Note: Descriptions are shown in the official language in which they were submitted.
CA 02641236 2008-10-17
=
TITLE OF THE INVENTION
CLEANING AND PURIFYING COMPOSITIONS AND ASSOCIATED METHOD
FOR PURIFYING PROCESS WATER FROM THE REFINEMENT OF
PETROLEUM
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to cleaning and purifying
compositions and, more particularly, to compositions for cleaning and
purifying
process water that results from the refinement of petroleum.
2. Background Art
Wastewaters from petroleum refining consist of cooling water, process water,
storm water, and sanitary sewage water. Process water accounts for a
significant
portion of the total wastewater. Process wastewater arises from desalting
crude oil,
steam stripping operations, pump gland cooling, product fractionator reflux
drum
drains and boiler blowdown. Because process water often comes into direct
contact
with oil, it is usually highly contaminated. The process water must be treated
so that it
may either be reused in parts of the refinery or discharged through the
process area
rainwater treatment system. Treatment of process water must effectively remove
napthenic acid, separate out any hydrocarbons, and effectively drop out any
solids.
Napthenic acid, obtained as a byproduct of petroleum refining, is a mixture of
carboxylic acids that possess cyclopentane rings and is slightly soluble in
water.
Methods of treatment of refinery process water have been known in the art for
years,
and are the subject of several patents, including: U.S. Patent No. 6,536,523
entitled
"WATER TREATMENT PROCESS FOR THERMAL HEAVY OIL RECOVERY;"
U.S. Patent Nos. 5,651,833 and 5,562,834 entitled "WASTE CONCENTRATION
1
CA 02641236 2008-10-17
AND DESTRUCTION PROCESS;" and U.S. Patent No. 4,274,968 entitled
"PROCESS FOR THE PURIFICATION OF WATER."
U.S. Patent. No. 6,536,523 appears to disclose the transfer of heat energy
into
a heated separator and re-boiler exchanger to distill oil reservoir produced
water and
recover distilled water and a concentrated brine or solid product.
U.S. Patent Nos. 5,651,833 and 5,562,834 appear to disclose removing volatile
organic compounds from the wastewater stream by steam stripping and then
contacting a stream comprising steam and the stripped organic compounds with a
catalyst at an elevated temperature so as to convert the hydrocarbon portion
of the
organic compounds to a mixture of hydrogen and carbon dioxide.
U.S. Patent No. 4,274,968 appears to disclose the addition of an effective
amount of chemical flocculant to the feed water and subjecting said water to
flocculation; passing the flocculated water to a clarifier where suspended
solids are
separated from the partially purified water; adding about 1 to about 100 parts
powdered activated carbon per million parts of water from the clarifier;
contacting the
water with said carbon in a reaction zone so as to achieve substantial
reduction of
contaminants in the water; separating the activated carbon from the purified
water;
and recycling a portion of the separated activated carbon to the clarifier
effluent.
An experiment at Stanford University employed clay to purify process water,
but this resulted in a new problem of contaminating the clay with
hydrocarbons.
None of the above-identified or any other prior-art references accomplished
removal
of napthenic acid, separation of hydrocarbons, and dropping of solids from
petroleum
refinery process water to yield water free of these contaminants.
It is therefore an object of the present invention to provide a composition
(i.e.
a mixture or combination of chemicals) and a method for their use that results
in the
2
CA 02641236 2008-10-17
treatment of petroleum refinery process water to yield purified water that is
free of
contaminating napthenic acid, hydrocarbons, and/or solids.
SUMMARY OF THE INVENTION
In one embodiment, the present invention is directed to a cleaning and
purifying composition comprising: (a) at least one solvent; (b) an alkaline
agent; (c) a
deflocculant; (d) one or more surfactants selected from the group comprising
an
alcohol ethoxylate surfactant; an alkylamino-polyethoxy-sulfate surfactant; a
polyether-phosphate ester surfactant; a surfactant that is a phosphate ester
of an
ethoxylated alcohol; and a surfactant that is a polyethyleneglycol monoaklyl
ether;
and (e) a bonding agent.
In a preferred embodiment of the present invention, the at least one solvent
comprises a polar solvent, such as water.
In another preferred embodiment of the present invention, the alkaline agent
comprises at least one of a hydroxide salt and/or a carbonate salt.
In yet another preferred embodiment of the present invention, the alkaline
agent comprises at least one of the group comprising Li0H, NaOH (i.e. caustic
soda),
KOH, RbOH, Cs0H, FrOH, Be(OH)2, Mg(OH)2, Ca(OH)2, Sr(OH)2, Ba(OH)2,
Ra(OH)2, and mixtures thereof.
