CN100537727C - A kind of solid alcohol fuel and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of solid alcohol fuel, it is by industrial spirit 90.73%, stearic acid 4.76%, and NaOH 0.62%, paraffin 1.30%, distilled water 2.59% is percentage ratio by weight, is prepared from two steps under 70 ℃ constant temperature.Solid alcohol fuel of the present invention, have easily light, combustion heat value height, no black smoke, free from extraneous odour, burning back residue is few, shelf lives is long, does not soften characteristics such as separation, especially under vacuum anoxybiotic condition, still can keep flameholding, flame is vigorous, has good combustionproperty, still can burn in the plateau of more than 6300 meter of height above sea level or mountain region environment.The more common solid fuel of solid alcohol fuel of the present invention has the wider scope of application, uses in the high altitude anoxia area to have clear superiority, and be the first-selected thermal source of highlands household, travelling, motion or soldier's field exercise and plateau mountain operations.

Description

A kind of solid alcohol fuel and preparation method thereof

technical field

The invention relates to a solid fuel, in particular to a portable, safe, easy-to-store and transport high-calorific-value solid alcohol fuel and a preparation method thereof.

Background technique

As a portable, safe, convenient, and economical food and beverage heat source, solid fuel has been widely used in military and civilian applications. As a heat source for military use, because of its high strength at room temperature, urotropine solid fuel is easy to store and has a high calorific value, so it is still used as fuel for individual combat and is widely used in foreign or domestic troops. . The product is white solid, can be used outdoors, is easy to carry, and is not volatile. However, due to its chemical properties (molecular formula (CH ₂ ) ₆ N ₄ ), it is easy to produce nitrogen oxides that are harmful to the human body and the environment when burning, and it is not easy to burn fully, and it will produce a lot of black smoke, pollute heating appliances, and give Repeated use brings inconvenience, especially in the case of plateau hypoxia, the combustion quality is low, it is difficult to give full play to the advantages of solid fuel, and the price of raw material urotropine is relatively high, and the market competitiveness is poor.

On the other hand, in civil heat sources, many new types of fuel solid alcohol have appeared. Compared with traditional charcoal, it has the characteristics of instant combustion, uniform flame size, uniform flame temperature, small flame deviation, and no dust and charcoal falling. Safe and clean, easy to use and elegant, easy to carry and other advantages, it is widely used in hot pot fuel and outdoor heat source. Current literature introduces the latest solid alcohol fuel (improvement of solid alcohol fuel production process, Wang Maoyuan, etc., Applied Science and Technology, April 2002, Vol.29, No.4, P52-53), using industrial alcohol, sodium hydroxide, hard alcohol, etc. Fatty acid, paraffin, and copper nitrate are processed as main raw materials. The solid fuel product prepared in this way still has many deficiencies: first, the melting point is relatively low and cannot be stored for a long time at a higher temperature; Industrialized continuous production; third, under the condition of low air pressure and insufficient oxygen, the combustion vacuum degree is not enough and the duration is short, so it cannot be used in high altitude environment. Therefore, can not satisfy the equipment requirement of military solid alcohol fuel.

Contents of the invention

The purpose of the present invention is to provide a kind of fuel oil that has the characteristics of easy ignition, high combustion calorific value, no black smoke, no peculiar smell, less residue after combustion, long storage period under high temperature conditions, no softening and separation, and is suitable for use in plateau anoxic environment. solid alcohol fuel.

Another object of the present invention is to provide the preparation method of this solid alcohol fuel.

Solid alcohol fuel of the present invention, it is made up of following component by weight percentage:

Industrial alcohol 90.73%,

Stearic acid 4.76%,

NaOH 0.62%,

Paraffin 1.30%,

Distilled water 2.59%.

Wherein, the mass concentration of said industrial alcohol is 95%.

The invention provides a method for preparing solid alcohol fuel. According to the above composition, all operations are carried out at 70°C. 55.7% of stearic acid, paraffin and industrial alcohol are heated in a three-necked flask, stirred and refluxed, and sodium hydroxide , distilled water and 44.3% industrial alcohol are heated in the conical flask, and then the solution in the conical flask is slowly injected into the three-necked flask, and the mixed solution is continued to be heated and stirred at 70°C, poured into the container while it is hot, and cooled naturally , The uniform, translucent gel-like solid obtained by solidification and molding is solid alcohol fuel.

In the above preparation method, all operations are carried out in a constant temperature water tank with a water bath temperature of 70°C.

The specific operations of the preparation method are:

In the first step, stearic acid is dissolved in alcohol:

①The temperature of the water bath in the fixed constant temperature water tank is 70°C, and the stirring speed of the electric stirrer is 250r/min.

