Q&A

(2013) Question 100: What specific changes in yields and product qualities might be expected when processing large percentages of tight oil-derived feeds? What operational changes can be made to address any problems created by these effects?

We are currently running varying degrees of tight oil at the majority or our refineries. At the refineries that are running a larger percentage of tight oil, the largest field impacts we have identified have been the shift to lighter products. At the same time, it insignificantly increased volume gains and significantly decreased slurry yield.

(2010) Question 70: How can you minimize the possibility of ignition and fire in the structured packing of main fractionators after they are opened for maintenance? Do you use chemicals to improve this procedure?

Zyme-flow products have been used in our past FCC turnarounds to mitigate pyrophoric compounds as well as decrease the amount of time to hydrocarbon free the main fractionator and associated pumparound circuits.

(2010) Question 71: For the main column, "tri lines" can be utilized to monitor bottoms level. When other level instruments are being verified or have failed, what are the best operating and safety practices being employed to verify the level? What do refiners use to monitor and control level in the bottom of the main column?

For the main column, "tri lines" can be utilized to monitor bottoms level. When other level instruments are being verified or have failed, what are the best operating and safety practices being employed to verify the level? What do refiners use to monitor and control level in the bottom of the main column?

(2010) Question 72: With advance controls on the FCCU and gas plants, what are refiners doing to train new operators and keep their experienced operators sharp and ready to handle FCCU upsets and emergencies? Are refiners using simulators to help with the training and retraining?

Sunoco employs Dynamic Matrix Control (DMC) on all the FCC gas plants and DMC on reactor and regenerator systems. One FCC has a complete process training simulator, and we are in the process of installing simulators on all of our FCC’s.

(2010) Question 73: What levels of distillate boiling range material do you include in the FCC feeds? Discuss the yield and heat balance implications of varying the feed distillate content. What equipment/technology options do you employ to minimize the distillate levels

There are several examples of how yield data can be used to identify hardware issues in the FCCU. For example, a decrease in cat to oil and/or catalyst circulation (which leads to a decrease in overall conversion and liquid yield) can be the result of a high regenerator dense bed temperature at constant process conditions. Several mechanical/hardware issues can contribute to higher regenerator temperatures.

(2010) Question 74: Please discuss how yield data can be used to identify hardware issues. What hardware issues can you address to fix dry gas and benzene production?

(2010) Question 75: What have refiners done to mitigate or eliminate coke buildup in reactors? How do you monitor and vary feed quality, reactor severity, catalyst formulation and other variables to impact coke formation. How does feed distributor operation and design impact reactor coke buildup?

A lot of coke formation can occur during start-ups and shutdowns and upsets of the unit. During start-up, it is important to make sure that all the reactor internals are hot and at operating temperature before introducing oil. If the temperature is too low, the hydrocarbon will condense and form coke. It is also desirable to initially start-up during the first few hours without resid in the feed so there are less chances of heavy hydrocarbon condensing in cold spots.

(2010) Question 76: How can you tell if spent catalyst stripping is "good"? We don't believe our hydrogen on coke results

From the equation it’s easy to see that inerts can be minimized by reducing catalyst circulation rate or increasing the catalyst density in the standpipe. Reducing the catalyst circulation will linearly reduce the amount of inerts.

(2010) Question 77: How do you minimize the entrainment of inerts from the regenerator which eventually enter the fuel gas system and sulfur recovery units reducing available capacity?

In the Shaw RFCC, we utilize a withdrawal well design that allows the catalyst to deaerate before it enters the RCSP. The withdrawal well achieves a very high catalyst density at a stable flux. It can also help the pressure balance.

(2010) Question 79: Backwash containing catalyst fines collected by main column bottoms hydrocyclones, filters or electrostatic precipitators are normally routed back to the FCC reactor riser. In your experience, how does the recycle of catalyst fines in main column bottoms impact particulate emissions from the FCCU?

The distribution of pumparound duties in the Main Fractionator dictates th amount of LCO recovery from the bottom's product. The primary handle to adjust LCO production is the pumparound duty below the LCO section (slurry pumparound or slurry and HCO pumparounds in towers with an), not the LCO pumparound.

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