 |
Description  |
|
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a water-glycol soluble liquid capable of removing
iron sulfide and sludge from metal surfaces, particularly metal surfaces
in a glycol system, and to a method of removing such iron sulfide and
sludge from interior metal surfaces, wherein the composition of the
present invention is employed onstream. More particularly, the present
invention is directed to such water-glycol soluble liquid composition and
method of removing iron sulfide and sludge therewith, wherein an amine
salt formed in situ by reaction of acetic acid and a high molecular weight
linear diamine is a principal active ingredient thereof.
2. Summary of the Invention
Due to the difficulties generally encountered in the removal of iron
sulfide and sludge from metal surfaces in various systems, including
glycol systems, a composition was developed in accordance with the present
invention which effectively allows penetration of a film crust of iron
sulfide and associated sludge. This provides for dispersion of the iron
sulfide and sludge in finally divided solid form, allowing easy removal
from the system. The composition of the present invention, effective for
the removal of iron sulfide and sludge from metal surfaces, comprises:
A. FROM ABOUT 2 TO ABOUT 15% BY WEIGHT OF A HIGH MOLECULAR WEIGHT LINEAR
DIAMINE;
B. FROM ABOUT 2.5 TO ABOUT 18% BY WEIGHT OF ACETIC ACID;
C. FROM ABOUT 1 TO ABOUT 10% BY WEIGHT OF AN ORGANIC NITROGEN SUBSTITUTED
IMIDAZOLINE;
D. FROM ABOUT 6 TO ABOUT 15% BY WEIGHT OF A NONIONIC SURFACTANT;
E. FROM ABOUT 2 TO ABOUT 8% BY WEIGHT OF A QUATERNARY AMMONIUM CHLORIDE;
F. FROM ABOUT 1 TO ABOUT 15% BY WEIGHT OF AN ALCOHOL SOLVENT; AND
G. THE REMAINDER, WATER.
The method of the present invention is carried out to remove iron sulfide
and sludge from interior metal surfaces, particularly in a glycol system,
by adding to the effluent of the system for in-line, onstream treatment an
effective iron sulfide and sludge removing amount of the above
composition. Generally, such composition is employed in accordance with
the present invention in an amount of about 200 to about 1,000 parts per
million of effluent.
Accordingly, it is a principal feature of the present invention to provide
a water-glycol soluble composition capable of removing iron sulfide and
sludge from metal surfaces, wherein such composition effectively disperses
iron sulfide and sludge in finally divided solid form, thereby allowing
effective removal of the same;
It is a further feature of the present invention to provide such
water-glycol soluble composition capable of removing iron sulfide and
sludge from metal surfaces, particularly in a glycol system, wherein such
composition includes as a principal active component thereof an amine salt
formed in situ from a molecular weight linear diamine and acetic acid;
It is yet a further feature of the present invention to provide such
water-glycol soluble composition capable of removing iron sulfide and
sludge from metal surfaces, wherein the composition comprises a high
molecular weight linear diamine, acetic acid, an organic nitrogen
substituted imidazoline, a non-ionic surfactant, a quaternary ammonium
chloride, an alcohol solvent, and water.
It is still a further feature of the present invention to provide a method
of removing iron sulfide and sludge from interior metal surfaces,
particularly in a glycol system, which method comprises adding to the
effluent of the system for in-line onstream treatment an effective iron
sulfide and sludge removing amount of the composition of the present
invention;
Yet a further feature of the present invention involves such method of
removing iron sulfide and sludge from interior metal surfaces, wherein the
composition of the present invention is employed in an amount of from
about 200 to about 1,000 parts per million of effluent;
Still further features and advantages of the present invention will become
apparent from the following more detailed description thereof.
DESCRIPTION OF PREFERRED EMBODIMENTS
The foregoing features of the present invention and the advantages
associated therewith are associated with a water-glycol soluble
composition which is effective in the removal of iron sulfide and sludge
from metal surfaces, particularly in a glycol system. The composition of
the present invention and the method of utilizing the same allow the
effective removal of the iron sulfide and sludge through a combination of
components which provides for penetration of the film crust on the
interior metal surfaces and dispersion of the iron sulfide and sludge as
finally divided solids. The composition of the present invention can be
utilized in small quantities to disperse large amounts of iron sulfide and
sludge and provides only slight discoloration of the effluent utilized.
