FIELD OF THE INVENTION
The invention relates to compositions and methods for inhibiting fouling
in hydrocarbons and petrochemicals. More specifically the invention relates to inhibiting
fouling on structural parts exposed to a fluid hydrocarbon or petrochemical stream.
4 BACKGROUND OF THE INVENTION
Petroleum hydrocarbons, petrochemicals, and their feedstocks are
commonly heated to temperatures ranging from 100 OF to about 1000 OF during
processing. Similarly, many petroleum hydrocarbons used as heating fluids on the "hot
side" of heating and heat exchange systems are also heated to such temperature ranges.
When heated to elevated temperatures, petroleum hydrocarbons produce a separate phase
known as fouling deposits within the petroleum hydrocarbon. As the name implies, these
fouling deposits form deposits on the surfaces of processing and heating equipment,
thereby fouling such surfaces. These deposits are of considerable concern in the
petroleum hydrocarbon processing and heating industries.
In petroleum hydrocarbon processing, the deposits reduce the rate of heat
transfer to the crude oil, and eventually, reduce throughput rates. In some cases, the
fouling can even block the flow of crude oil through processing equipment and piping or
clog filter screens, valves, and traps. Accordingly, fouling results in increased energy
I costs, increased maintenance costs for cleaning or screen replacements, and increased
I capital costs for the modification or replacement of refinery equipment. I
I ~ The exact mechanism of fouling is not fully understood, however it
appears that several different components of crude oil may contribute to fouling. Such
components include asphaltenes, coke, organic polymers and organic reaction products,
inorganic silicates, inorganic salts, and metal oxides or sulfides. The metal oxides or
sulfides may further exacerbate fouling by accelerating the hydrocarbon oxidation rate by
promoting degenerative chain branching, resulting in free radicals. The free radicals may
initiate oxidation and polymerization reactions which form gum and sediments.
BRIEF DESCRIPTION OF THE INVENTION
It was surprisingly discovered that some antifoulant compositions or
blends thereof produce robust antifoulant compositions that are effective at inhibiting
fouling in variety of crude types or processed hydrocarbons. Specifically, these
antifoulant compositions were more effective than current formulations at inhibiting
4 fouling in some types of heavy crudes. These antifoulant compositions are also effective
at inhibiting fouling tendencies in hydrocarbons and petrochemicals during high
temperature processing.
Accordingly compositions and methods are disclosed for inhibiting
fouling on structural parts of a system exposed to a fluid hydrocarbon or petrochemical
stream. In one embodiment, a method is disclosed wherein the antifoulant composition
may comprise at least one alkylphenol sulfide ("APS"). In yet another embodiment, the
antifoulant composition may further comprise at least one additional antifouling
component selected from a polyalkylene anhydride ester ("PAAE") dispersant, an alkyl
phosphate phenate sulfide ("APPS"), a polyalkylene succinimide ("PAS"), and a
polyalkylene thiophosphonic acid ester ("PETPA). In another embodiment, the PAAE
4P dispersant may comprise an adduct of at least one acid ester of mono- or polycarboxylic
acid and an acylating reagent selected from the group consisting of fumaric acid, maleic
anhydride, maleic acid, succinic anhydride, and succinic acid. In another embodiment,
the ester may have a polyisobutenyl and/or a pentaerythritol moiety. In yet another
embodiment, the acylating reagent may be succinic anhydride or succinic acid.
In another embodiment, the alkylphenol sulfide APS may be
dodecylphenol sulfide. In yet another embodiment, the alkylphenol sulfide APS may be
overbased with calcium. Likewise, the alkyl phosphate phenate sulfide APPS may be
overbased with calcium.
I In another method, the antifoulant composition may be added to the fluid
hydrocarbon or petrochemical stream in an amount ranging from about 10 to about
100,000 ppm by volume of the fluid hydrocarbon or petrochemical stream. Alternatively,
the antifoulant composition may be added to the fluid hydrocarbon or petrochemical
stream in an amount ranging from about 50 to about 5,000 ppm by volume of the
hydrocarbon or petrochemical stream.
In yet another method, at least one structural part is selected from
hydrocarbon or petroleum storage units, heat exchangers, piping, pumps, flow meters,
valves, desalters, preheat furnaces, furnaces, coker preheaters, cokers, distillation
e columns, fractionation columns, atmospheric columns, pipe stills, debutanizers, reactors,
fluid catalytic cracking units, fluid catalytic cracking slurry settlers, hydrocracking units,
steam cracking units, thermal cracking units, visbreakers, reflux units, condensers, and
scrubbers.
