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Opportunity knocks

A group of interesting articles* deals with opportunity crudes, a mixed breed that includes very heavy, sour and high total acid number types as well as those with unexceptional naphthenic acid content but which do have significant concentrations of aliphatic acids or possess the ability to generate them during processing. They all sell at substantial discounts that give refiners who can process them the opportunity to reap higher profits. Hence their name.

Note that phrase "who can process them". It's not easy. Opportunity crudes can cause severe problems in the desalter, crude heat trains, fired heaters, atmospheric and vacuum towers and downstream process units all the way to waste water treatment facilities. Every piece of equipment can be at risk. Yet some of these crudes, such as Grane have a very flat TBP curve in the vacuum gas oil boiling range. High vacuum gas oil yield is the opportunity for those with a properly designed deepcut vacuum unit.

More important than any chemical treatment program is the flexibility that must be built into the basic process design. It must have the necessary resilience to accommodate varying crude characteristics. Proper metallurgy is critical but selection must depend as much on metal availability and cost as on specifics of corrosion resistance. Desalters have to handle not just brine and sediment but surface active molecules that tend to form stable emulsions. Wash water systems must be able to deal with different salt chemistries. Fractionation sections must concentrate refractory sulfur species without downgrading valuable distillates. Vacuum unit fired heaters must be specially designed to minimize coking.

No combination of measures can eliminate all these problems but put together in a rational and coherent process design they can extend refinery runs from months to years providing refiners with the opportunity to profit rather than suffer from the vagaries of the uncertain and skittish crude Market.

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Opportunity knocks

A group of interesting articles* deals with opportunity crudes, a mixed breed that includes very heavy, sour and high total acid number types as well as those with unexceptional naphthenic acid content but which do have significant concentrations of aliphatic acids or possess the ability to generate ...
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