FIELD OF THE INVENTION
The present invention relates to compositions and processes for breaking
emulsions in crude oil. More particularly, the compositions and processes may be used to
break water-in-oil emulsions at an oilfield or in a desalter in a crude oil refinery.
BACKGROUND OF THE INVENTION
Crude oil is produced from geological formations where it is in intimate
contact with brine (salt water). As the oil and brine are produced, their movement through
geological formations produces an emulsion ofwater-in-oil, wherein tiny droplets of
water are suspended in a continuous phase of oil. Generally, the amount of water
produced from the formation in the oil field ranges from 1-2% and may even be higher
than 90%. Refineries operate with much lower water content in the crude oil, generally
not exceeding 0.5%.
In oilfield industries, these water-in-oil emulsions are often referred to as
primary emulsions. Though less common, oil-in-water emulsions, wherein tiny droplets
of oil are suspended in a continuous phase of water, also occur and are often referred to
as reverse emulsions. Another type of emulsion is a multiple, or complex, emulsion
where tiny droplets are suspended in bigger droplets that are suspended in a continuous
phase.
To render the crude oil more suitable for refining, the crude oil is
demulsified by separating the primary or reverse emulsions into separate oil and water
phases. While the water in the oil is a problem for refiners, it is the dissolved salts which
cause the most problems since they can deposit and foul heat transfer surfaces. Calcium
chloride and magnesium chloride decompose at operating temperatures of the refinery to
produce HCI (hydrochloric acid) which corrodes the distillation towers. To remove the
brine and the salts it contains, the crude oil is heated to around 1200 C and mixed with
2
about 5% fresh water by passing the water and oil through a mixing valve and thence to a
vessel, such as an oil refinery desalter, where it has a residence time of about 30 minutes
to allow the emulsion to break and the oil and water to separate.
Generally, the steps in demulsification are flocculation followed by
coalescence and, finally, sedimentation. During the flocculation step, the suspended
droplets aggregate to form larger droplets. During coalescence, the larger droplets come
together to form a large drop. Sedimentation takes advantage of the fact that water is
denser than oil. During sedimentation the water and oil phases become stratified into
distinct layers as large drops of water fall to the bottom. There are several methods for
demulsifying oil field emulsions, including thermal, mechanical, electrical, and chemical
methods.
Chemical methods employ the use of chemicals that neutralize the effects
of emulsion stabilizing agents and to accelerate the demulsification process by reducing
the interfacial tension. These demulsifying chemicals are often referred to as emulsion
"breakers" because they break, or separate the emulsions into the separate oil and water
phases. Demulsifying chemicals used to break water-in-oil emulsions, or primary
emulsions, are often referred to as primary emulsion breakers. Primary emulsion breakers
are added to the continuous oil phase and are generally oil-soluble, though they may be
water-soluble. Likewise, demulsifying chemicals used to break oil-in-water emulsions, or
reverse emulsions, are often referred to as reverse emulsion breakers. Reverse emulsion
breakers are generally water-soluble, though they may be oil-soluble, and are added to
the continuous water phase. Some of the water is removed from the crude oil by adding
surfactant chemicals to demulsify the water and oil at the well or near the point of
production. These surfactants are optimized to separate, or "break", the oil and water at
relatively low temperatures, common in the oil field. Without emulsion breakers, more
time is required to separate the phases, limiting the amount of oil the refinery can
process.
The most effective demulsifying chemistries and formulations typically
vary with the crude composition. The crude composition, however, continuously varies
3
based on the crude source or well, the treatment, if any, at the well, well stimulation
practices, "smearing", or contamination effects from adjacent pipeline transports, and the
crude blend composition. The crude composition may be further altered by a myriad of
chemistries that may have been added to the crude between the time it is collected at the
well and the time it enters a desalter at a refinery. Such chemistries may include, but are
not limited to, corrosion inhibitors, biocides, drag reducers, H2S scavengers, etc.
Most of the effects on crude composition mentioned above are beyond a
refinery's control, yet the refinery is often left with the burden of analyzing the crude
composition and determining the most effective demulsifying treatment.
BRIEF DESCRIPTION OF THE INVENTION
It was surprisingly discovered, however, that blends of one or more C4-C12
alkyl phenol-formaldehyde resin alkoxylates with a surfactant produced a robust
demulsifying composition that was effective at resolving emulsions in a variety of crude
types.
Accordingly, in one embodiment, a method of resolving an emulsion
present in a hydrocarbon stream is disclosed. The method may comprise providing the
hydrocarbon stream and providing a demulsifying composition. The demulsifying
composition may comprise 1) at least one C4-C12 alkyl phenol-formaldehyde resin
alkoxylate and 2) at least one surfactant, wherein the surfactant comprises at least two
blocks of alkylene oxide units. The hydrocarbon stream may be contacted with the
demulsifying composition, thereby coalescing aqueous droplets from the emulsion to
form an aqueous stream. The aqueous stream may then be removed.
In another embodiment, the hydrocarbon stream may comprise crude oil.
In yet another embodiment, the coalescing of aqueous droplets from the emulsion to form
an aqueous stream may occur in a desalter.
In another embodiment, at least one C4-C12 alkyl phenol-formaldehyde
resin alkoxylate may comprise 30-90% alkoxylate units by weight and may have a
polymerization number of 2-20. In another embodiment, the C4-C12 alkyl phenol-
4
formaldehyde resin alkoxylate may comprise ethylene oxide units. The C4-C12 alkyl
phenol-formaldehyde resin alkoxylate may be nonylphenol formaldehyde resin
ethoxylate.
In yet another embodiment, the C4-C12 alkyl phenol-formaldehyde resin
alkoxylate may comprise at least two alkyl phenol-formaldehyde resin alkoxylates having
different amounts of alkoxylation. The two alkyl phenol-formaldehyde resin alkoxylates
may comprise a first alkyl phenol-formaldehyde resin alkoxylate having a percent A by
weight of alkoxylation and a second alkyl phenol-formaldehyde resin alkoxylate having a
percent B by weight of alkoxylation. A minus B may be 10-50%. The ratio by weight of
an amount of the first alkyl phenol-formaldehyde resin alkoxylate relative to the second
alkyl phenol-formaldehyde resin alkoxylate may be 1:9 to 9: 1. In another embodiment,
the C4-C12 alkyl phenol-formaldehyde resin alkoxylate may comprise a mixed resin with
units of nonylphenol formaldehyde alkoxylate and units of butylphenol formaldehyde
alkoxylate. Alternatively, the C4-C12 alkyl phenol-formaldehyde resin alkoxylate may
comprise a first resin with units of nonylphenol formaldehyde alkoxylate and a second
resin with units of amylphenol formaldehyde alkoxylate.
In another embodiment, at least one surfactant may comprise ethylene
oxide units and propylene oxide units wherein the ratio by weight of the ethylene oxide
units to the total number of ethylene and propylene oxide units is 30-50%.
In yet another embodiment, at least one surfactant may comprise a
polyalkylene oxide triblock polyol having the formula:
CH3
H'o~'}VlO~O}H
x y z
wherein x, y, and z are any integer greater than one where the molecule has a molecular
weight of 1000-9000.
Alternatively, at least one surfactant may comprises a molecule with 2-6
branches each comprising at least one polyalkoxylate block, and wherein said molecule
has a molecular weight of 3000-25000. The surfactant may have the formula:
5
where xl, x2, x3, and x4 may be the same or different and represent the number of
polyethylene oxide units and where yl, y2, y3, and y4 may be the same or different and
represent the number of polypropylene oxide units, and wherein a ratio of the
polyethylene oxide units to polypropylene oxide units is from 10:90 to 90: 10.
In another embodiment, the surfactant may comprise at least two
surfactants.
In yet another embodiment, the demulsifying composition may further
comprise at least one non-polar organic solvent and/or at least one aqueous solvent.
Suitable non-polar organic solvents include, but are not limited to, naphtha, light
aromatic naphtha, heavy aromatic naphtha, pentane, cyclopentane, hexane, cyclohexane,
benzene, ethyl benzene, 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, toluene,
xylene, cumene, IA-dioxane, chloroform, diethyl ether, methyl esters of fatty acids
(biodiesel), and diethylene glycol butyl ether. In yet another embodiment, the
demulsifying composition may comprise an organic solvent and an aqueous solvent in an
aggregate amount of about 10 wt% to about 90 wt% based on a total weight of the
demulsifying composition. The demulsifying composition may be a colloidal micellar
solution including an oil phase and an aqueous phase.
