DE1217696B - Propellants or fuels with high combustion heat - Google Patents

Description

Propellants or fuels with high heat of combustion The invention relates to fuels or fuels based on liquid hydrocarbons with a high Heat of combustion.

According to the invention, 20 to 60 percent by weight is friable Magnesium alloy or intermetallic compound of low deformability Magnesium with calcium, aluminum, silicon or boron in liquid hydrocarbons dispersed with the formation of liquid fuels or fuels of high heat of combustion. By grinding in the liquid hydrocarbon, the solid metal becomes particles crushed below 1 micron in size. The dispersions are fuels high heat of combustion, which are liquid, pumpable and easily ignitable.

Liquid fuels based on hydrocarbons are already known, which contain an addition of aluminum or magnesium particles, which are in the form of sheet-like Particles from 1 to 200 microns are present. In contrast, the inventive Fuel friable, substantially equiaxed alloy particles of lesser Particle size, resulting in a fuel with a higher caloric value.

You also have very small amounts of magnesium or magnesium oxide added to the fuel to contain corrosive vanadium compounds to oppose.

According to another known method, the combustion air or the liquid fuel, small amounts of magnesium or magnesium oxide powder added to accelerate combustion. The object of the invention, a flowable To create fuel in which magnesium makes up the predominant part of the heat of combustion is not resolved by this procedure.

The term "magnesium alloy" refers to alloys the magnesium either in greater or lesser proportions or in the same proportion as others Contain combustible components of the alloy. Friable magnesium products low deformability, which have the desired friability to relative To form equiaxed particles after grinding are magnesium-aluminum alloys with an aluminum content of about 14 to 85 percent by weight, the intermetallic Compound Mg "A1" is particularly suitable; Magnesium-calcium alloys are also suitable with a calcium content of about 15 to 80 percent by weight with the range of calcium from the eutectic point at 16.3 percent by weight calcium to about 45 percent by weight, The intermetallic compound Mg2Ca is particularly suitable, magnesium-silicon alloys With a silicon content of about 3 to 60 percent by weight and magnesium-boron compounds, which correspond to the composition MgBz, MgB4 and MgBs. From the friable magnesium alloys Magnesium-calcium alloys are or compounds of low ductility and the magnesium-aluminum alloys are preferred. These metals have a low specific weight and burn with high heat generation.

As a liquid hydrocarbon one can in the propellants or fuels of the invention z. B. benzene ,. Toluene and light petroleum fractions, such as gasoline, kerosene, Use diesel oil and the fuels currently used as jet fuel. The expression "light petroleum fraction" means the known petroleum fractions with a density at 15 ° C of 0.8757 and higher.

The dispersion becomes one over against the magnesium alloy or compound chemically inert dispersant which is soluble in the liquid hydrocarbon incorporated. The dispersant adsorbs in a preferred orientation the surface of the particles, prevents their agglomeration, thereby sets the Viscosity drops considerably and improves the pumpability of the Dispersion. Examples of suitable Dispersiopsrpittgl. are Le, aitbin, certain Sorbitan esters, such as sorbitan trioleate, substituted ones which are soluble in liquid hydrocarbons Oxazolines, such as 2-heptadecenyl-4-methyl-4-methanol-2-oxazoline, the dioctyl ester of Sodium salt of sulfosuccinic acid, polyoxyethylene auryl ether and propylene oxide stearyl ether. Change dispersants that affect the dispersion of the magnesium product during the Grinding support can also be used provided they are of the magnesium alloy or compound used in the dispersion attacked, and they are practically inert to this. When using this The dispersions have relatively low viscosity values, which remain considerably constant over a longer storage period. It just has to be a small one Amount of dispersant to be used. ' Generally the amount is of the dispersant used, however, between 1 and 10 percent by weight, based on the weight of the liquid hydrocarbon. A preferred amount is between 4 and 6 percent by weight. The dispersant is the liquid hydrocarbon preferably added before the alloy or compound is comminuted. Very often the fuel of the invention becomes proportionate by mixing large particles of the alloy with the liquid hydrocarbon and then Comminution of the alloy produced in the mixture to the desired particle size. The use of a dispersant during grinding provides a dispersion with smaller particles and considerably lower viscosity for a given concentration the dispersed phase than without using a dispersant in the grinding. The dispersant applied to the surface of the particles prevents both pressure welding of the particles under the force of the grinding as well as agglomeration of the particles.

