Q&A

(2016) Question 34: The cycle life of a high-pressure ULSD unit operating for maximum aromatic saturation and liquid yield is limited by aromatics equilibrium at elevated temperatures. What strategies or solutions do you employ to extend operation with maximum liquid yield?

This question is more related to EOR conditions when you have employed all of the operational techniques but wish to further optimize the EOR performance without yield decline. If you are already maximizing H2 pp (partial pressure), achieving full catalyst utilization with state-of-the art reactor internals, and adjusting bed profiles at MOR/EOR (middle-of-run/end-of-run) to remain in region of optimum aromatic saturation, the following example illustrates the benefits of optimizing the nickel-molybdenum catalyst for your application.

(2016) Question 24: How do you manage reactor maldistribution once identified?

Reactor maldistribution is a phenomenon that is typically caused by inadequately designed or installed reactor internals, improperly/unevenly loaded catalyst bed, catalyst migration from an upstream bed, or process fouling. The main problems generated by flow maldistribution are the overuse of part of a catalyst inventory and the formation of hot spots, which can create a process safety risk, as well as limit the performance of the cycle.

(2010) Question 21: Silica uptake on gas oil and diesel hydrotreating units is an increasing problem. In your experience, what is the source of silica in these feeds? Do you have effective ways to manage this silica?

The main source of silicon in Hydrotreaters is polysiloxane compounds (such as polydimethylsiloxane) used to control foaming in delayed coker units. It has also been reported that indigenous silicon is present in some heavy oils.

(2010) Question 22: In your experience, how are ULSD units maximizing catalyst life/ cycle length? Do you use feedstock or catalyst analysis to locate sources of contaminants, especially arsenic?

Many factors impact the cycle length in a ULSD unit, and in order to ensure the longest possible cycle length in such units it is important to: Have an optimal flow distribution and gas mixing using latest generation reactor internals designed for the actual operating conditions. This is very important in order to ensure maximum catalyst utilization with no channeling in the catalyst bed.

(2010) Question 85: What is the typical range that you employ for iron content on FCC equilibrium catalyst? What methods are available to determine how iron is accumulated on the catalyst surface? How does the distribution of iron on the catalyst surface impact the FCC operation, yield structure and emissions?

There are several methods available to quantify iron contamination on catalyst. Scanning Electron Microscopy (SEM) pictures are a valuable means to qualitatively assess iron laydown morphology on the catalyst particle.

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Q&A

(2016) Question 34: The cycle life of a high-pressure ULSD unit operating for maximum aromatic saturation and liquid yield is limited by aromatics equilibrium at elevated temperatures. What strategies or solutions do you employ to extend operation with maximum liquid yield?

(2016) Question 24: How do you manage reactor maldistribution once identified?

(2010) Question 21: Silica uptake on gas oil and diesel hydrotreating units is an increasing problem. In your experience, what is the source of silica in these feeds? Do you have effective ways to manage this silica?

(2010) Question 22: In your experience, how are ULSD units maximizing catalyst life/ cycle length? Do you use feedstock or catalyst analysis to locate sources of contaminants, especially arsenic?