• Can an ultra heavy crude oil of 12 deg API be converted to 22 Deg API by mixing Diesel?



  • Erick Gamas, The Business Shop, edgamas@hotmail.com

    - Blending heavy streams with much ligher streams is a common industry practice to meet pipeline/transportation specifications

    - Physical properties (viscosity, API) are modified by interactions, some physical some chemical, between molecules in each stream, the blended stream might show the properties of a much a lighter, "normal", feed. This is a proper approach as long as both streams are chemically compatible, otherwise many complications will be encountered if a proper experimental testing for chemical compatibility is not carried out. Fluid transport equipment may undergo fouling, two phase flow, pumps cavitation due to evaporation of lighter fractions, etc.

    - If the heavy feed has high concentration of asphaltenes, when blending with a diesel fraction (highly paraffinic nature) an asphaltene-rich sludge will precipitate during transport in tankers and pipelines, during storage in tanks farms and in process lines when refining the blended material.

    - Much higher level of contaminants, not seen in light not blended streams,  should be expected when refining a blended ultra heavy feed: Higher nickel, vanadium, calcium in the gasoil/Resid fractions will impact FCCU operations (much higher catalyst addition rates, much higher coke make, higher Regent T, etc.))

    - While procurement of an ultraheavy material might seem a very attractive proposition due to their much lower price, due diligence is required in order to assess the impact on transportation and refining operations.

    -Proper documentation of the blended streams (crude assay), as well as assays for the separate streams using for blending,  should be required as the lighter blended feed, purchased only based on physical properties, might seem "normal" until complications start showing. The cost of cleaning tankers, tanks, pipelines and processing equipment will quickly offset the apparent economic incentive of processing a blended stream.



  • Jose V. Gomez, Tecnicas Reunidas, jvgomez@trsa.es

    I do not see any problem with that based on the following fact (please refer to page D2 of the link below):


    (alternatively, you may also Google the following: The value of extra-heavy crude oil from the Orinoco Belt, which will take you to the link above).

    In that paper, it is explained how currently 8.5 Deg API Extra-Heavy crude (from the Orinoco Belt, in Venezuela) is converted (and commercialized) to 16 Deg API Merey crude by blending it with 38.2% of 30 Deg API Mesa crude (the latter being like a heavy diesel).