② Weigh 55.7% of stearic acid, paraffin and industrial alcohol respectively, and add them into a three-necked flask in turn. Then install an electric stirrer, a thermometer and a reflux condenser on the there-necked flask;

③Heat and stir the three-necked flask in a water bath. A small amount of evaporated alcohol is condensed by the reflux condenser and returned to the three-necked flask until it dissolves into a uniform and transparent colorless solution.

In the second step, dissolve sodium hydroxide in alcohol:

① Weigh 44.3% of sodium hydroxide, distilled water and denatured alcohol respectively, and add them in the Erlenmeyer flask successively;

② At the same time, heat the Erlenmeyer flask under the same conditions as above for the same time until it becomes a uniform and transparent solution;

The third step is to slowly inject the solution in the Erlenmeyer flask into the three-necked flask, and continue to heat and stir the mixed solution at 70°C for 2 minutes, then pour it into the container while it is hot, let it cool naturally, and solidify into shape , sealed packaging, you can get a uniform, translucent high-strength gel-like solid alcohol fuel.

The solid alcohol fuel prepared by the method of the present invention has the characteristics of easy ignition, high combustion calorific value, no black smoke, no peculiar smell, less residue after combustion, long storage period at high temperature (such as above 50 ° C), and no softening and separation. Especially under the condition of vacuum anoxic, it can still maintain stable combustion, strong flame and good combustion performance. It can still burn in the plateau or mountain environment with an altitude of more than 6300 meters, which is impossible for other similar products. The solid alcohol fuel of the present invention has a wider scope of application than ordinary solid fuels, and has obvious advantages in hot environments and plateau anoxic areas. Preferred heat source.

Description of drawings

Figure 1 is a quantitative relationship curve between the average burning velocity and the diameter of the combustion tank in the solid alcohol combustion experiment.

Detailed ways

A good solid alcohol fuel should have the characteristics of easy ignition, high combustion calorific value, no black smoke, no peculiar smell, less residue after combustion, easy storage, and no softening and separation. In addition, it should have good economy, easy to obtain raw materials, simple process and low cost, and is suitable for industrialized production.

Solid alcohol fuel of the present invention is by fatty alcohol, sodium stearate, dispersant as main raw material, is to make fatty alcohol solidify into required combustion block (also known as convenient fuel block) under the effect of gelling agent sodium stearate ). Utilize the property that stearic acid softens when heated and resolidifies after cooling, the fatty alcohol is firmly wrapped in the network skeleton of sodium stearate. Because the price of sodium stearate is expensive and difficult to buy on the market. For this reason the present invention adopts under certain temperature, stearic acid and sodium hydroxide mixed reaction are made sodium stearate, thereby greatly reduced the cost of solid alcohol fuel. Adding a certain amount of dispersant to the solid fuel can change the microstructure of the gel, increase the physical strength of the solid fuel, and improve the stability of the solid fuel. Since the dispersant used is also a hydrocarbon, it does not affect the stability of the solid fuel. Combustion characteristics, and can make the combustion more durable and can release high heat energy, which is safer and more convenient in practical applications.

Main raw material used in the present invention has:

Industrial ethanol (contains 95% ethanol): molecular formula CH ₃ CH ₂ OH, scientific name ethanol, commonly known as alcohol, colorless transparent liquid with wine aroma, volatile, flammable, combustion calorific value 29.67kJ/g. Refractive index 1.3651, surface tension (20°C) 22.8mN/m, viscosity (20°C) 1.41mPa s, vapor pressure (20°C) 5.732kPa, specific heat capacity (23°C) 2.58J/(g°C), flash point 12.8°C, relative density 0.816, boiling point 78.15°C, freezing point -114°C, spontaneous ignition point 793°C. In the present invention, ethanol is the main component of the fuel, which is easy to obtain and cheap.

Stearic acid: molecular formula CH ₃ (CH ₂ ) ₁₆ COOH, scientific name octadecanoic acid. White glossy leaf-like solid. Molecular weight 284.48, melting point 67-70°C, boiling point 376.1°C (decomposition), 232°C (2.0kPa), relative density (20/4°C) 0.9408, refractive index 1.4299 (80°C), heat of combustion 42.98kJ/g. Slowly volatilize at 90-100°C. Almost insoluble in water (only 0.00029g dissolved in 100ml of water at 20°C), soluble in alcohol, acetone, easily soluble in ether, chloroform, benzene, carbon tetrachloride, carbon disulfide, amyl acetate and toluene, etc. Commercial stearic acid is actually a mixture of 45% stearic acid and 55% palmitic acid, and contains a small amount of oleic acid, which has a slightly fatty smell. The product is irritating and non-toxic. In the present invention, as the main component of the gel, it is an important carrier for enclosing fuel alcohol.

