Motor installations at hydrogen peroxide for small satellites. Motor installations at hydrogen peroxide for small satellites blow from depth
HYDROGEN PEROXIDE H 2 O 2 - the simplest representation of the peroxide; High-boiling oxidizing agent or single-component rocket fuel, as well as a source of vapor to drive TNA. Used in the form of aqueous solution high (up to 99%) concentration. Transparent liquid without color and smell with "metal" flavor. The density is 1448 kg / m 3 (at 20 ° C), T pl ~ 0 ° C, Ting of ~ 150 ° C. Weakly toxic, when burning, causes burns, with some organic substances forms explosive mixtures. Pure solutions are quite stable (the decomposition rate usually does not exceed 0.6% per year); In the presence of traces of a number of heavy metals (for example, copper, iron, manganese, silver) and other impurities, decomposition accelerates and can move into an explosion; To increase stability during long-term storage in hydrogen peroxide Stabilizers (phosphorus and tin compounds) are introduced. Under the influence of catalysts (for example, iron corrosion products) decomposition hydrogen peroxide Oxygen and water goes with the release of energy, while the temperature of the reaction products (vapor) depends on the concentration hydrogen peroxide: 560 ° C at 80% concentration and 1000 ° C at 99%. It is best compatible with stainless steel and pure aluminum. In the industry is obtained by hydrolysis of the supporting acid H 2 S 2 O 8, which is formed during the electrolysis of sulfuric acid H 2 SO 4. Concentrated hydrogen peroxide Found widespread use in rocket technology. Hydrogen peroxide It is a source of parogase for the TNA drive to a row (FAU-2, "Redstone", "Viking", "East", etc.), a rocket fuel oxidizer in rockets (Black Arrow, etc.) and aircraft ( 163, X-1, X-15, etc.), one-component fuel in spacecraft engines (Soyuz, Union T, etc.). It is promising its use in a pair with hydrocarbons, pentaboran and beryllium hydride.
H2O2 hydrogen peroxide is a transparent colorless liquid, noticeably more viscous than water, with a characteristic, albeit weak odor. Anhydrous hydrogen peroxide is difficult to get and stored, and it is too expensive for use as rocket fuel. In general, high cost is one of the main drawbacks of hydrogen peroxide. But, compared to other oxidizing agents, it is more convenient and less dangerous in circulation.
The proposal of peroxide to spontaneous decomposition is traditionally exaggerated. Although we observed a decrease in concentration from 90% to 65% in two years of storage in liter polyethylene bottles at room temperature, but in large volumes and in a more suitable container (for example, in a 200-liter barrel of sufficiently pure aluminum) decomposition rate of 90% Packsi would be less than 0.1% per year.
The density of anhydrous hydrogen peroxide exceeds 1450 kg / m3, which is much larger than liquid oxygen, and a little less than that of nitric acid oxidants. Unfortunately, water impurities quickly reduce it, so that 90% solution has a density of 1380 kg / m3 at room temperature, but it is still a very good indicator.
The peroxide in the EDD can also be used as unitary fuel, and as an oxidizing agent - for example, in a pair with kerosene or alcohol. Neither kerosene nor alcohol is self-proposal with peroxide, and to ensure ignition in fuel, it is necessary to add a catalyst for the decomposition of peroxide - then the released heat is sufficient for ignition. For alcohol, a suitable catalyst is acetate manganese (II). For kerosene, also there are appropriate additives, but their composition is kept secret.
The use of peroxide as unitary fuel is limited to its relatively low energy characteristics. Thus, the achieved specific impulse in vacuo for 85% peroxide is only about 1300 ... 1500 m / s (for different degrees of expansion), and for 98% - approximately 1600 ... 1800 m / s. However, the peroxide was applied first by the Americans for the orientation of the descent apparatus of the Mercury spacecraft, then, with the same purpose, the Soviet designers on the Savior Soyk QC. In addition, hydrogen peroxide is used as an auxiliary fuel for the TNA drive - for the first time on the V-2 rocket, and then on its "descendants", up to P-7. All modifications "Sexok", including the most modern, still use peroxide to drive TNA.