Another method is disclosed that may comprise adding an antifoulant
composition to the fluid hydrocarbon or petrochemical stream. The antifoulant
composition may comprise at least one polyalkylene anhydride ester ("PAAE)
dispersant. The dispersant may comprise an adduct of at least one acid ester of mono- or
polycarboxylic acid and an acylating reagent selected from the group consisting of
fumaric acid, maleic anhydride, maleic acid, succinic anhydride, and succinic acid. In
another embodiment, the acid ester may have a polyisobutenyl andlor a pentaerythritol
@ moiety. In another embodiment, the acylating reagent may be succinic anhydride or
succinic acid. In yet another method, the dispersant may be a polyisobutenyl succinic
-
anhydride derived ester ("PASAE) with a molecular weight, M" , of about 1,000 to
about 25,000 in an aromatic solvent. In another embodiment, the dispersant may be added
in an amount of about 1 to about 1000 ppm by volume of the hydrocarbon or
petrochemical stream.
The antifoulant composition may further comprise at least one additional
antifouling component. Suitable antifouling components include, but are not limited to,
an alkylphenol sulfide ("APS"), an alkyl phosphate phenate sulfide ("APPS"), a
polyalkylene succinimide ("PAS"), and a polyalkylene thiophosphonic acid ester
("PETPA).
In another embodiment, at least one alkylphenol sulfide APS may be
selected from the group consisting of nonylphenol sulfide and dodecylphenol sulfide. In
yet another embodiment, the alkylphenol sulfide APS may be overbased with calcium. In
another embodiment, the alkyl phosphate phenate sulfide APPS may be overbased with
calcium.
In another embodiment, the antifoulant composition may be added to the
fluid hydrocarbon or petrochemical stream in an amount ranging from about 10 to about
a 100,000 ppm by volume of the fluid hydrocarbon or petrochemical stream. Alternatively,
the antifoulant composition may be added to the fluid hydrocarbon or petrochemical
stream in an amount ranging from about 50 to about 5,000 ppm by volume of the fluid
hydrocarbon or petrochemical stream.
Antifoulant compositions for inhibiting fouling on structural parts of a
system exposed to a fluid hydrocarbon or petrochemical stream are also disclosed. In one
embodiment, the antifoulant composition may comprise at least one polyalkylene
anhydride ester ("PAAE) dispersant. The dispersant may comprise an adduct of at least
one acid ester of mono- or polycarboxylic acid and an acylating reagent selected from the
group consisting of fumaric acid, maleic anhydride, maleic acid, succinic anhydride, and
succinic acid. In another embodiment, the dispersant may be a polyisobutenyl succinic
m -
anhydride derived ester ("PASAE) with a molecular weight, MW , of about 1,000 to
about 25,000 in an aromatic solvent.
In another embodiment, the antifoulant composition may further comprise
at least one additional antifouling component selected from an alkylphenol sulfide
CAPS"), an alkyl phosphate phenate sulfide ("APPS"), a polyalkylene succinimide
("PAS"), and a polyalkylene thiophosphonic acid ester ("PETPA). In another
embodiment, at least one alkylphenol sulfide APS may be selected from the group
consisting of nonylphenol sulfide and dodecylphenol sulfide. In another embodiment, the
alkylphenol sulfide APS may be overbased with calcium. In yet another embodiment, the
alkyl phosphate phenate sulfide APPS may be overbased with calcium.
Other antifoulant compositions for inhibiting fouling on structural parts of
a system exposed to a fluid hydrocarbon or petrochemical stream are also disclosed
comprising at least one alkyl phenol sulfide CAPS"). In yet another embodiment, the
antifoulant compositions may further comprise at least one additional antifouling
component selected from a polyalkylene anhydride ester ("PAAE) dispersant, an alkyl
phosphate phenate sulfide ("APPS"), a polyalkylene succinimide ("PAS"), and a
polyalkylene thiophosphonic acid ester ("PETPA). In another embodiment, the
e dispersant may comprise an adduct of at least one acid ester of mono- or polycarboxylic
acid and an acylating reagent selected from the group consisting of fumaric acid, maleic
anhydride, maleic acid, succinic anhydride, and succinic acid. The dispersant may be a
polyisobutenyl succinic anhydride derived ester ("PASAE) with a molecular weight,
-
M\v , of about 1,000 to about 25,000 in an aromatic solvent.
In another embodiment, the alkylphenol sulfide APS may be
dodecylphenol sulfide. In yet another embodiment, the alkylphenol sulfide APS may be
overbased with calcium. Likewise, the phosphate phenate sulfide APPS may be
overbased with calcium.
BRIEF DESCRIPTION OF THE DRAWINGS
8 FIG. 1 shows Hot Liquid Process Simulator ("HLPS") HLPS curves of the
differences in inlet and outlet temperatures of various treatments in flashed crude from
the United States.
FIG. 2 shows HLPS outlet temperature curves of various treatments in
residual oil from the United Arab Emirates.