In yet another embodiment, the demulsifying composition may be added
to the hydrocarbon stream in an amount ranging from about I to about 200 ppm by
volume of the hydrocarbon stream.
In another embodiment, the method may further comprise contacting the
hydrocarbon stream with a dispersant, wherein the dispersant is an adduct of at least one
acid ester of mono- or polycarboxylic acid and an acylating reagent. Suitable acylating
reagents include, but are not limited to fumaric acid, maleic anhydride, maleic acid,
succinic anhydride, and succinic acid. In another embodiment, the acid ester may have a
polyisobutenyl and a pentaerythritol moiety and the acylating reagent may be succinic
6
anhydride or succinic acid. In yet another embodiment, the dispersant may be a
polyisobutenyl succinic anhydride derived ester with a molecular weight, Mw , of about
20,000 to about 25,000 in an aromatic solvent.
In yet another embodiment, the dispersant may be added in an amount of
about 1 to about 1000 ppm by volume of the hydrocarbon stream.
In another embodiment, a demulsifying composition for treating a
hydrocarbon stream is disclosed. The demulsifying composition may comprise 1) at least
one C4-C12 alkyl phenol-formaldehyde resin alkoxylate, wherein the C4-C12 alkyl phenolformaldehyde
resin alkoxylate comprises 30-90% alkoxylate units by weight and has a
polYmerization number of 2-20 and 2) at least one surfactant, wherein the surfactant
comprises ethylene oxide units and propylene oxide units and the ratio by weight of the
ethylene oxide units to the total number of ethylene and propylene oxide units is 30-50%.
In another embodiment, the C4-C12 alkyl phenol-formaldehyde resin
alkoxylate may comprise at least two alkyl phenol-formaldehyde resin alkoxylates having
different amounts of alkoxylation. The two alkyl phenol-formaldehyde resin alkoxylates
may comprise a first alkyl phenol-formaldehyde resin alkoxylate having a percent A by
weight of alkoxylation and a second alkyl phenol-formaldehyde resin a1koxylate having a
percent B by weight of alkoxylation. A minus B may be 10-50%. The ratio by weight of
an amount of the first alkyl phenol-formaldehyde resin alkoxylate relative to the second
alkyl phenol-formaldehyde resin alkoxylate may be 1:9 to 9: 1. In yet another
embodiment, the C4-C12 alkyl phenol-formaldehyde resin alkoxylate may be nonylphenol
formaldehyde resin ethoxylate. In another embodiment, the C4-C12 alkyl pheno1formaldehyde
resin alkoxylate may comprise a mixed resin with units of nonylphenol
formaldehyde alkoxylate and units of butylphenol formaldehyde alkoxylate.
Alternatively, the C4-C12 alkyl phenol-formaldehyde resin alkoxylate may comprise a
first resin with units of nonylphenol formaldehyde alkoxylate and a second resin with
units of amylphenol formaldehyde alkoxylate.
In yet another embodiment, at least one surfactant has formula:
7
where xl, x2, x3, and x4 may be the same or different and represent the number of
polyethylene oxide units and where yI, y2, y3, and y4 may be the same or different and
represent the number of polypropylene oxide units, and wherein a ratio of the
polyethylene oxide units to polypropylene oxide units is from 10:90 to 90: IO.
In another embodiment, the demulsifying composition may further
comprise at least one non-polar organic solvent and/or at least one aqueous solvent.
Suitable non-polar organic solvents include, but are not limited to, naphtha, light
aromatic naphtha, heavy aromatic naphtha, pentane, cyclopentane, hexane, cyclohexane,
benzene, ethyl benzene, 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, toluene,
xylene, cumene, IA-dioxane, chlorofonn, diethyl ether, methyl esters of fatty acids
(biodiesel), and diethylene glycol butyl ether. In yet another embodiment, the
demulsifying composition may comprise an organic solvent and an aqueous solvent in an
aggregate amount of about 10 wt% to about 90 wt% based on a total weight of the
demulsifying composition. The demulsifying composition may be a colloidal micellar
solution including an oil phase and an aqueous phase.
In yet another embodiment, the demulsifying composition may further
comprise a dispersant comprising a polyisobutenyl succinic anhydride derived ester with
a molecular weight, Mw , of about 20,000 to about 25,000 in an aromatic solvent.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
It was surprisingly discovered that blends of one or more C4-C12 alkyl
phenol-fonnaldehyde resin alkoxylates with one or more surfactants produced a robust
demulsifying composition that was effective at resolving emulsions in a variety of crude
types. Specifically, these demulsifying compositions were more effective than current
fonnulations in resolving emulsions in some types of heavy crudes. For example,
8
embodiments of the demulsifying composition are particularly effective on crudes or
crude blends with an American Petroleum Institute ("API") gravity ranging from about
22 to 40 (degrees). The crudes or crude blends may comprise greater than, or equal to,
about 0.5 wt% asphaltenes. These crudes may also have more than about 60 pounds of
filterable solids per thousand barrels; such as 20-500 lbs., or 20-200 lbs., or 60-200 lbs.
Exemplary blends for which the demulsifying composition is particularly effective
include blends of Canadian crude oils with American shale oils, sweet crudes, or Bakken
crude. In particular, blends of crude oil containing Western Canadian Select are
preferred. The present invention is particularly applicable to oil blends having between 170%,
such as 20-50%, by volume of Western Canada Select crudes.
While an organic solvent may be used as part of the formulation, it was
also surprisingly discovered that water may be used as a solvent for the demulsifying
compositions. Water is generally less expensive than the organic solvents and alcohols
frequently used in demulsifying compositions. Accordingly, novel demulsifying
compositions are disclosed comprising ethoxylated surfactants in water. These
demulsifying compositions are stable as the oil phase does not separate from the aqueous
phase.
Without limiting this specification to any particular theory of operation, it
is thought that the demulsifying compositions with water are stable because they are
colloidal solutions and not true solutions as previously thought.
Colloidal solutions of surfactants contain micelles. Micelles are groups of
surfactant molecules dispersed in a liquid forming a colloidal solution. Typically,
micelles are spherical with the hydrophilic portion of the surfactant molecules forming
the outside of the micelle and the hydrophobic portion filling the micelle's interior. Based
upon factors such as concentration and temperature as well as the surfactant's chemical
structure, other shapes are possible such as rods, tubes, or sheets.
The micelles only form when the concentration of the surfactant in the
liquid is greater than the critical micelle concentration ("CMC"). The CMC may vary
depending on the surfactant and the liquid used. Other factors that affect the CMC are
9
temperature, pressure, and the presence of any other compounds that affect the surface
tension of the liquid.
Primary emulsion breakers typically have multiple components, including,
but not limited to, ethoxylated surfactants in an organic solvent, or "oil", like naphtha or
toluene. An "oil" is any liquid that is soluble in another oil or organic solvent, but is not
soluble in water. Thus the micelles in primary emulsion breakers are "inverse" micelles
because the hydrophobic portion of the surfactant forms the outside of the micelle, and
the hydrophilic portion fills the interior. It is thought that when added to primary
emulsion breakers, aqueous solvents, such as water, enter into the interior of the micelles
and "hydrate" the hydrophilic, or polar portion, of the ethylene oxide molecules. The
organic solvents may include aromatic and/or non-aromatic organic solvents.
It was surprisingly discovered, however, that replacing some or all of the
organic solvents, like naphtha or toluene, with water, resulted in stable demulsifying
compositions, even though the primary emulsion breakers may comprise oil-based
components. Without limiting the invention to one theory, it is thought that instead of
"inverse" micelles, typical micelles are formed, where the hydrophilic portions of the
surfactant molecules form the outside of the micelle and the hydrophobic portions, or
non-polar regions of the surfactant molecules, fill the micelle's interior. Accordingly,
demulsifying compositions and methods of use are disclosed wherein the demulsifying
compositions may comprise an oil phase and an aqueous phase that form a colloidal
micellar solution.
The present invention is directed to a demulsifying composition and a
method of demulsifying an emulsion with such demulsifying composition. In one
embodiment, a method of resolving an emulsion present in a hydrocarbon stream is
disclosed. The method may comprise: providing a hydrocarbon stream; providing a
demulsifying composition comprising an oil phase and/or a water phase in contact with
the hydrocarbon stream. If the solvents are all organic, than an oil phase will be present.
