(2019) Question 47: For units not challenged by standpipe fluidization, are there benefits to reducing fresh catalyst 0-40 um particle content?

There are multiple benefits to reducing fresh catalyst 0–40-micron particle content for FCCs not challenged by fluidization. A significant portion of the 0-40 content cannot be retained in the FCC.

(2019) Question 48: What is your experience with carbon on regenerated catalyst levels in partial burn operations?  How do you confirm an optimal level of carbon to ensure desired product yields?  How do metal amounts or feedstock play a role in controlling carbon on regenerated catalyst?

The optimal level of carbon on regenerated catalyst (CRC) is often a balance between conversion and feed rate. Lowering CRC can be achieved by increasing air rate. In FCCs that are air blower or regenerator temperature limited, this can result in a feed rate reduction or residue processing reduction.

(2019) Question 49: What are your reliable methods to monitor expansion joint temperature?  Are some joints more critical than others?  What temperature range is acceptable?  How do you increase or decrease temperatures if they are out of the desired range?

What are your reliable methods to monitor expansion joint temperature?  Are some joints more critical than others?  What temperature range is acceptable?  How do you increase or decrease temperatures if they are out of the desired range?

(2019) Question 50: What methods or operating parameters do you use to monitor/diagnose FCCU regenerator air and catalyst maldistribution?  What can be done operationally to mitigate air and catalyst maldistribution?  What mechanical changes have been successful at improving air and catalyst distribution?

Localized regenerator afterburn is a common symptom of non-optimal air and/or spent catalyst distribution. Regional CO bed breakthrough will combust and afterburn in the regenerator dilute phase and cyclones indicating a stochiometric imbalance of air and coke. In a partial combustion operation, localized afterburn confirms confined oxygen breakthrough from the bed resulting in CO combustion in the dilute phase and cyclones.

(2019) Question 51: What are some parameters that affect performance and reliability of FCC feed nozzles?  Can you describe any experiences with nozzle erosion inside the riser?  What about an external leak in the nozzle sleeve?

What are some parameters that affect performance and reliability of FCC feed nozzles?  Can you describe any experiences with nozzle erosion inside the riser?  What about an external leak in the nozzle sleeve?

(2019) Question 53: What are some of your industry practices for upgrading gas plant piping to post weld heat treat to manage carbonate cracking risk?  Please comment on methods such as requirement for new piping, systematic replacement of existing piping, risk-based replacement, or inspection based?

What are some of your industry practices for upgrading gas plant piping to post weld heat treat to manage carbonate cracking risk?  Please comment on methods such as requirement for new piping, systematic replacement of existing piping, risk-based replacement, or inspection based?

(2018) Question 9: Are you adding unusual feeds to catalytic condensation or oligomerization units?

Refiners have been pursuing the use of more atypical feeds to their olefin oligomerization units for various reasons. Units have historically operated on FCC LPG cuts, but an interest to process Coker LPGs or even heavier FCC olefins have begun.

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