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(2017) Question 69: What operational or other changes prompt evaluation and optimization of standpipe aeration? What do you monitor to ensure the standpipes remain fluidized across a range of conditions?

Standpipe aeration is something which has been studied and reported on since the inception of cat cracking. Some standpipes require no attention and may not even have any aeration provisions provided. Others may be so sensitive to changing conditions that adjusting aeration is a daily action. Standpipe design is the most important factor. They tend to be very sensitive to changing direction, such as going from vertical to slanted. 
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(2017) Question 70: Electrostatic precipitator (ESP) fines handling is often complicated by fluidization and mechanical integrity issues. How often do you experience these types of fines handling issues, and what are some of your Best Practices to successfully mitigate these issues? What are your Best Practices for safe fines withdrawal from the ESP?

Electrostatic precipitators (ESPs) represent an effective medium for particulate emissions control and are, therefore, commonly used within the FCC industry, especially in North America. Although ESPs are not designed to capture all of the catalyst particles present in the regenerator flue gas, they usually exhibit sufficient performance to successfully reduce the particulate content in the flue gas below 50 mg/Nm3. As the question suggests, fluidization and mechanical integrity issues can significantly hinder the withdrawal and handling activities of catalyst fines.
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(2017) Question 71: What are your recommended configurations for main fractionator flash zone thermocouples to measure the flash zone temperature under the slurry bed?

It is important to measure the main fractionator flash zone temperature in the proper location such that it provides meaningful information. Temperature indicators (TIs) located below the slurry bed are at risk of coking, subject to maldistribution of vapor entering the tower, and are at a location before the vapors have been de-superheated.
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(2017) Question 72: Current economics drive unit operation to minimum slurry production limits, as defined by physical properties and rundown velocities/flow rates. What are your typical slurry limits, and what are your options to overcome those limits to further reduce slurry?

It is fair to say that past, current, and future economics will almost always call for the minimization of slurry production. As slurry production is minimized, the risk increases to foul exchangers or plug lines due to low velocities. Additionally, as slurry is minimized, the quality of the slurry will degrade, which will also increase the risk of fouling.
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(2017) Question 55: Given the expansion of the Industrial Internet of Things (IIoT), “Big Data”, cloud-based technologies, and advanced analytics, how are you applying these cutting-edge aspects into their work processes and toolkit to optimize FCC yield, reliability, and safety performance?

With the advent of “Big Data” and cloud-based technologies, refiners are now able to harvest mega data in a process environment. Hundreds of thousands of values are being generated every few seconds to measure, monitor, control, and optimize plant operations. The major benefit of “Big Data” is to demystify the different plant data used by various parts of the organization by using with a common set of information that is utilized by all departments. In the modern refinery, the key is transparency in strategy, philosophy, and shared goals.
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(2017) Question 56: 1973 FCC Process Question 13: When an older cat cracker is modified to incorporate riser cracking, has anyone encountered a limitation on the amount of conversion that could be obtained? In order to achieve maximum conversion, has anyone found it necessary to return to using a limited level of bed cracking?

Technip has a process in which a combination of riser cracking and bed cracking is used to maximize conversion. We have found that there are limits to the conversion that can be achieved in traditional riser cracking.
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(2017) Question 57: Advanced (Closed)-Riser Termination Systems have been around since the 1990s. Explain any technology improvements you have seen based on experience and learnings.

The primary goal of a modern riser termination system which considers the close coupling of the primary and secondary separating devices is the reduction of residence time and, thus, the minimization of undesirable thermal cracking reactions. This post-riser cracking usually translates to dry gas yield at the expensive of other, more valuable products.
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(2017) Question 58: What are your Best Practices for reliably measuring level in the bottom of the main fractionator?

The following tables list the demonstrated technologies to reliably measure main column bottoms (MCB) level. Regardless of the technology used, it is important to have redundant level indication. The Best Practice is to employ two level transmitters with a selector switch for MCB level control. For displacers, guided-wave radar, and dP level transmitters, redundant transmitters should be on independent vessel taps. There are benefits to having two different level technologies employed. For point level measurement, at least two points should be measured for high and low levels.
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(2017) Question 73: Gasoline octanes continue to have a high value for many refineries. What fractionation strategies do you apply to increase gasoline octane? What rules of thumb do you apply for estimating changes in octane with gasoline endpoint adjustments?

RVP and endpoint both have a minor effect on gasoline octane. With other operating parameter changes and repeatability of octane results in the lab (+/- 0.5 RON), it is difficult to quantify small changes in octane caused by fractionation changes. Literature suggests that for every 1.5 psi RVP increase, RON will increase 0.3. We have very little data to support the literature, because the octane and RVP value of mixed C4s is much greater as alkylate than on the frontend of FCC gasoline.
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