U.S. patent application number 12/535252 was filed with the patent office on 2011-02-10 for processes for removing hydrogen sulfide from refined hydrocarbon streams.
Invention is credited to Sherif Eldin, Larry John KARAS, Malcolm Craig Winslow.
Application Number | 20110031165 12/535252 |
Document ID | / |
Family ID | 43478134 |
Filed Date | 2011-02-10 |
United States Patent
Application |
20110031165 |
Kind Code |
A1 |
KARAS; Larry John ; et
al. |
February 10, 2011 |
PROCESSES FOR REMOVING HYDROGEN SULFIDE FROM REFINED HYDROCARBON
STREAMS
Abstract
A method for reducing the amount of hydrogen sulfide present in
refined hydrocarbon streams and reducing the amount of corrosion in
processing equipment contacting the refined hydrocarbon stream. The
method includes adding a corrosion inhibitor to the refined
hydrocarbon stream in contact with the processing equipment to
protect the processing equipment and adding glyoxal to the refined
hydrocarbon stream in contact with the protected processing
equipment. The corrosion inhibitor includes an organic soluble
compound having a nitrogen-containing ring.
Inventors: |
KARAS; Larry John; (The
Woodlands, TX) ; Eldin; Sherif; (Bellaire, TX)
; Winslow; Malcolm Craig; (Houston, TX) |
Correspondence
Address: |
General Electric Company;GE Global Patent Operation
2 Corporate Drive, Suite 648
Shelton
CT
06484
US
|
Family ID: |
43478134 |
Appl. No.: |
12/535252 |
Filed: |
August 4, 2009 |
Current U.S.
Class: |
208/48AA |
Current CPC
Class: |
C10G 2300/1044 20130101;
C10G 29/22 20130101; C10G 2300/1055 20130101; C10G 2300/1059
20130101; C10G 2300/80 20130101; C10G 2300/207 20130101; C10G
2300/104 20130101; C10G 2300/4075 20130101; C10G 75/02 20130101;
C10G 2300/1077 20130101; C10G 2300/1051 20130101 |
Class at
Publication: |
208/48AA |
International
Class: |
C10G 75/04 20060101
C10G075/04 |
Claims
1. A method for reducing the amount of hydrogen sulfide present in
a refined hydrocarbon stream and reducing the amount of corrosion
in processing equipment contacting the refined hydrocarbon stream,
said method comprising adding a corrosion inhibitor to the refined
hydrocarbon stream in contact with the processing equipment to
protect the processing equipment and adding glyoxal to the refined
hydrocarbon stream in contact with the protected processing
equipment, wherein said corrosion inhibitor comprises an organic
soluble compound having a nitrogen-containing ring.
2. The method of claim 1 wherein the refined hydrocarbon stream is
selected from the group consisting of gas oil, naphtha, FCC slurry,
diesel fuel, fuel oil, jet fuel, gasoline, kerosene and vacuum
residua.
3. The method of claim 1 wherein the refined hydrocarbon stream is
at an elevated temperature.
4. The method of claim 3 wherein the refined hydrocarbon stream is
at a temperature of from about ambient to about 150.degree. C.
5. The method of claim 1 wherein the processing equipment is a
pipeline or a holding tank.
6. The method of claim 5, wherein the processing equipment is made
of carbon steel.
7. The method of claim 1, wherein the corrosion inhibitor comprises
a five-membered or six-membered nitrogen-containing ring.
8. The method of claim 7, wherein corrosion inhibitor is an
imidazoline derivative.
9. The method of claim 8, wherein the corrosion inhibitor is a
fatty acid imidazoline.
10. The method of claim 8, wherein the fatty acid imidazoline has
the following structure: ##STR00003## wherein R and R' are each,
separately, a C.sub.6 to C.sub.36 alkyl, alkylene or aromatic
group.
11. The method of claim 7, wherein the nitrogen-containing ring is
a pyrimidine derivative.
12. The method of claim 11 wherein the pyrimidine derivative is a
fatty acid pyrimidine.
13. The method of claim 12 wherein the fatty acid pyrimidine has
the following structure: ##STR00004## wherein R.sub.a and R.sub.b
are each, separately, a C.sub.6 to C.sub.36 alkyl, alkylene or
aromatic group.