FIG. 3 shows HLPS outlet temperature curves of various treatments in gas
oil from the Russian Federation.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
It was surprisingly discovered that some anti foulant compositions or
blends thereof produce robust antifoulant compositions that are effective at inhibiting
fouling in variety of crude types or processed hydrocarbons. Specifically, these
antifoulant compositions were more effective than current formulations at inhibiting
fouling in some types of heavy crudes. For example, embodiments of the antifoulant
compositions are particularly effective on crudes or crude blends with an American
Petroleum Institute ("API") gravity ranging from about 20 to 54 (degrees). The crudes or
crude blends may comprise greater than, or equal to, about 0.1 wt% asphaltenes. These
crudes may also have more than about 60 pounds of filterable solids per thousand barrels;
a such as 20-500 lbs., or 20-200 lbs., or 60-200 lbs. Exemplary blends for which the
antifoulant compositions are particularly effective include blends of Canadian crude oils
with American shale oils, sweet crudes, Bakken crude, Russian crude oil and crude oil
from the United Arab Emirates. These antifoulant compositions are also effective at
inhibiting fouling tendencies in hydrocarbons and petrochemicals during high
temperature processing.
Without limiting the invention to one theory of operation, it is thought that
the polar atoms in the dispersants and detergents of the antifouling compositions
generally function to disperse and suspend the undesirable carbonaceous materials, such
as asphaltene macromolecules, that form during heating of the crude oil. These polar
atoms may function to chelate with the undesirable carbonaceous materials to thereby
m assist in the dispersion of the same in the liquid phase. Thus, the antifouling compositions
inhibit or prevent the accumulation of undesirable carbonaceous materials on the internal
surfaces of the equipment.
The antifoulant compositions may be added to any hydrocarbon or
petrochemical system where fouling is a concern. Examples of such systems include, but
are not limited to, hydrocarbon tank farms, ships, tankers, and railway cars transporting
hydrocarbons, and crude oil refineries. Specific types of units found in these systems,
include, but are not limited to, hydrocarbon or petroleum storage units, heat exchangers,
piping, pumps, flow meters, valves, desalters, preheat furnaces, furnaces, coker
preheaters, cokers, distillation columns, fractionation columns, atmospheric columns,
pipe stills, debutanizers, reactors, fluid catalytic cracking units, fluid catalytic cracking
slurry settlers, hydrocracking units, steam cracking units, thermal cracking units,
visbreakers, reflux units, condensers, and scrubbers.
Accordingly, compositions and methods are disclosed for inhibiting
fouling on structural parts of a system exposed to a fluid hydrocarbon or petrochemical
stream. In one embodiment, a method is disclosed that may comprise adding an
antifoulant composition to the fluid hydrocarbon or petrochemical stream. The
antifoulant composition may comprise at least one polyalkylene anhydride ester
("PAAE") dispersant. The dispersant may comprise an adduct of at least one acid ester of
mono- or polycarboxylic acid and an acylating reagent selected from the group consisting
of fumaric acid, maleic anhydride, maleic acid, succinic anhydride, and succinic acid. In
another embodiment, the acid ester may have a polyisobutenyl and/or a pentaerythritol
moiety. In another embodiment, the acylating reagent may be succinic anhydride or
succinic acid. In yet another method, the dispersant may be a polyisobutenyl succinic
-
anhydride derived ester ("PASAE) with a molecular weight, M w , of about 1,000 to
about 25,000 in an aromatic solvent. In another embodiment, the dispersant may be added
in an amount of about 1 to about 1000 ppm by volume of the hydrocarbon or
petrochemical stream.
In another embodiment, a polyalkylene anhydride ester ( " P M ' )
0 dispersant, such as an alkyl succinic anhydride based material, may be used as an
antifoulant composition. Alternatively, it may be used with other antifoulant
compositions to improve performance. The alkyl succinic anhydride based material may
be a polyisobutenyl succinic anhydride based material. The polyisobutenyl succinic
anhydride-based material does not have nitrogen, sulfur or metals, making it more
environmentally friendly than many other dispersants, in addition to being harmless to
the processing of hydrocarbons and petrochemicals. The polyisobutenyl succinic
anhydride-based material is not just useful in upstream applications, such as oil fields and
transportation vessels, it may be used in downstream applications, for example in a
refinery in the preheat train or in hydrotreaters. In addition, this material has special
properties that will work conjunctively with demulsifying compositions to better resolve
emulsions in the desalting processes.
Asphaltenes in the crude oil are believed to have hydrophilic
functionalities which may result in a colloidal aggregation or flocculation of the
asphaltenes due to the insolubility in a given composition of the hydrocarbon or
petrochemical mixture, resulting in adsorption at the interface of the aqueous phase and
oil phase in a desalter, or at other metallic surfaces of processing equipment. The
antifoulant compositions are believed to adsorb onto the asphaltenes and decrease the
colloidal aggregation or flocculation and deposition of the asp haltenes at the oil-water
interface and surfaces of processing equipment to both accelerate emulsion resolution and
mitigate fouling.
