FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See sections 10 & rule 13)
1. TITLE OF THE INVENTION
COMPOSITIONS ANDMETHODS FOR DETECTINGFREEWATERIN
HYDROCARBONS
2. APPLICANTS (S)
NAME NATIONALITY ADDRESS
Bharat Petroleum Corporation Bharat Bhawan, 4 & 6 Currimbhoy
IN
Limited Road, Ballard Estate, Mumbai-400001,
India.
3. PREAMBLE TO THE DESCRIPTION COMPLETE
The following specification particularly describes the invention and the manner
in which it is to be performed.

COMPOSITIONSANDMETHODSFORDETECTINGFREEWATERIN
HYDROCARBONS
FIELDOFTHE INVENTION
[0001] The present invention relates to a new and improved composition for detecting the presence of free suspended or entrained water in aviation turbine fuels and other hydrocarbons. More particularly, the present invention is concerned with a new and improved chemical composition which when contacted with an aviation turbine or other hydrocarbon fuels containing trace amounts of free water, undergoes a change in color according to the amount of free water dispersed in the fuel.
BACKGROUND OF THE INVENTION
[0002] Water present in aviation turbine fuels (ATF) in suspended or dissolved state can be the cause of several adverse effects such as freezing, blocking of fuel pipelines, etc. which can result in accidents. Entrained water, water suspended in fuel in minute globules, may not be perceptible to the naked eye and may cause the fuel to take hazy/milky appearance. The presence of haze in such samples is generally indicative of dispersed water but the absence of haze does not necessarily mean that no free water is present. These fuels may also contain considerable quantities of dispersed water even though no haze is discernible.
[0003] Detection of free water in hydrocarbon fuels is of particular importance with regard to ATF which is used for high altitudes operations. At the temperatures prevailing at high altitudes, any water dispersed in turbo-jet fuel quickly freezes to form ice crystals which may block fuel lines, screens and orifices in the fuel system. To minimize this hazard, it is a normal practice to check ATF for the presence of free water as it is being loaded into aircraft. The presence of free water even in small trace amounts may cause several adverse effects leading to potential operational problems. Special filter separators are used for removing free water from jet fuels, but testing of fuel samples just prior to fuelling of aircrafts is necessary to check conformance of fuel, being loaded into aircraft, to required standards and specifications.

[0004] US patent 3,341,298 discloses an improved method for determining the presence and the amount of free water in hydrocarbon fuels. According to the method disclosed therein, the fuel to be tested is intermixed with sodium tetrabromo fluorescein and treated with ammonia. The intensity of pink color of the ammoniated sodium tetrabromo fluorescein is then compared with standard fuel sample containing predetermined amounts of free water. [0005] US patent 3,066,221 discloses a method for measuring free water contained in liquids of low water solubility. This method employed a saturated solution of potassium fluorescein which was incorporated onto one side of a filtering element so as to form a thin uniform film thereon. Any free water present in the fuel will cause a yellow –green stain on the treated side of the filtering element which was visible under ultra-violet light.
[0006] US patent 3,389,967 discloses a method for detecting trace amounts of both free and dissolved water present in organic or inorganic liquid. The method comprises contacting the liquid with a test paper comprising methyl orange indicator paper coated with a thin layer of finely divided particles of phosphorus pent oxide for a sufficient period to obtain a color change. [0007] US patent 3,873,271 discloses a method and apparatus for detecting the presence of free water in hydrocarbons in which the water reacts with freshly prepared ground fuchsia dye and calcium carbonate. The reagents are prepackaged in an evacuated glass vial. A sample of the hydrocarbon is admitted to the interior of the evacuated vial by a cannula mounted in a special receptacle adapted to receive the vial. The fuel is drawn in by the vacuum present within container where it reacts with the reagents, producing a pink color should an excessive amount of free water be present, or remaining clear if less than 10 ppm free water is present. [0008] All of these known compositions and test methods for detecting free waters in hydrocarbon fuels suffer from poor sensitivity if the free water concentration in the hydrocarbon fuel is very low. Specifically, free water detection sensitivity is not particularly good and generally detection of trace amounts of less than 10 parts per million (ppm) are difficult or impossible to obtain with these known prior art methods.
[0009] Accordingly, there is a need to develop a process for monitoring trace amounts of free water present in aviation turbine fuels by a commercially viable method such as using commercially available low-cost chemical ingredients and unsophisticated laboratory and field test methods. Desirably, the free water detecting composition and test methods should be capable of detecting free water concentration at amounts less than 10 ppm.