14. The method of claim 1 wherein the corrosion inhibitor is
injected into the refined hydrocarbon stream.
15. The method of claim 1 wherein the corrosion inhibitor is
present from about 2 ppm by volume to about 100 ppm by volume,
based on the volume of the refined hydrocarbon stream.
16. The method of claim 1, wherein the corrosion inhibitor provides
a protective coating onto the processing equipment after at least
about 5 minutes of adding the corrosion inhibitor to the refined
hydrocarbon stream in contact with the processing equipment.
17. The method of claim 1, wherein glyoxal is added to the refined
hydrocarbon stream in an amount of from about 1 ppm to about 3000
ppm by volume, based on the volume of the refined hydrocarbon
stream.
18. The method of claim 1, wherein the corrosion inhibitor
continues to be added to the refined hydrocarbon stream after the
glyoxal has been added.
19. The method of claim 18, wherein the corrosion inhibitor
continues to be added in an amount of from about 1 ppm by volume to
about 20 ppm by volume, based on the volume of the refined
hydrocarbon stream.
20. The method of claim 1, wherein the glyoxal further comprises a
catalyst.
21. The method of claim 20, wherein the catalyst is a quaternary
ammonium salt.
22. The method of claim 21, wherein the catalyst has formula I:
R.sub.1R.sub.2R.sub.3R.sub.4N.sup.+X.sup.- I wherein R.sub.1,
R.sub.2, R.sub.3 and R.sub.4 are each independently an alkyl group
having from 1 to 30 carbon atoms, an aryl group having from 6 to 30
carbon atoms or an arylalkyl group having from 7 to 30 carbon
atoms; and X is a halide, sulfate, nitrate or carboxylate.
23. The method of claim 22, wherein the quaternary ammonium salt is
alkyl benzyl ammonium chloride or benzyl cocoalkyl
(C.sub.12-C.sub.18) dimethylammonium chloride.
24. The method of claim 21, wherein the catalyst is present from
about 0.01 to about 15 percent by weight based on the weight of
glyoxal.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to processing hydrocarbon
media, and more particularly, to methods for removing hydrogen
sulfide from a refined hydrocarbon stream.
BACKGROUND OF THE INVENTION
[0002] Hydrocarbon media, such as a refined hydrocarbon stream, may
contain hydrogen sulfide, which is highly corrosive and poisonous
in very small concentrations. The risk of exposure to hydrogen
sulfide from handling hydrocarbon media is a health and safety
concern during storage, transportation (shipping, truck or
pipeline) and processing.
[0003] Hydrogen sulfide scavengers can be used to remove hydrogen
sulfide from hydrocarbon media. One type of hydrogen sulfide
scavenger is glyoxal. During production of glyoxal, acidic
byproducts are often formed. These byproducts can lead to increased
corrosion rates during hydrocarbon processing. When glyoxal is
added to a refined hydrocarbon stream, the acidic byproducts, which
are not soluble in the refined hydrocarbon stream, can settle out
from the refined hydrocarbon stream into a separate aqueous phase.
For example, the aqueous phase may run along the bottom of the
processing or refinery equipment as small tributaries in pipelines
or stagnate at the bottom of holding tanks. This acidic aqueous
phase is highly corrosive and can cause troughing in the processing
or refinery equipment.
[0004] What is needed is an improved method for removing hydrogen
sulfide from a refined hydrocarbon stream without causing corrosion
to processing equipment.
BRIEF DESCRIPTION OF THE INVENTION
[0005] In one embodiment, a method for reducing the amount of
hydrogen sulfide present in a refined hydrocarbon stream and
reducing the amount of corrosion in processing equipment contacting
the refined hydrocarbon stream, said method includes adding a
corrosion inhibitor to the refined hydrocarbon stream in contact
with the processing equipment to protect the processing equipment
and adding glyoxal to the refined hydrocarbon stream in contact
with the protected processing equipment, wherein said corrosion
inhibitor includes an organic soluble compound having a
nitrogen-containing ring.
[0006] The various embodiments provide an improved hydrogen
scavenging process for refined hydrocarbon streams that reduces
hydrogen sulfide while minimizing corrosion to processing
equipment.