As an oxidizer, hydrogen peroxide is effective with various combustible. Although it gives a smaller specific impulse, rather than liquid oxygen, but when using a high concentration peroxide, the values \u200b\u200bof the UI exceed that for nitric acid oxidants with the same flammable. Of all space-carrier missiles, only one used peroxide (paired with kerosene) - English "Black Arrow". The parameters of its engines were modest - Ui of engine I steps, a little exceeded 2200 m / s at the Earth and 2500 m / s in vacuo, "since only 85% concentration was used in this rocket. This was done due to the fact that to ensure self-ignition peroxide decomposed on a silver catalyst. More concentrated peroxide would melt silver.
Despite the fact that interest in the peroxide from time to time is activated, the prospects remain foggy. So, although the Soviet EDR RD-502 ( fuel vapor - Peroxide plus pentabran) and demonstrated a specific impulse of 3680 m / s, it remained experimental.
In our projects, we focus on the peroxide also because the engines on it turn out to be more "cold" than similar engines with the same UI, but on other fuels. For example, the combustion products of "caramel" fuels have almost 800 ° with a larger temperature with the same UI. This is due to a large amount of water in peroxide reaction products and, as a result, with a low average molecular weight of the reaction products.
the effect of a strong catalyst. One ten-thousand part of cyanide potassium almost completely destroys the catalytic action of platinum. Slowly slow down the decomposition of peroxide and other substances: serougerium, strikhnin, phosphoric acid, sodium phosphate, iodine.
Many properties of hydrogen peroxide are studied in detail, but there are also those that still remain a mystery. The disclosure of her secrets had direct practical importance. Before the peroxide is widely used, it was necessary to solve the old dispute: what is the peroxide - an explosive, ready to explode from the slightest shock, or innocuous liquid that does not require precautions in circulation?
Chemically pure hydrogen peroxide is a very stable substance. But when pollution, it starts to decompose violently. And chemists told engineers: you can carry this fluid to any distance, you only need one so that it is clean. But it can be contaminated on the road or when stored, what to do then? Chemists answered this question: add a small number of stabilizers, catalyst poisons into it.
Once, during the Second World War, such a case occurred. At the railway station stood a tank with hydrogen peroxide. From unknown reasons, the temperature of the fluid began to rise, and this meant that the chain reaction has already begun and threatens an explosion. The tank was watered with cold water, and the temperature of hydrogen peroxide was stubbornly raised. Then the tank was poured several liters of a weak aqueous solution of phosphoric acid. And the temperature quickly fell. The explosion was prevented.
Classified substance
Who did not see painted in blue colour Steel cylinders in which oxygen is transported? But few people know how much such transportation is unprofitable. The cylinder is placed a little more than eight kilograms of oxygen (6 cubic meters), and weighs one only a cylinder over seventy kilograms. Thus, you have to transport about 90 / about useless cargo.
It is much more profitable to carry liquid oxygen. The fact is that in the cylinder oxygen is stored under high pressure-150 atmospheres, so the walls are made quite durable, thick. Vessels for transporting liquid oxygen the wall thinner, and they weigh less. But when transporting liquid oxygen, it is continuously evaporated. In small vessels, 10 - 15% oxygen disappears per day.
Hydrogen peroxide connects the advantages of compressed and liquid oxygen. Almost half of the weight of the peroxide is oxygen. Losses of peroxide PC proper storage insignificant - 1% per year. There is a peroxide and one more advantage. Compressed oxygen has to be injected into cylinders with powerful compressors. Hydrogen peroxide is easy and simply poured into the vessels.