The polyalkylene anhydride ester ("PAAE) dispersant may be a treated
ester that is a mono- or polycarboxylic acid ester that is krther 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:
where R', R2, R3, and R4 are the same or different and are selected from the group
consisting of H, an alkyl, and -cH(oH)(R~); wherein R5 is H or Cl to Clo alkyl; and
wherein X and Y are the same or different and are H or C1 to Clo alkyl, with the proviso
that at least one of R', R2, R3, and R4 is the -cH(oH)(R') moiety. Suitable alkyls may be
polyalkenes, including interpolymers of various alkenes, and may include, but are not
limited to, ethylene, propene, isoprene, 1-butene, 2-butene, isobutene, 3-pentene, 1-
hexene, 1 -octene, 4-oxtene, 2-methyl-1 -heptene, 3-cyclohexyl- 1 -butene, 2-methyl-5-
propyl-1-hexene, styrene, butadiene, and piperylene The -cH(oH)(R~) 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
the dispersant is a polyisobutenyl succinic anhydride ester ("PiBS ester") with a polyol
moiety 'as in the following formula:
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 polyisobutenyl succinic anhydride based material may be a
polyisobutenyl succinic anhydride derived ester with a molecular weight, zw , of about
m 1,000 to about 25,000 in an aromatic solvent. The % actives may range from about 10-
50% and the solvent may be aromatic naphtha.
The antifoulant composition may further comprise at least one additional
antifouling component. Suitable antifouling components include, but are not limited to,
an alkylphenol sulfide CAPS"), an alkyl phosphate phenate sulfide ("APPS"), a
polyalkylene succinimide ("PAS"), and a polyalkylene thiophosphonic acid ester
("PETPA). The ratio by weight of an amount of the first polyalkylene anhydride ester
("PAAE) dispersant relative to the additional antifouling component or components may
be 1.9 to 9:l.
As used herein, an APS is an alkylphenol sulfide salt highly overbased
with an alkaline earth metal, such as calcium (Ca), manganese (Mg), or barium (Ba), to
neutralize the salt. The alkaline earth metal may be the oxides or hydroxides of alkaline
earth metals such as Ca(OH)2, CaO, MgO, Mg(OH)2, etc. Accordingly, in one
embodiment, the alkylphenol sulfide APS may be overbased with calcium.
A suitable APS may have the general formula:
where R~ is a C5 to CZ4 alkyl, x is an integer from 1 to 4, y is an integer from 0 to 3, and z
is an integer from 1 to 5. Accordingly, in another embodiment, at least one alkylphenol
sulfide APS may be selected from the group consisting of nonylphenol sulfide and
dodecylphenol sulfide.
A portion of the APS described above may be esterified with phosphoric
acid to produce an alkyl phosphate phenate sulfide APPS wherein about 20-40% of the
phenol hydroxy groups have been phosphonated. In yet another embodiment, the alkyl
phosphate phenate sulfide APPS may be overbased with calcium.
The polyalkylene succinimide ("PAS") may be the reaction product of an
alkyl succinic acid or anhydride and a polyalkylene polyamine. A suitable PAS includes
polyisobutenyl succinimide that is a reaction product of ethylenediamine or
diethylenetriamine with a polyisobutenyl succinic anhydride. The polyalkylene
thiophosphonic acid ester PETPA may be the reaction product of alkenyl polymers with
P2S5. A suitable PETPA includes the reaction product that is a pentaerythritol ester of
polyisobutenylthiophosphonic acid wherein the polisobutenyl moiety has an average
molecular weight of about 1300.
In another embodiment, the antifoulant composition may be added to the
fluid hydrocarbon or petrochemical stream in an amount ranging from about 10 to about
100,000 ppm by volume of the fluid hydrocarbon or petrochemical stream. Alternatively,
the antifoulant composition may be added to the fluid hydrocarbon or petrochemical
stream in an amount ranging from about 50 to about 5,000 ppm by volume of the fluid
hydrocarbon or petrochemical stream.
Another method is disclosed wherein the antifoulant composition may
comprise at least one alkylphenol sulfide ("APS')). In yet another embodiment, the
antifoulant composition may hrther comprise at least one additional antifouling
e component selected from a polyalkylene anhydride ester ("PAAE) dispersant, an alkyl
phosphate phenate sulfide ("APPS"), a polyalkylene succinimide ("PAS"), and a
polyalkylene thiophosphonic acid ester ("PETPA). In another embodiment, the PAAE
dispersant may comprise an adduct of at least one acid ester of mono- or polycarboxylic
acid and an acylating reagent selected from the group consisting of fumaric acid, maleic
anhydride, maleic acid, succinic anhydride, and succinic acid. In another embodiment,
the ester may have a polyisobutenyl and/or a pentaerythritol moiety. In yet another
embodiment, the acylating reagent may be succinic anhydride or succinic acid. In another
embodiment, the alkylphenol sulfide APS may be dodecylphenol sulfide. The ratio by
weight of an amount of the first alkylphenol sulfide CAPS") relative to the additional
antifouling component or components may be 1 :9 to 9: 1. * In another method, the antifoulant composition may be added to the fluid
hydrocarbon or petrochemical stream in an amount ranging from about 10 to about
100,000 ppm by volume of the fluid hydrocarbon or petrochemical stream. Alternatively,
the antifoulant composition may be added to the fluid hydrocarbon or petrochemical
stream in an amount ranging from about 50 to about 5,000 ppm by volume of the
hydrocarbon or petrochemical stream.
