DE1157034B - Preservation of kerosene fuels containing water against bacterial growth - Google Patents

Description

GERMAN

PATENT OFFICE

St 18463 IVd / 46a ⁶

REGISTRATION DATE: OCTOBER 23, 1961

NOTICE
THE REGISTRATION
AND ISSUE OF
EDITORIAL: NOVEMBER 7, 1963

The invention relates to the preservation of water-containing kerosene fuels against bacterial growth when storing.

It is known that hydrocarbon fuels when stored in storage tanks, such as. Am Oil refineries, distribution stations and in the tanks for engine fuels, almost always small quantities Contain water at the bottom of the container. Some bacteria and types of sponges that are common found in the earth and in the groundwater, such reservoirs also occur in the water at the bottom and remove the nutrients they need from the hydrocarbon phase, as well as those in the Trace elements contained in the water phase. Because of this metabolism, certain amounts of petroleum products are produced consumed; this metabolism is also the cause of the corrosion of the tanks and causes the general product pollution due to the formation of rust, hydrogen sulfide, rubbery Products, peroxides, acids, colored substances and hair fiber products in the border zone between the water and the hydrocarbons.

Bacteria seem to prefer hydrocarbons with a long carbon chain as food. The abovementioned bacteria are therefore particularly frequently found in kerosene stores stored in water deposits, and the life of these bacteria there is by far more difficult to control than gasoline stores stored in water deposits. Gasoline generally has a final boiling point below 238 ° C and often below 228 ° C. Even if the final boiling point is 238 ⁰ C, seldom exceeds the amount which has a boiling point above 228 ° C, 10%. Gasoline has at least 40% components with a boiling point below 120 ° C. In the following, the term »kerosene« is intended to include hydrocarbon fuels in which at least 30% of the components boil above 228 ° C or in which no more than 15% of the components boil below 120 ° C or both criteria apply. Kerosene stocks are almost always unleaded, ie they do not contain any tetraalkyl lead compounds. Such products include diesel oil, which is a fraction of crude oil with a boiling point between about 150 and 370 ° C and at least 90% of which boils above 205 ° C, and jet fuels for turbo-propeller or jet aircraft. These latter fuels are blends of petroleum fractions which must meet a number of requirements and which have a boiling range of approximately 38 to 315 ° C and preferably between approximately 65 and 290 ° C. The following preservation of hydrous

Kerosene fuels
against bacterial growth

Applicant:

The Standard Oil Company,
Cleveland, Ohio (V. St. A.)

Representative: Dr.-Ing. Dr. jur. F. Redies,

Dipl.-Chem. Dr. rer. nat. B. Redies

and Dr. rer. nat. D. Türk, patent attorneys,

Opladen, Rennbaumstr. 27

Claimed priority:
V. St. v. America of October 27, 1960 (No. 65 268)

Richard John DeGray, Shaker Heights, Ohio,

and Lawrence Neil Killian,

Bedford, Ohio (V. St. A.),

have been named as inventors

Data is given to illustrate a particular fuel, JP-4, which is a fairly broad fraction of petroleum.
Distillation sample

20% evaporates at 132 ° C
50% evaporates at 182 ° C
90% evaporates at 244 ° C

Residue 1.5 percent by volume

Loss 1.5%

Sulfur content .. max. 0.4 percent by weight

Melting point -60 ° C

Kcal / kg 2093

Flash point -12 ° C

As can be seen from the above information, about 35% of the constituents boil above 205 ° C. Im JP-5 fuel boils 80 to 90% above 205 ° C. In a narrow kerosene fraction with a boiling point at 150 ° C ± 4 ° C, none of the components boil below 120 ° C.

Also, kerosene stocks appear to be more of a water-in-oil emulsion than gasoline stocks to stabilize the silt and hairy fibers produced by microbiological activity Material is caused. Therefore, a large

309 747/198

In addition, the selected compound must not change the properties of kerosene as a fuel. This requirement is particularly difficult to meet in cases where the fuel is for military Jet aircraft is intended, because of the very high requirements, especially what the Freedom of the fuels from precipitation is concerned. Fulfilling these requirements is imperative Requirement for the usability of the

some of these impurities are suspended in the kerosene phase and easily clogged filters and sieves the storage and transport devices as well as the filters of machines that run on kerosene.