Where desired, a filter or other similar means can be utilized to extract
a high content of the dispersed iron sulfide and/or sludge.
The composition of the present invention has as a principal active
component an amine salt formed in situ by the reaction of two of the
composition's components, a high molecular weight linear diamine and
acetic acid. This amine salt, which is formed in situ, has a polar
attraction for the iron present in the iron sulfide and sludge and,
presumably due to this polar attraction, effectively dislodges the iron
ions from the sludge, attaching to the metal surfaces in the form of a
corrosion-inhibiting barrier. A further active component in the
composition of the present invention is a partial amide-amine diacetate
formed in situ by the reaction of acetic acid and an organic nitrogen
substituted imidazoline. This component also is effective to dislodge the
iron ions from the sludge, dispersing the same for easy removal.
The remaining components of the composition of the present invention in a
secondary manner act as solvents and surface active components, providing
for the dissolving of the active components and the necessary penetration
of the composition through the sludge. These components are a non-ionic
surfactant, preferably a linear alcohol polyglycol ether, a quaternary
ammonium chloride, preferably an alkyl dimethyl benzyl ammonium chloride,
an alcohol solvent, preferably diacetone alcohol, and water.
The composition of the present invention generally has a pH within the
range of 4.5 to 6, the pH generally being around pH 5.0-5.2.
When carrying out the method of the present invention, the composition of
the present invention can be added directly to the effluent stream of a
glycol system to provide in-line, onstream treatment effective for the
removal of iron sulfide and sludge. Alternatively, prior to introduction,
the composition of the present invention can be mixed with the effluent in
any desired proportion. The composition of the present invention is
employed in an amount effective to provide the desired removal of the iron
sulfide and sludge, with an amount of about 200 to about 1000 parts of the
composition of the present invention per million parts of effluent being
generally employed. It should be apparent, however, that depending upon
the nature of the sludge, and depending upon the amount of the iron
sulfide and sludge deposit, the composition of the present invention can
be employed in slightly greater or lesser amounts than described above.
The onstream ability of the composition of the present invention to
effectively remove iron sulfide and sludge is an advantage of the
composition and method of the present invention over previously developed
systems. Accordingly, when utilizing the composition and method of the
present invention, it is unnecessary to shut down the system and the
simple introduction of the composition of the present invention into the
effluent stream in an amount effective to remove the iron sulfide and
sludge is all that is required. This provides for great economic savings.
The composition of the present invention will now be described by reference
to the individual components, including preferred embodiments thereof,
with specific reference being made to the weight percentage of each
component in the composition of the present invention. It should be
understood that more than one of each of the following components can be
effectively utilized.
HIGH MOLECULAR WEIGHT LINEAR DIAMINE
The diamine employed in the composition of the present invention is a high
molecular weight linear diamine, preferably a diamine having a carbon
chain derived from a higher fatty acid. In accordance with the preferred
embodiment of the present invention, such diamine contains from 12 to 30
carbon atoms, with exemplary diamines useful in accordance with the
present invention including, for example, tallow diamine having an amine
value of 325 to 240, or coco diamine having an amine value of about 400.
Of course, any and all diamines falling within the above description of
carbon chain length can be applicably utilized in accordance with the
present invention.
The diamine is employed in an amount of from about 2 to about 15% by
weight, preferably 3 to 8% by weight. In the most preferred embodiment of
the present invention, the diamine is employed in an amount of 4 to 6% by
weight. Of course, slight deviations from the foregoing amounts can be
tolerated, and the use of slightly greater or lesser amounts is still
within the spirit and scope of the present invention.