But oxygen obtained from peroxide is much more expensive than compressed or liquid oxygen. The use of hydrogen peroxide is justified only where Sobat
economic activity retreats to the background, where the main thing is compactness and low weight. First of all, this refers to reactive aviation.
During World War II, the name "hydrogen peroxide" disappeared from the lexicon of warring states. In official documents, this substance began to call: Ingolin, component T, Renal, aurol, heprol, subsidol, thymol, oxylin, neutraline. And only a few knew that
all these pseudonyms of hydrogen peroxide, its classified names.
What makes it take to classize hydrogen peroxide?
The fact is that it began to be used in liquid jet engines - EDD. Oxygen for these engines is in liquefied or in the form of chemical compounds. Due to this, the combustion chamber turns out to be possible to file a very large amount of oxygen per unit of time. And this means that you can increase the engine power.
First combat aircraft with liquid jet engines appeared in 1944. A chicken alcohol was used as a fuel in a mixture with hydrazine hydrate, 80 percent hydrogen peroxide was used as an oxidizing agent.
The peroxide has found the use of long-range reactive projectiles, which the Germans fired at London in the fall of 1944. These shell engines worked on ethyl alcohol and liquid oxygen. But in the projectile there was also an auxiliary engine, which moved fuel and oxidative pumps. This engine is a small turbine - worked at hydrogen peroxide, more precisely, on a vapor-gas mixture formed during the decomposition of peroxide. Its power was 500 liters. from. - This is more than the power of 6 tractor engines.
Peroxide works per person
But truly widespread use of hydrogen peroxide found in the postwar years. It is difficult to name this branch of technology where hydrogen peroxide would not be used or its derivatives: sodium peroxide, potassium, barium (see 3 pp. Covers of this log number).
Chemists use peroxide as a catalyst when obtaining many plastics.
Builders with hydrogen peroxide receive a porous concrete, the so-called aerated concrete. For this, peroxide is added to the concrete mass. The oxygen formed during its decomposition permeates the concrete, and bubbles are obtained. The cubic meter of such concrete weighs about 500 kg, that is, twice the lighter of water. Porous concrete is an excellent insulating material.
In the confectionery industry, hydrogen peroxide perform the same functions. Only instead of the concrete mass, it extends the dough, well replacing the soda.
In medicine, hydrogen peroxide has long been used as a disinfectant. Even in the toothpaste you use, there is a peroxide: it neutralizes the oral cavity from microbes. And most recently, its derivatives are solid peroxide - found new application: one tablet from these substances, for example, abandoned in a bath with water, makes it "oxygen".
In the textile industry, with the help of peroxide, the fabrics whiten, in food - fats and oils, in paper - wood and paper, in oil refinery add peroxide to diesel fuel: It improves the quality of fuel, etc.
Solid peroxide are used in diving spaces from insulating gas masks. Absorbing carbon dioxide, peroxide separated oxygen required for breathing.
Every year hydrogen peroxide conquers all new and new applications. Recently, it was considered uneconomical to use hydrogen peroxide during welding. But in fact, in repair practice there are such cases when the volume of work is small, and the broken car is somewhere in a remote or hard-to-reach area. Then, instead of a bulky acetylene generator, the welder takes a small benzo-tank, and instead of a heavy oxygen cylinder - a portable ne] a recording device. Hydrogen peroxide, filled into this device, is automatically supplied to the camera with a silver mesh, decomposes, and the separated oxygen goes to welding. All installation is placed in a small suitcase. It is simple and convenient
New discoveries in chemistry are really made in the situation not very solemn. At the bottom of the test tube, in the eyepiece of a microscope or in a hot crucible, a small lump appears, maybe a drop, maybe a grain of a new substance! And only the chemist is able to see his wonderful properties. But it is in this that the real romance of chemistry is to predict the future of a newly open substance!