When crushing the friable magnesium alloys or compounds of low deformability, relatively equiaxed ones are obtained. Particle. These particles are smooth, and combustible . In the presence of a suitable dispersant, dispersed in the combustible liquid hydrocarbon, they do not increase the viscosity of the liquid too much. When comminuting ductile cavities or metals, for example magnesium or aluminum; relatively dug, flaky particles are obtained which considerably increase the viscosity of the dispersion compared to the dispersion with the same metal concept, but in which the metal particles are equiaxed. Thus, when using: a friable alloy which produces equiaxed particles when milled, the concentration of the milled particles in the liquid hydrocarbon can be increased to up to about 60 percent by weight without increasing the viscosity of the mixture to such an extent that it is no longer easy can be pumped or handled.

Besides making a special type of particle for control The viscosity of the dispersion must match the particle size of the dispersed alloy or connection below 1 micron. The preferred particle size is in the range from 0.1. up to 0.5 microns. It goes without saying that there will be a quick and complete combustion facilitated by extremely small particles. Dargbe, r also sit down smaller ones Particles fall off less quickly than larger particles. However, it is known that dispersions solid parts settle in a continuous liquid phase, if that specific weight of the particle is greater than that of the liquid. The, se inclination can be switched off if a gelling agent is incorporated into the propellant or fuel, which increases the thixotropy or pseudoplasticity of the dispersions. Dispersions with thixotropic or pseudoplastic rheological properties have a relatively high absolute viscosity at low speed gradient, however, the absolute viscosity becomes high as the speed gradient increases decreased. Thus, such dispersions are in retirement (a state that the Settling suppressed) extremely viscous, but they become when shaken or stirred fluid. Suitable gelling agents for the above purpose are certain Small amounts of metal soaps, for example aluminum stearate and aluminum octoate. These compounds can be added to the dispersions in powder form before grinding be incorporated, or they can be incorporated with the. liquid hydrocarbon containing the Contains dispersant, warming gently to achieve full Solution or rapid dispersion to be mixed. It was determined; that one suitable concentration of the gelling agent between 0.25 and 1 percent by weight, based on the weight of the liquid hydrocarbon.

To produce the particles from the magnesium alloy or compound with the required size, grinding can be carried out in a ball mill. In general, a milled or atomized powder or milling chips, e.g. B. very fine turnings of the alloy, with an inert liquid containing a dispersion medium, and puts the mixture in a ball mill, in which the required reduction in particle size is obtained. Any liquid inert to the magnesium alloy or compound can be used as the lubricant, provided the dispersant is soluble therein. Very often, however, the grinding liquid used in the propellant. or Brennstoffdef OF INVENTION d LRNG fiüssigenKohlenwasserstofl used: One can in this way the grinding and mixing processes vereimgen PRTD smelling receives the, crushing the fuel or fuel of the invention. In general, approximately equal parts by weight of the desagnesium product and the liquid are used. A propellant or fuel with a lower content of all the alloy can be obtained in a simple manner by diluting the concentrated comminuted product with more liquid hydrocarbons; If the liquid collated hydrogen, which is supposed to be part of the fuel, is not used as the milling liquid, the comminuted alloy is separated from the milling liquid after grinding, for example by filtering off or other known milling liquids, and mixed with the liquid hydrocarbon, which is part of the propellant : Fuel should be the invention. To make a dispersion in a liquid that is too viscous to mill effectively in the ball mill without heating it, one can make a dispersion in a low boiling carrier such as benzene. This dispersion then takes the appropriate amount of what is ultimately desired relatively viscous liquid are mixed, whereupon the benzene is distilled off from the mixture. The time required to reduce the particle size of the alloy to the desired size can range from a few hours to about 96 hours, depending on the particle size of the alloy being fed into the mill and the particular mill being used. For example, particles of the magnesium-aluminum compound Mg1, A1 "with an average particle size of 150 microns are ground to particles on the order of 0.1 microns by grinding in kerosene for 96 hours in a ceramic mill with sintered alumina balls For steel with hardened steel balls, the time required for this is only 48 hours.

For the production of the propellant or propellant according to the invention. Fuels will No protection is claimed within the scope of the invention.

The fuels or fuels according to the invention have a high heat of combustion and their viscosity with the viscosity of one made from pure magnesium Dispersion compared.

For this comparative experiment, cookies are made from a magnesium alloy with 17% calcium, remainder magnesium, with a particle diameter in the range of 150 microns mixed with about the same weight of kerosene that is about Contains 6 percent by weight sorbitan trioleate. This mixture is placed in a ball mill given from steel and ground for 48 hours. The particle size of the alloy is then decreased to about 0.1 micron. The viscosity of the resulting slurry is measured in a Brookfield rotary viscometer. It is at 12 rpm 1090 cP at 25 ° C. This propellant or fuel slurry can be sprayed smoothly and ignite and burn with intense heat development.