Antifoulant compositions for inhibiting fouling on structural parts of a
system exposed to a fluid hydrocarbon or petrochemical stream are also disclosed. In one
embodiment, the antifoulant composition may comprise at least one polyalkylene
I anhydride ester ("PAAE) dispersant. The dispersant may comprise an adduct of at least
I
l one acid ester of mono- or polycarboxylic acid and an acylating reagent selected from the
group consisting of fumaric acid, maleic anhydride, maleic acid, succinic anhydride, and
succinic acid. In another embodiment, the dispersant may be a polyisobutenyl succinic
-
anhydride derived ester ("PASAE) with a molecular weight, Mw , of about 1,000 to
about 25,000 in an aromatic solvent.
I : In another embodiment, the antifoulant composition may further comprise
I
at least one additional antifouling component selected from an alkylphenol sulfide
("APS"), an alkyl phosphate phenate sulfide ("APPS"), a polyalkylene succinimide
a ("PAS"), and a polyalkylene thiophosphonic acid ester ("PETPA). In another
embodiment, at least one alkylphenol sulfide APS may be selected from the group
consisting of nonylphenol sulfide and dodecylphenol sulfide. In another embodiment, the
alkylphenol sulfide APS may be overbased with calcium. In yet another embodiment, the
alkyl phosphate phenate sulfide APPS may be overbased with calcium.
Other antifoulant compositions for inhibiting fouling on structural parts of
a system exposed to a fluid hydrocarbon or petrochemical stream are also disclosed
comprising at least one alkyl phenol sulfide ("APS"). In yet another embodiment, the
antifoulant compositions may further comprise at least one additional antifouling
component selected from a polyalkylene anhydride ester ("PAAE) dispersant, an alkyl
phosphate phenate sulfide ("APPS"), a polyalkylene succinimide ("PAS"), and a * polyal kylene thiophosphonic acid ester ("PETPA). In another emobidment, the
dispersant may comprise an adduct of at least one acid ester of mono- or polycarboxylic
acid and an acylating reagent selected from the group consisting of fumaric acid, maleic
anhydride, maleic acid, succinic anhydride, and succinic acid. The dispersant may be a
I polyisobutenyl succinic anhydride derived ester ("PASAE) with a molecular weight,
-
Mw , of about 1,000 to about 25,000 in an aromatic solvent.
In another embodiment, the alkylphenol sulfide APS may be
dodecylphenol sulfide. In yet another embodiment, the alkylphenol sulfide APS may be
overbased with calcium. Likewise, the phosphate phenate sulfide APPS may be
overbased with calcium.
EXAMPLES
HLPS ANTIFOULANT TEST
A Hot Liquid Process Simulator ("HLPS") was used to compare the
antifouling efficacy of overbased calcium dodecy 1 phenol sulfides ("DDP S') and DDPS
blends with currently used antifoulant compositions.
The HLPS is an annular heat exchanger with a steel tube in the center that
e is heated to a constant temperature. Oil samples with various treatment compositions are
passed once through the annulus. As fouling deposits build up on the heated tube surface,
the deposits act as an insulator, resulting in a temperature drop in the oil sample at the
annulus outlet. The overall heat-transfer coefficient, U, is calculated every 2 minutes
during the test by measuring the temperatures of the oil sample at the inlet and outlet of
the annulus. The U coefficient is then used to calculate the area under the various heattransfer
curves of the treated oil samples. These areas are then compared with the area
under the heat-transfer curve for a control, or blank, wherein no antifoulant treatment is
added. The percent reduction in fouling is determined by comparing the calculated area
under the heat-transfer curve for a control, or blank, ( A~onrrol ) with the calculated area
under the heat-transfer curve of the treated oil samples ( A~reat ) as in equation 1.
6
FIG. 1 shows the curves of the differences in inlet and outlet temperatures
of various treatments in flashed crude from the United States. The inner steel tube of the
HLPS was maintained at 450 O C . The exemplary treatment composition included a
polyalkylene anhydride ester dispersant; in this case, a polyisobutenyl succinic anhydride
derived ester ("PASAE). The comparative treatment compositions included blends of
calcium overbased nonylphenol sulfides and overbased calcium alkyl phosphate phenate
sulfides ("NPSPPS I"), a polyalkylenemethiophosphonic acid ester ("PETPA"), and a
blend thereof ("PETPA + NPSPPS"). The data for NPSPPS 1 is an average of two
HLPS test results.