If the only solvent is water, then a water phase will be present. If the solvents are a
mixture of oil and water, then this will result in a dispersed phase and a continuous phase,
10
depending on the amount of organic solvents and water present. In another method, the
hydrocarbon stream may comprise crude oil. In yet another method the emulsion may be
resolved in a desalter of a crude oil refinery. The demulsifying composition may be
added to the desalter or, preferably, upstream of the desalter. The demulsifying
composition may be added right before the mixing valve upstream of the desalter.
The amount of the demulsifying composition used will vary with
refineries and the amount of emulsification present in the hydrocarbon stream.
Accordingly, in another method, the demulsifying composition may be added to the
hydrocarbon stream in an amount ranging from about I to about 200 ppm by volume of
the hydrocarbon stream. Alternatively, the demulsifying composition may be added to the
hydrocarbon stream in an amount ranging from about I to about 100 ppm, or about I to
about 30 ppm, or about 2 to about 25 ppm by volume of the hydrocarbon stream.
The hydrocarbon stream may be contacted with the demulsifying
composition to coalesce aqueous droplets from the emulsion form an aqueous stream.
The aqueous stream may then be removed.
The demulsifying composition may comprise one or more C4-C12 alkyl
phenol-formaldehyde resin alkoxylates, each of which shall be individually referred to
herein as a "demulsifying resin" and collectively as "demulsifying resins". The
demulsifying composition may also comprise one or more surfactants. The surfactants
may be polymers which include two or more blocks of polyalkoxylates, such as
polyethylene oxide, polypropylene oxide, and/or polybutylene oxide. The polymers
which include two or more blocks of polyalkoxylates shall be referred to herein
individually as a "block polyalkoxylates surfactant" and collectively as "block
polylkoxylate surfactants". The demulsifying composition may also comprise an aqueous
and/or an organic solvent. The demulsifying composition may also include other
components as more specifically identified below.
In another embodiment, the demulsifying composition may comprise a
demulsifying resin and a block polyalkoxylate surfactant. The demulsifying resin may be
present in an amount of about 90-50% by weight based upon a combined weight of the
11
demulsifying resin and the block polyalkoxylate surfactant, and the block polyalkoxylate
surfactant may be present in an amount of about 10-50% by weight based upon a
combined weight of the demulsifying resin and the block polyalkoxylate surfactant.
The demulsifying composition preferably comprises one or two
demulsifying resins. Each demulsifying resin is preferably a C4-C12 alkyl phenolformaldehyde
resin alkoxylate, such as a Cs-C9 alkyl phenol-formaldehyde resin
alkoxylate, and may be present in from 1-20%, such as 3-11%, of the weight of the
demulsifying composition. Preferably, each alkyl phenol formaldehyde resin alkoxylate
is present in the demulsifying composition at or above its critical micelle concentration.
Each demulsifying resin may contain 30-90% alkoxylate by weight, such
as 35-85, 50-85%, 60-85%, 80-85%, 35-60%, or 50-55% alkoxylate by weight. Each
demulsifying resin may have a polymerization number (i.e. the number of alkyl phenol
formaldehyde units) of 2-20, 2-9, 2-8, 6-8, 8-9, or 9. The alkoxylate portion can include
. ethylene oxide ("EO") units, propylene oxide ("PO") units, or a mixture of EO and PO
units, but EO units are preferred. The demulsifying resin is preferably nonylphenol
formaldehyde resin alkoxylate and is more preferably nonylphenol formaldehyde resin
ethoxylate.
In yet another embodiment, the demulsifying composition may comprise
at least two different demulsifying resins. The two different demulsifying resins may
differ in terms of the degree of polymerization, amount of alkoxylation, the type of alkyl
phenol, etc. Preferably, there is a difference in alkoxylation where one of the
demulsifying resins has an alkoxylation that is 50-85%, 60-85%, or 80-85% of the weight
of the molecule, while the other demulsifying resin has an alkoxylation that is 30-60%, or
35-60%, or 50-55% of the weight of the molecule. Preferably, the difference in
alkoxylation between a first demulsifying resin and a second demulsifying resin ranges
from lO-50%, or any range within this range, such as 25-30%. Thus, if one resin has 85%
alkoxylation, and the other one has 35% alkoxylation, then the difference is 50%. If one
demulsifying resin has 60% alkoxylation and the other has 50%, then the difference is
10%. Similarly, if one has 85% alkoxylation and the other one has 55%, then the
12
difference is 30%, and if one has 80% and the other has 55%, then the difference is 25%.
By using two different demulsifying resins with a different amount of alkoxylation, as
identified above, the performance of the demulsifying composition is improved,
particularly with the types of crude oils mentioned above. Each of the two demulsifying
resins would be used as 1-20%, or more preferably, 3-11% by weight of the demulsifying
composition. The ratio of the amount of one demulsifying resin to the other may be 1:9 to
9: 1, 1:3 to 3: 1, and 1: 1. As stated above, the preferred alkoxylation is with EO and/or PO.
The two resins are each preferably used in the demulsifying composition at or above their
critical micelle concentration. At least one of the demulsifying resins may be a
nonylphenol formaldehyde resin alkoxylate with a degree of polymerization of about 8-9
and is about 55% ethylene oxide by weight.
In yet another embodiment, the demulsifying resin may comprise an
adduct of at least one C4-C12 alkyl phenol-formaldehyde resin alkoxylate and the
nonylphenol formaldehyde resin alkoxylate that is at least 50% ethylene oxide by weight.
For example, the demulsifying resin may be an adduct of monomers of a nonylphenol
formaldehyde resin alkoxylate that is at least 50% ethylene oxide by weight, such as 5090%
ethylene oxide, or 70-90% ethylene oxide, and monomers of a butylphenol
formaldehyde resin alkoxylate that is at least 50% ethylene oxide by weight, such as 5090%
ethylene oxide, or 70-90% ethylene oxide by weight. The total degree of
polymerization for both monomers may be 3-10 or 6-9. The ratio of the number of
monomers containing butylphenol versus nonylphenol in the final resin may be 9: 1 to
1:9, or preferably 2: 1 to 1:2. This particular resin is appropriate for crudes having an API
of 28-40. The amount of this resin that can be used is 1-20%, preferably 3-11 % by
weight relative to the demulsifying composition. This resin may be used by itself or in
conjunction with another demulsifying resin described in the present application.
Accordingly, the demulsifying resin may comprise two different resins, each resin with
different alkyl phenol units. For example, the demulsifying resin may comprise a
nonylphenol formaldehyde resin alkoxylate and an amyphenol formaldehyde resin
13
alkoxylate. Alternatively, the demulsifying resin may comprise different alkyl phenol
units, such as nonylphenol and butylphenol, within one resin.
In another embodiment, at least one C4-C12 alkyl phenol-formaldehyde
resin alkoxylate may be a nonylphenol formaldehyde resin alkoxylate that is at least 50%
ethylene oxide by weight. In another embodiment, at least one C4-C12 alkyl phenolformaldehyde
resin alkoxylate may be a nonylphenol formaldehyde resin alkoxylate with
a degree of polymerization of about 8-9 and is about 55% ethylene oxide by weight. In
another embodiment, the C4-C12 alkyl phenol-formaldehyde resin alkoxylate may be
amyl phenol-formaldehyde resin alkoxylate.
As stated above the demulsifying composition also may comprise one or
more surfactants. The surfactants may be polymers which include twoor more blocks of
polyalkoxylates, such as polyethylene oxide, polypropylene oxide, and/or polybutylene
oxide. Thus, the surfactant may be a polyalkylene oxide block copolymer. The
demulsifying composition may contain between 0.5-10% by weight of each block
polyalkoxylate surfactant in the demulsifying composition, and preferably 1.5-6%.
Preferably, the amount of the surfactant is at or above its critical micelle concentration.
The block polyalkoxylate surfactant may be a triblock polyol where the
ratio between EO and PO by weight relative to the total aggregate amount ofEO and PO
may be 30-50% EO and 50-70% PO, and more preferably 40-50% EO and 50-60% PO.
Thus, the block polyalkoxylate surfactant may be less than about 50% ethylene oxide by
weight. In the triblock polyol, there are preferably two blocks of EO (EO1 and E02), and
one block of PO. The ratio by weight between EOI and E02 relative to the total
aggregate amount of EO may be 30-70% EO1 and 30-70% E02, preferably 45-55% EO1
and 45-55% E02, and most preferably, EOI is about the same as E02. The block
polyalkoxylate surfactant, such as the triblock polyol, may have a molecular weight of
1000-9000, preferably from 4000-5000, and usually has an average molecular weight,
Mw , less than about 6,000 g/mol. Preferably, the demulsifying composition contains one
or two block polyalkoxylate surfactants, one of which is preferably the triblock polyol.
