RU2050966C1 - Method and device for obtaining gases - Google Patents

Abstract

FIELD: obtaining gases. SUBSTANCE: solid fuel of 100-500 kcal/kg in caloricity are used for obtaining gases. The device consists of the housing made up as a cartoon cartridge with the cap, ignitor, main gas generating compositions, filter, and grid. The main composition is made up as a monolithic multi-passage unit. The area of passages must be 5-30% of area of the unit face. EFFECT: enhanced efficiency. 3 cl, 7 dwg

Description

The invention relates to the field of gas production and can be used in pressurization systems of rescue equipment on water and any rubber products (RTI), in systems for displacing or aerating liquids or powders, as well as in other fields of technology where autonomous sources of any gases are required for different pressures to the ambient temperature or no higher than 100 ° ^C.

 Currently, the most widely used for pressurization of solid rubber goods are compressed gas systems at pressures of 150-250 atm (GOST 949-73). These systems have large dimensions and weight (Table 1) and low reliability, since in some cases there are gas leaks during storage, which requires regular monitoring, repair and refueling in stationary conditions of special workshops. Such failures and only 10-25% provision with means of rescue of passengers of river and sea transport lead to mass deaths in accidents.

Existing sources of gas to solid fuel gas generators even in the presence of special devices for cooling the gases by heat exchange or heat consumption for decomposition of inert substances not allow to obtain gases with temperatures below 300 ^{° C} and lose all of their operational advantages in size and weight, while maintaining the advantages constant readiness for work and autonomy [1]
Other methods and devices allow to obtain low-temperature gases O ₂ ; H ₂ ; Cl ₂ ; F ₂ , but they are stationary and cannot be implemented in stand-alone devices.

Closest to the proposed is a method of producing gases based on the combustion of solid fuels in the forced convection mode. This mode consists in the fact that solid fuel is ignited, the gases formed during its combustion are passed through the initial substance, transferring all the thermal energy to this substance [2]
The disadvantage of the prototype method is that during the exothermic interaction of chemicals during the combustion of solid fuels, there is a transition to volume combustion and explosion, accompanied by the destruction of the gas source or system and the supply of high-temperature gas to the system.

Known apparatus for producing gases of solid chemical reagents, which does not allow to obtain gases with temperatures below 300 ^{° C,} even with special devices for their cooling by heat exchange or heat consumption of the decomposition of inerts.

Closest to the proposed device for producing gases is a device [3] consisting of a body in the form of a cardboard sleeve with a capsule, igniter and main gas generating compositions, a filter and a grid. This device allows to obtain a gas with a temperature not above 50 ° ^C. However, this device has a low gas capacity per unit volume (0.4-0.3 l / cm ³⁾ and has such a drawback that composition can not be increased more than the length of its three diameters, which affects the overall gas production of the product, since the composition is not pressed and its compaction occurs during operation, which is associated with a significant increase in pressure and a spread in the time characteristics of the product, it is impossible to increase the length even with a set of separately pressed x blocks, since the gas-dynamic resistance increases and the pressure also increases, which leads to an increase in the weight of the body and dimensions.

 A disadvantage of the known method and device is that they do not provide a safe process for producing gas and high gas productivity.

 The purpose of the invention is to increase gas production and create the conditions for a safe process for producing gas in the forced convection mode of combustion products through the starting material.

The goal is achieved in that in a method of producing gases based on the combustion of solid fuels, substances with a calorie content of 100-500 kcal / kg are used. This is explained by the fact that in the method of producing gases by exothermic decomposition of a substance, the generated gases are passed through the channels of the block of the initial substance, transferring heat to the next layer and initiating a chemical reaction in it. Moreover, for a number of compositions to obtain H ₂ ; N ₂ ; F ₂ ; N ₂ + CO ₂ , it was found that there are upper and lower limits for the caloric content of the substance, namely: when the caloric content is below 100 kcal / kg, a stable layer-by-layer decomposition does not occur in the substance and the decomposition process ceases, and when the caloric content exceeds 500 kcal / kg volumetric combustion, during which hot gas is formed and destruction of the housing is possible. And only a substance with a calorific value of 100-500 kcal / kg for various compositions allows one to obtain a stable layer-by-layer decomposition of a substance with a constant mass velocity and with a gas temperature at the outlet of the unit equal to the ambient temperature.