Sodium hydroxide: Molecular formula NaOH, commonly known as caustic soda, caustic soda, caustic soda, etc., molecular weight: 40.00, density: 2.130g/cm ³ , melting point: 318°C, boiling point: 1390°C. The relative density is 2.130. Pure sodium hydroxide is a colorless and transparent crystal. Not combustible, but solid Contact with water or moisture may generate sufficient heat to ignite combustible materials. Industrial sodium hydroxide contains a small amount of sodium chloride and sodium carbonate, and is a white opaque solid. Commercially available products are block, sheet, granular and rod, collectively referred to as solid alkali. The common name of the product in the solution state is liquid caustic soda. Liquid caustic soda contains more impurities such as sodium chloride than solid caustic soda. Sodium hydroxide solution is highly alkaline and has a strong corrosive effect on skin, fabrics, paper, etc., so special attention should be paid to safety when using it. In the present invention, it is a very effective curing agent for stearic acid saponification reaction and gel formation.

Paraffin: a mixture of polymer hydrocarbons, which is an odorless and tasteless white solid (yellow when it contains impurities). The density increases with the melting point, usually 0.88-0.915g/cm3, the melting point is 50-70°C, the boiling point is 300-550°C, and the heat of combustion is 47.55kJ/g. Insoluble in water, very low solubility in alcohols and ketones, easily soluble in carbon tetrachloride, chloroform, ether, benzene, paraffin ether, carbon disulfide, various mineral oils and most vegetable oils, usually with the increase of melting point, Solubility decreased. It is a saturated hydrocarbon with stable chemical properties and is not easy to react with alkalis, inorganic acids and halogens. It melts when exposed to heat, and decomposes when exposed to high heat. Used as a dispersant in the process of saponification reaction in the present invention, it can inhibit the agglomeration formed by local saponification reaction and improve the uniform distribution of the gel.

Experimental principle:

After stearic acid is mixed with sodium hydroxide, the following reactions will occur:

The sodium stearate produced by the reaction is a polar molecule with a long carbon chain, which is not easily soluble in alcohol at room temperature. At a certain temperature, sodium stearate can be evenly dispersed in liquid alcohol, and after cooling, it will form a gel system, which can bind alcohol molecules between interconnected macromolecules, making alcohol in a non-flowing state, thereby Alcohol in a solid state is obtained. The gel process is a non-crystallization process. Therefore, in order to reduce the inhomogeneity of the gel process, the stability of the gel process should be promoted as much as possible to ensure that the alcohol molecules are stably bound in the gel. Therefore, in the gel It is extremely important to add an appropriate amount of dispersant to the mixture with alcohols. The function of the dispersant is mainly to make the lipophilic group of stearic acid under the affinity of the hydrocarbon hydrocarbon of the dispersant, make the dispersion uniform, avoid local excess of sodium salt, solidification and agglomeration, and form a uniform sodium stearate and a solution of fatty alcohol, and then by lowering the temperature, the solution slowly forms a gel state of sodium stearate, so that the liquid fatty alcohol is uniformly dispersed in the network structure of the gel, forming a gel with high hardness and stability Good solid alcohol fuel.

The process conditions for preparing the solid alcohol fuel of the present invention are as follows: set the stirring speed of the electric stirrer, raise the water bath of the constant temperature water tank to 70°C; then place the three-neck flask of the reaction kettle with a certain amount of raw materials in the water bath to heat for a certain period of time; At the same time, at the same water bath temperature, heat the conical flask with a certain amount of raw materials for the same time; then inject the solution in the conical flask into the three-necked flask, and mix and react for a certain period of time; finally, pour the product into the container while it is hot, and naturally After cooling, solid alcohol as white as jade and with good hardness can be obtained.

Embodiment 1, the preparation of solid alcohol fuel

Raw materials: 1.3 grams of paraffin, 4.76 grams of stearic acid, 0.62 grams of NaOH, 90.73 grams of industrial alcohol, and 2.59 grams of distilled water.

Adopt two-step method to prepare solid alcohol fuel, experimental procedure is:

In the first step, stearic acid is dissolved in alcohol. The specific operation is as follows:

①The temperature of the water bath in the fixed constant temperature water tank is 70°C, and the stirring speed of the electric stirrer is 250r/min.

② Weigh stearic acid, paraffin and 50.55 grams of industrial alcohol respectively, and add them into a three-necked flask in turn. Then install an electric stirrer, a thermometer and a reflux condenser on the three-neck flask.

③Heat and stir the three-necked flask in a water bath. A small amount of evaporated alcohol is condensed by the reflux condenser and returned to the three-necked flask until it dissolves into a uniform and transparent colorless solution.

In the second step, sodium hydroxide is dissolved in alcohol, and the specific operation is as follows:

① Weigh sodium hydroxide and distilled water into the Erlenmeyer flask to dissolve them, and then add 40.18 grams

industrial alcohol.

②At the same time, heat and stir until it becomes a uniform and transparent solution.

The third step is to slowly inject the solution in the Erlenmeyer flask into the three-necked flask, and continue to heat and stir the mixed solution at 70°C for 2 minutes, then pour it into the container while it is hot, let it cool naturally, and solidify into shape , sealed packaging, you can get uniform, translucent high-strength gel-like solid alcohol.