[0010] The present invention satisfies the existing needs, as well as others, and generally overcomes the deficiencies found in the prior art.
OBJECTS OF THE INVENTION
[0011] It is therefore an object of the present invention to provide a new and improved
chemical composition useful for detecting trace amounts of free suspended or entrained water in
aviation turbine and other hydrocarbon fuels.
[0012] It is a further object of the present invention to provide an improved chemical
composition which can react with very low concentration of free water admixed with
hydrocarbons and produce a sharp and distinct color change.
[0013] It is another object of the present invention to provide a simple yet reliable test method
to detect the presence of free water in hydrocarbons at very low concentrations.
[0014] It is another object of the present invention to provide a simple yet reliable test method
to detect the presence of free water in hydrocarbons at very low concentrations in field
conditions without using any sophisticated laboratory equipment.
[0015] It is another object of the present invention to enhance the sensitivity of an indicator
dye and protect other chemical reagents used in the composition from exposure to moisture
during storage to enhance the storage life for the composition.
SUMMARY OF THE INVENTION
[0016] The present invention provides a chemical composition useful for detecting trace amounts of free suspended or entrained water in hydrocarbons comprising
(a) a water soluble indicator dye capable of changing color in pH range between about 7 and about 11;
(b) a pH stabilizer; and
(c) an anhydrous base material;
wherein said water soluble indicator dye is selected from the group consisting of o-cresolphthalein, phenolphthalein and thymolphthalein;

wherein said pH stabilizer is selected from the group consisting of anhydrous alkaline earth oxide, anhydrous alkaline hydroxide and mixtures thereof; and
wherein said anhydrous base material is selected from the group consisting of calcium carbonate, barium carbonate, barium sulfate, magnesium carbonate and mixtures thereof. [0017] In one aspect, the present invention provides a method for detecting trace amounts of free suspended or entrained water in a hydrocarbon, comprising the steps of:
(a) obtaining a sample of said hydrocarbon in a container;
(b) agitating said hydrocarbon sample with an effective amount of the chemical
composition of the present invention;
(c) permitting solids to settle in said hydrocarbon sample; and
(d) comparing the color of the settled solids with a predetermined standard.
[0018] The present invention provides a new and improved chemical composition which can
react with very low concentration of free water admixed with hydrocarbons and produce a sharp
and distinct color change thereby enabling determination of presence and extent of free water in
hydrocarbons at very low concentrations.
[0019] The present invention provides an evacuated capsule containing the chemical
composition of the present invention which when contacted with a hydrocarbon containing free
water indicates a sharp and distinct color change.
[0020] The present invention provides a method to enhance the sensitivity of the indicator dye
and protect other chemical reagents used in the composition from exposure to moisture.
DETAILED DESCRIPTION OF THE INVENTION
[0021] For those skilled in the art, numerous embodiments described below are for illustration
purpose only and do not limit the scope of the present disclosure in any manner.
[0022] Before describing the present invention in detail, it is to be understood that this
invention is not limited to specific compositions or process steps, as such may vary. It must be
noted that, as used in this specification and the appended claims, the singular form “a”, “an” and
“the” include plural referents unless the context clearly dictates otherwise.
[0023] The detection of free suspended or entrained water in aviation turbine fuels and other
hydrocarbons can be quickly and easily determined by contacting a sample of the hydrocarbon

with a small amount of the composition of present invention. The present method provides determination of presence as well as extent of the free suspended or entrained water in aviation turbine fuels and other hydrocarbons.
[0024] The present invention provides a new and improved composition and method for detecting trace amounts of free suspended or entrained water in aviation turbine fuels and other hydrocarbons which is considerably more sensitive and reliable than methods employed for this purpose in the past. The method of the present invention can be utilized as a qualitative laboratory test to detect the presence of free suspended or entrained water in aviation fuel at concentrations of 0, 10,15,20,30 ppm respectively. The accuracy of the method of the present invention is not adversely affected by the presence of dissolved water or additives commonly employed in aviation turbine fuels. The composition of the present invention may be employed without extensive laboratory equipment and give results which are readily susceptible to visual and other interpretation, and can be inexpensive to use.
[0025] In one aspect, the present invention provides a new and improved chemical composition useful for detecting trace amounts of free water in hydrocarbons comprising
a) a water soluble indicator dye capable of changing color in the pH range between about 7 and about 11;
b) a pH stabilizer; and
c) an anhydrous base material;
wherein said water soluble indicator dye is selected from the group consisting of o-cresolphthalein, phenolphthalein and thymolphthalein;
wherein said pH stabilizer is selected from the group consisting of anhydrous alkaline earth oxide, anhydrous alkaline hydroxide and mixtures thereof; and
wherein said anhydrous base material is selected from the group consisting of calcium
carbonate, barium carbonate, barium sulfate, magnesium carbonate and mixtures thereof. [0026] In one embodiment of the present invention, the anhydrous alkaline earth oxide is selected from the group comprising calcium oxide, barium oxide and magnesium oxide. [0027] In another embodiment of the present invention, the anhydrous alkaline hydroxide is selected from the group comprising calcium hydroxide, barium hydroxide and magnesium hydroxide.

