U.S. patent application number 11/721088 was filed with the patent office on 2011-06-02 for viscous hydrocarbon treatment method by in-situ asphaltene inerting.
This patent application is currently assigned to INSTITUTFRANCAIS DU PETROLE. Invention is credited to Jean-Francois Argillier, Isabelle Henaut, Francois Henry.
Application Number | 20110127196 11/721088 |
Document ID | / |
Family ID | 34953342 |
Filed Date | 2011-06-02 |
United States Patent
Application |
20110127196 |
Kind Code |
A1 |
Henaut; Isabelle ; et
al. |
June 2, 2011 |
Viscous Hydrocarbon Treatment Method by In-situ Asphaltene
Inerting
Abstract
The invention concerns a method for treating viscous hydrocarbon
containing asphaltenes, which consists in performing the following
steps: precipitating at least part of the asphaltenes by adding
into the hydrocarbon an appropriate solvent; adding into the
hydrocarbon polymerization products adapted to encapsulate the
precipitated asphaltenes to inert same.
Inventors: |
Henaut; Isabelle;
(Rueil-Malmaison, FR) ; Argillier; Jean-Francois;
(Rueil-Malmaison, FR) ; Henry; Francois;
(Bourg-La-Reine, FR) |
Assignee: |
INSTITUTFRANCAIS DU PETROLE
Rueil-Malmaison Cedex
FR
|
Family ID: |
34953342 |
Appl. No.: |
11/721088 |
Filed: |
November 24, 2005 |
PCT Filed: |
November 24, 2005 |
PCT NO: |
PCT/FR2005/002943 |
371 Date: |
December 23, 2009 |
Current U.S.
Class: |
208/309 |
Current CPC
Class: |
C10G 21/003 20130101;
F17D 1/16 20130101; B01J 13/16 20130101; C10G 29/20 20130101 |
Class at
Publication: |
208/309 |
International
Class: |
C10G 71/00 20060101
C10G071/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 7, 2004 |
FR |
0413002 |
Claims
1) A method of treating a viscous asphaltene-containing
hydrocarbon, wherein the following stages are carried out:
precipitating at least part of the asphaltenes by adding a suitable
solvent to the hydrocarbon, adding to the hydrocarbon
polymerization products suited to encapsulate the precipitated
asphaltenes so as to inert them.
2) A method as claimed in claim 1, wherein the asphaltenes are
precipitated with n-alkane.
3) A method as claimed in claim 1, wherein polymerization products
are added to form a membrane around the asphaltene particles by
interfacial polycondensation.
4) A method as claimed in claim 3, wherein di or triamine, or a
mixture thereof, and an acyl dichloride are added to form an
aromatic polyamide at the surface of the asphaltene particles.
5) A method as claimed in claim 1, wherein alkyd resins suited to
cross-link at the surface of the asphaltene particles are
added.
6) A method as claimed in claim 5, wherein a siccative acting as an
agent favouring cross-linking is added.
7) Application of the method as claimed in claim 1 to obtain a
decrease in the viscosity of a viscous asphaltene-containing
hydrocarbon.
8) Application of the method as claimed in claim 7 for pipe
transportation of a viscous asphaltene-containing hydrocarbon.
9) A method as claimed in claim 2, wherein polymerization products
are added to form a membrane around the asphaltene particles by
interfacial polycondensation.
10) A method as claimed in claim 9, wherein di or triamine, or a
mixture thereof, and an acyl dichloride are added to form an
aromatic polyamide at the surface of the asphaltene particles.
11) A method as claimed in claim 2, wherein alkyd resins suited to
cross-link at the surface of the asphaltene particles are
added.
12) A method as claimed in claim 11, wherein a siccative acting as
an agent favouring cross-linking is added.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of production and
transportation of viscous effluents, notably crude oils referred to
as heavy crudes, for example because of their asphaltene
content.
BACKGROUND OF THE INVENTION
[0002] Known viscous crude transportation methods consist in
thinning down the crude by heating, mixing with a thinning product
or by treatment prior to transportation, for example by passing
into aqueous emulsion. However, these techniques are energy-costly
or they implement complex processes requiring considerable
infrastructures that penalize reservoir development.
[0003] In the present description, what is referred to as slurry is
a suspension or a dispersion of solid particles in a liquid that
can be circulated, notably by pumping. This type of slurry flow is
already commonly used during estuary or river dredging operations,
and in the mining industry. The advantage is to allow
transportation of a maximum amount of solid cuttings with as little
pumping energy as possible. Concerning the petroleum industry,
slurry transportation is used to enrich fuels in coal particles and
thus to increase their heating value. The solid content can reach
60% by mass while keeping acceptable flow properties.