FIG. 2 shows the curves of the outlet temperature of various treatments in
residual oil from the United Arab Emirates. The inner steel tube of the HLPS was
maintained at 550 OC. The exemplary treatment compositions included overbased
calcium dodecylphenol sulfides ("DDPS") and blends of DDPS and overbased calcium
alkyl phosphate phenate sulfides ("DDPSPPS"). The comparative treatment
m compositions included polyisobutylene succinimide ("PiBS") and a blend of calcium
overbased nonylphenol sulfides and overbased calcium alkyl phosphate phenate sulfides
("NPSPPS"). The percent reduction in fouling ("% Reduction ") in the treated residual
oil samples was 2.7% for the PiBS-treated oil, 15% for the oil treated with 20 ppm
NPSPPS, 28.8% for the oil treated with 50 ppm NPSPPS, 25.2% for the DDPS-treated
residual oil, and 26.3% for the DDPSPPS-treated residual oil.
FIG. 3 shows the curves of the outlet temperature of various treatments in
gas oil from the Russian Federation. The inner steel tube of the HLPS was maintained at
I
525 OC. The exemplary treatment compositions included overbased calcium
dodecylphenol sulfides ("DDPS") and blends of DDPS and overbased calcium alkyl
phosphate phenate sulfides ("DDPSPPS"). The comparative treatment composition was
0 a blend of calcium overbased nonylphenol sulfides and overbased calcium alkyl
phosphate phenate sulfides ("NPSPPS"). The percent reduction in fouling
((Lc'o Reduction ") in the treated gas oil samples was 50.1% for NPSPPS-treated gas
oil, 55.3% for the DDPS-treated gas oil, and 59.4% for the DDPSPPS-treated gas oil.
TURBISCAN@ TEST
As the detergents and dispersants are thought to disperse and suspend the
undesirable carbonaceous materials in the liquid hydrocarbon phase, the effectiveness of
various treatments may be evaluated by evaluating the stability, or in contrast, the
separability of the dispersions created by the various treatments. A TurbiscanQ
dispersion stability analyzer measures the separability of a given dispersion by measuring
light backscattering and transmission along the height of the sample with respect to time.
Accordingly, the analyzer detects particle migration and changes in particle size. Both
particle migration and an increase in particle size may indicate separation of the solid and
liquid phases in the dispersion. Thus, samples with a low separability number are highly
stable dispersions that are less likely to result in the accumulation of fouling deposits in
the interior surfaces of equipment.
The TurbiscanQ results of various treatments on different crude sources
e are shown in Tables 1 through 4 below. Table 1 shows the separability numbers of
various treatment compositions on asphaltenic crude ("Batch 1") from U.S. location A.
The comparative treatment compositions are either a polyalkylenemethiophosphonic acid
ester ("PETPA), a polyisobutylene succinimide ("PiBS"), or blends of calcium
overbased nonylphenol sulfides and overbased calcium alkyl phosphate phenate sulfides
("NPSPPS"). All the exemplary treatment compositions comprise a calcium overbased
dodecylphenol sulfide salt ("DDPS")). In addition to DDPS, the exemplary compositions
may hrther comprise known antifoulant compositions such as NPSPPS, PETPA, PiBS,
or combinations thereof.
Table 1 - U. S. Location A; Batch 1
Exemplary
Comparative
Exemplary
Exemplary
Exemplary
Comparative
Blank
500
150
250
150
400
500
500
250
200
100
4.4
6.1
7
9.8
10.6
12.8
12.7
Table 2 shows the separability numbers of various treatment compositions
on a second batch of asphaltenic crude ("Batch 2") from U.S. location A. The
comparative treatment compositions are either polyalkylenemethiophosphonic acid ester
("PETPA), blends of calcium overbased nonylphenol sulfides and overbased calcium
alkyl phosphate phenate sulfides ("NPSPPS"), or blends of PETPA and NPSPPS. All
the exemplary treatment compositions comprise a calcium overbased dodecylphenol
sulfide salt ("DDPS"). In addition to DDPS, the exemplary compositions may further
e comprise known antifoulant compositions such as NPSPPS, PETPA, PiBS, or
combinations thereof.
Table 2 - U.S. Location A; Batch 2
Table 3 shows the separability numbers of various treatment compositions
on crude from U.S. location B. The comparative treatment compositions are either
polyalkylenemethiophosphonic acid ester ("PETPA), blends of calcium overbased
nonylphenol sulfides and overbased calcium alkyl phosphate phenate sulfides
("NPSPPS"), or blends of PETPA and NPSPPS. All the exemplary treatment
compositions comprise a calcium overbased dodecylphenol sulfide salt ("DDPS"). In
Exemplary
Comparative
Exemplary
Comparative
Blank
200
5 0
150
200
150
5 0
6
7.3
8.5
11.3
12.8 * 0.7
addition to DDPS, the exemplary compositions may further comprise known antifoulant
compositions such as NPS/PPS, PETPA, PiBS, or combinations thereof.