[0028] The composition of the present invention is particularly useful in detection of trace or ultra trace amounts of free suspended or entrained water present in aviation turbine fuels at concentrations less than 10 ppm.
[0029] The water soluble indicator dyes used in the composition of the present invention are readily available from commercial sources as fine anhydrous crystalline powders. These dyes are, upon contact with water, capable of effecting color change of the composition of the present invention in the pH range between about 7 and about 11, preferably between about 8 and about 10. These dyes are employed in the present compositions in an amount sufficient to provide the desired color change. In general, such dyes may be employed in concentrations ranging from between about 0.001 to 0.005 Wt% ratio, based on the total weight of the present composition. The preferred indicator dye for the free water detection composition of the present invention is selected from group of o-cresolphthalein, phenolphthalein and thymolphthalein etc.; [0030] The composition of the present invention includes a pH adjusting agent in order to preferably maintain the pH of the composition in the range of about 7 to about 11, most preferably about 8 to about 10. Any suitable commercially available pH adjusting agent or mixture of such agents can be used in the composition of the present invention. The pH adjusting agent can be used in an amount sufficient to maintain a pH of from about 7 to about 11 and the amount of the agent can be adjusted to achieve this desired pH range. When alkaline earth oxide/ hydroxide is used as the pH adjusting agent, the most preferred pH in the range of about 8 to about 10 has been achieved.
[0031] The anhydrous base material mixed with the dye to form the free water detection composition of this invention is selected from the group consisting of calcium carbonate, barium carbonate, barium sulfate, magnesium carbonate, and mixtures thereof. Preferably, the base material employed in the present composition is barium carbonate or calcium carbonate. The anhydrous base material may be used in the form of a finely-divided technical grade crystalline powder.
[0032] The components of the present composition including indicator dye, pH stabilizer and the base material are preferably blended for a time sufficient to obtain homogeneity. Thus obtained homogeneous mixture is packaged in capsules and the capsules may contain sufficient amount of said mixture for one test. To ensure for greater sensitivity of the dye and provide protection for the mixture from moisture, the capsule containing the homogeneous mixture of the

composition can be evacuated or provided with an inert atmosphere and the capsule broken just before the mixture is added to aviation fuel sample for testing. The testing for presence of free water in the sample is carried out as per the method approved by DGCA.
[0033] The indicator dye, pH stabilizer and the base material are present in the composition of the present invention in a ratio of from about 0.0010:0.0200:0.9790 to 0.0030:0.0290:0.9680 by weight of the composition. Preferably from about 0.0015:0.0210:0.9775 to 0.0028:0.0260:0.9712 by weight of the composition.
[0034] The developed compositions can react with very low concentration of water admixed with aviation turbine and other hydrocarbon fuels and produce a sharp and distinct color change thereby enabling detection of free suspended and entrained water in hydrocarbon fuels at very low concentrations. Upon contact with water present in the hydrocarbon fuel, the composition undergoes a change in color from colorless to pink or blue. The intensity of the pink or blue color particles is then compared with predetermined standard samples to determine the amount of free water concentration. The method enables for conducting of this test in field conditions and without requirement for any sophisticated test equipment.
[0035] The amount of the composition of the present invention added to the hydrocarbon sample to be tested may be varied from about 0.1 to about 2 grams per 100 milliliters of the hydrocarbon. It is preferred to add from about 0.1 to about 0.2 gram of the composition to each 100 milliliters of the hydrocarbon to be tested.
EXAMPLES
[0044] The present invention is further explained in the form of following examples. However it is to be understood that the foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.

Example 1
[0045] Water detecting capsule was prepared by mixing 100 gm of anhydrous barium carbonate and 0.26 gm of phenolphthalein and 2.8 gm of barium hydroxide and blending the mixture for a sufficient time to obtain homogeneity and there after packaging the ingredients in dry capsules in presence of inert gas to provide a uniformity of response. The reagent mixture would be added to a hydrocarbon fuel sample about 0.25 g of the mixture to 100 milliliters of the hydrocarbon fuels. The test was performed according to the instructions provided by DGCA method.

