EP2049455A1

EP2049455A1 - Fuel on h2o2-basis and apparatus for its utilization as rocket fuel and fuel for rotor tip engines

Info

Publication number: EP2049455A1
Application number: EP06761220A
Authority: EP
Inventors: Peter Jeney
Original assignee: Jeney Peter
Current assignee: Innosuisse Development AG
Priority date: 2006-07-13
Filing date: 2006-07-13
Publication date: 2009-04-22
Also published as: WO2008006228A1

Abstract

Described is a colloidal fluid composition, comprising H2O2, a hydrocarbon mixture and at least one additive, in particular at least one the colloid fluid stabilizing agent. The composition can be made using aqueous H2O2 solutions comprising e.g. 30 to 50 % H2O2 and is suitable as fuel, in particular for rocket engines.

Description

Fuel on H2O2-Basis and apparatus for its utilization as rocket fuel and fuel for rotor tip engines

5 Technical Field

The present invention relates to rocket fuels, in particular rocket fuels that are suitable as pro- pellants for helicopters and a rocket engine suitable for use with this fuel.

-10

Background Art

H2O2 in concentration of 85 % is a recognized rocket propellant . It is known that the fuel decomposes in a chamber under high pressure and temperature in the

15 presence of catalysts, whereby the fuel is converted to H20 in the form of steam and oxygen, and the gas stream exits the chamber at high speed. This process can be compared to other well-known rocket-propelled processes.

Normally, the catalyst consists of precious

20 or rare metals such as silver, platinum, palladium or related alloys, which trigger the required decomposition process when the concentrated H2O2 flows through it. For aerospace applications in the past, inexpensive catalysts made out of other materials such as sodium or potassium

25 permanganate have been used to activate the decomposition of the concentrated H2O2 • All these technologies, however, have the significant disadvantage that the catalysts have a limited shelf-life and the systems only work with highly concentrated H2O2 • Another serious shortcom-

30 ing is the relatively low energy content of concentrated H2O2, as well as the eminent dangers referring to handling, storage and transport of this product. Furthermore, another crucial factor for aerospace applications is the space requirement for placing the catalyst.

35 Disclosure of the Invention Hence, it is a general object of the invention to eliminate the above disadvantages and simultaneously create a cost-effective and environmentally friendly fuel that is easy to store.

It is another object of the present invention to provide a method for the production of such a colloidal fluid composition and its use as fuel, in particular for rocket engines . Now, in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the fuel is manifested by the features that it is a colloidal fluid composition comprising a H2O2 (calculated for 100% H2O2) :hydrocarbon mixture ratio of from about 31% : about 7% to about 47% : about 6%, preferably from 31.3% H2O2 and 6.9% hydrocarbon mixture to 46.9% H2O2 and 6.3% hydrocarbon mixture and at least one additive.

The composition can be made by mixing 93 to 94.5 % by weight of aqueous H2O2 having a concentration of 30 to 60 % by weight, in particular 30 to 50 % by weight, with 7 to 5.5 % by weight hydrocarbon mixture to give a total of 100% by weight. To this mixture at least one of the following stabilizing additives are added: - anti-knock additives

- anti-oxidant additives

- static dissipater additives

- icing inhibitor additives

- corrosion inhibitor additives - power boosting additives

- stabilizer additives

The hydrocarbon mixture is primarily composed of aromatic hydrocarbons, olefinic hydrocarbons, also known as alkene hydrocarbons, and saturated hydrocarbons, i.e. alkanes, also known as paraffinic hydrocarbons, and/or cycloalkanes . A composition with the above described ratio of aqueous H2O2 and hydrocarbons can be brought into a stabilized dispersion by the addition of one or more further additives as mentioned above. One essential additive for stabilizing the dispersion is the stabilizing additive that in general is one or more alcohols, in particular ethanol and/or propanol (n-propanol and/or isopropa- nol) . The necessary amount can easily be determined by simple storage experiments. In general it is in the range of 1.5 to 15%, whereby for ethanol preferably at least 5 % vol. are present, while in the case of isopropanol 1.5 % vol. are sufficient. The minimally necessary and/or the optimal amount may vary dependent on other additives present . An obvious benefit of this invention is that the inventive mixture in spite of the high water content has a high energy value and therewith represents a significant advantage for all flying objects where endurance and long range is desired and where the ratio between fuel and total take-off weight is of importance. Furthermore, this new fuel is very safe to handle and - due to its high water content - can not be ignited with an open flame .