[0004] The present invention preferably applies to heavy crudes. It
also applies to extra-heavy crudes, bitumen, bituminous sand or
equivalent. It thus consists in modifying the structural
organization of the heavy crude which behaves like a viscous
colloidal suspension, to obtain a particle suspension of lower
viscosity. The particles concerned by this change are, within the
scope of a preferred embodiment of the present invention,
asphaltenes. Asphaltenes are the molecules of highest molecular
weight contained in certain crudes. They are characterized by their
high polarity and by the presence of polycondensed aromatic rings.
Overlap of these particles spread in the crude is greatly
responsible for the high viscosity of heavy crudes. This overlap
can be eliminated by maintaining the asphaltenes in form of
encapsulated solid particles in the crude. This configuration
change can be reached by combining, in the crude, precipitation and
inerting of the asphaltenes, then by dispersing the encapsulated
asphaltenes in the base liquid, notably under strong mechanical
stirring. A non limitative method of operation has been developed
and it has been checked that the resulting morphology change of the
crude in suspension form indeed leads to a viscosity decrease.
[0005] Advantageously, according to the invention, the asphaltene
particles are transported in solid form by the crude base liquid in
which these asphaltenes are dispersed so that the liquid obtained
is more fluid than the original crude. Thus, transportation by
pumping in pipes is facilitated up to refining plants. In these
refining plants, the slurry is fed either as it is into these
treating plants, or after a stage of separation of the suspended
solid particles, the asphaltenes, which may simplify downstream
processes.
SUMMARY OF THE INVENTION
[0006] The present invention thus relates to a method of treating a
viscous asphaltene-containing hydrocarbon, wherein the following
stages are carried out:
[0007] precipitating at least part of the asphaltenes by adding a
suitable solvent to the hydrocarbon,
[0008] adding to the hydrocarbon polymerization products suited to
encapsulate the precipitated asphaltenes so as to inert them.
[0009] According to the method, the asphaltenes can be precipitated
with n-alkane.
[0010] Polymerization products can be added to form a membrane
around asphaltene particles by interfacial polycondensation.
[0011] Di or triamine, or a mixture thereof, and an acyl dichloride
can be added to form an aromatic polyamide at the surface of the
asphaltene particles so as to form a membrane.
[0012] Alkyd resins suited to cross-link at the surface of the
asphaltene particles can be added.
[0013] A siccative can be added as an agent favouring
cross-linking.
[0014] The invention also relates to the application of the method
intended to obtain a decrease in the viscosity of a viscous
asphaltene-containing hydrocarbon.
[0015] The method can apply to pipe transportation of a viscous
asphaltene-containing hydrocarbon.
BRIEF DESCRIPTION OF THE FIGURES
[0016] Other features and advantages of the present invention will
be clear from reading the description hereafter of embodiments
given by way of non limitative example, with reference to the
accompanying figures wherein:
[0017] FIG. 1 shows the results of an embodiment according to the
invention, and
[0018] FIG. 2 shows the performance with time of the method
according to the invention.
DETAILED DESCRIPTION
[0019] According to the invention, at least two polymerization
modes for encapsulating asphaltenes contained in a viscous
hydrocarbon so as to inert them can be described.
[0020] The invention shows how encapsulation of the asphaltenes
within a heavy crude allows to durably decrease the viscosity of
such oils.
[0021] The invention is not limited to these two encapsulation
modes.
[0022] The first embodiment of the invention is a polymerization
that consists in an interfacial polycondensation. The goal is to
achieve a polymer material synthesis at the solid-liquid interface
between the asphaltenes and their environment. This method is based
on the selection of two appropriate monomers, one soluble in the
liquid phase and the other having great affinities with
asphaltenes. It can be noted that the polymer obtained forms a
membrane around the asphaltenes and should not be soluble in the
liquid phase. The protocol of the preferred operating method uses
synthesis of aromatic polyamides obtained from the reaction between
a di or triamine and an acyl dichloride. Because of its high
polarity, the di or triamine is preferably located at the surface
of the asphaltenes. On the other hand, acyl dichloride is soluble
in the medium surrounding the asphaltenes. The polyamide obtained
is insoluble in the liquid phase and it foul's at the surface of
the asphaltene particles. It belongs to the polyaramids family
whose aromatic structure is known to provide them with temperature
resistance, high mechanical properties and good solvent and
oxidizing agent resistance [Odian: "Principles of Polymerization",
3.sup.rd Ed., John Wiley & Sons, Inc., 1994].
[0023] The operating method developed allows to modify the
structural organization of the heavy crude by changing it into a
suspension of non colloidal encapsulated particles of greatly and
durably reduced viscosity. This protocol is carried out in situ; it
requires no prior crude deasphalting with asphaltene extraction,
treatment and reincorporation. The encapsulation method described
simply requires prior addition of an n-alkane in controlled
proportion in order to precipitate the asphaltenes. The
encapsulation reaction is then directly carried out on the
encapsulated asphaltenes without requiring filtering, then
dispersing them. Once the polymer membrane formed, the n-alkane is
evaporated, possibly to be recycled. Besides, part of the alkane
can be left in place. A light petroleum cut can also be added to
adjust the viscosity value.