Hydrogen peroxide H 2 O 2 - transparent colorless liquid, noticeably more viscous than water, with characteristic, albeit weak odor. Anhydrous hydrogen peroxide is difficult to get and stored, and it is too expensive for use as rocket fuel. In general, high cost is one of the main drawbacks of hydrogen peroxide. But, compared to other oxidizing agents, it is more convenient and less dangerous in circulation.
The proposal of peroxide to spontaneous decomposition is traditionally exaggerated. Although we observed a decrease in concentration from 90% to 65% in two years of storage in liter polyethylene bottles at room temperature, but in large volumes and in a more suitable container (for example, in a 200-liter barrel of sufficiently pure aluminum) decomposition rate of 90% Packsi would be less than 0.1% per year.
The density of anhydrous hydrogen peroxide exceeds 1450 kg / m 3, which is significantly larger than in liquid oxygen, and a little less than that of nitric acid oxidants. Unfortunately, water impurities quickly reduce it, so that 90% solution has a density of 1380 kg / m 3 at room temperature, but it is still a very good indicator.
The peroxide in the EDD can also be used as unitary fuel, and as an oxidizing agent - for example, in a pair with kerosene or alcohol. Neither kerosene nor alcohol is self-proposal with peroxide, and to ensure ignition in fuel, it is necessary to add a catalyst for the decomposition of peroxide - then the released heat is sufficient for ignition. For alcohol, a suitable catalyst is acetate manganese (II). For kerosene, also there are appropriate additives, but their composition is kept secret.
The use of peroxide as unitary fuel is limited to its relatively low energy characteristics. Thus, the achieved specific impulse in vacuo for 85% peroxide is only about 1300 ... 1500 m / s (for different degrees of expansion), and for 98% - approximately 1600 ... 1800 m / s. However, the peroxide was applied first by the Americans for the orientation of the descent apparatus of the Mercury spacecraft, then, with the same purpose, the Soviet designers on the Savior Soyk QC. In addition, hydrogen peroxide is used as an auxiliary fuel for the TNA drive - for the first time on the V-2 rocket, and then on its "descendants", up to P-7. All modifications "Sexok", including the most modern, still use peroxide to drive TNA.
As an oxidizer, hydrogen peroxide is effective with various combustible. Although it gives a smaller specific impulse, rather than liquid oxygen, but when using a high concentration peroxide, the values \u200b\u200bof the UI exceed that for nitric acid oxidants with the same flammable. Of all space-carrier missiles, only one used peroxide (paired with kerosene) - English "Black Arrow". The parameters of its engines were modest - Ui of engine I steps, a little exceeded 2200 m / s at the Earth and 2500 m / s in vacuo, "since only 85% concentration was used in this rocket. This was done due to the fact that to ensure self-ignition peroxide decomposed on a silver catalyst. More concentrated peroxide would melt silver.
Despite the fact that interest in the peroxide from time to time is activated, the prospects remain foggy. So, although the Soviet EDRD of the RD-502 (fuel pair - peroxide plus pentabran) and demonstrated the specific impulse of 3680 m / s, it remained experimental.
In our projects, we focus on the peroxide also because the engines on it turn out to be more "cold" than similar engines with the same UI, but on other fuels. For example, the combustion products of "caramel" fuels have almost 800 ° with a larger temperature with the same UI. This is due to a large amount of water in peroxide reaction products and, as a result, with a low average molecular weight of the reaction products.
1 .. 42\u003e .. \u003e\u003e Next
Low alcohol frost temperature allows you to use it in a wide range of ambient temperatures.
Alcohol is produced in very large quantities and is not a deficient flammable. Alcohol has an aggressive impact on structural materials. This allows you to apply relatively cheap materials for alcohol tanks and highways.
Methyl alcohol can serve as a substitute for ethyl alcohol, which gives a somewhat worse quality with oxygen. Methyl alcohol is mixed with ethyl in any proportions, which makes it possible to use it with a lack of ethyl alcohol and add to a slide in a fuel. Fuel based on liquid oxygen is used almost exclusively in long-range missiles, allowing and even, due to greater weight, requiring rocket refueling with components at the start site.
