| American Fuel & Petrochemical Manufacturers

Question 2: What are the operating constraints in co-processing coker naphtha in a ULSD (ultra-low sulfur diesel) and/or a gas oil hydrotreater unit?

There are some constraints relative to processing coker naphtha. I have outlined a few of them on the slide. Key with coker naphtha are the changes in the process chemistry that occur starting, perhaps, with the dilution of the hydrogen partial pressure due to the vaporization of the naphtha.

Question 1: For refiners using Layers of Protection Analysis (LOPA) in their OSHA (Occupational Safety and Health Administration) PHA (Process Hazard Analysis) studies, how do you quantify the frequency and consequences of initiating events?

I have a lengthy description of LOPA itself to help address this question. Layers of Protection Analysis is the structured process used to determine the appropriate layers of protection required to provide adequate safeguards for adverse and sometimes catastrophic events in process units.

Question 101: What analytical methods can distinguish between organic and inorganic iron (Fe) compounds in the feed? What type of iron, organic or inorganic, affects catalyst performance? Considering the relatively long reaction residence time of most laboratory test units used to measure activity, will activity testing properly reflect the actual in-FCCU activity under conditions of Fe contamination? What is your best method to monitor the catalyst performance under Fe contamination? Is ther

We have not routinely attempted to identify the organic and inorganic iron components in our feeds. An internal expert suggested two approaches. First to determine the organic iron using ICP-OES, then wash the same sample with DI water, or slightly acidified water, and utilizing atomic absorption, determine the inorganic iron.

Question 100: What conditions or contaminants will deactivate ZSM-5 additive? What is the half-life of ZSM-5 in clean feed operation? Will contaminants such as vanadium, sodium or other metals adversely affect the propylene selectivity of ZSM-5? What is the best way to monitor the effectiveness of the ZSM-5?

The deactivation mechanism for FCC catalyst is primarily related to unit cell size reduction, and eventually, collapse or sintering of the zeolite crystal. The mechanism of ZSM-5 deactivation is quite different. The deactivation mechanism is simply the dealumination of the ZSM-5 crystal and activity is lost through the loss of active aluminum sites.

Question 99: Are there any uncommon FCC metal contaminants showing up on equilibrium catalyst in addition to Ni, V, Fe, Na, and Ca? Are metals traps able to protect the catalyst by selectively capturing Fe, Na, Ca, or any of these uncommon contaminants?

Each of these catalyst poisons may have a significant impact on the FCC catalyst circulating inventory depending upon their concentration. Vanadium will form vanadic acid resulting in the sintering of the zeolite crystal thereby reducing activity. Nickel increases hydrogen yield potentially leading to wet gas compressor constraints and increases delta coke leading to main air blower &/or regenerator temperature constraints.

Question 98 What measures have you taken to minimize catalyst expenses due to rare earth price inflation? Please include an economic comparison of using a high rare earth catalyst at a lower catalyst addition rate versus using a low rare earth catalyst at a higher catalyst addition rate. Are there alternatives to replace rare earth in FCC catalyst? Are there any negative yield shifts with these new technologies?

Rare earth is an integral component of today's FCC catalyst. Rare earth adds catalyst stability and activity, functions as a vanadium trap and is the oxidizing agent within most SOx additives. Rare earth has also increased in price by over 1500% in the last 18 months. Rare earth has a direct impact on the split between LPG and gasoline in the FCC unit. As rare earth concentration is decreased LPG yield will increase potentially leading to wet gas compressor limitations.

Question 97: Disposal of catalyst fines from the slurry tank is expensive since they are handled as a hazardous waste. Do you have a way to reinject these tank fines back into the FCC where it would recover? What are other disposal options for these oil laden fines?

I have seen operations at two refineries where FCC slurry tanks were decanted, and the remaining catalyst fines were resuspended with Orbijets and an LCO circulation loop. A slipstream of this LCO slurry was recycled to the riser. In FCC Unit A (~20,000 BPD) the recycled fines partitioned approximately 2/3 to the regenerator side and out with the flue gas and 1/3 partitioned to the reactor side and back out to storage with the main column bottoms product.

Question 96: What are your experiences using SOx reduction additives formulated with lower rare earth content?

Cerium oxide functions as an oxidant and oxygen carrier: the mixture of two oxidation states Ce(III) and Ce(IV) creates defect sites in the crystal structure where oxygen ions are missing (oxygen vacancies) – these get filled up in the regen and ceria acts as a kind of monatomic oxygen sponge.

Question 95: What NOx reduction additives have been successfully used to rapidly decrease NOx during operational excursions or hardware failure? What alternatives to additives and hardware exist for NOx reduction? Is there a synergy for combining NOx reduction control methods that may reduce operating or project costs?

Intercat has developed a line of highly successful NOx abatement additive for use in the FCC unit. These additives tend to be most effective when added on a steady state basis. These include a platinum free combustion promoter and an additive designed to reduce NOx emissions for those refineries not using platinum promoters.

Question 94: What is your experience regarding corrosion of hexmesh anchorage in regenerators using non-phosphate bonded abrasion resistant lining materials?

The fact that a significant number of full burn regenerators have suffered severe abrasion resistant lining failures in recent years due to under-lining corrosion is not in dispute.

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