In another aspect of the present invention, the deflocculant comprises at
least
one of a sodium silicate and an anhydrous sodium metasilicate.
In a preferred embodiment of the present invention, the bonding agent
comprises an organic sulfonate, such as, for example, sodium xylene sulfonate.
Preferably, the percent by mass or percent by volume for each component
identified in the compositions range from approximately 1 percent to
approximately
33 percent.
3
CA 02641236 2008-10-17
The present invention is also directed to a cleaning and purifying
composition,
comprising: (a) water; (b) caustic soda; (c) a deflocculant; (d) an alcohol
ethoxylate
surfactant; (e) an alkylamino-polyethoxy-sulfate surfactant; (f) a polyether-
phosphate
ester surfactant; (g) a surfactant that is a phosphate ester of an ethoxylated
alcohol; (h)
a surfactant that is a polyethyleneglycol monoaklyl ether; and (i) a bonding
agent.
The present invention is further directed to a cleaning and purifying
composition, comprising: (a) water; (b) caustic soda; (c) sodium silicate; (d)
an
alcohol ethoxylate surfactant; (e) an alkylamino-polyethoxy-sulfate
surfactant; (f) a
polyether-phosphate ester surfactant; (g) a surfactant that is a phosphate
ester of an
ethoxylated alcohol; (h) a surfactant that is a polyethyleneglycol monoaklyl
ether; and
(i) sodium xylene sulfonate.
A process for purifying petroleum refinery process wastewater, is also
disclosed as comprising the steps of: (a) providing a composition, comprising:
water;
caustic soda; a deflocculant; an alcohol ethoxylate surfactant; an alkylamino-
polyethoxy-sulfate surfactant; a polyether-phosphate ester surfactant; a
surfactant that
is a phosphate ester of an ethoxylated alcohol; a surfactant that is a
polyethyleneglycol monoaklyl ether; and a bonding agent; (b) transferring
process
water into a first fractioned pond and introducing the composition into the
first
fractioned pond, thereby partially treating the process water; (c)
transferring the
partially treated process water from the first fractioned pond into a second
fractioned
pond; (d) transferring the partially treated process water from the second
fractioned
pond into a third fractioned pond; (e) transferring the partially treated
process water
from the third fractioned pond to a hydrocyclone; (f) transferring the
partially treated
process water from the hydrocyclone to a precipitating tank thereby fully
treating the
same; and (g) recovering treated water from the precipitating tank.
4
CA 02641236 2008-10-17
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the drawings wherein:
Figure 1 of the drawings is a schematic representation of a process for
purifying petroleum refinery process wastewater in accordance with the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
While this invention is susceptible of embodiment in many different forms,
there is shown in the drawings and described herein in detail several specific
embodiments with the understanding that the present disclosure is to be
considered as
an exemplification of the principles of the invention and is not intended to
limit the
invention to the embodiments illustrated.
In accordance with the present invention, novel compositions (i.e. a mixture
or
combination of chemicals) are provided which are introduced into a process
that
results in the purification of petroleum refinery process water. The
composition
provides unique characteristics and properties that include, but are not
limited to,
being non-toxic and safe for the environment, low foaming, biodegradable, non-
carcinogenic, disinfectant, non-flammable, and unexpectedly effective.
In a first embodiment of the present invention, a cleaning and purifying
composition comprises: one or more solvents, an alkaline agent, a
deflocculant, one or
more surfactants including, an alcohol ethoxylate surfactant, an alkylamino-
polyethoxy-sulfate surfactant, a polyether-phosphate ester surfactant, a
surfactant that
is a phosphate ester of an ethoxylated alcohol, and a surfactant that is a
polyethyleneglycol monoaklyl ether, and a bonding agent.
Preferably the one or more solvents comprises a polar solvent, such as water.
However, it will be understood that any one of a number of other polar
solvents that
5
CA 02641236 2008-10-17
would be known to those having ordinary skill in the art are likewise
contemplated for
use.
The compositions of the present invention also comprise an alkaline agent,
such as a hydroxide salt and/or a carbonate salt. Hydroxide salts include, for
example,
LOH, NaOH (e.g. caustic soda), KOH, RbOH, Cs0H, FrOH, Be(OH)2, Mg(OH)2,
Ca(OH)2, Sr(OH)2, Ba(OH)2, Ra(OH)2, and mixtures thereof Carbonate salts
include,
for example, group I and II carbonates. It will be understood that the
alkaline agent
serves to maintain alkalinity and/or enhance the properties of the anionic
surfactants
present in the composition. It further serves to neutralize napthenic acid and
aid in its
precipitation as insoluble salts. Applicant has uncovered that liquid caustic
soda
(typically 40-60% caustic) in combination with solid caustic soda appears to
be a
superior form of caustic soda.