[0024] Operating Method Example
[0025] The n-alkane selected is added in the desired proportion to
the crude. After 20-minute mechanical stirring during which the
asphaltenes precipitate, the di or triamine is introduced in the
selected proportion by mass in relation to the amount of
asphaltenes. Tributylamine is also added. Its purpose is to
neutralize the hydrochloric acid released during the reaction
between an amine group and an acyl chloride function. The mixture
is stirred for one hour during which the di or triamine adds on to
the precipitated asphaltene particles. The acyl dichloride is then
introduced in the selected proportion by mole in relation to the di
or triamine. Encapsulation then takes place by synthesis of the
polyamide between the di or triamine and the acyl dichloride at the
surface of the asphaltenes. The reaction is initiated by slight
heating between 30.degree. C. and 35.degree. C., which is
maintained under reflux for one hour. The n-alkane is then
evaporated. A suspension of granulous aspect is obtained, the size
of the particles reaching several hundred microns.
[0026] Test 1: Influence of the Proportion of N-Alkane Added
[0027] Three samples were prepared for encapsulation of the
asphaltenes of a heavy crude containg 17% by mass thereof. The
monomers selected to produce the interfacial polycondensation
reaction are melamine (supplied by Sigma-Aldrich for example) and
sebacoyl dichloride (supplied by VWR). The triamine is introduced
in a proportion of 5% by mass of the asphaltenes. The proportion of
acyl dichloride is set at 1.7 mole to 1 mole of melamine. The
n-alkane selected for precipitating the asphaltene particles is
pentane. Its proportion is known to influence both the size of the
particles and the precipitation efficiency. This parameter is
varied between 10, 15 and 20 ml/g crude. In each case, after the
interfacial polycondensation reaction and pentane evaporation, the
samples are observed by optical microscopy and their viscosity is
measured by means of a controlled-stress rheometer. In this
example, the size of the capsules changes with the proportion of
pentane, ranging respectively, for the samples prepared with 10, 15
and 20 ml/g crude respectively, between 300, 700 and 50 .mu.m.
[0028] FIG. 1 gives the viscosity V of the samples (in Pas) as a
function of the proportion of pentane added Q (in ml/g). The
results show that the encapsulated samples are less viscous than
the original heavy crude and that there is an optimum n-alkane
content for better reducing the viscosity. This optimum content
(here between 10 and 15 ml/g) has to be calibrated according to the
nature of the heavy crude, i.e. the state of solvation and of
concentration of its asphaltenes.
[0029] Test 2: Influence of the Proportion of Monomers on the
Viscosity Decrease of the Encapsulated Samples
[0030] In order to observe the influence of the proportion of
monomers on the quality of the encapsulated products, four samples
were prepared from 2.5, 5, 10 and 20% by mass of melamine in
relation to the asphaltenes. The proportion of sebacoyl dichloride
is still set at 1.7 mole per mole of melamine introduced. The tests
use pentane as the n-alkane with a content of 15 ml/g crude. In
each case, after interfacial polycondensation reaction and pentane
evaporation, the samples are observed by optical microscopy and
their viscosity is measured by means of a controlled-stress
rheometer. The optical microscopy images allow to visualize the
excess polymer formed with the high monomer concentrations, a
polymer whose presence in excess causes a high viscosity. Table 1
shows that the viscosity increases with the proportion of monomers.
To observe the temperature resistance of these samples, the
microscopic analyses are resumed after heating them to 80.degree.
C. for 1 hour. The total results show that a 5% melamine content is
preferred to obtain a good compromise between the viscosity level
and the temperature resistance.
TABLE-US-00001 TABLE 1 Viscosity at 20.degree. C. of the samples
encapsulated by interfacial polycondensation with various monomer
proportions 2.5% 5% 10% 20% monomers monomers monomers monomers
Viscosity 35 Pa s 45 Pa s 100 Pa s 150 Pa s
[0031] Test 3: Resistance with Time of the Samples Encapsulated by
Interfacial Polycondensation
[0032] In order to check the resistance with time of crudes
containing asphaltenes encapsulated by interfacial
polycondensation, the viscosity of a sample was measured at
different time intervals. The sample used is the one prepared from
5% mass melamine, 1.7 mole/mole of sebacoyl dichloride,
precipitation of the asphaltenes being obtained with pentane
introduced in a proportion of 15 ml/g crude. The rheological
measurements are shown in FIG. 2, which gives the viscosity V (in
Pas) as a function of the shear rate t (s.sup.-1). Curve 1
represents the crude, curve 2 after encapsulation, curve 3 40 days
later, and curve 4 66 days later. The curves show the stability of
the product with time.
