Q&A

(2013) Question 11: What changes have refiners made in metallurgy from design specifications? What recommendations have the licensors incorporated into new specifications based on experience and user feedback? Comment on both HF and sulfuric acid alkylation.

The short answer is that there are not very many deviations from the design metallurgy in HF units. Any changes that have been made are based on observed corrosion rates within the unit.

(2013) Question 12: Gasoline blending is becoming more difficult due to the increases in quality specifications; lower sulfur and benzene, for example. What changes are being made to blending facilities and operations to accommodate these changes? Please discuss tankage allocations, working inventories, online analyzer needs, procedural changes, in-line blending, etc.

Blending has indeed become more difficult with the lower product specifications, but our blend methods have only experienced small evolutionary changes in response to the new specs. Most of the changes involved recertification of established methods to demonstrate compliance with the new standards.

(2013) Question 13: What are the typical causes for failing JFTOT and aviation turbine (AVTUR) specifications?

Assuming the jet fuel is on-spec with regard to other quality parameters, with the exception of perhaps copper strip corrosion and mercaptan sulfur, we have found that instability reaction precursors and catalysts are typically the root causes of JFTOT failures.

(2013) Question 14: What is industry experience of using tri-metal (platinum-rhenium with promoter) catalysts?

Promoted or multi-metallic reformer catalysts have been a topic of research since at least the early 1970s. They have been tried commercially in various forms over the years, all with the objective of improving yields by suppressing the demetallization reactions.

(2013) Question 15: What is the Best Practice process for sampling, handling, and measuring research octane (RONC) and naphthene content in reformer feed and product? Are refiners considering online RONC and/or other property monitoring?

If you have a poor octane result, the Best Practice is to blame the lab. Isn’t that what we do? The reality is that there are at least four key components of a sample system that all need some attention: sample conditioning, container contamination, sample degradation between collection and analysis, and the analysis method.

(2013) Question 57: What problems are associated with processing crude with high solids content? What steps can be taken to reduce or remove these solids from the crude?

High solids crude processing presents some increasing challenges for refineries running conventional crudes, tight oil crudes, and heavy Canadian bitumens. As you can see in the graph, some of the heavy Canadian solids run as high as 300 ptb (pounds per 1000 barrels).

(2013) Question 58: What issues are experienced at the desalter and pre-heat train when recirculating brine at the desalter?

Before answering this question, I want to clarify that the panel has defined ‘recirculating brine’ as brine going back to the freshwater makeup.

(2013) Question 59: How does improper control of desalter washwater and brine affect crude unit overhead pH?

Guidelines around the addition of desalter washwater were historically 3 to 5% on volume based on crude charge. Some years back, with a shift towards heavy Venezuelan and unconventional crudes, the trend pushed up towards the 7 to 10% range or higher.

(2013) Question 60: What has been done to address corrosion problems either inside your desalter or in the brine handling circuit?

Some refiners have used acids in the desalter washwater as a means to assist in emulsion resolution. We always look for other solutions as this practice may present other challenges including operator exposure, corrosion to the desalter internals/water circuit, and additional acid load to the atmospheric tower.

(2013) Question 61: What are some of the potential strategies to mitigate iron carryover from the desalter?

High iron content on desalted crude manifests itself in two main areas. These are inability to make anode-grade coke and as a FCC catalyst poison. The iron can be in many forms. Three of the most common forms of iron we see are iron oxide, which is rust; iron sulfide, which is corrosion; and, siderite, which is essentially crystalline iron carbonate that we are seeing more and more of in certain tight oils.

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