Q&A

(2015) Question 1: When preparing reformer or isomerization vessels for maintenance, do you measure the benzene content of the unit? If so, what methods and locations are monitored and what criteria are used to establish safe levels for work to begin?

The corresponding OSHA regulation 1910.1082 states that the actionable limit for contact with the airborne benzene is 0.5 ppm (parts per million) on an eight-hour time-weighted average (TWA) and 5 ppm for a 15-minute TWA basis. In our facility, we have set our practices to meet that standard.

(2015) Question 2: What are your Best Practices concerning the potential for flash fires in dust collectors and vent drums in a reformer's continuous catalyst regenerator when performing maintenance?

Our main concern here is iron sulfide, which is pyrophoric; meaning that if it is exposed to air, it will self-ignite. There is also hydrocarbon present, so you can get a sustained fire if these lights are off.

(2015) Question 3: How have you developed integrity operating windows (IOWs) to follow American Petroleum Institute (API) Recommended Practice (RP) 584? How are the IOWs maintained and communicated to the operating staff?

Shell and Motiva have been on a journey, for well over 15 years, to educate our operators and provide them with the information necessary to operate their units within the safe operating window. The starting point is to define the unit operating window in terms of temperature, pressure, flows, etc.

(2015) Question 4: How will increased production of naphtha from light tight oil (LTO) and Tier 3 regulations affect the economics for alkylate and reformate production? Are there other options for processing light naphtha streams?

That was a great Keynote address this morning because it talked about the LTOs, and Ramón Loureiro described them in detail. A couple of other options are to take the light naphtha through an isomerization unit and separate out the C5s and C6s to possibly get the benzene precursor removed from the reformer.

(2015) Question 5: Automobile manufacturers are considering requiring the use of higher-octane fuels in order to meet a mandated increase in Corporate Average Fuel Economy (CAFE) standards. What strategies might you employ should demand for higher octane gasolines increase?

Even without potential regulatory increases in minimum octanes, in a low-price gasoline environment, it seems clear that lower prices result in premium gasoline demand.

Question 6: Do LTOs contain higher concentrations of nitrogen? If so, how has this higher concentration effected gasoline processing units?

The LTOs generally do not contain a higher concentration of nitrogen. LTOs are typically characterized as light, sweet, low-sulfur, low-nitrogen crudes. For example, the Eagle Ford and the Bakken nitrogen typically contains less than 2 ppm. Nonetheless, the gasoline processing units are impacted when refineries process higher percentage of the LTOs because of the crudes.

(2015) Question 7: Recognizing that onstream factor is an important component of margin capture, what are the common areas of improvement for each of the gasoline processing units to reduce downtime or increase turnaround interval?

Turnaround time intervals approaching 60 months are becoming more frequent as processes and procedures improve over time. The incentive to extend the turnaround cycle beyond 60 months does nothing more than prolong turnaround times.

(2015) Question 8: How will the recently announced EPA regulations on emissions impact your refinery operation and specific technologies [FCC, hydroprocessing, coking, CDU/VDU (crude distillation unit/vacuum distillation unit), reforming, etc.]?

Refinery risk and technology rules were adopted last week on September 29th. They are expected to have a significant impact on the refining industry. The rules require additional control and monitoring of the emissions from the refineries and the emission reporting that is available to the public and other neighboring communities.

(2015) Question 9: Is there a limit on the amount of time acid can remain stagnant in the reaction section of the alkylation unit? What adverse effects may occur if this limit is exceeded? What issues could arise on a restart from a stagnant-acid condition?

We have found that if we can bring the unit down in a controlled fashion – specifically, if we can clean up the acid by circulating isobutane for a few hours and clear the acid of any reactants, then we can let it sit there for 24 to 36 hours, maybe even 48 hours, without any kind of issue.

(2015) Question 10: Where is carbonyl sulfide found in alkylation units? What effects can it have on the unit, and what are the prevalent management strategies?

Again, I am focusing mostly on sulfuric acid units because that is where I have experience. Carbonyl sulfide (COS) is a noncombustible gas that will follow propane and propylene. So, if you are running all of your FCC olefins, then you will get it into the reactor and into the refrigeration section.

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