Water content in ATF (ppm) Remarks

10 ppm 15 ppm 20 ppm 30 ppm
CRDC-WDC 1-2 pink particles 3-4 pink particles 7-8 pink Distinct pink particles particles Working as per DGCA approved method
Example 2
[0046] Water detecting capsule was prepared by mixing 100 gm of anhydrous calcium carbonate and 0.22 gm of thymolphthalein and 2.5 gm of calcium hydroxide and blending the mixture for a sufficient time to obtain homogeneity and there after package the ingredients in dry capsules in presence of inert gas to provide a uniformity of response. The reagent mixture would be added to a hydrocarbon fuel sample about 0.25 g of the mixture to 100 milliliters of the hydrocarbon fuels. The test was performed according to the instructions provided by DGCA method using distilled water for saturation of ATF

Water content in ATF (ppm) Remarks

10 ppm 15 ppm 20 ppm 30 ppm
CRDC-WDC 1-2 blue particles 3-4 blue particles 7-8 blue particles Distinct blue particles Working as per DGCA approved method

Preparation of saturated aviation turbine fuel (ATF) for testing water detecting capsules:
[0047] The following "water saturated ATF sample" preparation and test methods were performed according to the directions provided by DGCA.
[0048] 1000 ml of ATF was added with 10 ml of distilled water in a separating funnel. The contents of the separating funnel were shaken vigorously for 30 seconds and allowed to settle for 30 seconds. After 30 seconds, the contents were again shaken and the cycle was repeated for thrice. The separating funnel was allowed to settle for 48-72 hours. After layer separation, five lots of samples, each containing 100 ml of ATF saturated with water, were taken from the supernatant layer. ATF saturated with water corresponds to ATF with zero ppm water. To each lot added 1.0, 1.5, 2.0, 2.5 and 3.0 micro liters of distilled water using a micro syringe and mixed for 2 minutes. These five samples correspond to ATF containing 10, 15, 20, 25 and 30 ppm of free suspended water respectively.
Test method:
[0049] The samples prepared according to the method described above were intermixed with the contents of the capsule by shaking for about 30 seconds and the capsule materials were allowed to settle at the bottom. The presence of free water was detected by observing the change in color of the settled capsule material from colorless to pink or blue. The intensity of colour and number of colour particles indicated the amount of free water present in the ATF as described in example1 &2.
ADVANTAGES OF THE PRESENT INVENTION
[0036] The present invention provides a new and improved chemical composition capable of detecting trace and ultra trace amounts of free suspended and entrained water in aviation turbine and other hydrocarbon fuels.
[0037] The present invention provides a simple yet reliable test method to detect the presence of free water in hydrocarbon fuels at very low concentrations.

[0038] The present invention provides an accurate process for monitoring trace amounts of
free water present in aviation turbine fuels by a method using commercially available low-cost
chemical ingredients and unsophisticated laboratory and field test methods.
[0039] The present invention provides a new and improved chemical composition which can
be prepackaged in an evacuated capsule and the contents of the capsule can be added to the test
sample at the time of testing.
[0040] The present invention provides a method to enhance the sensitivity of the dye and
protect the composition from exposure to moisture.

CLAIMS We claim,
1. A composition useful for detecting trace amounts of free water in aviation turbine and other
hydrocarbon fuels comprising
(a) a water soluble indicator dye capable of changing color in the pH range between about 7 and about 11;
(b) a pH stabilizer; and
(c) an anhydrous base material;
wherein said water soluble indicator dye is selected from the group consisting of o-cresolphthalein, phenolphthalein and thymolphthalein;
wherein said pH stabilizer is selected from the group consisting of anhydrous alkaline earth oxide, anhydrous alkaline hydroxide and mixtures thereof; and
wherein said anhydrous base material is selected from the group consisting of calcium
carbonate, barium carbonate, barium sulfate, magnesium carbonate and mixtures thereof.
2. The composition of claim 1, wherein said anhydrous base material is barium carbonate.
3. The composition of claim 1, wherein the anhydrous alkaline earth oxide is selected from the group comprising calcium oxide, barium oxide and magnesium oxide.
4. The composition of claim 1, wherein the anhydrous alkaline hydroxide is selected from the group comprising calcium hydroxide, barium hydroxide and magnesium hydroxide.
5. The composition of claim 1, wherein said indicator dye, pH stabilizer and anhydrous base material are present in a ratio of from about 0.0010:0.0200:0.9790 to about 0.0030:0.0290:0.9680 by weight of the composition.
6. The composition of claim 1, wherein said composition is capable of detecting the presence of free water at concentrations of 0, 10, 15, 20, 25 and 30 ppm.

7. A method for detecting the presence of free water in a hydrocarbon, comprising the steps of:
(a) obtaining a sample of said hydrocarbon in a container;
(b) agitating said hydrocarbon sample with an effective amount of composition of claim 1;
(c) permitting solids to settle in said hydrocarbon sample; and
(d) comparing the color of the settled solids with a predetermined standard.

8. The method of claim 7, wherein said hydrocarbon sample is agitated with from about 0.1 to about 2 grams of said composition per 100 milliliters of said hydrocarbon sample.
9. The method of claim 7, wherein said hydrocarbon sample is agitated with from about 0.1 to about 0.2 grams of said composition per 100 milliliters of said hydrocarbon sample.
10. An evacuated capsule comprising the composition of claim 1.