14
In yet another method, the surfactant may be a polyalkylene oxide triblock
polyol having the formula:
wherein x, y, and z are each preferably 20, 40, and 20 moles, respectively, and wherein
Mw is about 4,200. Also, x, y, and z may be 76 moles, 32 moles, and 76 moles,
respectively wherein Mw is about 8,400 g/mol. However, x, y, and z may be any integer
greater than one where the molecule has a molecular weight of 1000-9000, preferably
from 4000-5000. The ratio between EO and PO by weight relative to the total aggregate
amount ofEO and PO may be 30-50% EO and 50-70% PO, and more preferably 40-50%
EO and 50-60% PO. Thus, the block polyalkoxylate surfactant may be less than about
50% ethylene oxide by weight. In the triblock polyol, there are preferably two blocks of
EO, and one block of PO, and the ratio between the first block of EO and the second
block of EO by weight relative to the total aggregate amount of EO may be 30-70% of
the first block of EO and 30-70% of the second block of EO, preferably 45-55% of the
first block of EO and 45-55% of the second block of EO, and most preferably, the two
EO blocks have about the same weight as each other. The triblcok polyol may have a
molecular weight of 1000-9000, preferably from 4000-5000, and usually has an average
molecular weight, Mw less than about 6,000 g/mol. Preferably, the demulsifying
composition contains one or two block polyalkoxylate surfactants, one of which is
preferably the triblock polyol.
In another embodiment, the block polyalkoxylate surfactant may comprise
polyalkoxylate blocks on two or more branches of the block polyalkoxylate surfactant,
such as 2-6 branches and preferably 4-6 branches, most preferably four branches. The
polyalkoxylate blocks may be blocks of ethylene oxide ("EO") units, and/or propylene
oxide ("PO") units, and/or butylene oxide ("BO") units. The molecular weight of the
block polyalkoxylate surfactant with two or more branches with polyalkoxylate blocks
15
may be 3000-25000, or preferably 4000-10500, or more preferably 4700-7000.
Preferably, the block polyalkoxylate surfactant contains at least one block of EO units
and at least one block of PO units on each of its 2-6 branches. Preferably, each of these
branches includes only one block of EO units and one block PO units. Also preferably,
the PO blocks are closer to the branch point than the EO blocks. The block
polyalkoxylate surfactant with two or more branches may be included in the demulsifying
composition in an amount of 0.5% to 10%, or preferably 1% to 4% weight relative to the
total demulsifying composition. Preferably, the block polyalkoxylate surfactant is used in
the demulsifying composition at or above its critical micelle concentration.
Examples of this block polyalkoxylate surfactant with two or more
branches with polyalkoxylate blocks may include block copolymers based on
ethylenediamine, propylenediamine, diethylenetriamine, or triethylenetetramine.
Examples of these types. of copolymers are ethylenediamine ethylene oxide I propylene
oxide copolymer, propylenediamine ethylene oxide I propylene oxide copolymer,
diethylenetriamine ethylene oxide I propylene oxide copolymer, and triethylenetetramine
ethylene oxide I propylene oxide copolymer.
One example of the block polyalkoxylate surfactant with two or more
branches may have the formula:
HO(C2~O)XI(C3H60)YI"'- /(C3H60)Y4(C2H40)X4H
N--CH2--CH2-N
HO(C2~O)dC3H60)y2/ "'-(C3H60)Y3(C2H40)x3H
where xl, x2, x3, and x4 may be the same or different and represent the number of
polyethylene oxide units and where yl, y2, y3, and y4 may be the same or different and
represent the number of polypropylene oxide units. The ratio of the polyethylene oxide
units to polypropylene oxide units may range from 10:90 to 90: 10, or 50:50 to 30:70, and
may be about 30:70 or about 50:50. The ethylenediamine ethylene oxide I propylene
oxide copolymer may have about 40% EO by weight and an average molecular weight,
Mw ,of about 6,700.
16
In yet another method, the oil phase may comprise at least one non-polar
organic solvent. Suitable non-polar organic solvents include, but are not limited to,
naphtha, light aromatic naphtha, heavy aromatic naphtha, pentane, cyclopentane, hexane,
cyclohexane, benzene, ethyl benzene, 1,2A-trimethyl benzene, toluene, xylene, cumene,
1A-dioxane, chloroform, diethyl ether, methyl esters of fatty acids (biodiesel), and
diethylene glycol butyl ether (butyl carbitol).
In another method, the demulsifying composition may comprise an
aqueous solvent. The aggregate amount of solvent, whether organic or aqueous, may be
about 10% to 90%, such as 40-90% or 10-75%, or 50-85%, and is preferably 55-75% by
weight of the demulsifying composition. The oil phase and the aqueous phase in the
demulsifying composition may form a colloidal micellar solution. Any ratio of organic
solvent to aqueous solvent is within the scope of the present invention, with the extremes
being 100% aqueous solvent or 100% organic solvent relative to the amount of solvent.
Preferably, the ratio of aqueous solvent to organic solvent is 90:10 to 70:30.
In another method embodiment, the demulsifying composition may further
comprise a coupling agent or stabilizer, to further stabilize the demulsifying composition
and prevent the phase separation. Suitable stabilizers include, but are not limited to,
diethylene glycol butyl ether, hexylene glycol, methyl cellosolve (2-methoxyethanol),
butanol, and octanol. The coupling agent or stabilizer may be present in an amount of 550%,
such as 5-25%, and such as 5-20% of the demulsifying composition. The coupling
agent may be an organic solvent, an example being diethylene glycol butyl ether (i.e.
butyl carbitol). Accordingly, in another embodiment, the demulsifying composition may
further comprise diethylene glycol butyl ether.
In other embodiments, the demulsifying composition may further
comprise one or more aqueous or oil-based crude oil treatments or additives to aid in
demulsification. Accordingly, the aqueous phase may comprise one or more components,
including, but not limited to a pH adjuster, a water-soluble surfactant, a pH adjuster, a
water-soluble surfactant, a flocculant, a wetting agent, a metal complexing agent, a
reverse emulsion breaker, or a corrosion inhibitor. Some of these components are
17
described in other portions of this disclosure in more specificity. It is also anticipated that
the aqueous phase of the demulsifying composition may comprise one or more watersoluble
additives that aid in demulsification.
In one embodiment, the aqueous phase may comprise a water-soluble pH
adjusting agent. The pH adjusting agent may be a base or an acid. Suitable bases may be
hydroxide bases of Group IA and IIA metals. In one embodiment the hydroxide base may
be sodium or potassium hydroxide. In another embodiment, the pH adjuster may be an
organic acid, mineral acid, or a carboxylic acid. Examples of suitable acids include, citric
acid, propane-l ,2,3-tricarboxylic acid, glycolic acid, formic acid, acetic acid, propanoic
acid, butanoic acid, pentanoic acid, oxalic acid, glutaric acid, succinic acid, malonic acid,
ascorbic acid, and lactic acid. Citric acid has the added advantage in that is also a metal
complexing agent and may reduce the amount of metals in the stream being treated. The
pH adjusting agent, such as the hydroxide bases, may be added in effective amounts such
that the demulsifying composition will result in a pH of 6-8.
In one embodiment, the demulsifying composition comprises one or more
inorganic flocculants or coagulants, such as hydrated chlorides and sulfates. Suitable
hydrated chlorides include, but are not limited to, aluminum chloride, aluminum
chlorohydrate, iron chloride, and zinc chloride. Suitable sulfates include, but are not
limited to, aluminum sulfate, and iron sulfate.
In another embodiment, the aqueous phase may comprise one or more
wetting agents like sulfonates and their acids. Suitable sulfonates include, but are not
limited to, sodium dioctyl sulfosuccinate and sodium dodecylbenzene sulfonate and acids
thereof. In another embodiment, the demulsifying composition may further comprise, by
weight, 0.5-5%, or preferably, 1-2% ofa wetting agent, such as dodecylbenzene sulfonic
acid.
In yet another embodiment, the demulsifying composition may comprise a
water-soluble or oil-soluble corrosion inhibitor. The corrosion inhibitor may comprise at
least one imidazoline such as hydroxyethyl imidazoline, aminoethyl imidazoline, and
amidoethyl imidazoline.
