Nasty stuff
Heavy crudes are here to stay. As longs as oil prices remain high, Canadian, Venezuelan, Deep Water Gulf of Mexico, Mexican and other low API gravity crude oils will play an ever more important role in supplying world refineries. And prices promise to remain high because gainsayers notwithstanding, Hubbert was right.
A big question is how to handle best these nasty crudes? Do you revamp existing units or invest in new capacity? With refineries now running flat out, the balance might seem to favor grass roots expansion, but given the substantial cost multiplier over revamps, this could be questioned.
Whichever the case, however, an inescapable fact is that the process design of the project will prove crucial. Between the charge pump and the desalter and the units’ distillation columns there are many places where miscalculations in the process design could wreck the entire project.
Can you really be sure of attaining desired crude rates? Desalting viscous crude is extremely difficult. Minimizing coking or asphaltene precipitation in the heaters demands extreme care. Can you reasonably expect high diesel and HVGO recoveries, acceptable levels of nickel, vanadium, and microcarbon residue (MCR)? Refiners who cut deep should not be surprised when the HVGO product MCR is over 2 wt% and the vanadium content is in excess of 10 ppmw. Any one of such difficulties can result in lower revenue, unstable operation or even an inoperable unit. It is critical to understand that the inherent properties of these low API gravity crudes dictate that exact process design is of paramount importance.
The point of this litany of possible problems is to remind you not to skimp in the early phases of engineering. From the start of the LP work through the completion of front-end process engineering, actual product yield and product qualities depend on the process design.
The message is clear. Nasty crudes will continue to make up an increasing proportion of refineries’ crude slates. But time is precious. The sooner we face this fact, unwelcome as it may be, the more expeditiously we can adapt.
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Oil sands crude — profits and problems?
Canadian bitumen production currently runs about 1 MMbpd, with some being sold as Synbit and Dilbit. Over the next 10-12 years output is expected to increase to 3.5 MMbpd and more refiners will begin investing to process it and come to depend on the Synbit and Dilbit for a significant part of their supply. ...
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Heavy crudes are here to stay. As longs as oil prices remain high, Canadian, Venezuelan, Deep Water Gulf of Mexico, Mexican and other low API gravity crude oils will play an ever more important role in supplying world refineries. And prices promise to remain high because gainsayers notwithstanding, Hubbert ...
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Designing deepcut vacuum units that really work
Every barrel of vacuum gas oil (VGO) you can save from being reduced to coke in the delayed coker unit is a barrel more that can go to the FCCU. That’s a good reason to raise HVGO cutpoint. But how to do it? Some people think the job can be done just by running computer models in the engineering ...
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A time for grass roots thinking ?
Within the past year or two spiking crude prices and surging refinery margins have led to overheated talk about increasing refinery capacity worldwide. Plans for construction of as many 60 grass roots refineries have been discussed. But stretched out lead times for major equipment and inflated prices, ...
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A single integrated vacuum system
Failure to design the vacuum unit as an integrated system will invariably result in unsatisfactory yield and poor product quality (high vanadium, nickel, microcarbon, or asphaltenes), and ultimately, an unscheduled shutdown. To avoid these revamp problems the charge pump, fired heater, transfer line, ...
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Back in the late 1970’s and early 1980’s when fuel gas prices were high, energy utilization assumed major importance. A new method of calculating heat exchanger networks was developed. It was called Pinch Technology. Today pinch has been rediscovered by engineers who have access to fast computer ...
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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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Processing heavy Canadian crude
Reducing crude oil cost is the major incentive driving crude and vacuum unit projects to handle heavy Canadian crudes. But such crudes–Albian Heavy, Christina Lake, MacKay River and others derived from oil sands–today present refiners with a unique set of problems not just because of extra-low ...
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Why do many crude/vacuum units perform poorly?
In many cases it’s because the original design was based more on virtual than actual reality. There is no question: computer simulations have a key role to play but it’s equally true that process design needs to be based on what works in the field and not on the ideals of the process simulator. ...
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Why produce diesel from the vacuum unit?
Look ahead five years. The economy is likely to keep tightening and the rush to control pollution will inevitably be accompanied by demands for greater energy conservation. Consequence? A growing market for diesel which yields more energy per unit volume. Yet many continue to believe that producing diesel ...
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