| American Fuel & Petrochemical Manufacturers

Question 77 What is your experience with cooling water exchangers in an HF alkylation unit? How long do you go between cleanings? Do you have a special water treatment program for cooling towers dedicated to the alkylation unit?

KAISER (Delek Refining Ltd.) In my experience, the cooling water exchangers in an HF alkylation unit are really no more problematic than any other exchanger in the refinery when you’re looking at the waterside only. If you have an exchanger in the HF alkylation unit that suffers from low flow or it’s at the end of a header, trapped scale, and there are certainly critical exchangers inside the alkylation unit that you want to keep clean, it’s really no different if it’s in the alkylation unit or in some other unit in the refinery. You’re going to have water problems and that’s going to generate issues for you.

Question 76 The regeneration of feed dryers/sulfur guard beds on butane isomerization units generates a butane slop stream. Will processing this butane slop stream in an HF or sulfuric acid alkylation unit cause any problems? If so, what else may be done with this slop stream?

QUINTANA (Valero Energy Corporation) The spent Isom regenerant will contain butanes that are attractive to recover. They can come from generally any of three sources: either the treated normal butane feed downstream of the on-stream dryer, the fractionated isobutene from the Deisobutanizer fractionator overhead, or the isomerate product is used as the regenerant source. The spent regenerant also contains all of the sulfur and oxygenate impurities that were previously accumulated on the sieve; and after the spent regenerant coalescer, it will also be saturated with water.

Question 1: What is your best practice for safe and quick decontamination of solid media beds?

Safe and quick decontamination of solid media beds requires a good working knowledge of the unit, the bed material, and the nature of the contamination.

Question 75: The butane stream from a catalytic polymerization (cat poly) unit, which contains 69% isobutene, 14% butylenes, and 17% normal butane, would appear to be an excellent alkylation unit feedstock, especially if isobutene is i

METKA (Sunoco, Inc.) We operate a cat poly and sulfuric alkylation unit within the same refinery. The configuration offers flexibility and synergies that allow various operating and business demands to be met. In our configuration, the cat poly debutanizer overhead feeds the alkylation unit to recover the isobutane and any remaining butylenes.

Question 74: Have you experienced a shortage of KOH supply for your HF alkylation unit? Are you concerned about KOH availability? What are your alternatives if KOH is unavailable?

METKA (Sunoco, Inc.) Sunoco has experienced significant shortages of KOH in both our northeast and mid-continent refinery complexes. This appears to be a universal issue. In addition, a primary supplier to the northeast claimed force majeure earlier this year.

Question 73: Does alkylate volume yield decrease if T90 increases? Have you quantified the costs and benefits of reducing T90 by changing reaction conditions?

KAISER (Delek Refining Ltd.) With respect to alkylate yield and T90, the short answer to the question is, yes. When T90 increases, your alkylate yield is going to go down. And if that’s all you care about alkylation, you can go to sleep for the next five minutes and Jeff will wake you up when we get done. The two are tied together at the hip by the polymer make. The things that tend to give you heavier alkylate are doing so because the polymer make and the amount of tar in the unit is going up, and it’s influencing the T90.

Question 72 What feed contaminants can lead to metal corrosion in both sulfuric acid and HF alkylation units? What operating conditions promote corrosion? What do you do to reduce corrosion and/or remove contaminants?

GRUBB (Chevron USA, Inc.) I’ve consulted Gary Ash, the Pascagoula local expert, and Steve Mather, who is the corporate expert. They relayed to me that acid is still the biggest problem and not really necessarily the contaminants; but where the feed contaminants come in, they can make the acid more corrosive. They pointed out that water is the worst and that it could get less than a 92% acid strength, it’s dramatically more corrosive. Also, alcohols can also increase the corrosive nature of the acid.

Question 71 Is your company planning to install modified HF acid capability (usage of the volatility suppressing additive)? What are the incentives for doing this? What alternatives have you considered?

METKA (Sunoco, Inc.) In March 2006, in our continuing effort to support safe, reliable, and environmentally sound operation, we announced our plans to apply for a permit to independently initiate an alkylation process improvement project in our Philadelphia HF alkylation unit.

Question 70: How frequently do you have fires on reformer reactor flanges? What bolting techniques and gasket types do you use to prevent leaks? What other fixes, such as flange resurfacing, have you employed? Do you use steam ri

GRUBB (Chevron USA, Inc.) Chevron has had some experience with flange fires in the past, so I’ve consulted with Dave Reeves, our corporate expert and also our Best Practice that we’ve developed for this. I know that I said temporary fixes up on the slide, but it’s not really a temporary fix.

Is your company planning to install modified HF acid capability (usage of the volatility suppressing additive)? What are the incentives for doing this? What alternatives have you considered?

In March 2006, in our continuing effort to support safe, reliable, and environmentally sound operation, we announced our plans to apply for a permit to independently initiate an alkylation process improvement project in our Philadelphia HF alkylation unit.

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