18
In another embodiment, a dispersant, such as an alkyl succinic anhydride
based material, may be used in conjunction with the demulsifying composition to
improve performance. The alkyl succinic anhydride based material may be a
polyisobutenyl succinic anhydride based material. While a polyisobutenyl succinic
anhydride-based material may have been used as an antifoulant for crude oil, such as in
upstream applications, this material has special properties that will work conjunctively
with the demulsifying composition to better resolve emulsions in downstream
applications. Asphaltenes in the crude oil are believed to have hydrophilic functionalities
which may result in a colloidal aggregation or flocculation of the asphaltenes at the
interface of the aqueous phase and oil phase in a desalter. These hydrophilic
functionalities decrease the ability of the dispersed phases to migrate towards respective
continuous phases to resolve the emulsion. Thus, asphaltenes make resolving emulsions
in a desalter difficult. The polyisobutenyl succinic anhydride based material is believed to
adsorb onto the asphaltenes and decrease the colloidal aggregation or flocculation and
deposition of the asphaltenes at the oil-water interface, thereby accelerating the speed at
which the emulsion may be resolved by the demulsifying composition. The
polyisobutenyl succinic anhydride based material may be added together with the
demulsifying composition or separately, such as upstream of the addition of the
demulsifying composition. The advantage of the separate addition is that the addition
may be selective for crudes which have an asphaltene content of 0.5% or more, such as
0.5% to 50%, or 0.5% to 10%, or 0.5% to 8%.
The dispersant may be a treated ester that is a mono- or polycarboxylic
acid ester that is further treated with an acylating reagent. The mono- or polycarboxylic
acid ester may have at least one moiety that is a polyol as shown in any of the following
three formulas:
0 0
R2
0"""'- 0",,- 4 R'::c~:C'
............R R2 R4
0 ........ 3 0
R X a y
0 0
19
where R), R2
, R3
, and R4 are the same or different and are selected from the group
consisting ofH, an alkyl, and -GH(OH)(R5
); wherein R5 is H or Cl to CIO alkyl; and
wherein X and Yare the same or different and are H or C) to CIO alkyl, with the proviso
that at least one ofR), R2
, R3
, and R4 is the -GH(OH)(R5
) moiety. Suitable alkyls may be
polyalkenes, including interpolymers of various alkenes, and may include, but are not
limited to, ethylene, propene, isoprene, I-butene, 2-butene, isobutene, 3-pentene, 1hexene,
l-octene, 4-oxtene, 2-methyl-l-heptene, 3-cyclohexyl-l-butene, 2-methyl-5propyl-
l-hexene, styrene, butadiene, and piperylene. The -GH(OH)(R5
) moiety may be
mono or polyhydric alcohols, preferably polyhydric, such as glycerol, erythritol,
pentaerythritol, mannitol, and sorbitol.
The acylating reagent may be aliphatic mono- or polycarbocylic acids,
anhydrides, or halides. Suitable acylating reagents may include, but are not limited to,
fumaric acid, maleic anhydride, maleic acid, succinic anhydride, and succinic acid.
In a preferred embodiment, the acid ester has a polyisobutenyl and
pentaerythritol moiety and is treated with succinic anhydride or succinic acid such that
dispersant is a polyisobutenyl succinic anhydride ester ("PiBS ester") with a polyol
moiety as in the following formula:
o
II
R-a; - c-0-~ "'-.. /~-OI-I
~-c-O-~/~~-OH
II o
wherein R is a polyisobutenyl moiety.
Accordingly, in another embodiment, an alkyl succinic anhydride based
material, such as a polyisobutenyl succinic anhydride based material may be used as the
dispersant. The dispersant, such as the polyisobutylenyl succinic anhydride based
material may be added to the desalter or upstream of the desalter in an amount of 1-1000
20
ppm, or 2-200 ppm, or more preferably, 20-200 ppm by volume of the hydrocarbon
stream.
The polyisobutenyl succinic anhydride based material may be a
polyisobutenyl succinic anhydride derived ester with a molecular weight, Mw , of about
20,000 to about 25,000 in an aromatic solvent. The % actives may range from about 1050%
and the solvent may be aromatic naphtha.
In one embodiment, a method of resolving an emulsion present in a
hydrocarbon stream is disclosed. The method may comprise providing the hydrocarbon
stream and providing a demulsifying composition. The demulsifying composition may
comprise 1) at least one C4-C12 alkyl phenol-formaldehyde resin alkoxylate and 2) at least
one surfactant, wherein the surfactant comprises at least two blocks of alkylene oxide
units. The hydrocarbon stream may be contacted with the demulsifying composition,
thereby coalescing aqueous droplets from the emulsion to form an aqueous stream. The
aqueous stream may then be removed.
In another embodiment, the hydrocarbon stream may comprise crude oil.
In yet another embodiment, the coalescing of aqueous droplets from the emulsion to form
an aqueous stream may occur in a desalter.
In another embodiment, at least one C4-C12 alkyl phenol-formaldehyde
resin alkoxylate may comprise 30-90% alkoxylate units by weight and may have a
polymerization number of 2-20. In another embodiment, the C4-C12 alkyl phenolformaldehyde
resin alkoxylate may comprise ethylene oxide units. The C4-C12 alkyl
phenol-formaldehyde resin alkoxylate may be nonylphenol formaldehyde resin
ethoxylate.
In yet another embodiment, the C4-C12 alkyl phenol-formaldehyde resin
alkoxylate may comprise at least two alkyl phenol-formaldehyde resin alkoxylates having
different amounts of alkoxylation. The two alkyl phenol-formaldehyde resin alkoxylates
may comprise a first alkyl phenol-formaldehyde resin alkoxylate having a percent A by
weight of alkoxylation and a second alkyl phenol-formaldehyde resin alkoxylate having a
percent B by weight of alkoxylation. A minus B may be 10-50%. The ratio by weight of
21
an amount of the first alkyl phenol-formaldehyde resin alkoxy1ate relative to the second
alkyl phenol-formaldehyde resin alkoxylate may be 1:9 to 9: 1. In another embodiment,
the C4-C12 alkyl phenol-formaldehyde resin alkoxylate may comprise a mixed resin with
units of nonylphenol formaldehyde alkoxylate and units of butylphenol formaldehyde
alkoxylate (i.e., one resin with different alkylphenol units). Alternatively, the C4-C12 alkyl
phenol-formaldehyde resin alkoxylate may comprise a first resin with units of
nonylphenol formaldehyde alkoxylate and a second resin with units of amylphenol
formaldehyde alkoxylate.
In another embodiment, at least one surfactant may comprise ethylene
oxide units and propylene oxide units wherein the ratio by weight of the ethylene oxide
units to the total number of ethylene and propylene oxide units is 30-50%.
In yet another embodiment, at least one surfactant may comprise a
polyalkylene oxide triblock polyol having the formula:
CH3
H'O~VO~O}H
x y z
wherein x, y, and z are any integer greater than one where the molecule has a molecular
weight of 1000-9000.
Alternatively, at least one surfactant may comprises a molecule with 2-6
branches each comprising at least one polyalkoxylate block, and wherein said molecule
has a molecular weight of 3000-25000. The surfactant may have the formula:
where xl, x2, x3, and x4 may be the same or different and represent the number of
polyethylene oxide units and where yl, y2, y3, and y4 may be the same or different and
represent the number of polypropylene oxide units, and wherein a ratio of the
polyethylene oxide units to polypropylene oxide units is from 10:90 to 90: 10.
22
In another embodiment, the surfactant may compnse at least two
surfactants.
In yet another embodiment, the demulsifying composition may further
comprise at least one non-polar organic solvent and/or at least one aqueous solvent.
Suitable non-polar organic solvents include, but are not limited to, naphtha, light
aromatic naphtha, heavy aromatic naphtha, pentane, cyclopentane, hexane, cyclohexane,
benzene, ethyl benzene, 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, toluene,
xylene, cumene, 1,4-dioxane, chloroform, diethyl ether, methyl esters of fatty acids
(biodiesel), and diethylene glycol butyl ether. In yet another embodiment, the
demulsifying composition may comprise an organic solvent and an aqueous solvent in an
aggregate amount of about 10 wt% to about 90 wt% based on a total weight of the
demulsifying composition. The demulsifying composition may be a colloidal micellar
solution including an oil phase and an aqueous phase.
In yet another embodiment, the demulsifying composition may be added
to the hydrocarbon stream in an amount ranging from about I to about 200 ppm by
volume of the hydrocarbon stream.