Table 3 - U. S. Location B
Table 4 shows the separability numbers of various treatment compositions
on crude from U.S. location C. The comparative treatment compositions are either a
polyalkylenemethiophosphonic acid ester ("PETPA), a polyisobutylene succinimide
("PiBS"), or blends of calcium overbased nonylphenol sulfides and overbased calcium
alkyl phosphate phenate sulfides ("NPS/PPS7'). All the exemplary treatment compositions
comprise a calcium overbased dodecylphenol sulfide salt ("DDPS") or a polyisobutenyl
succinic anhydride derived ester ("PASAE). Exemplary treatment compositions may
comprise both DDPS and PASAE and/or may further comprise known antifoulant
compositions such as NPS/PPS, PETPA, PiBS, or combinations thereof.
Exemplary
Comparative
Exemplary
Comparative
Comparative
Blank
Table 4 - U. S. Location C
I Comparative I 1000 4.4 I
200
100
100
150
100
200
100
5 0
3.8
8.5
9.9
13.8
11.8 * 0.3
13.1 k 0.6
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,
I
I
I including making and using any devices or systems and performing any incorporated
a methods. The patentable scope of the invention is defined by the claims, and may include
i other examples that occur to those skilled in the art. 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 if they include equivalent structural elements with
insubstantial differences from the literal languages of the claims.

WE CLAIM :
1. A method of inhibiting fouling on structural parts of a system exposed to a fluid
hydrocarbon or petrochemical stream comprising adding an antifoulant composition to
said fluid hydrocarbon or petrochemical stream, said antifoulant composition comprising:
(1) at least one polyalkylene anhydride ester ("PAAE") dispersant, said dispersant
comprising an adduct of at least one acid ester of mono- or polycarboxylic acid and an
acy 1 ating reagent selected from the group consisting of fumaric acid, maleic anhydride,
maleic acid, succinic anhydride, and succinic acid.
a
i 2. The method of claim 1, wherein said acid ester has a polyisobutenyl and/or a
I pentaerythritol moiety.
3. The method of claim 1, wherein said acylating reagent is succinic anhydride or
succinic acid.
I
4. The method of claim 3, wherein said dispersant is a polyisobutenyl succinic
-
anhydride derived ester ("PASAE) with a molecular weight, MW , of about 1,000 to
about 25,000 in an aromatic solvent.
1 5. The method of claim 1, wherein said dispersant is added in an amount of about 1
I to about 1000 ppm by volume of said hydrocarbon or petrochemical stream.
6. The method of claim 1, wherein said antifoulant composition further comprises at
least one additional antifouling component selected from components (2), (3), (4), and (5)
wherein:
component (2) is an alkylphenol sulfide CAPS");
component (3) is an alkyl phosphate phenate sulfide ("APPS");
component (4) is a polyalkylene succinimide ("PAS"); and
component (5) is a polyalkylene thiophosphonic acid ester ("PETPA).
7. The method of claim 6, wherein at least one alkylphenol sulfide APS is selected
from the group consisting of nonylphenol sulfide and dodecylphenol sulfide.
8. The method of claim 6, wherein said alkylphenol sulfide APS is overbased with
calcium.
9. The method of claim 6, wherein said alkyl phosphate phenate sulfide APPS is
0 overbased with calcium.
10. The method of claim 1, wherein said antifoulant composition is added to said
fluid hydrocarbon or petrochemical stream in an amount ranging from about 10 to about
100,000 ppm by volume of said fluid hydrocarbon or petrochemical stream.
11. The method of claim 10, wherein said antifoulant composition is added to said
fluid hydrocarbon or petrochemical stream in an amount ranging from about 50 to about
5,000 ppm by volume of said fluid hydrocarbon or petrochemical stream.
12. The method of claim 1, wherein at least one structural part is selected from
0 hydrocarbon or petroleum storage units, heat exchangers, piping, pumps, flow meters,
valves, desalters, preheat furnaces, hrnaces, coker preheaters, cokers, distillation
columns, fractionation columns, atmospheric columns, pipe stills, debutanizers, reactors,
fluid catalytic cracking units, fluid catalytic cracking slurry settlers, hydrocracking units,
steam cracking units, thermal cracking units, visbreakers, reflux units, condensers, and
scrubbers.
13. A method of inhibiting fouling on structural parts of a system exposed to a fluid
hydrocarbon or petrochemical stream comprising adding an antifoulant composition to
said fluid hydrocarbon or petrochemical stream, said antifoulant composition comprising:
(2) at least one alkylphenol sulfide CAPS").