DETAILED DESCRIPTION OF THE INVENTION
[0007] The singular forms "a," "an" and "the" include plural
referents unless the context clearly dictates otherwise. The
endpoints of all ranges reciting the same characteristic are
independently combinable and inclusive of the recited endpoint. All
references are incorporated herein by reference.
[0008] The modifier "about" used in connection with a quantity is
inclusive of the stated value and has the meaning dictated by the
context (e.g., includes the tolerance ranges associated with
measurement of the particular quantity).
[0009] "Optional" or "optionally" means that the subsequently
described event or circumstance may or may not occur, or that the
subsequently identified material may or may not be present, and
that the description includes instances where the event or
circumstance occurs or where the material is present, and instances
where the event or circumstance does not occur or the material is
not present.
[0010] In one embodiment, a method for reducing the amount of
hydrogen sulfide present in a refined hydrocarbon stream and
reducing the amount of corrosion in processing equipment contacting
the refined hydrocarbon stream, said method includes adding a
corrosion inhibitor to the refined hydrocarbon stream in contact
with the processing equipment to protect the processing equipment
and adding glyoxal to the refined hydrocarbon stream in contact
with the protected processing equipment, wherein said corrosion
inhibitor includes an organic soluble compound having a
nitrogen-containing ring.
[0011] The refined hydrocarbon stream may be any type of refined
hydrocarbon stream containing hydrogen sulfide. In one embodiment,
the refined hydrocarbon stream includes, but is not limited to, gas
oil, naphtha, FCC slurry, diesel fuel, fuel oil, jet fuel,
gasoline, kerosene or vacuum residua. In one embodiment, the
refined hydrocarbon stream may be at an elevated temperature. In
another embodiment, the refined hydrocarbon stream may be at a
temperature of from about ambient to about 150.degree. C. In
another embodiment, the refined hydrocarbon stream may be at a
temperature of from about 40.degree. C. to about 100.degree. C.
[0012] The processing equipment in contact with the refined
hydrocarbon stream may be any type of equipment that can be used
for processing the refined hydrocarbon stream, such as pipelines
and holding tanks. Processing equipment subject to corrosion is
generally processing equipment made of carbon steel, but any type
of processing equipment may be protected.
[0013] The corrosion inhibitor includes an organic soluble compound
having a nitrogen-containing ring. In one embodiment, the corrosion
inhibitor is miscible in the refined hydrocarbon stream.
[0014] In one embodiment, the nitrogen-containing ring may be a
five-membered ring or a six-membered ring. In one embodiment, the
nitrogen-containing ring may be an imidazoline derivative. In
another embodiment, the corrosion inhibitor may be a fatty acid
imidazoline. In one embodiment, the fatty acid imidazoline has the
following structure:
##STR00001##
[0015] wherein R and R' are each, separately, a C.sub.6 to C.sub.36
alkyl, alkylene or aromatic group. In another embodiment, R and R'
are each, separately, a C.sub.8 to C.sub.22 alkyl, alkylene or
aromatic group. In another embodiment, R and R' are each,
separately, a C.sub.16 to C.sub.18 alkyl, alkylene or aromatic
group. In another embodiment, R and R' are each, separately, a
C.sub.6 to C.sub.36 alkyl, alkylene or aromatic group having
branched alkyl groups. In one embodiment, R may be stearyl,
napthyl, palmyl, olyl, linolyl or linolenyl. In one embodiment, R'
may be stearyl, napthyl, palmyl, olyl, linolyl or linolenyl.
[0016] In one embodiment, the fatty acid imidazoline compound
includes, but is not limited to, stearic acid imidazoline,
naphthenic acid imidazoline, palmitic acid imidazoline, oleic acid
imidazoline, linoleic acid imidazoline or linolenic acid
imidazoline.
[0017] In one embodiment, the fatty acid imidazoline may contain a
mixture of two or more fatty acid imidazoline compounds.