ACETIC ACID
Any industrial or commercial form of acetic acid can be advantageously
utilized in the composition and method of the present invention. The
acetic acid is generally employed in an amount of from about 2.5 to about
18% by weight, preferably 3 to 8% by weight. In the most preferred
embodiment of the present invention, the acetic acid is employed in an
amount of 3 to 5% by weight. Here again, as was the case with respect to
diamine, slight deviations from these amounts are within the scope of the
present invention.
As previously indicated, it is presumed that the amine and acetic acid
react in situ to form a salt, i.e., amine diacetate. This is the principal
active component of the composition of the present invention, which
component is responsible for the dislodgement and dispersion of the sludge
and iron sulfide in the oil system.
ORGANIC NITROGEN SUBSTITUTED IMIDAZOLINE
A third component of the composition of the present invention is an organic
nitrogen substituted imidazoline. This component also reacts in situ with
the acetic acid, forming a partial amide-amine effective to dislodge and
disperse iron sulfie and sludge. This component can be represented by the
formula:
##STR1##
wherein R is an alkyl radical.
In the preceding formula, R is preferably a long chain alkyl radical
derived from a fatty acid. Most preferably, R has from about 12 to about
20 or more carbon atoms. A typically preferred R radical is one derived as
follows: 46% oleic acid; 41% linoleic acid; and 13% other fatty acids
(predominantly C.sub.18).
The organic nitrogen substituted imidazoline is employed in the composition
of the present invention in an amount of from about 1 to about 10% by
weight, preferably 2-5% by weight, based on the weight of the composition.
In the most preferred embodiment of the present invention, this component
is employed in an amount of 2-3% by weight. Of course, slightly lesser or
greater amounts of this component can be employed where desired for
particular purposes.
NON-IONIC SURFACTANT
Any water soluble surfactant can be advantageously utilized in the
composition of the present invention. Generally, the surfactant is a
non-ionic surfactant, with adducts of ethylene oxide and alcohols or alkyl
phenols being preferred. These preferred surfactants can be generally
referred to as linear alcohol polyglycol ethers and alkylphenol polyethoxy
ethers.
Generally, the linear alcohol contains from about 6 to about 16 carbon
atoms, preferably 8-12 carbon atoms, and the alkyl group of the
alkylphenol contains a similar number of carbon atoms. The number of
ethylene oxide groups introduced into the surfactant molecule can vary
over wide limits, although the surfactants generally have from about 3 to
about 20 ethylene oxide groups, with from about 8 to about 12 ethylene
oxide groups being preferred. Various commercially available non-ionic
surfactants such as sold under the series names Triton, Igepol, among
others, are applicable. Descriptions of these and other surfactants useful
in the composition of the present invention can be found in the
Encyclopedia of Surface Active Agents, Vol. II 1964, hereby incorporated
by reference.
The surfactant is employed in the composition of the present invention to
reduce the interfacial tension of the composition when employed in a water
soluble system, e.g., a glycol system. In addition, however, it has been
discovered that, due to the action of the surfactant, the composition of
the present invention can be used in an oil system, particularly where
there is sufficient dispersion of the active components of the instant
composition.
In the composition of the present invention, the surfactant is generally
employed in an amount of from about 6 to about 15% by weight, preferably 8
to 13% by weight, based on the weight of the composition. In the most
preferred embodiment, the surfactant is employed in an amount of 10 to 12%
by weight. Here again, for particular purposes, slightly lesser or greater
amounts of surfactant can be used.
QUATERNARY AMMONIUM CHLORIDE
The composition of the present invention also includes a minor amount of
quaternary ammonium chloride. These materials, although known for their
bacteriacidal activity, provide unusual surface active characteristics to
the instant composition. Preferably, this component is an alkyl (or
dialkyl) dimethyl benzyl ammonium chloride, with the alkyl group varying
from C.sub.8 to C.sub.20, preferably C.sub.12 to C.sub.16. A suitable
commercially available material has the following alkyl group: C.sub.14 --
50%; C.sub.12 -- 40%; C.sub.16 -- 10%.
