SU735980A1 - Method of determining moisture-content - Google Patents

Description

The invention relates to measuring technique, namely, to a method for determining moisture content in products of combustible fuels or pyrotechnic compositions.

It is known to determine the moisture content of ⁵ in the absorption gases of its water-taking substances. Wet gas is passed through several series-connected absorption vessels filled with water-scavenging substances. Vessels are weighed before and after moisture absorption [1].

The known method can be used to determine the moisture content in products burned in a fuel bomb or pyrocomposition, when the moisture there is not only in the form of steam, but also water droplets scattered in the volume of the bomb. ₂ о The dry inert gas, supplied to the bomb, carries away gradually evaporating moisture, which is further absorbed by water-taking substances.

The closest technical solution to the invention is a method for determining the moisture content in fuel combustion products, in a calorimetric bomb, which consists in determining the partial pressure of superheated steam in a gas mixture £ 2]. In this way, it is possible to determine the water vapor content in large volumes of a gas mixture, for example, air. However, the method is not designed to measure the moisture content of moisture dispersed in a closed volume, · for example, in the form of drops.

The purpose of the invention is to improve the accuracy and reliability of determination.

To do this, the moisture in the gas mixture is transferred by heating in an isochoric process to superheated steam, and then the partial pressure and its specific volume are determined by the ratio of the measured temperature and pressure before and after heating. The essence of the method is as follows.

'3

The burning of fuel or pyro-composition in a bomb is carried out in an inert, dried environment. After burning, the bomb is thermostatically controlled at room temperature and pressure and temperature are measured, after which all moisture is transferred to superheated steam by heating, and under these conditions they are again thermostated and pressure and temperature are measured. The partial pressure of superheated steam is determined by the ratio of the measured pressure and temperature of both thermostats, the specific volume is found from the tables of superheated steam and, knowing the total volume of the bomb, the desired moisture content is found. The calculated experimental error is 2.0%.

In FIG. 1 and FIG. 2 section aa and bb, the installation for determining moisture content is shown. Electronite 1 contains a water thermostat 2 with insulation 3. A calorimeter bomb 4 is installed in the thermostat. It is equipped with two needle ventiles 5, a manometer B and a mercury thermometer 7. The tube 8 to which the manometer is connected has a cut into which the needle valve 9 is welded The lower end of tube 8 is welded into the bomb lid 10. The fuel to be burned is placed in a crucible, and the pyro-composition can be suspended on a wire 11 connecting the electricity-supplying contacts 12 and 13. The wire ignites the fuel or the pyro-composition.

The total volume occupied by gases and moisture after combustion,

V = d / 4V -X /

E B TP M YK »

X / X / ".VV - ^h respectively s> ΤΡ ^'ν Μ» wk but volumes bomb tube 8, a manometer tube and slag without Summary pore volume which is at the boiling temperature thermostating' water b 'WHr'',, »

The calculation of the temperature along the length of the tube 8 shows that 1/3 of its volume can be attributed to the temperature b _< , and 2/3, of the volume to room temperature, at which the pressure gauge is located.

The total volume at room temperature ⁴ where

The partial pressure of dry gases after combustion and temperature control at room temperature

P = p - p about e >>

Ρθ is the total pressure measured for this state;

P - part of the moisture saturating

O volume and determined by tables of saturated steam at room temperature.

The tables of dry saturated steam determine the temperature t in accordance with barometric pressure.

Volumes are reduced to a pressure of 1 kg / cm ^ and room temperature (t = 25 ° C). , °

The given volume of dry gases after combustion where

V = P · Χ / „ ^w sc s' a

The reduced volume in the process of boiling water in a thermostat v - p · bx / + Ί V Δ

KS 1C X · m 3 Yr /

Here is the partial pressure of the dry haprocess of boiling water in thermowells in the stat

R. = R-ic. 1 &

p is the total measured pressure 'in the process of boiling water in a thermostat.

The measured pressure is the sum of the readings of the manometer and barometer.