Another advantage of the present invention is that the fuel does not need a secondary injection for another fuel component (bi-fuel) .

While the fuel of the present invention, due to the high energy content, might allow the design of a smaller rocket engine, it can also be used with known en- gines.

Modes for Carrying out the Invention According to the present invention this aim is achieved by providing a liquid fuel and a method for its production. The fuel of the present invention is characterized by the benefit that it is a colloidal fluid composition comprising a H2O2 (calculated for 100% H2O2) : hydrocarbon mixture ratio of from about 31% : about 7% to about 47% : about 6%, preferably from a minimal H2O2 content of 31.3% to 6.9% hydrocarbon mixture to a maximal H2O2 content of 46.9% to 6.3% hydrocarbon mixture (all % are % by weight) and at least one additive, in particular at least a stabilizing additive.

Such a mixture can be produced by using a low concentration solution of aqueous H2O2, namely a concentration of 30-50 % by weight, although higher concentra- tions can also be used. Besides of this aqueous H2O2_A the liquid fuel comprises a certain amount of hydrocarbons and some additives to stabilize a colloidal fluid.

The composition can be made by mixing 93 to 94.5 % by weight of aqueous H2O2 having a concentration of 30 to 60 % by weight, in particular 30 to 50 % by weight, with 7 to 5.5 % by weight hydrocarbon mixture to give a total of 100% by weight. To this mixture at least one of the following stabilizing additives are added:

- anti-knock additives - anti-oxidant additives

- static dissipater additives

- icing inhibitor additivess

- corrosion inhibitor additivess

- power boosting additives - stabilizing additives

The hydrocarbon mixture preferably has the following composition (in % by weight) :

- approx. 10-20 % aromatic hydrocarbons,

- approx. 0.5-1.5 % olefinic hydrocarbons, also known as alkene hydrocarbons,

- approx. 80-85 % saturated hydrocarbons, i.e. alkanes, also known as paraffinic hydrocarbons, and/or cycloalkanes .

The aromatic hydrocarbons are primarily se- lected from benzene derivatives . They preferably are selected from the group consisting of toluene, xylene, ethyl benzene, and mixtures of two or more thereof. Much preferred, the aromatic component comprises toluene and xylene and ethyl benzene whereby in a three component mixture the minimal amount of each is 5%, preferably 10%, wherein the three xylenen isomers are considered as one component .

Preferred olefinic hydrocarbons are C3 to C15 hydrocarbons with 1 to 3 double bonds. They can be used in pure form or in mixture with one or more compounds falling under the above definition. Suitable olefinic hy- drocarbons or mixtures of olefinic hydrocarbons are liquid at room temperature.

The aliphatic hydrocarbons are selected from liquid hydrocarbons and liquid hydrocarbon mixtures, in particular from linear and branched C4 to C15 hydrocar- bons, and/or from cycloalophatic hydrocarbons, in particular from alkyl substituted cyclopentanes and alkyl substituted cyclohexanes, in particular from alkyl substituted cyclopentane or alkyl substituted cyclohexane having a total carbon content of 15 C-atoms, preferably 13 C-atoms . Suitable aliphatic or cycloaliphatic hydrocarbons or mixtures of such hydrocarbons are liquid at room temperature.

Further to the above basic elements additives are required to obtain a colloidal fluid with H2O2, water and the hydrocarbon content and -if present - a critical mixture of at least one organic nitrogen compound or a nitrated aromatic compound. In general, the additives are added in the following amounts :

- Anti-knock additives 2-5.7 mg/1

- Antioxidant additives 10-15 mg/1

- Static dissipater additives 0.6-4.5 % vol

- Icing inhibitors about 0.10-0.15 mg/1

- Corrosion inhibitors about 0.05-0.20 mg/1 - Stabilizer additives 1.5-15 % vol.