[0033] The second method proposed for encapsulating the asphaltenes
of a crude consists in causing cross-linking of alkyd resins at the
surface thereof. Alkyd resins are unsaturated polyesters (presence
of double bonds) obtained from polyol and natural fatty acids. They
are characterized by their vegetable oil content, referred to as
oil length, which provides them with a siccative power, i.e. a
capacity to polymerize in the presence of oxygen. This
cross-linking process involves several physico-chemical mechanisms
according to whether the doubles bonds are simple or conjugated
[Marshall et al., Polymer, 28, 1093, 1987], [Solomon, "The
chemistry of organic film formers", Wiley-Intersciences, New York,
1967].
[0034] It can include addition of a siccative whose purpose is to
accelerate cross-linking by favouring oxygen supply. The siccatives
used are in most cases metallic oxides. As for the first
polymerization mode by interfacial polycondensation described
above, the operating method developed for this second mode allows
to modify the structural organization of the heavy crude by
changing it into a suspension of encapsulated particles of greatly
and durably reduced viscosity. This protocol is carried out in situ
; it requires no prior deasphalting of the crude with extraction,
treatment and reincorporation of the asphaltenes. The encapsulation
method described simply requires prior addition of an n-alkane in
controlled proportion in order to precipitate the asphaltenes. The
alkyd resins are preferably located at the surface of the
asphaltenes. The cross-linking reaction then takes place directly
on the precipitated asphaltenes. Once the membrane formed, the
n-alkane is evaporated, possibly to be recycled. Besides, part of
the alkane can be left in place. A light petroleum cut or a solvent
can also be added to adjust the viscosity value.
[0035] Operating Method Example
[0036] The n-alkane selected is added in the desired proportion to
the crude. After 15-minute mechanical stirring during which the
asphaltenes precipitate, the alkyd resins, the possible siccative
and a dispersant are introduced. Mechanical stirring is maintained
under heating at 35.degree. C. for two hours. The n-alkane is
finally evaporated. A smooth suspension is obtained.
[0037] Test 4: Influence of the Proportion of Alkyd Resins on the
Viscosity Decrease
[0038] In order to observe the influence of the proportion of alkyd
resins on the quality of the encapsulated products, three samples
were prepared from 4.6 and 8% by mass of Synolac 6883 (supplied by
the DSM Company) in relation to the asphaltenes. The proportion of
siccative (Combi QS from the Nuodex Company) is set at 4% by mass
in relation to the resin and the proportion of dispersant (Montane
80 from the Seppic Company) is 1% by mass of the alkane added. The
tests are carried out using pentane as the n-alkane in a proportion
of 10 mug crude. In each case, after cross-linking reaction and
evaporation, the viscosity of the samples is measured by means of a
controlled-stress rheometer. The results of Table 2 show that the
lowest viscosity level is obtained for a 6% resin content.
TABLE-US-00002 TABLE 2 Viscosity at 20.degree. C. of the samples
encapsulated by cross-linked alkyd resins 4% 6% 8% monomers
monomers monomers Viscosity 75 Pa s 50 Pa s 70 Pa s
[0039] Test 5: Temperature Resistance of the Cross-Linked
Samples
[0040] In order to check the temperature resistance of the
cross-linked products, the viscosity of a sample was measured after
heating at 50.degree. C. and 80.degree. C. for 1 hour. The sample
used was the one prepared from 6% by mass of alkyd resins Synolac
6883 (see test 4). The rheological measurements are given in Table
3 and show a good product stability. Despite the intensive thermal
treatment, notably at 80.degree. C., the viscosity of the crude is
not affected.
TABLE-US-00003 TABLE 3 Temperature resistance of the samples
encapsulated by cross-linked alkyd resins, viscosity measured at
20.degree. C. Without thermal After 1 h After 1 h treatment at
50.degree. C. at 80.degree. C. Test with siccative 50 Pa s 60 Pa s
80 Pa s
[0041] Test 6: Influence of the Siccative
[0042] In order to observe the influence of the added siccative, a
sample was prepared with 6% Synolac resins without adding any
siccative. Its viscosity was measured after preparation and after
heating at 50.degree. C. and 80.degree. C. for 1 hour. The results
show that the sample without siccative has the same viscosity as
the equivalent sample with siccative (50 Pas). On the other hand,
the sample without siccative is much less resistant to the
intensive thermal treatment performed at 80.degree. C. (see Table
4).
TABLE-US-00004 TABLE 4 Temperature resistance of the samples
encapsulated by cross-linked alkyd resins, influence of the
siccative, viscosity measured at 20.degree. C. Without thermal
After 1 h After 1 h treatment at 50.degree. C. at 80.degree. C.
Test without siccative 50 Pa s 60 Pa s 180 Pa s
* * * * *