The reduced volume of dry gases in volume | at a temperature t _χ where

V, \\ / -x / t, c sc Kc

For dry gases in volume, the equation of state of the reduced and at boiling water in the thermostat will be ^R cChs ₌ where

Tov v _tlt

2? 5J6 ° + 25 °

Then the partial pressure of that water vapor in the volume at a temperature £

P = p-p

I overkill

For the state and is determined by the tables of superheated water vapor its specific volume

Desired moisture content Q

In v

An example implementation of a method for determining the moisture content of a pyrocomposition (22% by weight of zirconium and 88% barium chromate), made in the form of washers and burned in a calorimetric bomb in helium medium. Barometric pressure p _b : = 1.003 kg / cm ² , boiling point of water = 99.1 C.

Absolute pressure

P _o = 1,429 kg / cm ^"2" p = 2.533 kg / sm2V = 287.28 + 2.0 + = 307.84 cm?

V _T = 287.28 + 1 / 3-2

286.5 cm ^,

V _K = 20 + 2 / 3-2 = 21.34 s "?

At 25 ° C F ₀ O, O32 kg / cm ² = R _S R _O ~ R _b - 1.429 - 0.032 • * = = 1.397 kg / cm ^2,

1.397 · 307.84430 cm ³ ,

WvH ^ ² - ⁵³³ - °> ⁰³²⁾ - 21.34 = 53.5 cm?

-V _Kc = '430 -53.5 -376.5 cm ^: p - ^ c (273 ^ 16_ ± ti.) .. ₄ ' ^Ctl 4.1 (273.16 + 25 °) both thermostats 20.0 - 1 , 44 =

- 1.44 = g>

t, + 376.5 (273.16 + 99.1)

--------—.————-— = 1 Qy kg / m ³

286.5 (273.16 + 25) = ² · ⁵³³ - h ⁷ 1

- = 0.863 kg / cm

735 980 6

According to the tables of superheated steam V 2,133 ⁼ m ³ / kg

Ute ^ 1V

1b from where the moisture content _ 286.5 _ „_ ~, TK ^{11 4g}

The possibility of obtaining water vapor in an overheated state, which is controlled by checking the tables of superheated water vapor, depends on the volume of the bomb, the temperature of the thermostatic liquid, the amount of substance burned and its moisture, which is established during the design of the study.

At the proposed installation, it is possible to simultaneously determine the volume of gases released.

Claims (2)