For comparison, instead of the friable magnesium-calcium alloy Cookies made from relatively pure magnesium are used, which are also of a particle size of about 150 microns. The mixture of the magnesium and the sorbitan trioleate Luminous kerosene containing kerosene is ground in the ball mill as described above. After 48 hours of milling, the particle size is about 1.3 micro-eggs. The mixture is pasty, and its viscosity can be determined by the method described above cannot be measured because it is too high.

Similarly, high heat of combustion fuels are made from two magnesium-calcium alloys. Alloy A contains 15 percent by weight and alloy B 45 percent by weight calcium, the remainder being magnesium. These fuels are compared to two similar dispersions made using magnesium-calcium alloys with less than 15 weight percent calcium. In the manufacture of each of the fuels, the magnesium-calcium alloy in the form of cookies with a particle size in the range of 150 microns is placed in the ball mill with kerosene and ground for 48 hours. Other details are shown in Table I below. It can be seen that with the magnesium-calcium alloys with a calcium content of 8.4 or 3.6 percent by weight, the remainder being magnesium, the dispersions obtained are pasty. Table I. Solid amount of the absolute Formed in the dispersion hair dryer viscosity after Dispersed magnesium product fuel particle size Dispersant in percent by weight, BI p O kfie 1 d Weight or on the liquid in cP Alloy composition percent micron hydrocarbon 12 rpm A 15 Ca, remainder Mg 45 0.5 2-heptadecenyl-6 13.40 4-methyl- 4-methanol 2-oxazoline B 45 Ca, remainder Mg 50 0.2 same 6 15.25 Comparative 8.4 Ca, remainder Mg 50 0.8 like 6 pasty alloy Comparative 3.6 Ca, remainder Mg 50 1.0 like 6 pasty alloy Similarly, high heat of combustion fuels are made using magnesium-silicon alloys C and D. Alloy C contains 37 percent by weight, alloy D 10 percent by weight silicon, the remainder being magnesium. These fuels are compared to a dispersion containing 2 weight percent silicon which made a paste. Luminous kerosene is used as a liquid hydrocarbon. The alloy particles, initially on the order of 150 microns, are ball milled for 48 hours. Further details are given in Table II below. Table II Solid amount of absolute Dispersed magnesium product contained in particle size dispersant viscosity according to Fuel dispersant in percent by weight, B rook fie 1 d Alloy composition by weight or on the liquid in cP Percent Micron Hydrocarbon 12 RPM C 37 Si, remainder Mg 50 0.5 dioctyl ester 5 650 of Na salt the sulfoboron ustinic acid D 10 Si, remainder Mg 50 0.8 sorbitan trioleate 4 820 Comparative 2 Si, remainder Mg 50 1.0 dioctyl ester 6 pasty alloy of sodium salt the sulfoboron _ ustinic acid In a similar manner, four high-heat combustion fuels containing a magnesium-aluminum alloy are produced. The magnesium-aluminum alloys used contain 15, 32, 65 or 67 percent by weight aluminum, the rest is magnesium. Further details are given in Table III below. Table III Solid content Amount of the absolute Dispersed in the fuel particle dispersant viscosity according to Magnesium product size dispersant in percent by weight B rookfie 1 d Weight = respectively on the liquid at 12 rpm Per cent of microns of hydrocarbon 15 Al, remainder Mg 55 0.7 sorbitan trioleate 6 950 32 Al, remainder Mg 50 0.2 2-heptadecenyl-4-methyl-6 1530 4-methanol-2-oxazoline 45 Al, remainder Mg 60 0.1 same as 54 2210 67 Al, remainder Mg 50 0.2 lecithin 6 1720

Claims (3)

Claims: 1. Propellants or fuels based on liquid carbons with high heat of combustion, which contain metallic material in dispersed form, characterized in that the propellants or fuels are a liquid mixture 20 to 60 percent by weight (based on the total weight of fuel) of a friable Magnesium alloy or intermetallic compound of low deformability Magnesium with calcium, aluminum, silicon or boron and liquid hydrocarbon are. 2. propellants or fuels according to claim 1, characterized in that the liquid hydrocarbon is a light petroleum fraction containing between 1 and 10 Contains percent by weight of a dispersing agent dissolved. 3. propellants or fuels according to claim 2, characterized in that the dispersant is sorbitan trioleate. Documents considered: German Auslegeschrift No. 1113 331; Swiss Patent No. 302160; French patent specification No. 1123 234.