- Power boosting additives 0.02-2.00 % vol. The amount of additives added is referred to the aqueous H2O2 and hydrocarbon mixture comprising composition (basic composition), i.e. mg/1 basic composition and % by volume with the basic composition being 100%. Examples for anti-knock additives are additives based on propylene alcohol and/or ketones and/or aldehydes. (See also stabilizer additives)

Examples for antioxidant additives are phenols or organic sulphides or polysulphides, dithiocar- bamates, phosphates and phosphonates . The antioxidant additives are added to prevent the formation of gum deposits and to prevent other oxidation problems .

Examples for static dissipater additives are nitroso compounds based. They are not required but added for security reasons to reduce the creation of electricity which may be generated by the movement of the fuel through modern, high-flow-rate fuel transfer lines.

Examples for icing inhibitors are isopropanol and isopropylen and mixtures thereof that are e.g. used among others to prevent the formation of ice crystals. These additives are also helpful to create a colloidal fluid between hydrocarbons and the aqueous H2O2. (see also stabilizer additives)

Examples for corrosion inhibitors are phenol derivatives such as dibutylmethylphenol (BHT) and butyl- hydroxyanisol (BHA) . The corrosion inhibitor additives serve the protection of ferrous metals in fuel handling systems .

Examples for stabilizer additives are liquid alcohols such as ethanol or propanol, whereby in the case of ethanol preferably at least 5 % vol. are present, while in the case of isopropanol 1.5 % vol. are sufficient. The stabilizer additives are added to stably keep the mixture colloidal. The alcohols can be used in mix- ture of two or more thereof, whereby the amount of long chain alcohols must be limited to avoid phase separation, (see also anti-knock Additives and icing inhibitors) Examples for power boosting additives are nitrated aromatics , e.g. trinitrobenzene and related compounds. The addition of power boosting additives is optional. As can be seen from the above list, some of the compounds may have different functions such as e.g isopropanol that can act as stabilizer additive and icing inhibitor additive. In such cases, the two amounts are additive . With extensive tests mixing relations between hydrocarbons and 30-60 %, preferably 30 to 50 % concentrated H2O2 could be found that provide an easy to store, non-explosive, colloidal fluid which, according to this invention, has an energy value of approximately 3 times the normally used high concentrated 85 % H2O2 mono-fuel.

These tests showed that the mixture relation between H2O2 (calculated for 100% H2U2)is from 31% H2O2 to 7% hydrocarbon mixture : 47% H2O2 to 6% hydrocarbon mixture, preferably from 31.3% H2O2 to 6.9% hydrocarbon mixture : 46.9% H2O2 to 6.3% hydrocarbon mixture. If 30- 50 % concentrated H2O2 is used, the mixing ratio of said H2O2 preferably should be in relation of 93.1 % H2O2 to 6.9 % hydrocarbon mixture, up to 93.7 % H2O2 to 6.3 % hydrocarbon mixture respectively whereas the hydrocarbon mixture preferably is the hydrocarbon mixture described in this invention.

A composition in this ratio can be brought into a stabilized dispersion by the addition of one or more further additives as mentioned above. One essential additive for stabilizing the dispersion is the stabilizing additive.

An obvious benefit of this invention is that the inventive mixture with a substantially higher energy value represents significant advantages for all flying objects where endurance and long range is desired and where the ratio between fuel and total take-off weight is of importance. Furthermore, this new fuel is very safe to handle and can not be ignited with an open flame.

Another advantage of the present invention is that the fuel does not need a secondary injection for an- other fuel component (bi-fuel) . In order to improve ignition, it might be advantageous to pre-treat the fuel with a pre-dissociation enhancing substance. Such pre- dissociation enhancing substance could be a catalyst (e.g. a mixture of CoO + MgO) . While there are shown and described presently preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

1. A colloidal fluid composition, comprising a H2O2 (calculated for 100% H2O2) .-hydrocarbon mixture ratio of from about 31% : about 7% to about 47% : about 6%, preferably from 31.3% H2O2 and 6.9% hydrocarbon mixture to 46.9% H2O2 and 6.3% hydrocarbon mixture and at least one additive .