Embodiment 2: the influence of each factor when preparing solid alcohol fuel

This example examines in detail the factors that have an impact on the quality of solid alcohol fuel products. In this experiment, the heating time in the water bath was 10 minutes, the mixing reaction time was 2 minutes, and the mechanical stirring speed was 250 r/min. Wherein the alcohol (alcohol 1) consumption is 50.55g in the three-necked flask, and the alcohol (alcohol 2) consumption is 40.18g (the whole material benchmark is 100g) in the Erlenmeyer flask.

1. The influence of temperature

Based on the melting point of stearic acid being 67-70°C, the experimental temperature t=60°C, 65°C, 70°C, and 75°C were taken as four levels to investigate the influence of temperature on the experiment and the product.

The amount of raw materials required for the experiment is as follows:

Table 1-1 The amount of experimental raw materials when examining the temperature factor

Wherein, alcohol 1 is the amount in the there-necked flask, and alcohol 2 is the amount in the Erlenmeyer flask, that is, the alcohol used accounts for 90.73% of the raw materials.

In this experiment, by changing the temperature of the constant temperature water bath, the influence of temperature on the performance of the product was investigated, and the conclusions drawn are shown in the following table:

Table 1-2 Specific experimental phenomena when examining temperature factors

It can be seen from Table 1-2 that when the temperature is low (i.e. 60°C, 65°C), the reaction kettle has been partially cured, which has a great impact on the subsequent overall curing and seriously affects the quality of the product; and When the temperature is too high (that is, 75°C), because it is close to the boiling point of ethanol, the reflux of alcohol is too large, and the phenomenon of local advanced curing also occurs, which is also an unstable operation like the case of too low temperature. Therefore, the products at a temperature of 70°C have reached the standard in all aspects and met the requirements of military equipment.

2. The effect of the amount of dispersant

In this experiment, the consumption of other raw materials is fixed, only the consumption of dispersant paraffin is changed, and five levels are selected to investigate the influence of the variation of dispersant consumption on product quality (the whole material benchmark is 100g).

In this experiment, by changing the amount of dispersant, experiments were carried out at the above-mentioned experimental level, and the following conclusions can be drawn:

Table 2 Specific experimental phenomena when investigating the amount of dispersant

It can be seen from Table 2 that the addition of an appropriate amount of dispersant has a great influence on the hardness of the product. Without dispersant, the product has soft texture, large gel particles, low hardness, and poor stability; if an appropriate amount of dispersant is added, the hardness of the product will be improved, and it can be cut arbitrarily and made into various shapes. High transparency, this is because a proper amount of dispersant has affinity to the hydrocarbon group of stearic acid, which can avoid local solidification due to excessive acid-base concentration, and has played an extremely effective dispersion effect. However, when the dispersant is too much, due to the difference in solubility, stratification is easy to occur, and turbidity is easy to occur after the curing agent is added. When the added amount of the dispersant was 1.30g, the performance index of the obtained product most met the requirements in all aspects.

3. The effect of curing agent dosage

According to the acid-base reaction of stearic acid and sodium hydroxide, it can be known that the amount of curing agent sodium hydroxide directly affects the reaction molar ratio of stearic acid and sodium hydroxide. In this experiment, the amount of alcohol and stearic acid is kept constant. Next, different experiments were carried out. First change the amount of sodium hydroxide to adjust it to a suitable molar ratio. After the optimum amount of curing agent has been determined, keep the amount of curing agent unchanged, and then adjust the amount of alcohol. Through such a series of exploration and experimental research, determine the optimal amount of curing agent and alcohol.

In this experiment, the amount of fixed other raw materials remains unchanged, and the molar ratio of NaOH to stearic acid is 0.73:1, 0.83:1, 0.92:1, 1.02:1, 1.12:1 as five levels to investigate the curing agent The impact of dosage changes on product quality (the whole material benchmark is 100g).

Table 3 Specific experimental phenomena when investigating the amount of curing agent

It can be seen from Table 3 that the addition of an appropriate amount of curing agent also has a great impact on product quality. The curing agent is NaOH and a small amount of water, wherein the main function of a small amount of water is to make NaOH in an ion state, so that the reaction with stearic acid is more fully and completely, thereby obtaining the required gelling agent sodium stearate. If the amount of NaOH added is too much or too little, the desired effect cannot be achieved. Therefore, when the addition amount of curing agent is 0.62g, the performance index of the obtained product meets the requirements most in all aspects.

4. The influence of water content in alcohol

Generally speaking, the purity of industrial alcohol is more than or equal to 95% (mass percentage). If there is too much water in the alcohol, due to the solubility of water to sodium salt, it will destroy the strength of the gel, which will have a great impact on the quality of the product, and will also reduce the combustion calorific value of the product, affecting the performance of solid alcohol fuel. Use performance.