Clogging of the filters is a particular because of the possibilities of engine failure serious moment in jet aircraft that are operated with kerosene-type fuels. It also increases the tendency to constipation

Filtering in jet engines by the special io fuel. Furthermore, the bactericidal Verbin construction these machines and the way they are dung are sufficiently surface-active to Working method supported. The amount of water in Machine of a jet aircraft used propellant to penetrate the water phase so that they can Substance is very large and can act up to 4 7001 per hour the bacteria where they actually live, or more. With such a large fluid 15 At the same time, the connection must not have any such Quantities can have very low concentrations of increased surface activity that in one Detergent substances very quickly to disruptive back- unwanted amount of water-in-oil emulsion admitted amounts in the machine's filter system. forms is. There is still another requirement In addition, a jet aircraft instead of one has therein that the connection has balanced properties Fuel tanks have a large number of units in terms of extractability, i.e. i.e. that Other connected cells with numerous deep layers - they are not too easily extracted by water Nen places in which water can collect, otherwise an undesirably large one and in which the bacteria can live. In many a lot of connection by the water deposition jets and especially in military aircraft in the first storage tank of the distribution system These fuel cells go to a cleaning or a 25, which in turn has the consequence that inadequate rinsing practically inaccessible, and the microscopic amounts of the compound in the kerosene remain growth can continue to practice undisturbed and unchecked in order to combat the offense in the other tanks, divider system or in the fuel tank or the

It is already known that the action of the sponge machine itself has an effect on bacteria and that bacteria in storage containers of coal can. At the same time, however, it is also important to combat hydrogen fuels with an effective bactericide by treating certain amounts of the compound through the water phase of each fuel container with water deposits in the serially associated ones
check. From what has been said above, however, it is easy
it can be seen that this mode of treatment in cases where 35
the fuel tanks or fuel cells with a
Machine are not always feasible
is. In addition, there is such a control method
impracticable and uneconomical if a
Protection against the bacterial problem in a total of 40
th fuel distribution system is sought, and
because of the large number of tanks that make up
such a system exists.

It must be possible to add the bactericidal compound directly to the kerosene-like hydrocarbon so that they carry the kerosene from one storage boiler to another and through the fuel system the machine in which the fuel is burned, if necessary, can be transported further. on in this way an effective control of the bak 50 activity before using the fuel by simply adding the compound to the kerosene can be achieved prior to storage. In order to be able to fulfill the intended purpose, the bak-

Tanks are extracted so that a bactericidal concentration can be achieved there.

It has been found that a preservation of water-containing kerosene fuels against bacterial growth while meeting the above criteria in the best possible way by using triaryl borates the following general formula

■ O - B - O - <■

R '"

R '

R '

wherein R and R 'are hydrogen or a lower alkyl radical with preferably up to 3 carbon atoms means, is achieved, the triaryl borate being added to the kerosene in such an amount,

tericidal compound of course in kerosene in a 55 that the content in kerosene fuel of triaryl borate, be soluble to such an extent that one for the Bak- based on elemental boron, at least 0.0001 geteria lethal concentration in the fuel reaches weight percent. Examples of such connections are given. In addition, the compound must have a high level of bak- fertilize are triphenyl borate, tritolyl borate, trixylyl tericides Possess effectiveness. It has been found borate, tricumenyl borate, tri- (ethylphenyl) borate and that some compounds are initially the other 60 tri- (methylethylphenyl) borate. The development of bacteria prevents them but only the addition of hydrocarbon-soluble boron for are effective for a limited time because the acid esters are generally used as fuels on carbon dioxide get used to the connections and a hydrogen base is known per se. The additives certainly Generate immunity to this. To one we followed to improve the temperature resistance Solution to the above-mentioned problem 65 speed of the fuels.

To achieve such a resistance, of course, the resistance to be added to the fuel according to the invention

does not occur, but the selected bactericidal amount of the boron compound depends on various Compound must kill the bacteria. Factors. It was found that to achieve

a complete suppression of bacterial life, the water phase generally has a concentration the triaryl borate must have, which corresponds to about 0.03 percent by weight of elemental boron. the Concentration of the boron compound in kerosene, which is preferably given based on boron based on this number, taking into account the ratio of kerosene to water of the distribution factor the boron compound between the kerosene and the water phase can be estimated. Of the Distribution factor can be easily set for each compound by simply adding it to a mixture of kerosene and water of known composition, separate determination of the elemental content Boron can be obtained in both phases and dividing the larger number by the smaller number. When calculating the amount of water, it is not only necessary to estimate the water in each individual tank, but the number of tanks in the distribution system must also be taken into account, through which the kerosene is pumped, as each tank is normally a new one to be sterilized Represents the amount of water. The selection of the triaryl borate is decisive for how much of the boron compound is extracted into the water phase of the first tank and how much remains in the kerosene to then between the kerosene and the water in the subsequent tanks of the distribution system will. In general it can be said that the greater the number of carbon atoms in the substituents R and R 'of the compounds used in the present invention, the less the boron compound is extractable by water. It follows that the longer the carbon chain increases the effectiveness of the active ingredient drops on first contact with water, while the number of tanks with one can be treated by the distribution system directed kerosene charge increases. Also must be considered that not every kerosene charge of the water deposition of every tank is the full lethal one Dose of boron must be transferred because the following, a boron compound to be used according to the invention kerosene containing batches of kerosene can increase the boron content of the water up to a lethal dose. As from the above, the selected active ingredient or the active ingredient mixture to be used and the in the kerosene necessary amount of active ingredient for each distribution system, taking into account the above Considerations are worked out. However, an amount of active ingredient containing elemental boron of about 0.0001 percent by weight in kerosene is considered to be the smallest amount that produces some noticeable effect upon first contact. To be favoured the boron compounds are added to the kerosene in such amounts that they have a concentration between Generate 0.0004 and 0.004 percent by weight in kerosene, especially when dealing with two or more tanks should be. The use of amounts greater than 0.1% is not required and is generally also not justified for economic reasons.

