Q&A

These digital transcripts are meant to share information on process safety practices in order to help improve process safety performance and awareness throughout industry. The goal is to capture and share knowledge that could be used by other companies or sites when developing new process safety practices or improving existing ones. The documents being shared have been used by an industry member, but this does not mean it should be used or that it will produce similar results at any other site. Rather, it is an option to consider when implementing or adjusting programs and practices at a site.

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(2019) Question 5: How will Tier 3 rules impact gasoline-producing units at your facility?

ABIGAIL SLATER (HollyFrontier)
The Tier 3 gasoline regulation partially took effect in 2017 and will be fully implemented in 2020. The Tier 3 gasoline regulation has impacted the refining industry in a myriad of ways as refiners reduce sulfur further. These impacts will be similar to most refineries

Question 7: What are your typical precious metal recoveries from reforming catalysts? What factors impact this?

BILL KOSTKA (AXENS NORTH AMERICA)
Reported platinum recoveries from reforming catalyst following commercial utilization have typically ranged between 90 and 100 wt% and have rarely been less than 80 wt%. The magnitude of this range is both frustrating and at least somewhat explainable.

How one

Question 49: In the past year, a sulfuric alkylation unit released a significant amount of sulfur dioxide to atmosphere when light hydrocarbon flowed from the reaction zone through the acid blowdown system and into the spent acid tank. What measures do you recommend for preventing this?

We would recommend ensuring that the acid knockout drum be sized large enough to allow the hydrocarbons to disengage in the drum.

Question 51: Reforming unit stabilizer column top trays and overhead condensers can experience fouling with ammonium chloride salts, which are commonly removed by online water washing of the column overhead. What practices do you employ to reduce the risk of rapid corrosion and the potential failure associated with this fouling and subsequent water washing procedure?

Ammonium chloride salts are a common problem in both naphtha reforming and naphtha hydrotreating units.

Question 60: How do you detect leaks in an isomerization unit's steam charge heater? Have you been able to detect a leak before a significant portion of the catalyst bed was deactivated?

The common problem in these units is deactivation of the catalyst by the ingress of water over the catalyst, because water actually deactivates the catalyst. This is a slide of a typical flow scheme for these units, and kind of shows you the conundrum of designing and operating these units.

Question 61: Have you found that you needed to install a methanator upstream of a chlorided catalyst isomerization unit to remove carbon monoxide (CO) from the feed? What is the source of the CO and how much of a difference has the addition of the methanator made to catalyst life? What is the expected payout for the cost of the methanator?

The problem now comes from the oxygen ingress coming in with makeup hydrogen, with the culprit typically being CO and CO2.

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Q&A

(2019) Question 5: How will Tier 3 rules impact gasoline-producing units at your facility?

Question 7: What are your typical precious metal recoveries from reforming catalysts? What factors impact this?

Question 49: In the past year, a sulfuric alkylation unit released a significant amount of sulfur dioxide to atmosphere when light hydrocarbon flowed from the reaction zone through the acid blowdown system and into the spent acid tank. What measures do you recommend for preventing this?

Question 60: How do you detect leaks in an isomerization unit's steam charge heater? Have you been able to detect a leak before a significant portion of the catalyst bed was deactivated?