 The goal is to increase the gas productivity of a device consisting of a case in the form of a cardboard sleeve with a capsule, igniter and main gas-generating compounds, a filter and a mesh, the main composition is made in the form of a monolithic multichannel block, with the channel area being 5-30% of the block end area.

 The claimed values of calorie content, the total area of the holes allow you to organize a stable process of gas formation.

 As the feedstock, substances with a calorific value of 500-100 kcal / kg are used, and to increase the specific gas productivity, a pressed block with channels of a certain size and number is used, which makes it possible to organize the described gasification process.

+Q
NaN

Na+1,5N₂ при избытке NaN₃ образуется металлический натрий и дополнительное количество азота.As examples for the implementation of this method, you can give the test results of the compositions to obtain:
1. Nitrogen, which is formed by the reaction:
3NaN ₃ + 2Fe ₂ O ₃ = 3NaFeO ₂ + Fe + 4,5N

+ Q
NaN

Na + 1.5N ₂ with an excess of NaN ₃ , metallic sodium and an additional amount of nitrogen are formed.

 The test results of this mixture in convective combustion mode are given in table.2. The gas temperature was measured after a filter 1 cm thick.

2KF+NiF₂+F

Результаты испытаний приведены в табл.3.2. Fluorine, which is formed by the interaction of, for example, an excess of potassium hexafluoronickelate with aluminum by reaction:
K ₂ NiF ₆ + ² ₃ Al ² ₃ AlF ₃ + 2KF + NiF ₂ + Q
K ₂ NiF

2KF + NiF ₂ + F

The test results are shown in table.3.

K+B+2H₂
Результаты испытаний приведены в табл.4.3. Hydrogen / which is formed by the interaction of excess amounts of K ^- and Na ^- borohydrides with metal oxides:
3KVN ₄ + 2MoO ₃ __ → 3KVO ₂ + 2Mo + 6H ₂ + Q
KVN ₄

K + B + 2H ₂
The test results are given in table.4.

4. A mixture of gases, which is formed by the interaction of NaN ₃ with cellulose nitrates and sodium bicarbonate.

 The test results are shown in table.5.

 The data presented show that for various compositions there are conditions when, in the forced convection mode of decomposition products through a block of the starting substance, the organization of layer-by-layer combustion without transition to volumetric combustion and explosion is possible. This process proceeds with a caloric content of the initial compositions of 100-500 kcal / kg.

 Figure 1, 3, 4 presents the proposed device; figure 2 section aa in figure 1.

 A chemical gas source (CIG) consists of a housing 1, a sealing membrane 2, a thrust mesh 3, a filter 4, a glass of percale or silk mesh 5, a gas generating unit 6, an igniter composition 7, a cardboard wad 8, a capsule or an electric igniter 9. In the manufacture of a CIG diameter more than 50 mm, it is recommended to use a lid with a fitting 10 (Fig. 2), a thrust grill 11, and form the gas generating unit by a set of bundles of cords having a hexagonal shape 12 in cross section, which ensures their tight packing. The cavities of the truncated hexagonal block are filled with elements 13 of the same composition or with an inert mass. The axis of the channels are located on the sides of the regular hexagon or in concentric circles with a pitch of 3-10 mm and in their center.

 The operation of the device is as follows.