In another embodiment, the method may further comprise contacting the
hydrocarbon stream with a dispersant, wherein the dispersant is an adduct of at least one
acid ester of mono- or polycarboxylic acid and an acylating reagent. Suitable acylating
reagents include, but are not limited to fumaric acid, maleic anhydride, maleic acid,
succinic anhydride, and succinic acid. In another embodiment, the acid ester may have a
polyisobutenyl and a pentaerythritol moiety and the acylating reagent may be succinic
anhydride or succinic acid. In yet another embodiment, the dispersant may be a
polyisobutenyl succinic anhydride derived ester with a molecular weight, Mw , of about
20,000 to about 25,000 in an aromatic solvent.
In yet another embodiment, the dispersant may be added in an amount of
about I to about 1000 ppm by volume of the hydrocarbon stream.
In another embodiment, a demulsifying composition for treating a
hydrocarbon stream is disclosed. The demulsifying composition may comprise 1) at least
23
one C4-C12 alkyl phenol-formaldehyde resin alkoxylate, wherein the C4-C12 alkyl phenolformaldehyde
resin alkoxylate comprises 30-90% alkoxylate units by weight and has a
polymerization number of 2-20 and 2) at least one surfactant, wherein the surfactant
comprises ethylene oxide units and propylene oxide units and the ratio by weight of the
ethylene oxide units to the total number of ethylene and propylene oxide units is 30-50%.
In another embodiment, the C4-C12 alkyl phenol-formaldehyde resin
alkoxylate may comprise at least two alkyl phenol-formaldehyde resin alkoxylates having
different amounts of alkoxylation. The two alkyl phenol-formaldehyde resin alkoxylates
may comprise a first alkyl phenol-formaldehyde resin alkoxylate having a percent A by
weight of alkoxylation and a second alkyl phenol-formaldehyde resin alkoxylate having a
percent B by weight of alkoxylation. A minus B may be 10-50%. The ratio by weight of
an amount of the first alkyl phenol-formaldehyde resin alkoxylate relative to the second
alkyl phenol-formaldehyde resin alkoxylate may be 1:9 to 9: 1. In yet another
embodiment, the C4-C12 alkyl phenol-formaldehyde resin alkoxylate may be nonylphenol
formaldehyde resin ethoxylate. In another embodiment, the C4-C12 alkyl phenolformaldehyde
resin alkoxylate may comprise a mixed resin with units of nonylphenol
formaldehyde alkoxylate and units of butylphenol formaldehyde alkoxylate.
Alternatively, the C4-C12 alkyl phenol-formaldehyde resin alkoxylate may comprise a
first resin with units of nonylphenol formaldehyde alkoxylate and a second resin with
units of amylphenol formaldehyde alkoxylate.
In yet another embodiment, at least one surfactant has formula:
H(C2H40)X1(C3HaO)y\ )C3HaO)Y4(C2H40)X4H
/N-CH2CH2-N,
H(C2H40)x2(C3HaO)Y2 (C3HaO)Y3(C2H40)x3H
where xl, x2, x3, and x4 may be the same or different and represent the number of
polyethylene oxide units and where yI, y2, y3, and y4 may be the same or different and
represent the number of polypropylene oxide units, and wherein a ratio of the
polyethylene oxide units to polypropylene oxide units is from 10:90 to 90: 10.
24
In another embodiment, the demulsifying composItion may further
comprise at least one non-polar organic solvent and/or at least one aqueous solvent.
Suitable non-polar organic solvents include, but are not limited to, naphtha, light
aromatic naphtha, heavy aromatic naphtha, pentane, cyclopentane, hexane, cyclohexane,
benzene, ethyl benzene, 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, toluene,
xylene, cumene, 1,4-dioxane, chloroform, diethyl ether, methyl esters of fatty acids
(biodiesel), and diethylene glycol butyl ether. In yet another embodiment, the
demulsifying composition may comprise an organic solvent and an aqueous solvent in an
aggregate amount of about 10 wt% to about 90 wt% based on a total weight of the
demulsifying composition. The demulsifying composition may be a colloidal micellar
solution including an oil phase and an aqueous phase.
In yet another embodiment, the demulsifying composition may further
comprise a dispersant comprising a polyisobutenyl succinic anhydride derived ester with
a molecular weight, Mw , of about 20,000 to about 25,000 in an aromatic solvent.
EXAMPLES
Exemplary formulations are shown in Table 1. The exemplary
formulations may comprise 10 to 40% actives with the remainder of the formulations
comprising an organic or aqueous solvent or a combination thereof. The actives may
include a polyalkylene oxide triblock polyol with about 40% EO by weight and an
average molecular weight, Mw of about 4,200 ("EO/PO Surf. 40% EO") and at least one
alkyl phenol-formaldehyde resin alkoxylate. The EO/PO Surf. 40% EO may be present in
an amount ranging from about 10 wt% to about 50 wt% based on a combined weight of
the alkyl phenol-formaldehyde resin alkoxylate and the EO/PO Surf.
Suitable alkyl phenol-formaldehyde resin alkoxylates include nonylphenol
formaldehyde resin alkoxylates ("NPF") and/or amylphenol formaldehyde resin
alkoxylates ("APF") with a degree of polymerization ranging from about 4 to about 12
and are about 40% to about 80% ethylene oxide by weight. As shown in Table I, one
such APF may be an amylphenol formaldehyde resin alkoxylate with a degree of
25
polymerization of about 7-8 and is about 40% ethylene oxide by weight ("APF 40%
EO"). Also shown in Table I are suitable NPF. One such NPF may be a nonylphenol
formaldehyde resin alkoxylate with a degree of polymerization of about 6-7 and is about
50% ethylene oxide by weight ("NPF 50% EO"). Another NPF may be a nonylphenol
formaldehyde resin alkoxylate with a degree of polymerization of about 8-9 and is about
55% ethylene oxide by weight ("NPF 55% EO"). Another suitable NPF may be a
nonylphenol formaldehyde resin alkoxylate with a degree of polymerization of about 2-8
and is about 80% ethylene oxide by weight ("NPF 80% EO"). The alkyl phenolformaldehyde
resin alkoxylates may also be adducts of at least two alkyl phenolformaldehyde
resin alkoxylates. In one embodiment, the adduct may be an adduct of a
nonylphenol formaldehyde resin alkoxylate that is at least 50% ethylene oxide by weight
and a butylphenol formaldehyde resin alkoxylate that is at least 50% ethylene oxide by
weight ("NPFIBPF"). In other words, the NPFIBPF is a mixed resin with units of both
nonylphenol formaldehyde alkoxylate and butylphenol formaldehyde alkoxylate.
The actives may also comprise one or more aqueous or oil-based crude oil
treatments or additives to aid in demulsification. One such additive may be an
ethylenediamine ethylene oxide / propylene oxide copolymer with about 40% EO by
weight and an average molecular weight, Mw , of about 6,700 ("ED EO/PO"). The ED
EO/PO may be present in an amount ranging from about I to about 10 wt% of a total
weight of the demulsifying composition. Alternatively, the ED EO/PO may be present in
an amount ranging from about 2 to about 4 wt% of a total weight of the demulsifying
composition.
Another additive example is a wetting agent such as dodecylbenzene
sulfonic acid ("DDBSA"). In one embodiment, the DDBSA may be present in an amount
ranging from about I to about 10 wt% of a total weight of the demulsifying composition.
Alternatively, the DDBSA may be present in an amount ranging from about 2 to about 4
wt%.
TABLE I - DEMULSIFIER FORMULATIONS
26
Raw Materials (wt%)
Actives Solvents
APF NPF NPF
NPFI ED
EOIPO
40% 55% 80% Surf. DDBSA Heavy CaHlaO] HzO
EO EO EO
BPF EOIPO
400/0 EO
Naph.
ExA 10.70 10.70 3.43 5.14 55.03 15.00
ExB 7.13 7.13 2.29 3.43 65.02 15.00
ExC 7.14 7.14 2.29 3.43 20.00 60.00
ExD 3.57 3.57 1.15 1.71 20.00 70.00
ExE 7.14 7.14 2.29 4.43 3.00 15.00 62.00
ExF 3.57 3.57 1.15 1.71 3.00 15.00 72.00
ExG 7.14 7.14 2.29 3.43 20.00 60.00
ExH 3.57 3.57 1.15 1.71 20.00 70.00
ExI 7.14 7.14 2.29 3.43 3.00 15.00 62.00
ExJ 3.57 3.57 1.15 1.71 3.00 15.00 72.00
ExK 22.50 7.50 5.00 65.00
ExJ 22.50 7.50 5.00 5.00 60.00
Note: CSH1S0 3 IS diethylene glycol butyl ether (butyl carbltol)
The efficacy of similar demulsifying formulations was tested on u.s. and
Canadian crude oils. The formulations tested are listed in Table 2.