Other representative quaternary ammonium compounds include:
Didecyl Dimethyl Ammonium Chloride
Octyl Decyl Dimethyl Ammonium Chloride
Octyl Decyl Dimethyl Ammonium Chloride
Dioctyl Dimethyl Ammonium Chloride
The quarternary ammonium compound is generally employed in an amount of
from about 2 to about 8% by weight, preferably 4 to 7% by weight, based on
the weight of the composition. Most preferably, the quaternary ammonium
compound is employed in an amount of 4.5 to 6.5% by weight.
ALCOHOL SOLVENT
A solvent employed in the composition of the present invention is an
alcohol solvent. This material can be any conventional solvent material
having an alcoholic function. Preferably, the alcoholic solvent is a
material selected from lower aliphatic solvents and diacetone alcohol.
Diacetone alcohol is preferred due to the higher flash point this alcohol
solvent contributes to the composition, as compared, for example, with the
lower aliphatic alcohols. The lower aliphatic alcohols are generally those
having up to 6 carbon atoms with isopropyl alcohol being preferred. Of the
alcohol solvents applicable in accordance with the present invention, the
best results with respect to penetration of the iron sulfide and sludge
for dispersion of the same and removal of the same is achieved utilizing
diacetone alcohol.
The alcohol solvent is generally employed in an amount of from about 1 to
about 15% by weight, preferably 5 to 10% by weight based upon the weight
of the composition. In the most preferred embodiment of the present
invention, the alcohol solvent is employed in an amount of 8 to 10% by
weight. Again, as was the case with regard to the previously discussed
components, slightly lesser of greater amounts of the alcohol solvent can
be utilized in the composition of the present invention.
WATER
The remainder of the composition of the present invention is water.
In addition to formulation of the composition of the present invention in
accordance with the percentages described above, the relative ratios of
the various components can be maintained while reducing the amount of
water, thereby providing a composition in a more concentrated form. This
concentrate can then be mixed with additional water prior to use or can be
mixed with the effluent of the system in which it is to be used to provide
a composition of desired formulation. All of these embodiments fall within
the scope of the present invention.
The method of the present invention is preferably carried out by adding the
composition described above to the effluent of a water-glycol system. A
particular advantage of this method is that treatment for the removal of
iron sulfide and sludge can be carried out onstream, and it is unnecessary
to shut down operations for this cleaning. The composition can be added
directly to the effluent onstream, or can first be diluted with additional
effluent prior to addition. In either event, the composition is employed
in an amount effective to remove the iron sulfide and sludge present in
the system. Generally, it is employed in an amount of from about 200 to
about 1,000 parts of composition per million parts of effluent.
The present invention will now be described by reference to the following
example. It must be understood that such example is presented solely for
purposes of illustration, and the present invention cannot, under any
circumstances, be deemed limited thereby.
EXAMPLE
In this example, the following composition was utilized: 4.5% tallow
diamine, 3.5% acetic acid, 2.5% organic nitrogen substituted imidazoline
of the formula
##STR2##
wherein R is 46% oleic, 41% linoleic, and 13% other C.sub.18 fatty acid
group,
10% linear alcohol polyglycol ether (9 to 10 mols EO); 6.25% alkyl dimethyl
benzyl ammonium chloride (C.sub.14 -- 50%; C.sub.12 -- 40%; C.sub.16 --
10%); 8% diacetone alcohol, remainder water.
The above composition was employed to clean a gasproducing plant having a
700 gallon system . . . -10.degree. F. at gas to gas chiller. Five gallons
of the above composition were utilized per day for three days by addition
to glycol accumulator. After first treatment, gas to gas chiller
temperature went to -14.degree. F. in ten minutes. Temperature climbed
back to -10.degree. F. in one hour. The next day after second treatment,
temperature went from -14.degree. F. to -11.degree. F. Third day
temperature went from -11.degree. F. and remained stable. This illustrates
the effectiveness of the above composition in removing iron sulfide and
sludge.
While the present invention has been described primarily with respect to
the foregoing exemplifications of preferred materials and amounts, the
present invention cannot in any way be limited thereto, but, rather, must
be construed as broadly as any and all equivalents thereof.
* * * * *
|
|
 |
|
 |
Description |
|