A deflocculant is used, in accordance with the present invention, to aid in
the
treatment of the process water. The deflocculant serves as a de-emulsifier to
facilitate
the separation of water and oil from a water and oil emulsion. In a preferred
embodiment, a combination of liquid sodium silicate and anhydrous sodium
metasilicate (Drymet 59 available from the Crossfield Company) is utilized.
The compositions of the present invention also comprise one or more
surfactants, including an alcohol ethoxylate surfactant, an alkylamino-
polyethoxy-
sulfate surfactant, a polyether-phosphate ester surfactant, a surfactant that
is a
phosphate ester of an ethoxylated alcohol, and a surfactant that is a
polyethyleneglycol monoaklyl ether. An example of an alcohol-ethoxylate
surfactant
includes Triton XL-80N, which is commercially available from the Dow Chemical
Company. An example of an alkylamino-polyethoxy sulfate surfactant includes
Triton
QS-15, which is commercially available from the Dow Chemical Company. An
6
CA 02641236 2008-10-17
example of a polyether phosphate ester surfactant includes Triton QS-44, which
is
commercially available from the Dow Chemical Company. Suitable surfactants
that
are phosphate esters of ethoxylated alcohols include, for example, Tyrfac 5553
and
Tryfac 5554, which are commercially available from the Cognis Corporation. In
accordance with the present invention, surfactants that are polyethyleneglycol
monoaklyl ethers include, for example, Trycol 5968, Trycol 5949, and Trycol
5968,
which are commercially available from the Henkel Corporation. It will be
understood
that while specific examples of surfactants have been disclosed for
illustrative
purposes only, any one of a number of other surfactants that would be known to
those
having ordinary skill in the art likewise contemplated for use.
The compositions of the present invention also include a bonding agent, such
as, for example, a low foam, non-polar, bonding. One preferred bonding agent
is
sodium xylene sulfonate, which is commercially available as Vanwet XSX-40 from
the Univar Corporation.
Preferably, the percent by mass or percent by volume for each component
identified in the compositions range from approximately 1 percent to
approximately
50 percent, and more preferably range from approximately 1 percent to
approximately
30 percent.
It will be understood that compositions may also include colored dyes,
fragrances, etcetera. It will be appreciated by those skilled in the art that
the
compositions (i.e. mixtures of chemicals) employed in this invention can be
prepared
by any customary industry means.
In accordance with the present invention, the following non-limiting
composition is provided:
7
CA 02641236 2008-10-17
EXAMPLE I
1. Liquid caustic soda (40%-60% NaOH) (0.5-5 Gal.)
Caustic soda solid pellets (1-10 Lbs.)
2. Liquid sodium silicate (5-20 Gal.)
Anhydrous sodium metasilicate (75-125 Lbs.)
3. Triton XL-80N (1-10 Gals.)
Triton QS-15 (1-10 Gals.)
Triton QS-44 (1-10 Gals.)
4. Trycol 5968 (5-20 Gals.)
Trycol 5949 (5-20 Gals.)
5. Vanwet SXS-40 (0.5-5 Gal.)
6. Acid Red 14 (color to suit)
The compositions employed in this invention result in the treatment of
petroleum refinery process water to yield purified water that is free of
contaminating
napthenic acid, hydrocarbons, and solids when used in combination with the
process
elucidated in Example II.
EXAMPLE II
The present invention employs the mixture of chemicals in Example I with the
following process. Referring now to Figure 1, contaminated process water from
a
main pond is transferred into a first fractioned pond wherein the composition
in
Example I is provided (e.g. injected, infused, etcetera). Next, the first
stage treated
water from the first pond is transferred to a second fractioned pond. The
second state
treated water is then transferred to third fractioned pond. It will be
understood that
when the water is going through these ponds it is getting retention time,
starting the
separation. The water is next sent to a hydrocyclone after being associated
with the
8
CA 02641236 2015-09-23
fractioned ponds. The hydrocyclone assists with dropping out any solids. After
being
exposed to the hydrocyclone, a majority of the water is transferred to the one
or more
retaining tanks. The remaining water and solids in the hydrocyclone can be
sent back
to the -first fractioned pond. From the retaining tanks, the water is
transferred to a
precipitating vessel. In this vessel an auger will remove the salts at the
bottom created
from the napthenic acids. Once through the precipitating vessel, the bulk of
the clean
water is transferred back to the oil company for reuse. Water not to be reused
is sent
out as clean water for disposal.
The foregoing description explains and illustrates the invention and the scope
of the claims should not be limited by the preferred embodiments set forth in
the
examples, but should be given the broadest interpretation consistent with the
description as a whole.
9