[0018] In one embodiment, fatty acid imidazolines may be prepared
by the condensation reaction of at least one fatty acid and
diethylenetriamine. In one embodiment, the fatty acids may have a
C.sub.6 to C.sub.36 chain length. In another embodiment, the fatty
acids may have a C.sub.8 to C.sub.22 chain length. In another
embodiment, the fatty acids may have a C.sub.16 to C.sub.18 chain
length. In one embodiment, the fatty acids may include natural
acids derived from tall oils, oleic acid, stearic acid, palmitic
acid, linoleic acid, linolenic acid or naphthenic acid or may
include synthetically prepared fatty acids. The synthetically
prepared fatty acids may include acids with an even number of
carbon atoms or an odd number of carbon atoms. In one embodiment,
the condensation reaction may be at a reaction temperature of up to
about 400.degree. F. In another embodiment, the reaction
temperature may be from about 200.degree. F. to about 400.degree.
F.
[0019] In another embodiment, the nitrogen-containing ring may be a
pyrimidine derivative. In another embodiment, the corrosion
inhibitor may be a fatty acid pyrimidine. In another embodiment,
the fatty acid pyrimidine has the following structure:
##STR00002##
[0020] wherein R.sub.a and R.sub.b are each, separately, a C.sub.6
to C.sub.36 alkyl, alkylene or aromatic group. In another
embodiment, R.sub.a and R.sub.b are each, separately, a C.sub.8 to
C.sub.22 alkyl, alkylene or aromatic group. In another embodiment,
R.sub.a and R.sub.b are each, separately, a C.sub.16 to C.sub.18
alkyl, alkylene or aromatic group. In one embodiment, R.sub.a and
R.sub.b are each, separately, a C.sub.6 to C.sub.36 alkyl, alkylene
or aromatic group having branched alkyl groups. In one embodiment,
R.sub.a may be stearyl, napthyl, palmyl, olyl, linolyl or
linolenyl. In one embodiment, R.sub.b may be stearyl, napthyl,
palmyl, olyl, linolyl or linolenyl.
[0021] In one embodiment, the fatty acid pyrimidine compound
includes, but is not limited to, stearic acid pyrimidine,
naphthenic acid pyrimidine, palmitic acid pyrimidine, oleic acid
pyrimidine, linoleic acid pyrimidine or linolenic acid
pyrimidine.
[0022] In one embodiment, the fatty acid pyrimidine may contain a
mixture of two or more fatty acid pyrimidine compounds.
[0023] In one embodiment, fatty acid pyrimidines may be prepared by
the condensation reaction of at least one fatty acid with a fatty
acid-derived 1,3-propane diamine and paraformaldehyde. In one
embodiment, the fatty acids may have a C.sub.6 to C.sub.36 chain
length. In another embodiment, the fatty acids may have a C.sub.8
to C.sub.22 chain length. In another embodiment, the fatty acids
may have a C.sub.16 to C.sub.18 chain length. In one embodiment,
the fatty acids may include natural acids derived from tall oils,
oleic acid, stearic acid, palmitic acid, linoleic acid, linolenic
acid or naphthenic acid or may include synthetically prepared fatty
acids. The synthetically prepared fatty acids may include acids
with an even number of carbon atoms or an odd number of carbon
atoms. In one embodiment, the condensation reaction may be at a
reaction temperature of up to about 400.degree. F. In another
embodiment, the reaction temperature may be from about 200.degree.
F. to about 400.degree. F.
[0024] The corrosion inhibitor may be added to the refined
hydrocarbon stream in contact with the processing equipment to
protect the processing equipment. In one embodiment, the corrosion
inhibitor is added to the refined hydrocarbon stream, which then
contacts the processing equipment. In another embodiment, the
corrosion inhibitor is added to the refined hydrocarbon stream
while it is in contact with the processing equipment.
[0025] The corrosion inhibitor is added to the refined hydrocarbon
stream in any conventional manner. In one embodiment, the corrosion
inhibitor may be injected into the refined hydrocarbon stream. In
one embodiment, the corrosion inhibitor may be injected into the
refined hydrocarbon stream by a conventional in-line injection
system and may be injected at any point in-line suitable to allow
the corrosion inhibitor to mix with the refined hydrocarbon stream.
The corrosion inhibitor may be added to the refined hydrocarbon
stream in a continuous manner or can be added in one or more batch
modes and repeated additions may be made.
[0026] In another embodiment, the corrosion inhibitor is injected
into the refined hydrocarbon stream as the refined hydrocarbon
stream is flowing through a pipeline. In one embodiment, the
corrosion inhibitor is injected into the refined hydrocarbon stream
as it enters a pipeline. In another embodiment, the corrosion
inhibitor is injected into refined hydrocarbon stream in a holding
tank. In another embodiment, the corrosion inhibitor is injected
into the refined hydrocarbon stream as it enters a holding
tank.