In this experiment, the purity of alcohol is used as an investigation index, that is, the mass fraction of water in raw alcohol is 1%, 3%, 5%, 7%, and 9% as five levels to investigate the water content of alcohol Impact on product quality (the whole material benchmark is 100g).

The amount of each component of the raw materials required for the experiment is shown in Table 2-4:

In this experiment, the purity of the alcohol (i.e. the water content in the alcohol) is used as a variable, and the experiment is carried out, and the experimental results are as follows:

Table 4-1 The amount of experimental raw materials when examining the water content in alcohol

Wherein, alcohol 1 is the amount in the there-necked flask, and alcohol 2 is the amount in the Erlenmeyer flask, that is, the alcohol used accounts for 90.73% of the raw materials.

Table 4-2 Specific experimental phenomena when examining alcohol purity factors

It can be seen from Table 4-2 that the water content in alcohol has a great influence on product quality. When the water content of the alcohol is too small, there is a partial solidification phenomenon in the reaction kettle; when the water content of the alcohol is too high, the strength of the gel will be destroyed due to the solubility of the sodium salt by water, and the quality of the product will be greatly affected. , the combustion calorific value of the product will decrease. Therefore, when the water content of the alcohol is 5%, the resulting product works best.

Determine optimum process condition of the present invention and raw material proportioning by above experiment: operating temperature 70 ℃, the chemical composition of solid alcohol fuel is respectively by weight ratio, dispersant 1.30%, stearic acid 4.76%, the consumption of NaOH 0.62% , the mass concentration is 90.73% of 95% denatured alcohol and 2.59% of distilled water. The solid alcohol fuel produced by this process is smooth and flat, white as jade, uniform and fine gel particles, high hardness, high stability, good heat resistance, uniform texture, easy to form and package, especially suitable for small and medium-sized enterprises and household production, with Broad market prospects.

Embodiment 3, the performance test of solid alcohol fuel

The solid alcohol fuels of the present invention used in this example are prepared by optimizing the process conditions and raw material ratios in Example 2. The similar product (reference substance 1) of contrast, raw material industrial alcohol 500ml, sodium hydroxide 2.5g, stearic acid 14.5g, paraffin 4.0g, water 10g are that main raw material is processed with the same process as embodiment 2. The control sample urotropine (reference substance 2) military solid fuel was purchased from Beijing Dongxin International Health Products Co., Ltd.

1. Melting point experiment of solid alcohol fuel:

Experiment method: carried out in a stable super constant temperature water bath, the specific operation steps are as follows:

Before the measurement, lower the temperature of the water bath to 40°C, fix the small Erlenmeyer flask with the sample in the water bath, and heat it slowly. At the beginning, the temperature was raised every 20 minutes, each time the temperature was raised to 4°C, and then kept for 20 minutes, and the Erlenmeyer flask was carefully observed, no abnormal phenomenon occurred. Continue to raise the temperature. When the temperature of the water bath reaches 48°C, raise the temperature every 30 minutes with a temperature increase of 1°C each time, and then keep it for 30 minutes. Carefully observe the phenomenon in the Erlenmeyer flask. When the sample in the Erlenmeyer flask begins to slump and wet, and there is also dripping liquid, this indicates that the sample has begun to melt, and the temperature at this time is recorded as the melting point.

For the determination of melting point, there are at least two repeated data, and a new Erlenmeyer flask must be replaced for each determination.

After repeating the experiment twice, it can be determined that the actual temperature of the water bath is 52 °C when the set temperature of the water bath is 51 °C, so it is confirmed that the melting point of the solid alcohol fuel is 52 °C.

For this reason, it can be seen from the experimental results that the solid alcohol fuel produced under the optimum process conditions of the present invention has a melting point of 52° C., has good physical properties, can be stored for a long time, and is easy to carry or transport. The melting point of reference substance 1 measured by the same method was 50°C.

2. Combustion experiment of solid alcohol fuel

The combustion experiment method is as follows. Put a thermal insulation device on the electronic balance, then put a small container to be heated on it, put in solid fuel, ignite and burn, and record the burning time and the amount of solid fuel reduction at regular intervals. Through these data, you can Calculate the burning speed and the average burning speed of the burning process, and also calculate the residue rate of the burning process.

The formula for calculating the residue rate is as follows:

See Table 5 for the experimental results.

