Origin and Composition of Petroleum Products Flashcards
Which type of units are used to remove sulfur, nitrogen and oxygen ?
Hydrotreatment units
What are hydrotreatment units for ?
They are used to remove sulfur, oxygen and nitrogen
Why do we want to remove sulfur, oxygen and nitrogen ?
Because they are poison for catalysts used in the conversion units (like reforming units)
Where are heavy metals mostly concentrated ?
Heavy metals are concentrated in te asphaltenes (=bitumens)
Which heavy metals do we find mostly in crude oil ?
Nickel and Vanadium are the metals found in crude oil
Why are heavy metals a problem for crude oil ?
They are a poison for catalysts
What is the link between API and specific gravity ?
API and specific gravity are inversely proportional
What makes crude oil black ?
Crude oil is black because of asphaltenes, which are polyaromatic structures
In the atmospheric and vaccuum columns, which streams do we expect to be black ?
Distillation and vacccuum residue should be black
What is the meaning of a black stream for a side-stream in the distillation or vaccuum column ?
It is the sign of the presence of asphlatenes and therefore of pollution of this stream
For n-parraffins, what is the relation between the number of carbon, boiling point and specific gravity ?
If the number of carbon increases, so does the boiling point and specific gravity
What is the component family most present in crudes ?
Paraffins are always the most present in crudes
Which component family doesn”t exist in natural state in crude oil ?
Olefins don’t naturally exist in crude oil
Why is H2S a problem ?
H2S is a lethal gas (1000 ppm = instant death). It’s also a problem for the environment (acidic rains)
How is sulfur treated in a refinery
Sulfur is first turned into H2S in hydrotreatment units and then turn into elementary sulfur (Claus unit)
According to the PIANO classification, what do we want in a gasoline grade ?
In a gasoline grade, we want isoparaffins and aromatics but we absolutely don’t want n-paraffins
According to the PIANO classification, what do we want in a diesel grade ?
In a diesel grade, we want n-paraffins and we absoluetly want to avoid isoparaffins and aromatics
What is the feed temperature at the inlet of the atmospheric distillation ?
The Feed of the atmospheric distillation is between 360 and 370°C
Why do we need a vaccuum column ?
We need vaccuum to reduce BP of heavy products and be able to separare them without cracking them
Which cuts are used for diesel ?
Light and Heavy gas oils are used for diesel but also kerosene
What is the kerosen cut used for ?
The kerosen cut is used for jet fuel and diesel
What are the possible outcomes for the VGO cuts ?
They can be used for lubricants or send to the FCC or the hydrocracker
Why are they two VGO cuts
One is always safe (without Ni or Vd) and can be sent directly to FCC or HCK. The other can be contaminated and needs to be checked regularly
What does VGO stand for ?
Vaccuum Gas Oil