[0027] The corrosion inhibitor disperses into the refined
hydrocarbon stream and eventually contacts the processing equipment
and deposit onto the processing equipment, forming a protective
coating or film. The corrosion inhibitor may be added in any amount
suitable for forming a protective coating or film on the processing
equipment. In one embodiment, the corrosion inhibitor may be added
to the refined hydrocarbon stream in an amount of from about 2 ppm
by volume to about 200 ppm by volume, based on the volume of the
refined hydrocarbon stream. In another embodiment, the corrosion
inhibitor may be added to the refined hydrocarbon stream in an
amount of from about 5 ppm by volume to about 100 ppm by volume,
based on the volume of the refined hydrocarbon stream. In another
embodiment, the corrosion inhibitor is added to the refined
hydrocarbon stream in an amount of from about 10 ppm by volume to
about 100 ppm by volume, based on the volume of the refined
hydrocarbon stream. In another embodiment, the corrosion inhibitor
is added to the refined hydrocarbon stream in an amount of from
about 20 ppm by volume to about 100 ppm by volume, based on the
volume of the refined hydrocarbon stream. The corrosion inhibitor
may be added in a single batch or may be added in continuing
dosages to the refined hydrocarbon stream.
[0028] The corrosion inhibitor will begin to deposit evenly on the
processing equipment as it contacts the equipment. A protective
coating will form on the processing equipment as the refined
hydrocarbon stream containing the corrosion inhibitor continues to
contact the processing equipment. The amount of time suitable for
forming a protective coating will depend on many factors, such as
the amount of corrosion inhibitor in the refined hydrocarbon
stream, the temperature of the refined hydrocarbon stream, the
amount of time that the refined hydrocarbon stream is in contact
with the processing equipment and the speed at which the refined
hydrocarbon stream may be traveling as it contacts the processing
equipment. In one embodiment, the corrosion inhibitor will provide
a protective coating or film onto the processing equipment after at
least about 5 minutes of adding the corrosion inhibitor to the
refined hydrocarbon stream in contact with the processing
equipment. In another embodiment, the corrosion inhibitor provides
a protective coating onto the processing equipment from about 5
minutes to about 100 hours of adding the corrosion inhibitor to the
refined hydrocarbon stream in contact with the processing
equipment. In another embodiment, a protective film or coating is
formed onto the processing equipment from about 15 minutes to about
75 hours of adding the corrosion inhibitor to the refined
hydrocarbon stream in contact with the processing equipment. In
another embodiment, a protective film or coating is formed onto the
processing equipment from about 30 minutes to about 60 hours of
adding the corrosion inhibitor to the refined hydrocarbon stream in
contact with the processing equipment. In another embodiment, a
protective film or coating is formed onto the processing equipment
from about 1 hour to about 50 hours of adding the corrosion
inhibitor to the heavy oil in contact with the processing
equipment. In another embodiment, a protective film or coating is
formed onto the processing equipment from about 10 hours to about
40 hours of adding the corrosion inhibitor to the refined
hydrocarbon stream in contact with the processing equipment. In
another embodiment, the corrosion inhibitor provides a protective
coating to the processing equipment from about 12 hours to about 36
hours of adding the corrosion inhibitor to the refined hydrocarbon
stream in contact with the processing equipment.
[0029] Glyoxal is added to the refined hydrocarbon stream in
contact with the protected processing equipment to reduce the
hydrogen sulfide. Glyoxal is a water-soluble aldehyde and may
include oligomers of glyoxal. Glyoxal is commercially available as
a 40 weight percent aqueous solution.
[0030] The glyoxal may be added to the refined hydrocarbon stream
in any conventional manner. In one embodiment, the glyoxal may be
injected into the refined hydrocarbon stream by a conventional
in-line injection system and may be injected at any point in-line
suitable to allow the glyoxal to mix with the refined hydrocarbon
stream. The glyoxal may be added to the refined hydrocarbon stream
in a continuous manner or can be added in one or more batch modes
and repeated additions may be made.