Experiment 1 Experiment 2 Experiment 3 Experiment 4 Experiment 5 Experiment 6 Combustion disc mass (g) 53.86 27.16 26.70 24.49 8.35 12.83 Diameter of combustion disc (cm) 5.948 3.960 3.520 2.964 2.520 2.024 Total mass before combustion (g) 69.61 34.26 34.39 30.25 22.98 15.47 Total mass after burning (g) 54.84 27.61 27.19 24.85 18.65 13.00 Average burning speed (g/s) 0.035 0.017 0.012 0.009 0.007 0.005 Last extinguishing time (min) 7' 6'26" 10'53" 11'10" 11'56" 9'55" Residue rate (%) 6.22 6.34 6.37 6.25 6.48 6.44 burning state The flame is strong and stable; smokeless, odorless and non-toxic The flame is strong and stable; smokeless, odorless and non-toxic The flame is strong and stable; smokeless, odorless and non-toxic The flame is strong and stable; smokeless, odorless and non-toxic The flame is strong and stable; smokeless, odorless and non-toxic The flame is strong and stable; smokeless, odorless and non-toxic

From the analysis of the above results, it can be seen that the burning speed of solid alcohol fuel is different in combustion vessels with different diameters. Under the condition of the same amount of combustion, the larger the area of the container, that is, the larger the diameter, the more vigorous the burning flame, the higher the heat released during combustion, and the faster the burning speed. The average burning speed of solid alcohol fuel increases with the diameter. reduced by the reduction. Moreover, when the diameter of the combustion disc is small, the amount of residue is relatively high. This is because the fatty alcohol volatilized during combustion does not contact sufficiently with the oxygen in the air, and the combustion is not complete enough, so naturally a little more residue is obtained.

Combined with the average burning velocity obtained from the above six groups of experiments, the quantitative relationship curve between burning velocity and diameter can be obtained by using nonlinear regression, as shown in Figure 1. The curve equation is Y=0.013X ^1.833 and the correlation coefficient is 0.9932. It shows that the correlation is very good, where Y represents the burning speed in g/s, and X represents the diameter of the container in cm.

This equation shows that the burning rate is not linearly related to the area of the burning vessel. Under the same experimental conditions, the burning speed of solid alcohol fuel in different combustion containers is different. From the perspective of energy transfer, the larger the combustion area, the greater the energy loss, so the size of the combustion container should be reasonably determined according to the bottom area of the heated container. This quantitative relationship between burning velocity and diameter reveals the nature of the combustion. It can also be known from the regression curve that the average burning speed of the solid alcohol fuel when it burns in combustion containers with different areas can also be calculated at the same time, the consumption of the solid alcohol fuel at different times.

3. Water heating experiment of solid alcohol fuel

The experimental method is similar to that of the combustion experiment. Put 400g of cold water on a burning plate containing 13.8 grams of solid alcohol fuel. After igniting it, record the burning time and temperature of the water regularly. From these data, you can get that the solid alcohol fuel heats water. The relationship between water temperature rise and burning time during the experiment. Among them, 400g of water is exactly the amount of water needed to cook a bag of instant noodles when working in the field.

After boiling, it can continue to burn for at least 3 minutes, which meets the requirements for field operations.

In a similar way, the water heating test was carried out with urotropine military solid fuel. The results show that when there is a burning container, the burning speed drops obviously, the firepower is small, and it is difficult to boil water when the ambient temperature is relatively cold; the urotropine without a burning container can continue to burn after reaching boiling More than 3 minutes, which meets the use requirements of field operations. During the experiment, it was observed that the military solid fuel of urotropine took 40 seconds from ignition to complete combustion, and it was not easy to ignite, but easy to extinguish.

This experiment shows that under the combustion conditions, the concentration of oxygen in the environment and the transfer rate of oxygen are very important, and the combustion performance of solid alcohol fuel is better under the same conditions, even under the condition of a little oxygen deficiency, it can fully burn, Compared with urotropine military solid fuel, it is more adaptable to plateau areas.

In addition, it can also be seen from the combustion experiment that when the solid fuel of urotropine is burned, the environment is seriously polluted due to the emission of toxic and pungent odor gases such as nitrogen oxides, especially when it is burned indoors or in a tent, it is harmful to the human body. The danger is great. Burning under these two conditions, the final result can be seen that a large amount of soot and black ash remains on the heating surface of the heated container, which is difficult to remove and brings inconvenience to repeated use, thus reducing the convenience of solid fuels. .

4. Storage experiment of solid alcohol fuel

In order to investigate the storage conditions of solid alcohol fuel, repeated water bath heating experiments were carried out on solid alcohol fuel at high temperature. Through careful observation of the phenomenon, the temperature limit of solid alcohol fuel storage was obtained.

The experimental method of the storage experiment is similar to that of the melting point determination, and the specific operation steps are as follows:

① Solidify the ready-made solid alcohol fuel directly in the three-necked bottle. After the solidification is complete, set the temperature of the constant temperature water bath to 44°C, and fix the three-necked bottle in the water bath to heat.

②At the beginning, the temperature was raised every 1 hour, each time the temperature was increased by 2°C, and then kept for 1 hour, and the three-necked bottle was carefully observed. The surface of the sample was dry and free of moisture, and no abnormal phenomenon occurred.