2. The colloidal fluid composition of claim 1, wherein the at least one additive comprises a stabi- lizing agent.

3. The colloidal fluid of anyone of the preceding claims wherein the at least one additive is selected from the group consisting of anti-knock additives, anti-oxidant additives, static dissipater additives, ic- ing inhibitor additives, corrosion inhibitor additives, power boosting additives, and mixtures of two or more thereof, preferably all.

4. The colloidal fluid of anyone of the preceding claims wherein the at least one additive if added is added in the following amounts :

- Anti-knock additives 2-5.7 mg/1

- Antioxidant additives 10-15 mg/1

- Static dissipater additives 0.6-4.5 % vol

- Icing inhibitors about 0.10-0.15 mg/1 - Corrosion inhibitors about 0.05-0.20 mg/1

- Stabilizer additives 1.5-15 % vol.

- Power boosting additives 0.02-2.00 % vol.

5. The colloidal fluid of anyone of the preceding claims wherein the hydrocarbon mixture has the following composition:

- approx. 10-20 % by weight aromatic hydrocarbons,

- approx. 0.5-1.5 % by weight olefinic hydrocarbons, also known as alkene hydrocarbons, - approx. 80-85 % by weight saturated hydrocarbons, i.e. alkanes, also known as paraffinic hydrocarbons, and/or cycloalkanes .

6. The colloidal fluid of claim 5, wherein the aromatic hydrocarbons are primarily selected from benzene derivatives, in particular from the group consisting of toluene, xylene, ethyl benzene, and mixtures of two or more thereof, and/or wherein the olefinic hydrocarbons are primarily selected from C3 to C15 hydrocarbons with 1 to 3 double bonds, in particular from olefinic hydrocarbons or mixtures of olefinic hydrocarbons that are liquid at room temperature, and/or wherein the aliphatic hydrocarbons are selected from linear and branched C4 to C15 hydrocarbons, and/or from cycloalo- phatic hydrocarbons, in particular from aliphatic or cycloaliphatic hydrocarbons or mixtures of such hydrocarbons are liquid at room temperature.

7. The colloidal fluid of anyone of the preceding claims, wherein the additives are selected from the following groups: The anti-knock additives are selcted from propylene alcohol, ketones, aldehydes and mixtures thereof; the antioxidant additives are selected from phenols, organic sulphides or polysulphides, dithio- carbamates, phosphates, phosphonates and mixtures thereof; the static dissipater additives are selected from nitroso compounds; the icing inhibitors are selected from isopropanol, isopropylen and mixtures thereof; the corrosion inhibitors are selected from phenol derivatives in particular from dibutylmethylphenol (BHT) , butylhy- droxyanisol (BHA) , and mixtures thereof; the stabilizer additives are selected from at room temperature liquid alcohols, in particular from ethanol, propanol, and mix- tures thereof; the power boosting additives are selected from nitrated aromatics, in particular from trinitroben- zene .

8. A method for producing a colloidal fuel composition of anyone of the preceding claims wherein 93 to 94.5 % by weight of aqueous H2O2 having a concentration of 30 to 60 % by weight, in particular 30 to 50 % by weight, is mixed with 7 to 5.5 % by weight hydrocarbon mixture to give a total of 100% by weight, and wherein the additives, if present, are added at any time.

9. The method of claim 8 wherein 30-50 % by weight concentrated H2O2 is mixing with the hydrocarbon mixture in a relation of 93.1 % by weight H2O2 to 6.9 % by weight hydrocarbon mixture, up to 93.7 % by weight H2O2 to 6.3 % by weight hydrocarbon mixture.

10. Use of the colloidal fluid composition of anyone of claims 1 to 7 as a liquid fuel for engines, in particular rocket engines.