All the formulations in Table 2 comprised a surfactant that was a
polyalkylene oxide triblock polyol with about 40% EO by weight and an average
molecular weight, Mw of about 4,200 ("EOIPO Surf. 40% EO") and at least one alkyl
phenol-formaldehyde resin alkoxylate (see Table 2). Comparative example 2 ('Comp 2")
comprised an amylphenol formaldehyde resin alkoxylate with a degree of polymerization
of about 7-8 and was about 40% EO by weight ("APF 40% EO"). All the rest of the
formulations tested comprised at least one nonylphenol formaldehyde resin alkoxylate
("NPF"). The first NPF was a nonylphenol formaldehyde resin alkoxylate with a degree
of polymerization of about 6-7 and was about 50% ethylene oxide by weight ("NPF 50%
EO"). The second NPF was a nonylphenol formaldehyde resin alkoxylate with a degree
of polymerization of about 8-9 and was about 55% ethylene oxide by weight ("NPF 55%
EO"). The third NPF was a nonylphenol formaldehyde resin alkoxylate with a degree of
27
polymerization of about 2-8 and was about 80% ethylene oxide by weight ("NPF 80%
EO").
Comparative examples I and 2 ("Comp I" and "Comp 2" respectively)
have no water in the formulations. Comp2 also comprised an oil-soluble surfactant that
was a polyalkylene oxide triblock polyol with about 10% EO and an average molecular
weight, Mw of about 4,400 ("EO/PO Surf. I0% EO").
The resulting formulations, Examples I through 4 (i.e. Ex 1- Ex 4), all had
water in the formulations and were stable, micellar solutions that did not separate when
stored at ambient temperature for more than 30 days. Examples I through 4 also included
an ethylenediamine ethylene oxide / propylene oxide copolymer ("ED EO/PO") that was
about 40% EO by weight and had an average molecular weight, Mw , of about 6,700.
TABLE 2 - DEMULSIFIER FORMULAnONS
Raw Materials (wt%.)
Actives Solvents
APF NPF NPF NPF EOIPO EOIPO
40% 50% 55% 80%. ED Surf. Surf. Heavy Light C,HI40 2 C.H1.03 H2O
EO EO EO EO EOIPO 10% 40% Naph. Naph.
EO EO
Comp
27.0 23.5 4.5 45.0 1
Comp
2 28.0 6.0 6.0 30.0 20.0 10.0
Ex 1 12.5 12.5 4.0 6.0 55.0 10.0
Ex2 12.5 12.5 4.0 6.0 5.0 60.0
Ex3 12.5 12.5 4.0 6.0 55.0 10.0
Ex4 12.5 12.5 4.0 6.0 5.0 60.0
Note: C6HI40 2 IS hexy1ene glycol; CgH180 3 IS diethylene glycol butyl ether (butyl carbltol)
EXAMPLE SET I - CANADIAN CRUDE AND AMERICAN SHALE OIL BLEND
_ A desalter process with an electric field and desalter mix valve was
simulated to evaluate the effect the emulsion breaker (demulsifier) formulations in Table
I had on breaking water and crude oil emulsions. The crude oil used was a blend of
Canadian crudes and American shale oils. The Basic Sediments and Water ("BS&W") of
the crude was about 50 pounds of solids per thousand barrels and 0.1 wt% water. Comp I
28
was used as the comparative example. For these examples, 95 vol% crude oil was mixed
with 5 vol% wash water (pH = 7) in a test tube. Then 3 ppm by volume of a demulsifier
was added to the crude oil and wash water mixture and mixed at 6,000 rpm in a blender
for 2 seconds. For the sedimentation step, the mixture was allowed to settle at a
temperature of about 110 °C and at an electrical field strength of 10 kV. The volume of
free water (mL) was measured at 2, 4,8, 16, and 32 minutes.
The mean water drop is the average measured volume of free water. The
mean water drop indicates both the speed of water drop and the amount of water that had
separated from the emulsion. The water drop with respect to time for Example Set 1 is
shown in FIG. 1. The mean water drop for the various demulsifier fonnulations are
shown in FIG. 2.
EXAMPLE SET 2 - CANADIAN CRUDE OIL
A desalter process with an electric field and desalter mix valve was
simulated to evaluate the effect the emulsion breaker (demulsifier) fonnulations in Table
1 had on breaking water and crude oil emulsions. The crude oil used was Canadian crude
oil from Samia, Ontario. The BS&W of the crude was about 50 pounds of solids per
thousand barrels and 0.1 wt% water. Comp 2 was used as the comparative example. For
these examples, 95 vol% crude oil was mixed with 5 vol% wash water (pH = 7) in a test
tube. Then 3 ppm by volume of a demulsifier was added to the crude oil and wash water
mixture and mixed at 13,000 rpm in a blender for 4 seconds. For the sedimentation step,
the mixture was allowed to settle at a temperature of about 120°C and at an electrical
field strength of 10 kV. The volume of free water (mL) was measured at 2,4,8,16, and
32 minutes.
The mean water drop is the average measured volume of free water. The
mean water drop test indicates both the speed of water drop and the amount of water that
had separated from the emulsion. The water drop with respect to time for Example Set 2
is shown in FIG. 3. The mean water drop for the various demulsifier fonnulations are
shown in FIG. 4.
29
EXAMPLE SET 3 - VENEZUELAN HEAVY CRUDE OIL
A desalter process with an electric field and desalter mix valve was
simulated to evaluate the synergistic effect a dispersant, in this case a polyisobutenyl
succinic anhydride based ester ("PiB ester"), had on breaking water and crude oil
emulsions. For this test, diluted crude oil similar to Venezuelan heavy crude oil was
prepared. The BS&W of the crude was about 84 pounds of solids per thousand barrels
and 0.1 wt% water. Comp 1 was used as the comparative example. For these examples,
95 vol% crude oil was mixed with 5 vol% wash water (pH = 7) in a test tube. Then 3 ppm
of a demulsifier (Comp 1) and/or 100 ppm of a dispersant (PiBS ester) was added to the
crude oil and wash water mixture and mixed at 13,000 rpm in a blender for 4 seconds.
For the sedimentation step, the mixture was allowed to settle at a
temperature of about 120°C and at an electrical field strength of 10 kV. The volume of
free water (mL) was measured at 2, 4,8, 16, and 32 minutes.
The mean water drop is the average measured volume of free water. The
mean water drop test indicates both the speed of water drop and the amount of water that
had separated from the emulsion. The water drop with respect to time for Example Set 3
is shown in FIG. 5. The mean water drop results for the various demulsifier and/or
dispersant treatments are shown in FIG. 6.
This written description uses examples to disclose the invention, including
the best mode, and also to enable any person skilled in the art to practice the invention,
including making and using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the claims, and may include
other examples that occur to those skilled in the art. For example, those skilled in the art
will recognize that the demulsification compositions have multiple applications,
including but not limited to, oil-field or "down-hole" applications or in crude oil refining
applications. Such other examples are intended to be within the scope of the claims if
they have structural elements that do not differ from the literal language of the claims, or
30
if they include equivalent structural elements with insubstantial differences from the
literal languages of the claims.
31

WE CLAIM :
1. A method of resolving an emulsion present in a hydrocarbon stream comprising:
(a) providing said hydrocarbon stream;
(b) providing a demulsifying composition comprising 1) at least one C4-C12 alkyl
phenol-formaldehyde resin alkoxylate and 2) at least one surfactant, wherein said
surfactant comprises at least two blocks of alkylene oxide units;
(c) contacting said hydrocarbon stream with said demulsifying composition;
(d) coalescing aqueous droplets from said emulsion to form an aqueous stream;
and
(e) removing said aqueous stream.
2. The method of claim 1, wherein said hydrocarbon stream comprises crude oil.
3. The method of claim 1, wherein said coalescing of aqueous droplets from said
emulsion to form an aqueous stream occurs in a desalter.
4. The method of claim 1, wherein at least one C4-C12 alkyl phenol-formaldehyde
resin alkoxylate comprises 30-90% alkoxylate units by weight and has a polymerization
number of 2-20.