③Continue to increase the temperature. When the temperature of the water bath reaches 48°C, raise the temperature every 2 hours, each time the temperature rises by 1°C, keep for 2 hours, and carefully observe the phenomenon in the three-necked bottle. When the temperature is 51°C, the phenomenon in the three-neck flask is shown in Table 6, and it still maintains a relatively stable state at this temperature.

④ When the temperature rises to 52°C, after keeping for 1 hour, a little liquid has seeped out from the surface of the sample in the three-necked bottle, and droplets also appear on the wall of the bottle. At this time, the three-necked bottle is taken out, and there is still liquid after cooling at room temperature.

⑤It can be seen that the temperature limit of the storage conditions of the solid alcohol fuel developed in this experiment is 51°C. If the ambient temperature is higher than 51°C, the solid alcohol fuel may be affected by the high temperature and the liquid wrapped in the polymer gel may Alcohol bleeds, resulting in poor solid alcohol fuel quality.

Table 6 Storage experiment phenomenon when the temperature is 51°C

As can be seen from Table 6, after heating for half an hour, the solid alcohol fuel oozes a very small amount of liquid film on the part in contact with the glass wall. When heated at high temperature, the moisture on the wall is easy to seep out from the solid alcohol fuel. It can be seen from specific tests that the solid alcohol fuel can still return to its original state after recooling, so it has little impact on the quality of the product. After heating for one hour, the surface of the solid alcohol fuel was dry without droplets; after another hour, the surface of the solid alcohol fuel remained dry. This shows that the solid alcohol fuel is in a good storage condition at this temperature, and can be stored at this temperature for a long time after a certain package. This is because the gel component in the solid fuel in the gel state is formed by the saponification reaction of acid and alkali. Fatty acid salt, the composition is extremely stable and will not change with time, as long as it is stored at an appropriate storage temperature, it can be stored for three years.

Continue to adjust the temperature. Through repeated experiments, it can be known that the storage temperature of solid alcohol fuel should be below the limit temperature of 51°C. However, the storage temperature limit of the reference product 1 is 49° C., and if it exceeds this limit, good physical properties cannot be maintained. Generally, the solid alcohol fuel can be stored at normal temperature, but in special circumstances such as desert environment and hot environment, the solid alcohol fuel of the present invention still has good performance indicators. Therefore, the product of the present invention has a long shelf life and is convenient for long-term storage and long-distance transportation. , not only suitable for the hotel and catering industry, but also suitable for tourism, field work and army camping training.

5. Vacuum combustion experiment of solid alcohol fuel

This experiment is used to verify the combustion state of the product of the present invention in an oxygen-deficient environment.

This experiment is carried out in a vacuum drying oven, and the absolute amount of air in the vacuum drying oven is adjusted by an air valve and a vacuum pump to simulate the real natural environment of solid fuel burning in a plateau climate.

① Weigh 1.57g of solid alcohol fuel, ignite it in a combustion disc (the smallest diameter combustion disc) with a diameter of 2.024cm, put it into a vacuum drying oven after the combustion is stable, and close the drying oven tightly so that the air content in the entire drying oven Definitely, not changing with the external environment;

② Turn on the power of the vacuum pump. At this time, the absolute amount of air in the vacuum drying box changes, so the reading of the vacuum gauge also changes. When the absolute amount of air gradually decreases, the reading of the vacuum gauge continues to increase. Adjust the inflation valve. Make the vacuum degree increase at a stable speed, the combustion process of the sample is stable, and it is convenient to observe the phenomenon and record the data;

③ Carefully observe the burning phenomenon of the sample, and pay attention to the change of the reading of the vacuum gauge at the same time. When the sample is extinguished under a certain vacuum degree, record the vacuum degree at this time, which is the obtained experimental data;

④ In order to ensure the reliability of the experimental data, the experiment was repeated 3 times and the average value was taken;

Similarly, 1.57g of the reference substance 1 and 1.60g of the reference substance 2 urotropine solid fuel were weighed to carry out parallel experiments under the same conditions. Since the combustion of urotropine is extremely insufficient in the burning dish, the burning dish is not used for urotropine, and it is directly ignited in a glass dish. After the combustion is stable, it is put into a drying box.

The concrete phenomenon of the vacuum combustion contrast experiment of solid alcohol fuel and reference substance is as shown in table 7:

Table 7 Vacuum combustion experiment record table

It can be seen from observation that the solid alcohol fuel burns immediately at one point, put it into the vacuum drying box, and turn on the power of the vacuum pump. At first, the flame is very weak. After the air content in the vacuum drying box is stable, the combustion is stable and the flame is strong. Gradually weaken again until it goes out; the main fuel of reference substance 1 is also alcohol, and it is basically the same as the combustion phenomenon of solid alcohol fuel of the present invention during combustion; Put it into the vacuum drying box, and then turn on the power of the vacuum pump, so that the flame is very large at the beginning. After the air content in the vacuum drying box is stable, the combustion also tends to be stable, and the flame is strong. When the experiment progresses to the later stage, the flame gradually weakens until off,

From the vacuum combustion experiment, the different combustion properties of the solid alcohol fuel and the reference substance in the absence of oxygen can be obtained. According to the vacuum degree value obtained from the experimental results, combined with the conversion relationship between the vacuum degree and the altitude, that is, every 12 meters rises, the atmospheric pressure Reduce 1mmHg, so by simple calculation, you can get the maximum altitude when the fuel is combustible under the condition of plateau anoxic.