[0031] The glyoxal is added to the refined hydrocarbon stream in
any amount sufficient to reduce the levels of hydrogen sulfide in
the refined hydrocarbon stream. In one embodiment, glyoxal may be
added in an amount of from about 1 ppm to about 3000 ppm by volume,
based on the volume of the refined hydrocarbon stream. In another
embodiment, glyoxal may be added in an amount of from about 10 ppm
by volume to about 2000 ppm by volume, based on the volume of the
refined hydrocarbon stream. In another embodiment, glyoxal may be
added in an amount of from about 50 ppm by volume to about 1500 ppm
by volume, based on the weight of the refined hydrocarbon stream.
In another embodiment, glyoxal may be added in an amount of from
about 100 ppm by volume to about 1200 ppm by volume, based on the
volume of the refined hydrocarbon stream.
[0032] Any amount of hydrogen sulfide in the refined hydrocarbon
stream may be reduced and the actual amount of residual hydrogen
sulfide will vary depending on the starting amount. In one
embodiment, the hydrogen sulfide levels are reduced to 150 ppm by
volume or less, as measured in the vapor phase, based on the volume
of the refined hydrocarbon stream. In another embodiment, the
hydrogen sulfide levels are reduced to 100 ppm by volume or less,
as measured in the vapor phase, based on the volume of the refined
hydrocarbon stream. In another embodiment, the hydrogen sulfide
levels are reduced to 50 ppm by volume or less, as measured in the
vapor phase, based on the volume of the refined hydrocarbon stream.
In another embodiment, the hydrogen sulfide levels are reduced to
20 ppm by volume or less, as measured in the vapor phase, based on
the volume of the refined hydrocarbon stream.
[0033] During the production of glyoxal, acidic byproducts are
formed and the glyoxal can have a pH in the range of about 2 to
about 3. These byproducts can be highly corrosive. Glyoxal is
water-based and after an initial dispersion throughout the refined
hydrocarbon stream, will eventually settle out of the heavy oil in
an aqueous phase. This aqueous phase will be very acidic and can
corrode processing equipment. The coating or film formed by the
corrosion inhibitor on the processing equipment protects the
processing equipment and reduces or eliminates the corrosion from
the acidic aqueous phase.
[0034] The corrosion inhibitor may continue to be added as the
glyoxal is added to the refined hydrocarbon stream in contact with
the protected processing equipment. The corrosion inhibitor will
continue to deposit on the processing equipment and maintain the
protection on the processing equipment. The additional corrosion
inhibitor may be added in amounts of from about 1 ppm by volume to
about 20 ppm by volume, based on the volume of the refined
hydrocarbon stream. In another embodiment, the corrosion inhibitor
may be added in an amount of from about 5 ppm by volume to about 10
ppm by volume, based on the volume of the refined hydrocarbon
stream.
[0035] In one embodiment, a catalyst may be added to enhance the
removal of the hydrogen sulfide. In one embodiment, the catalyst is
a quaternary ammonium salt. The catalyst may be any suitable
quaternary ammonium salt. In one embodiment, the catalyst has
formula I:
R.sub.1R.sub.2R.sub.3R.sub.4N.sup.+X.sup.- I
wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each
independently an alkyl group having from 1 to 30 carbon atoms, an
aryl group having from 6 to 30 carbon atoms or an arylalkyl group
having from 7 to 30 carbon atoms; and X is a halide, sulfate,
nitrate or carboxylate. The alkyl groups and the aryl groups may be
substituted or unsubstituted.
[0036] In one embodiment, R.sub.1 is an alkyl group having from 1
to 24 carbon atoms. In one embodiment, R.sub.2 is an alkyl having
from 1 to 24 carbon atoms, an aryl group having from 6 to 24 carbon
atoms or an arylalkyl group having from 7 to 24 carbon atoms.
[0037] In one embodiment, R.sub.3 and R.sub.4 are each,
independently, an alkyl group having from 1 to 24 carbon atoms. In
another embodiment, R.sub.3 and R.sub.4 are each, independently, an
alkyl group having from 1 to 4 carbon atoms.
[0038] The alkyl group includes, but is not limited to, methyl,
ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, decyl or
dodecyl. The aryl group may be phenyl. The arylalkyl group include
may be benzyl. The halide may be chloride, bromide or iodide. The
sulfate may be a methyl sulfate. The nitrate may be a bisulfate
nitrate. The carboxylate may be acetate.