 When triggering the initiation means (electric igniter 9) and composition 7 in the gas generating unit 6, a chemical reaction is initiated, the products formed move through the channel of the unit through the mesh 5, filter 4, thrust mesh 3, grille 11 and the nozzle 10 of the lid into the pressurized object. Membrane 2 protects the composition from the influence of the external environment and breaks at the initial moment of CIG operation, the grill 11 takes up loads and prevents the filter and slags from being ejected into the pressurized product, filter 4 cleans the gas from solid and liquid impurities and partially cools, silk mesh 5 or percale prevent entry filter material and igniter composition in the channels of the unit, wad 8 serves to place the igniter capsule.

Testing the HIG showed that their work is significantly affected by the geometric parameters of the block. The tests were carried out on samples with a diameter of 20 mm with a density of 1.4 g / cm ³ . The test results are given in table 6-7.

Tests showed that the proposed design allows to increase gas removal to 0.6-0.7 l / cm ³ while the prototype, this value is 0.3-0.4 l / cm ³ , i.e. gas removal per unit volume increases 1.5-2.0 times, which reduces the size and weight of the HIG.

 The area of the channels affects the second gas flow rate.

 Thus, with an increase in the area of the channels, the second gas flow rate can be reduced by 2.5 times.

 Thus, reducing the area of the channels, you can reduce the second flow rate by 1.5 times.

 That is, by changing the geometry of the gas generating unit, to develop a HIG with different flow characteristics.

When changing the length of the block, it was found that the prototype with a length of the composition equal to its five diameters, the pressure in the bottom rose to 190 kg / cm ² , while in the proposed embodiment it is 9-15 kg / cm ² , t. e. the pressure is less than in the prototype 10-20 times. With lengths equal to ten block diameters in the prototype, the compositions either do not burn, or the combustion is progressive in nature with a large variation in operating time, reaching three times. At the same time, the channel unit allows you to maintain a constant flow and time characteristics.

 Low pressure values in the generator housing allow the use of cardboard, plastic, aluminum for the manufacture of cases, which leads to a decrease in dimensions and weight, and the constancy of the geometric dimensions of the block ensures the constancy of time characteristics. So, if currently produced HIG EG-2 in accordance with the prototype have a time spread from 0.5 to 20 s, which is associated with various factors of an objective and subjective nature, then EG-2M on a multi-channel unit provides a working time of 3.0 -4.2 sec

 At the same time, it was found that CIG equipment with a diameter of up to 50 mm is conveniently produced with one gas generating unit with a diameter equal to the inner diameter of the hull. With large dimensions of the HIG, difficulties arise when forming blocks with the number of channels more than twenty, consisting in increasing the block by shifting the channels to the center. In this case, the manufacture of blocks of large diameters is possible only with a set of individual cords made of a gas-generating composition. To increase the density of filling the housing with a gas-generating composition, it is envisaged to manufacture cords of hexagonal cross section and any length by the method of continuous pressing.

 Small-sized CIG (Fig. 1) are intended for use as plug-in elements in the body of pressurization systems equipped with a shock mechanism, and CIG (Fig. 2) work as independent sources, replacing the balloon.

Thus the use of multi-channel blocks in the HIG to obtain a gas with a temperature not exceeding 100 ^{° C} allows to obtain the following advantages: increase gazosem a generator unit volume of 1.5-2.0 times; reduce the size and weight of the generator through the use of plastic and cardboard; repeatedly reduce the pressure in the housing; ensure the constancy of the temporal characteristics of the HIG; use longer blocks, which ensures longer HIG operation time.

Claims (2)

 1. A method of producing gases by convective combustion of a gas-generating solid fuel containing fuel, an oxidizing agent, characterized in that the gas-generating unit is ignited from a blank end and the entire mass of generated gases is passed through channels or pores of an initial fuel having a calorific value of 100 500 kcal / kg.  2. A device for producing gases, consisting of a housing, an ignition unit, including an initiating means and an additional igniter, a gas generating block of solid fuel, a filter and a grid, characterized in that it further comprises a cover with a fitting and a thrust grid, and the gas generating fuel is made in the form monolithic multichannel block, or typed in a bundle of cords of hexagonal shape, while the area of the channels is 5-30% of the area of the end face of the block.

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