(1) Solid alcohol fuel

For solid alcohol fuel, the vacuum degree is 0.07Mpa when the flame is extinguished.

Since 1mmHg=133Pa=0·000133MPa,

It can be converted into the pressure value under hypoxic environment P ₁ =0.07/0.000133=526.32mmHg

Then the altitude value under this pressure is H ₁ =526·32×12=6315.84m

It is thus concluded that the maximum altitude at which solid alcohol fuel can be burned is about 6300m in the plateau anoxic environment.

(2) Reference substance

For the two reference substances, the vacuum degree is 0.06Mpa when the flame is extinguished.

Since 1mmHg=133Pa=0.000133MPa,

It can be converted into the pressure value under hypoxic environment P ₂ =0.06/0.000133=451.13mmHg

Then the altitude value under this pressure is H ₂ =451.13×12=5413.56m

It is thus concluded that the maximum altitude at which the reference fuel can be burned is about 5400m in the plateau anoxic environment.

From the above comparative experiments, it can be known that under the condition of vacuum anoxic, the solid alcohol fuel of the present invention has obvious advantages, and it can still maintain stable combustion, strong flame and good combustion performance in such a harsh environment of plateau anoxic . However, the reference substance is slightly insufficient. Under the same environmental conditions, the combustion flame is not strong, the combustion process is unstable, and the vacuum limit value of combustion is also low, and its combustion performance in all aspects is not as good as that of solid alcohol fuel. According to the calculated data, the solid alcohol fuel can still burn in the plateau or mountain environment with an altitude of more than 6300 meters, while the reference product can only be used in the plateau or mountain environment with an altitude of less than 5400 meters. Apparently, the solid alcohol fuel of the present invention is more suitable for use in plateau anoxic regions and has obvious advantages. It is the preferred heat source for plateau soldiers' field training and plateau mountain operations, and can be widely used in modern military equipment.

Claims (4)

1. A solid alcohol fuel, which consists of the following components by weight percentage: Industrial Alcohol 90.73%, Stearic acid 4.76%, NaOH 0.62%, Paraffin 1.30%, Distilled water 2.59%; The mass concentration of described technical alcohol is 95%. 2. A preparation method of solid alcohol fuel, according to the components described in claim 1, all operations are carried out at 70°C, 55.7% of stearic acid, paraffin and industrial alcohol are heated in a three-necked flask and stirred to reflux, and the Sodium hydroxide, distilled water and 44.3% industrial alcohol are heated in the Erlenmeyer flask, and then the solution in the Erlenmeyer flask is slowly injected into the three-necked flask, and the mixed solution continues to be heated and stirred at 70°C, and it is poured into the container while it is hot , natural cooling, and the uniform, translucent gel-like solid obtained by solidification and molding is solid alcohol fuel. 3. The method for preparing solid alcohol fuel according to claim 2, characterized in that all operations are carried out in a constant temperature water tank with a water bath temperature of 70°C. 4. The preparation method of solid alcohol fuel according to claim 3, characterized in that, the specific operations are: In the first step, stearic acid is dissolved in alcohol: ①The temperature of the water bath in the fixed constant temperature water tank is 70°C, and the stirring speed of the electric stirrer is 250r/min. ② Weigh 55.7% of stearic acid, paraffin and industrial alcohol respectively, and add them into a three-necked flask in turn. Then install an electric stirrer, a thermometer and a reflux condenser on the there-necked flask; ③Heat and stir the three-necked flask in a water bath. A small amount of evaporated alcohol is condensed by the reflux condenser and returned to the three-necked flask until it dissolves into a uniform and transparent colorless solution. In the second step, dissolve sodium hydroxide in alcohol: ① Weigh 44.3% of sodium hydroxide, distilled water and denatured alcohol respectively, and add them in the Erlenmeyer flask successively; ② At the same time, heat the Erlenmeyer flask under the same conditions as above for the same time until it becomes a uniform and transparent solution; The third step is to slowly inject the solution in the Erlenmeyer flask into the three-necked flask, and continue to heat and stir the mixed solution at 70°C for 2 minutes, then pour it into the container while it is hot, let it cool naturally, and solidify into shape , sealed packaging, you can get a uniform, translucent high-strength gel-like solid alcohol fuel.

Images