[0039] In one embodiment, the quaternary ammonium salt is alkyl
benzyl ammonium chloride or benzyl cocoalkyl (C.sub.12-C.sub.18)
dimethylammonium chloride. In another embodiment, the quaternary
ammonium salt includes, but is not limited to dicocoalkyl
(C.sub.12-C.sub.18) dimethylammonium chloride,
ditallowdimethylammonium chloride, di(hydrogenated tallow alkyl)
dimethyl quaternary ammonium methyl chloride, methyl bis
(2-hydroxyethyl cocoalkyl (C.sub.12-C.sub.18) quaternary ammonium
chloride, dimethyl(2-ethyl)tallow ammonium methyl sulfate,
n-dodecylbenzyldimethylammonium chloride, n-octadecylbenzyldimethyl
ammonium chloride, n-dodecyltrimethylammonium sulfate, soya
alkyltrimethylammonium chloride or hydrogenated tallow alkyl
(2-ethylhyexyl)dimethyl quaternary ammonium methylsulfate.
[0040] In one embodiment, the catalyst is present from about 0.01
to about 15 percent by weight based on the weight of glyoxal. In
another embodiment, the catalyst is present from about 1 to about
10 percent by weight based on the weight of glyoxal.
[0041] The catalyst may be added to the refined hydrocarbon stream
simultaneously with the glyoxal or may be added separately from the
glyoxal. In one embodiment, the catalyst is preblended with the
glyoxal before being added to the refined hydrocarbon stream.
[0042] In order that those skilled in the art will be better able
to practice the present disclosure, the following examples are
given by way of illustration and not by way of limitation.
EXAMPLES
Example 1
[0043] Glyoxal is an aqueous-based compound having a pH from about
2 to about 3. When dispersed in refined hydrocarbon streams, it
will eventually settle out of the refined hydrocarbon streams into
an acidic aqueous phase and settle to the bottom of processing
equipment causing corrosion. To test the efficiacy of the corrosion
inhibitor for reducing corrosion, the corrosion test was simulated
in water.
[0044] Two metal coupons of Carbon C010 steel were weighed and
added to two spindles mounted on a stirring shaft in an 800 ml
Auto-Clave. The metal coupons were 180.degree. from each other. The
stirring shaft was placed into water and stirred at the revolutions
per minute as shown in Table 1. The revolutions per minute were
used to calculate the approximate flow through a pipeline and are
shown in Table 1. A corrosion inhibitor was added to the water at
room temperature in the amounts shown in Table 1. 15 minutes later,
glyoxal was injected into the water in the amounts shown in Table
1. The Auto-Clave was sealed and the water was heated to about
180.degree. F. to simulate the temperature of a typical refined
hydrocarbon stream during processing. After 4 hours, the metal
coupons were tested for corrosion by measuring any weight loss of
the metal coupons and averaging the metal coupons.
TABLE-US-00001 TABLE 1 Corrosion Glyoxal.sup.1 Inhibitor Pipeline
Corrosion (ppm by (100 ppm by Flow Weight Rate Sample volume)
volume) RPM (ft/min) Loss (g) (MPY) CE-1 None None 450 4 0.0033
43.1 CE-2 500 5K15.sup.2 450 4 0.0083 110.7 1 500 5K1642.sup.3 450
4 0.0001 <0.5 .sup.1Glyoxal used contains 2% by weight
quaternary ammonium catalyst and is available commercially as
S-1750 from GE Water. .sup.25K15 is a water-soluble corrosion
inhibitor available commercially as Philmplus .TM. 5K 15 from GE
Water. .sup.35K1642 is an organic-soluble corrosion inhibitor
available commercially as Philmplus .TM. 5K 1642 from GE Water and
containing a 3:1 by weight blend of oleic acid pyrimidine and
dimer/trimer acid.
[0045] The organic soluble corrosion inhibitor shows a marked
decrease in corrosion compared with the blank (sample CE-1). A
water-soluble corrosion inhibitor was tested (sample CE-2), but it
actually increased the corrosion.
Example 2
[0046] Additional corrosion tests were performed on organic soluble
corrosion inhibitors and were conducted in water in accordance with
Example 1. Results are shown in Table 2.