5. The method of claim 4, wherein said C4-C12 alkyl phenol-formaldehyde resin
alkoxylate comprises ethylene oxide units.
6. The method of claim 5, wherein said C4-C12 alkyl phenol-formaldehyde resin
alkoxylate is nonylphenol formaldehyde resin ethoxylate.
32
7. The method of claim 4, wherein said C4-C12 alkyl phenol-formaldehyde resin
alkoxylate comprises at least two alkyl phenol-formaldehyde resin alkoxylates having
different amounts of alkoxylation.
8. The method of claim 7, wherein the two alkyl phenol-formaldehyde resin
alkoxylates comprise a first alkyl phenol-formaldehyde resin alkoxylate having a percent
A by weight of alkoxylation and a second alkyl phenol-formaldehyde resin alkoxylate
having a percent B by weight of alkoxylation, wherein A minus B is 10-50%, and
wherein the ratio by weight of an amount of the first alkyl phenol-formaldehyde resin
alkoxylate relative to the second alkyl phenol-formaldehyde resin alkoxylate is 1:9 to 9:1.
9. The method of claim 4, wherein said C4-C12 alkyl phenol-formaldehyde resin
alkoxylate comprises a mixed resin with units of nonylphenol formaldehyde alkoxylate
and units ofbutylphenol formaldehyde alkoxylate.
10. The method of claim 4, wherein said C4-C12 alkyl phenol-formaldehyde resin
alkoxylate comprises a first resin with units of nonylphenol formaldehyde alkoxylate and
a second resin with units of amylphenol formaldehyde alkoxylate.
11. The method of claim 1, wherein at least one surfactant comprises ethylene oxide
units and propylene oxide units and the ratio by weight of the ethylene oxide units to the
total number of ethylene and propylene oxide units is 30-50%.
12. The method of claim 11, wherein the at least one surfactant comprises a
polyalkylene oxide triblock polyol having the formula:
CH3
H'o~<}VlO~O}H
x y z
33
wherein x, y, and z are any integer greater than one where the molecule has a molecular
weight of 1000-9000.
13. The method of claim 11, the at least one surfactant comprises a molecule with 2-6
branches each comprising at least one polyalkoxylate block, and wherein said molecule
has a molecular weight of 3000-25000.
14. The method of claim 13, wherein the at least one surfactant has the formula:
H(C2H40)X1 (C3HeO)y\ )C3HeO)y4(C2H4O)x4H
/N-CH2CH2-N,
H(C2H40)x2(C3HeO)Y2 (C3HeO)Y3(C2H40)x3H
where xl, x2, x3, and x4 may be the same or different and represent the number of
polyethylene oxide units and where yl, y2, y3, and y4 may be the same or different and
represent the number of polypropylene oxide units, and wherein a ratio of the
polyethylene oxide units to polypropylene oxide units is from 10:90 to 90: 10.
15. The method of claim 1, wherein the at least one surfactant comprises at least two
surfactants.
16. The method of claim 1, wherein said demulsifying composition further comprises
at least one non-polar organic solvent and/or at least one aqueous solvent.
17. The method of claim 16, wherein at least one non-polar organic solvent is selected
from the group consisting of naphtha, light aromatic naphtha, heavy aromatic naphtha,
pentane, cyclopentane, hexane, cyclohexane, benzene, ethyl benzene, 1,2,4-trimethyl
benzene, 1,3,5-trimethyl benzene, toluene, xylene, cumene, l,4-dioxane, chloroform,
diethyl ether, methyl esters of fatty acids (biodiesel), and diethylene glycol butyl ether.
34
18. The method of claim 16, wherein said demulsifying composition comprises an
organic solvent and an aqueous solvent in an aggregate amount of about 10 wt% to about
90 wt% based on a total weight of said demulsifying composition, and wherein a
colloidal micellar solution is formed including an oil phase and an aqueous phase.
19. The method of claim 1, wherein said demulsifying composition is added to said
hydrocarbon stream in an amount ranging from about 1 to about 200 ppm by volume of
said hydrocarbon stream.
20. The method of claim 1, further comprising contacting said hydrocarbon stream
with a dispersant, wherein said dispersant is an adduct of at least one acid ester of monoor
polycarboxylic acid and an acylating reagent selected from the group consisting of
fumaric acid, maleic anhydride, maleic acid, succinic anhydride, and succinic acid.
21. The method of claim 20, wherein said acid ester has a polyisobutenyl and/or a
pentaerythritol moiety.
22. The method of claim 21, wherein said acylating reagent is succinic anhydride or
succinic acid.
23. The method of claim 22, wherein said dispersant is a polyisobutenyl succinic
anhydride derived ester with a molecular weight, Mw , of about 20,000 to about 25,000
in an aromatic solvent.
24. The method of claim 20, wherein said dispersant is added in an amount of about 1
to about 1000 ppm by volume of the hydrocarbon stream.
25. A demulsifying composition for treating a hydrocarbon stream, said demulsifying
composition comprising 1) at least one C4-C12 alkyl phenol-formaldehyde resin
35
alkoxylate, wherein said C4-C12 alkyl phenol-formaldehyde resin alkoxylate comprises
30-90% alkoxylate units by weight and has a polymerization number of 2-20 and 2) at
least one surfactant, wherein said surfactant comprises ethylene oxide units and
propylene oxide units and the ratio by weight of the ethylene oxide units to the total
number of ethylene and propylene oxide units is 30-50%.
26. The demulsifying composition of claim 25, wherein said C4-C12 alkyl phenolformaldehyde
resin alkoxylate comprises at least two alkyl phenol-formaldehyde resin
alkoxylates having different amounts of alkoxylation.
27. The demulsifying composition of claim 26, wherein the two alkyl phenolformaldehyde
resin alkoxylates comprise a first alkyl phenol-formaldehyde resin
alkoxylate having a percent A by weight of alkoxylation and a second alkyl phenolformaldehyde
resin alkoxylate having a percent B by weight of alkoxylation, wherein A
minus B is 10-50%, and wherein the ratio by weight of an amount of the first alkyl
phenol-formaldehyde resin alkoxylate relative to the second alkyl phenol-formaldehyde
resin alkoxylate is 1:9 to 9: 1.
28. The demulsifying composition of claim 25, wherein said C4-C12 alkyl phenolformaldehyde
resin alkoxylate is nonylphenol formaldehyde resin ethoxylate.
29. The demulsifying composition of claim 25, wherein said C4-C12 alkyl phenolformaldehyde
resin alkoxylate comprises a mixed resin with units of nonylphenol
formaldehyde alkoxylate and units of butylphenol formaldehyde alkoxylate.
30. The demulsifying composition of claim 25, wherein said C4-C12 alkyl phenolformaldehyde
resin alkoxylate comprises a first resin comprising units of nonylphenol
formaldehyde alkoxylate and a second resin comprising units of amylphenol
formaldehyde alkoxylate.
36
31. The demulsifying composition of claim 25, wherein the at least one surfactant has
the formula:
where xl, x2, x3, and x4 may be the same or different and represent the number of
polyethylene oxide units and where yl, y2, y3, and y4 may be the same or different and
represent the number of polypropylene oxide units, and wherein a ratio of the
polyethylene oxide units to polypropylene oxide units is from I0:90 to 90: 10.
32. The demulsifying composition of claim 25, wherein said demulsifying
composition further comprises at least one non-polar organic solvent and/or at least one
aqueous solvent.
33. The demulsifying composition of claim 32, wherein at least one non-polar organic
solvent is selected from the group consisting of naphtha, light aromatic naphtha, heavy
aromatic naphtha, pentane, cyclopentane, hexane, cyclohexane, benzene, ethyl b~nzene,
1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, toluene, xylene, cumene, 1,4-dioxane,
chloroform, diethyl ether, methyl esters of fatty acids (biodiesel), and diethylene glycol
butyl ether.
34. The demulsifying composition of claim 32, wherein said demulsifying
composition comprises an organic solvent and an aqueous solvent in an aggregate amount
of about 10 wt% to about 90 wt% based on a total weight of said demulsifying
composition, and wherein a colloidal micellar solution is formed including an oil phase
and an aqueous phase.
37
35. The demulsifying composition claim 25, wherein said demulsifying composition
further comprises a dispersant comprising a polyisobutenyl succinic anhydride derived
ester with a molecular weight, Mw , of about 20,000 to about 25,000 in an aromatic
solvent.