Hydrogen peroxide
H2O2 hydrogen peroxide (i.e., 100% concentration) in the technique does not apply, since it is an extremely unstable product capable of spontaneous decomposition, easily turning into an explosion under the influence of any, seemingly minor external influences: impact , lighting, the slightest pollution by organic substances and impurities of some metals.
In rocket technology, "applied more resistant high-end-trained (most often 80"% concentrations) solutions of hydrogen pumping in water. To increase resistance to hydrogen peroxide, small amounts of substances prevent its spontaneous decomposition (for example, phosphoric acid) are added. The use of 80 "% hydrogen peroxide requires currently taking only conventional precautionary measures necessary when handling strong oxidizing agents. Hydrogen peroxide such a concentration is transparent, slightly bluish liquid with a freezing temperature -25 ° C.
Hydrogen peroxide when it is decomposed on oxygen and water pairs highlights heat. This heat release is explained by the fact that the heat of the formation of peroxide is 45.20 kcal / g-mol,
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GL IV. Fuel rocket engines
the time as the heat of water formation is equal to 68.35 kcal / g-mole. Thus, with the decomposition of the peroxide according to the formula H2O2 \u003d --H2O + V2O0, chemical energy is highlighted, equal difference 68.35-45,20 \u003d 23.15 kcal / g-mol, or 680 kcal / kg.
Hydrogen peroxide 80E / oo concentration has the ability to decompose in the presence of catalysts with heat release in the amount of 540 kcal / kg and with the release of free oxygen, which can be used for oxidation of fuel. The hydrogen peroxide has a significant specific weight (1.36 kg / l for 80% concentrations). It is impossible to use hydrogen peroxide as a cooler, because when heated it does not boil, but immediately decomposes.
Stainless steel and very clean (with an impurity content of up to 0.51%) aluminum can serve as materials for tanks and pipelines of engines operating on peroxide. Completely unacceptable use of copper and other heavy metals. Copper is a strong catalyst that contributes to the decomposition of hydrogen peroxy. Some types of plastics can be applied for gaskets and seals. The ingress of concentrated hydrogen peroxide on the skin causes heavy burns. Organic substances when the hydrogen peroxide falls on them light up.
Fuel based on hydrogen peroxide
Based on hydrogen peroxide, two types of fuels were created.
The fuel of the first type is the fuel of a separate feed, in which oxygen released when decomposing hydrogen peroxide is used to burn fuel. An example is the fuel used in the engine of the interceptor aircraft described above (p. 95). It consisted of a hydrogen peroxide of 80% concentration and a mixture of hydrazine hydrate (N2H4 H2O) with methyl alcohol. When the special catalyst is added, this fuel becomes self-igniting. Comparatively low calorific value (1020 kcal / kg), as well as small molecular weight of combustion products determine low temperature Combustion, which makes it easier to work the engine. However, due to low calorific value, the engine has a low specific craving (190 kgc / kg).
With water and alcohol, hydrogen peroxide can form relatively explosion-proof triple mixtures, which are an example of one-component fuel. The calorific value of such explosion-proof mixtures is relatively small: 800-900 kcal / kg. Therefore, as the main fuel for the EDD, they will hardly be applied. Such mixtures can be used in steamer-outer.
2. Modern rocket engines fuels
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The reaction of the decomposition of concentrated peroxide, as already mentioned, is widely used in rocket technology to obtain a vapor, which is a working fluoride of the turbine when pumping.
Known engines in which the heat of the peroxide decomposition served to create a force of traction. Specific traction of such engines is low (90-100 kgc / kg).
For decomposition of peroxide, two types of catalysts are used: liquid (potassium permanganate solution KMNO4) or solid. The application of the latter is more preferable, since it makes an excessive liquid catalyst system to the reactor.