The invention relates to a measurement technique, namely, to a method for determining moisture content in products of combustible fuels or pyrotechnic compositions. It is known to determine the moisture content of gases absorbed by water-removing substances. Through several successively connected absorption vessels filled with water-repelling substances, a moist gas is passed through. The vessels are weighed before and after absorbing moisture. L. The known method can be used in determining the moisture content in products, combustible fuels or pyro composites, when the moisture is not only there; o in the form of steam, but also water droplets scattered in the bomb volume. A dry inert gas fed into the bomb carries gradually evaporated water, absorbed further by water-removing substances :. The closest technical solution to the invention. is a method for determining moisture content in fuel combustion products in a calorimetric bomb, which consists in determining the partial pressure of superheated steam in a gas mixture 2. This method can determine the content of water vapor in large volumes of the gas mixture, for example, air. However, the method is not designed to measure moisture content of moisture dispersed in a closed volume, for example, in the form of droplets. The purpose of the invention is to improve the accuracy and reliability of the determination. ; For this, the moisture in the gas mixture is converted into superheated steam by heating in the Zaporizhia process and then the partial pressure and its specific volume are determined by the ratio of the measured temperature and pressure before and after heating. The essence of the method is as follows. Combustion of a fuel or pyrosol in a bomb is carried out in an inert, drained medium. After burning, the bomb is thermostated at room temperature and pressure and temperature are measured, after which all the moisture is transferred to superheated steam by heating, and in these conditions it is thermostatic and pressure and temperature are measured. The partial pressure of the superheated steam is determined by the ratio of the measurement of the pressure level and temperature of both thermostats, the specific volume of the superheated steam is found, and, knowing the total volume of the bomb, the desired moisture content is found. The calculated experimental error is 2.0%. FIG. 1 and FIG. 2, section A-A and B-B, shows an installation for determining the moisture content. On the electrolyte 1 there is a water thermostat 2 with insulation 3. The thermostat contains a calorimetric bomb 4, equipped with two needle valves 5, a pressure gauge 6 and a mercury thermometer 7. The tube S, to which the pressure gauge is connected, has a slit where the needle needle is welded 9. The lower end of the tube 8 is welded into the top 10 bomb. Burned fuel is placed in the crucible, and the pyrocompound can be hung on a wire 11 connecting the electrical supply pins 12 and 13. The ignition ignites the fuel or pyrosost Total volume occupied by gases and moisture after combustion, VV -VV -VEBtp m ilLrk - appropriate volumes of the bomb, tube 8, tube of the manometer and slag without n Total volume, which is at the boiling temperature of the thermostatic Vt, v, .iV-v Calculation of the temperature along the length of the tube 8 shows that it is possible 1/3 its volume is attributed to the temperature - L, and 2/3 of the volume - to room temperature ature at which the gauge is located. The total volume at room temperature is V V -V,. m 3 TP Partial pressure of dry gases e of incineration and thermostating at natal temperature p p – p c o fe P - total pressure measured for this state; p is the part of moisture that builds up the volume and is determined by the tables of saturated steam at room temperature. According to the tables of dry saturated steam, the temperature b is consistent with barometric pressure. Volumes are brought to a pressure of 1 cm and room temperature (t ° C). The reduced volume of dry gases of burning V P V-, s.c p. &amp; The reduced volume (+ tp) of the process of boiling water in the thermostat) Here is the partial pressure of dry boils of the process of boiling water in the R-termote P. P-P le r p - the total measured pressure in the process of boiling water in the thermostat. Measured pressure is the sum of the manometer and barometer drums, Reduced volume of dry gases in V, at temperature t V –V С C For dry gases in volume V equilibrium of the conditions given and at the pool of water in the thermostat will be Row, with deletion VjdgT tc a73 , i 275/6 ° + as Then the partial pressure of superheated steam in the volume V, temperature -t. -Р. in I.-ti For state i, and P "is determined from the tables of superheated water vapor its specific volume V.- i The desired moisture content Q D An example of the implementation of the method for determining the moisture content of the pyrotechnic composition (22% by weight of zirconium and 88% chromium bari), made in the form of washers burned in a calorimetric bom in an environment of gels. The barometric pressure is -1.003 kg / cm, the temperature to water is 99.1 ° C. The absolute pressure of both thermosets is PO 1.429 kg / cm p 2.533 kg / cm V -287.28 + 2.0 + 20.0 - 1 , 4 307.84 cm Vr -287.28 + 1 / 3-2 - 1.44 286.5 cm,. + 2 / 3-2 21.34 cm At 25 ° С РДЮ, 032 kg / cm - 1429 - 0, 397 kg / cm I 1.397 307.84430 cmЗ, V ic V | 4p 2.533 - 0.032 21, 34 53 , 5 cm, 43 -53.5 -376.5 P - tc (273.l6 + ti) cti-V (273.16-fc 25 °) + 376.5 (273.16 + 99.1) 28TiT5dB + 1ГГ P -P -P 2,533 - 1,67 b 0.863 kg / cm According to the tables of superheated steam V „2.133 where does the moisture content? -The possibility of obtaining steam in a superheated state, which is controlled by checking the tables of superheated water vapor, depends on the volume bombs, the temperature of the thermostatic fluid, the amount of the substance being burned and its moisture, which is established during the design of the study. At the proposed facility, it is possible to simultaneously determine the volume of evolved gases. Claims The method for determining the moisture content in the combustion products of a calorimetric bomb consists in determining the partial pressure of superheated steam in a gas mixture, characterized in that, in order to increase the accuracy and reliability of the determination, moisture in. gas mixtures are converted by heating in an isochoric process into superheated steam, and then the partial pressure of the superheated steam and its specific volume are determined by the ratio of the measured temperature and pressure before N after heating. Sources of information taken into account in the examination 1. Guben-Weyl, Methods of organic chemistry. M., 1967, p. 792, 2.Litvin A, M, Technical thermodynamics. M., 1947, p. 205 (prototype)   Nanometer O5razi, OTt10 .2Q-- 50