ENHANCING LIGHT-ENDS RECOVERY THROUGH JOINT ATMOSPHERIC DISTILLATION OF HEAVY CRUDE AND USED ENGINE OIL
ENHANCING LIGHT-ENDS RECOVERY THROUGH JOINT ATMOSPHERIC DISTILLATION OF HEAVY CRUDE AND USED ENGINE OIL
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Date
2011-11
Authors
RAHEEM, MOMOH OMUYA
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Abstract
Heavy crude oils are known to contain significant amount of high molecular-weight
substances such as asphalthenes and resins hence, when refined, produce low amount of lightends
(gasoline, kerosene and diesel fractions). Compared with light crude oils, as a refinery feed
stock this singular reason coupled with difficulty of processing has made heavy crude oil
business unattractive at local and global levels. In this work, enhancement of light-ends
recovery by joint atmospheric distillation of Venezuela, Mixed (50% Venezuela and 50% Antan
wt./wt.) and Antan heavy crude oils blended with used engine oil (UEO) was investigated. This
was carried out by subjecting these blends to spectrophotometric analysis for optimal feed
choice and subsequently acted as basis for true boiling point (TBP) distillation process. The
results show that blended Venezuela heavy crude with 1% UEO which corresponded to
maximum particle size of blend and 12% UEO corresponding to minimum particle size of the
blend enhanced the recovery of light-ends by extra 1.8% and 0.74% respectively. Similarly,
blended Mixed heavy crude with 16% UEO (max. particle size of blend) and 4% UEO (min.
particle size of blend) enhanced the recovery of the light-ends by 2.32% and 2.25% respectively.
Finally, blended Antan heavy crude with 19% UEO (max. particle size of blend) and 7% UEO
(max. particle size of blend) enhanced the recovery of the light-ends by 7.42% and 1.76%
respectively. All these confirm that on the average, the larger the particle size of the blend the
higher the chance of enhancement of the recovery of the light-ends.
However, the undefined pattern (i.e. positive and negative enhancements) of the product
slates of the fractional cuts prompted the need for further AAS analyses to check for the presence
of freed 3d-metals (V, Ni, Co, Fe.) from their complexes in the residues of the blends. This was to
confirm whether the enhancement was partially as a result of light cracking of the
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resin/asphalthenes (preferably porphyrins and porphins) and other organometallic compounds
that could have been originally present in the crude. The sequence of probable mechanism of the
light cracking is presented thus:
Since this type of cracking is of uncontrollable mechanism it underscored the reason why the
pattern of the distribution of the products was difficult to establish. While the free radicals
formed may recombine to yield gaseous product (methane, ethane, etc.) or light distillate like
naphtha/ kerosene fraction, it may as well yield heavier fractional cuts like vacuum distillate.
Used engine oil must have only provided enabling environment for these transformations to take
place because it must have reduced the energy of the bonding of crude oil micelle, hence
enhanced the recovery of the light-ends.
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Key Words: Heavy Crude Oil Used Engine Oil Light-ends Enhancement
Blends Asphalthene 3d-metal Complex Porphyrin
Description
A DISSERTATION SUBMITTED TO THE
SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
IN PARTIAL FULFILLMENT FOR THE AWARD
OF DOCTOR OF PHILOSOPHY IN
CHEMICAL ENGINEERING
DEPARTMENT OF CHEMICAL ENGINEERING
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
Keywords
ENHANCING LIGHT-ENDS,, JOINT ATMOSPHERIC DISTILLATION,, HEAVY CRUDE,, USED ENGINE OIL