14. The method of claim 13, wherein said antifoulant composition further comprises
at least one additional antifouling component selected from components (I), (3), (4), and
(5) wherein:
component (1) is a polyalkylene anhydride ester ("PAAE") dispersant, said
dispersant comprising an adduct of at least one acid ester of mono- or polycarboxylic acid
and an acylating reagent selected from the group consisting of fumaric acid, maleic
anhydride, maleic acid, succinic anhydride, and succinic acid;
component (3) is an alkyl phosphate phenate sulfide ("APPS");
component (4) is a polyalkylene succinimide ("PAS"); and
component (5) is a poly a1 kylene thiophosphonic acid ester ("PETPA).
15. The method of claim 14, wherein said ester has a polyisobutenyl andlor a
pentaerythritol moiety.
16. The method of claim 14, wherein said acylating reagent is succinic anhydride or
succinic acid.
17. The method of claim 13, wherein said alkylphenol sulfide APS is dodecylphenol
sulfide.
18. The method of claim 13, wherein said alkylphenol sulfide APS is overbased with
calcium.
19. The method of claim 14, wherein said alkyl phosphate phenate sulfide APPS is
overbased with calcium.
20. The method of claim 13, wherein said antifoulant composition is added to said
fluid hydrocarbon or petrochemical stream in an amount ranging from about 10 to about
100,000 ppm by volume of said fluid hydrocarbon or petrochemical stream.
21. The method of claim 20, wherein said antifoulant composition is added to said
fluid hydrocarbon or petrochemical stream in an amount ranging from about 50 to about
a 5,000 ppm by volume of said fluid hydrocarbon or petrochemical stream.
22. The method of claim 13, wherein at least one structural part is selected from
hydrocarbon or petroleum storage units, heat exchangers, piping, pumps, flow meters,
valves, desalters, preheat furnaces, furnaces, coker preheaters, cokers, distillation
columns, fractionation columns, atmospheric columns, pipe stills, debutanizers, reactors,
fluid catalytic cracking units, fluid catalytic cracking slurry settlers, hydrocracking units,
steam cracking units, thermal cracking units, visbreakers, reflux units, condensers, and
scrubbers.
23. An antifoulant composition for inhibiting fouling on structural parts of a system
exposed to a fluid hydrocarbon or petrochemical stream, said antifoulant composition
comprising (I) at least one polyalkylene anhydride ester ("PAAE") dispersant, said
dispersant comprising an adduct of at least one acid ester of mono- or polycarboxylic acid
and an acylating reagent selected from the group consisting of fumaric acid, maleic
anhydride, maleic acid, succinic anhydride, and succinic acid.
24. The antifoulant composition of claim 23, wherein said dispersant is a
polyisobutenyl succinic anhydride derived ester ("PASAE") with a molecular weight,
-
blw , of about 1,000 to about 25,000 in an aromatic solvent.
25. The antifoulant composition of claim 23, wherein said antifoulant composition
further comprises at least one additional antifouling component selected from
components (2), (3), (4), and (5) wherein:
component (2) is an alkylphenol sulfide CAPS");
component (3) is an alkyl phosphate phenate sulfide ("APPS");
component (4) is a polyalkylene succinimide ("PAS"); and
component (5) is a polyalkylene thiophosphonic acid ester ("PETPA).
a 26. The anti foulant composition of claim 25, wherein said at least one alkylphenol
sulfide APS is selected from the group consisting of nonylphenol sulfide and
dodecylphenol sulfide.
1 27. The anti foulant composition of claim 25, wherein said alkylphenol sulfide APS is
overbased with calcium.
28. The antifoulant composition of claim 25, wherein said alkyl phosphate phenate
sulfide APPS is overbased with calcium.
29. An antifoulant composition for inhibiting fouling on structural parts of a system
exposed to a fluid hydrocarbon or petrochemical stream, said antifoulant composition
comprising (2) at least one alkyl phenol sulfide ("APS").
3 0. The antifoulant composition of claim 29, wherein said anti foulant composition
further comprises at least one additional antifouling component selected from
components (I), (3), (4), and (5) wherein:
component (1) is a polyalkylene anhydride ester ("PAAE) dispersant, said
dispersant comprising an adduct of at least one acid ester of mono- or polycarboxylic acid
and an acylating reagent selected from the group consisting of fumaric acid, maleic
anhydride, maleic acid, succinic anhydride, and succinic acid;
component (3) is an alkyl phosphate phenate sulfide ("APPS");
component (4) is a polyalkylene succinimide ("PAS"); and
component (5) is a poly alky lene thiophosphonic acid ester ("PETPA").
3 1. The antifoulant composition of claim 30, wherein said dispersant is a
polyisobutenyl succinic anhydride derived ester ("PASAE) with a molecular weight,
-
Mw , of about 1,000 to about 25,000 in an aromatic solvent.
a 32. The antifoulant composition of claim 29, wherein said alkylphenol sulfide APS is
dodecylphenol sulfide.
33. The antifoulant composition of claim 29, wherein said alkylphenol sulfide APS is
overbased with calcium.
34. The antifoulant composition of claim 30, wherein said alkyl phosphate phenate
sulfide APPS is overbased with calcium.