Modern view at asphaltenes. (Lecture 4) презентация

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Component analysis
Paraffines [alkanes]: n-/izostructure
Naphthenes: [cycloalkanes]
Aromatic hydrocarbons [arenes]
Hydrocarbons of mixed structure: in Diesel fraction and above
Non-hydrocarbon oil components: S, N, O
Mineral components: H2O, salts
Macromolecular components
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High-molecular oil components
Wax:
С18-С35 (300-450 а.е.)
Cerezines:
С36-С55 (500-700 а.е.)
Resins-asphaltenic substances (RAS):
Resines: < 1000 а.е.
Asphaltenes: > 1000 а.е.
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RAS classification
Resins:
M <1000
soluble in alkanes
condensed systems related with aliphatic chains
Asphaltenes:
M > 1000
 ≈ 1 D and above
insoluble in alkanes
soluble in benzene,CS2, CCl4, etc.
tend to associations, define the structure of oil disperse systems
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АFМ-image of asphaltenes at solid surface
Energy&Fuels 2009
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Separating crude oil into saturates, aromatics, resins and asphaltenes (SARA)
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Molecular structure of proposed resin molecule
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The main properties and hypothetical asphaltene molecule
H/C = 0,8-1,4
molecular weight distribution Monomers= 500-1000 Oligomers= 1000-5000
Heteroatoms, мас. %:
S = 0,5 - 10; N = 0,6 – 2,6; O = 0,3 - 4,8 Metals: Ni, V, Fe
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Asphaltenes extracted with two alkanes

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Packing model of asphaltene structure (Yen, 1961)
Packing structures in diameter of 0,9-1,7 nm from 4-5 layers, being at 0,36 nm each one from other.
By rectilinear pieces are shown flat polyarenous, and broken lines - the saturated fragments of molecules.
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The scheme of association asphaltenes in process of introduction sedimentator (lungs n-alkanes) in the PDS (T.Yen, 1961)
I - molecular state
(up to 1 nm)
II – colloidal state
(1-100 nm)
III - disperse - stable state
(100 nm - 1 mc)
IY- disperse - unstable state
(> 1 mc)
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Organization level of ashaltens (1)
Monomers
Yen elementary particles (9 ÷ 17 Å)
Oligomers (25 ÷ 50 Å)
Polymers (> 150 Å)
+ Aggregation processes, including the processes of gel / glass
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Organization level of ashaltens (2)
Monomers Yen elementary particles
Oligomers (dimers, trimers, tetramers)
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Dimers structure
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Molecular structures of proposed asphaltens molecules
(a) Maya crude oil (Mexico) (b)Venezuelan crude oil

The histogram of distribution of components in the ODS of a destructive origin (the rests of thermal processes of oil refining)
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The scheme of allocation
carbens and carboids
Asphaltenes+carbens+ carboids
CCl4
asphaltenes (in solution CCl4) and
carbens + carboids
(in a deposit)
CS2
Carbens (in solution CS2) and
carboids (in a deposit)
cracking residues

A way of looking at aggregation behavior of asphaltenes with increasing concentration
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