TABLE-US-00002 TABLE 2 Corrosion Glyoxal.sup.1 Inhibitor Corrosion
(ppm by (ppm by Rate Sample volume) Corrosion Inhibitor volume)
(MPY) CE-3 500 None None 91.7 1 500 Oleic acid Pyrmidine and 100
39.2 Dimer/Trimer Acid (3:1 wt ratio).sup.2 CE-4 500 Dimer/Trimer
acid.sup.3 25 51.8 2 500 Oleic acid Imidazoline.sup.4 25 17.3 3 500
Oleic acid Imidazoline and 24 23.3 Dimer/Trimer Acid (3:1 wt.
Ratio) 4 500 Oleic acid Imidazoline and 100 14.0 Hydroxyacetic acid
(3:1 wt ratio).sup.5 5 500 Oleic acid Pyrimidine.sup.6 100 10.0
.sup.1Glyoxal used contains 2% by weight quaternary ammonium
catalyst and is available commercially as S-1750 from GE Water.
.sup.2Available commercially as Philmplus .TM. 5K 1642 from GE
Water. .sup.3Available commercially as Sylvadym .RTM. T-18 from
Sylvachem Corp. .sup.4Available commercially as CI-11C from GE
Water. .sup.5Available commercially as 5K2S from GE Water.
.sup.6Available commercially as 5K7 from GE Water.
[0047] The organic soluble corrosion inhibitors in Samples 1-5 show
improved corrosion resistance in comparison with the blank (sample
CE-3) and in comparison with an organic soluble dimer/trimer acid
(sample CE-4).
Example 3
[0048] Corrosion experiments and hydrogen sulfide scavenging were
tested in a mixture of oil gas and water in an 800 ml Auto-Clave.
The gas oil was initially spiked with an approximate 0.5 wt. %
solution of H.sub.2S in kerosene before being mixed with the water.
Two metal coupons of Carbon C1010 steel were weighed and added to
two spindles mounted on a stirring shaft. The metal coupons were
180.degree. from each other. The stirring shaft was placed into the
gas oil and water mixture and stirred at 300 rpm. The mixture of
oil gas and water was 200 ml of gas oil and 400 ml of water. The
2:1 volume ratio of water to gas oil ensured that the coupons were
always immersed in water @ 300 rpm to test the corrosion in an
aqueous phase. A corrosion inhibitor was added to the gas oil
mixture at room temperature in the amounts shown in Table 3. 15
minutes later, glyoxal was injected into the gas oil mixture in the
amounts shown in Table 3. The Auto-Clave was sealed and the gas oil
and water mixture was heated to about 180.degree. F. to simulate a
typical processing temperature. After 4 hours, the metal coupons
were tested for corrosion by measuring any weight loss of the metal
coupons, averaging the metal coupons and calculating the mils per
year (MPY).
[0049] Hydrogen sulfide testing was performed using the modified
ASTM 5705-95 test that measures vapor phase H.sub.2S two hours
after treatment (140.degree. F.) with Drager tubes. Final H.sub.2S
concentration measurements are shown in Table 3.
TABLE-US-00003 TABLE 3 Corrosion Glyoxal.sup.1 Inhibitor Final (ppm
by Corrosion (ppm by Corrosion H.sub.2S Sample volume) Inhibitor
volume) Rate (mpy) (ppm) CE-5 500 None None 49.1 <15 1 500 Oleic
acid 100 6.67 <15 Pyrmidine and Dimer/ Trimer Acid (3:1 wt
ratio).sup.2 .sup.1Glyoxal used contains 2% by weight quaternary
ammonium catalyst and is available commercially as S-1750 from GE
Water. .sup.2Available commercially as Philmplus .TM. 5K 1642 from
GE Water.
[0050] Both samples (CE-5 and 1) show removal of hydrogen sulfide
while Sample 1 also shows a marked decrease in corrosion compared
with the blank (sample CE-5).
[0051] While typical embodiments have been set forth for the
purpose of illustration, the foregoing descriptions should not be
deemed to be a limitation on the scope herein. Accordingly, various
modifications, adaptations and alternatives may occur to one
skilled in the art without departing from the spirit and scope
herein.
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