A surprising aspect of the invention lies in the fact that it is used to suppress bacterial activity a much lower boron content in the water phase in the form of the lipophilic organoboron compounds according to the invention is necessary than with the previously known treatment methods, according to which water-soluble boron compounds remove the water deposits can be added directly to the storage tanks containing kerosene. Because microbial growth occurs at the boundary phase, the conversion of the boron compounds from kerosene into the water phase must necessarily take place through the boundary layer. This does not apply if the boron compound differs from At the beginning is located in the water phase, since in this case no transfer from the water phase to the Kerosene phase occurs.

The boron compound can be added directly to the kerosene storage supply be supplied in the necessary quantities. If desired, a concentrate of the Boron compound can be prepared by using a suitable solvent, the concentrate is then added to the kerosene in order to set the desired boron concentration.

The invention will be more easily understood from the description of a test with kerosene stocks in which the actual storage conditions for such kerosene are mimicked via water separation so that the results are correlated with the results obtainable from the real circumstances. This test consists in that a kerosene inventory contains triarylborate compounds according to the invention and water in a ratio of 100: 1. In this test a device is used which consists of a large wheel with sixteen spokes, with two bottles similar to the "1-pint Mason" bottles attached to each spoke with the openings one on top of the other. Each of the pairs of bottles was ^{filled with 400 cm 3} of the kerosene to be tested and 4 cm ^{3 of} water. A polished steel rod was placed in each pair of bottles so that the influence of the bacteria on the corrosion could be observed. The influence of rust formation on the development of the bacteria mimics the circumstances existing under actual storage conditions. The water was taken from an artificial lake that contains bacteria similar to those found in the water at the bottom of the tanks. The wheel is then rotated at three revolutions per minute for 48 hours in order to study the growth of the bacteria, ie each pair of bottles is turned twice per revolution of the wheel, so that the contents of the bottles flow back and forth six times per minute during the test . This movement mimics what happens in a storage container when large quantities of kerosene are introduced or discharged, thereby keeping the contents of the tanks in a rolling motion.

At the end of the 48-hour test period, the bacterial density is estimated using the usual plate method. Here, plates are inoculated with a certain amount taken from the soil water and with progressive dilutions of the soil water sample by a power of ten. For this purpose, a 1 cm ^s sample is pipetted off the water layer of the kerosene-water mixture and transferred to a sterile Petri dish. Then about 20 cm ^{3 of} a sterile agar solution are poured into the dish and the contents swirled until completely mixed. The mixture on the plate is then allowed to cool to room temperature, whereupon the agar gels. The plate is then inverted and placed in an incubator held at 37 ° C. After 48 hours of incubation, the bacterial

colonies are enumerated using a lit, checkered plate. The result of the test will given in bacteria per cubic centimeter of the sample. The following table gives the results this test with kerosene samples that were untreated or with a bactericidal compound according to of the invention have been dealt with. A product was used as kerosene in this test that meets the requirements of a JP-4 fuel.

attempt
No. Addition (concentration
corresponds to 0.001 percent by weight boron) bacteria
per cubic
centimeter 1
2
3
4th no additive
(Starting kerosene)
Triphenyl borate
Tritolyl borate
Trixylyl borate 5,500,000
3
4th
1200

10 to predict. Mixtures 2, 3 and 4 showed no significant differences from Mixture 1 in the amount or nature of the precipitate produced, from which it can be concluded that the bactericidal agents of the invention do not have a deleterious effect on the basic fuels in terms of the precipitation rate or in any other respect to the inventor for use in turbo-prop and jet engines.

Claims (2)

PATENT CLAIMS: 1. Use of triaryl borates of the general formula: 20th The above results of this invention show that the compounds at low concentrations have a deliver very good bactericidal activity. Since trixylyl borate is the least extractable from water, its application is the least successful at the first contact with water. Because on the other hand more boron after the first contact remains in the kerosene phase, the trixylyl borate through a larger number of tanks in the distribution system be transported. All kerosene products listed in the table have successfully passed the Erdco-Coker test in accordance Subject to the American regulations ASTM-D1660. This test is used to check whether the kerosene fuel is burning properly; he is often considered the most reliable Test viewed to determine the actual performance of a fuel in turbo-prop and jet engines in which R and R 'denote hydrogen or a lower alkyl radical, for the preservation of water-containing Kerosene fuels against bacterial growth, the triaryl borate being the kerosene is added in such an amount that the content in the kerosene fuel is based on triaryl borate on elemental boron, is at least 0.0001 percent by weight. 2. Use of triaryl borates according to claim 1, characterized in that the triaryl borate Is triphenyl borate or tritolyl borate. Considered publications:
German publication No. 1082 453. © 309 7 + 7/198 10.63