SU711446A1 - Method of determining gas content - Google Patents

Description

The invention relates to the field of technical physics and can be used to determine the moisture content of a gas.

A psychrometric method is known, based on the measurement of temperatures by two thermometers: dry and wet and wet a tank wetted with water, and found in thermodynamic equilibrium with a Kpsoc gas medium. Evaporation from the surface of the tank of a wet thermometer is the more intense the lower the gas humidity, the difference between the readings of a dry thermometer depends on the value of humidity 1.

The closest technical solution to the invention is a method for determining the moisture content of a gas, including its cooling below the dew point and separation of the condensed moisture 2.,

A disadvantage of the known method is a longer duration for the condensation of a sufficient amount of water and a low accuracy. Moreover, this time is significantly increased, and the accuracy is reduced with a small amount of water vapor:. The known method is unacceptable in the case of

changes in vapor content over time.

The aim of the invention is to ensure continuity of determination and increase accuracy. This is achieved by passing the wet gas successively through two pre-calibrated capillaries, registering the pressure loss in them after the gas is released from the first capillary, is cooled, the condensed moisture is separated and the remaining moisture is absorbed. but by The gas content of the components is analyzed from the second capillary and, according to their specific weight and pressure loss on the capillaries, the moisture content is determined according to:

-feWb -4ac

20 2a

The proposed method is implemented by the construction shown in the drawing.

In the drawing, thermostat 1 is shown, in which capillaries 2 and 3 are placed with coils 4 and 5, between which there is a refrigerator-condenser b, a moisture separator 7 and a moisture absorber 8 outside the thermostat. Capillaries are connected to ratios 9 and 10. Wet the gas to be analyzed is supplied to the device via line 11, and dry gas is removed from the device via line 12, wet and dry gas lines (capillaries 2 and 3 coils 4 and 5, refrigerator b, moisture separator 7 and desiccant 8) to simplify the determination ( calculation of gas humidity - monosta tirovi ni. A wet gas line is connected to the line 13 of the granulating gas through a stop valve 14. The essence of the method is as follows. The wet analyte gas (pre-filtered from dust) is passed through a coil 4, and a capillary p 2 where gas pressure losses are equal; , p ... | j where; 4a is the resistance factor of the capillary 2; Wg — velocity of wet gas, m / s; specific gravity of wet gas, kgf / M j g - acceleration due to free fall, m / s. The pressure loss (differential pressure of a humid gas on the capillary 2) is recorded using a differential meter 9. Next, the analyzed gas is cooled below the dew point in the condenser 6, the condensed moisture in the moisture separator 7 is separated and the Residual moisture is absorbed in the desiccant 8, whereupon the dry test gas is passed through the coil 5 and the capillary, where the gas pressure loss occurs, which is (a) where: - the resistance of the capillary 3; We- speed of gas suzkzgo, m / s; “JTc is the specific gravity of dry gas, kgS / m. The pressure loss (pressure drop of dry gas; on the capillary 3 is recorded using the differential meter 10. After the capillary 3, the dry gas is analyzed for the components and the gas humidity is determined as follows. After passing through the capillaries 2 and 3, pre-pass any dry gas ,, Go you can get the dependence of the loss of gas pressure on the capillaries 2 and 3 at different flow rates in the form of dependencies:) (M where V is the flow rate of dry calibration gas under normal conditions, i.e. at T 273 ° K and P 760 mmHg RZ lRz pressure loss of dry gauge ase when passing th through the capillaries 2 and 3, respectively, at the temperature of the calibration gas T and its pressure P, rf / m. When the wet gas with a unit weight Jg passes through the capillary r 2, the temperature T-in and pressure Rdr a certain flow rate of this gas wipe the pressure with regard to (1) will be avny: ..3600-F a V aV V P.TT -T. ° in R. t the cross-sectional area of the capillary 2, and -Jbe- - consumption of the analyzed gas and its specific gravity under normal conditions. Thus dr-fe r ° UL. . 2 1 БОТТ | ОБ OBT Td (6) Similarly, we obtain the dependence for the pressure loss of the same gas, but dry, on the capillary, 3: where: Vp and - is the flow rate of the dry analyzed gas and its specific weight under normal conditions; Fg is the cross-sectional area of the capillary 3, m. For calibration conditions, these pressure losses will be equal to: / .ОГ2 У 2§ГЭ6ОО-Р2 /% Г where: Vpyr and flow of calibration gas with a specific weight equal to (7) by (6 ) taking into account the fact that in c we will have: fe / o V PO .L fv t For the conditions of the calibration, e "is equal to; I L Pg-Tr G-5OsYa: / OG T F fc G V7 Y 2 V SSSFjTor p; l G So we will have -Y7oc.j-P l V oB / lo -b But since. 2 MF OO-NPON bc m -r loo too-r Therefore V.Vjood: fj% r2 f roi9oo-rH, °° -7-o where; - percentage of water content in the wet gas analysis; The effective weight of paro under normal physical conditions Taking into account the TorOf that, .2.M p., Where: K., Kj2 are the coefficients of pa for capillaries 2 and 3 I1, respectively, are equal to:. .: / g 2.3bOo-F / / 2-2g-.3600-P will have: Aoo-gy. vi - .yr 00 / VK / d: 400Tc Solving the last equation, we get; -toV-k 4ac Gx OO-gi

and Tftci

where

(), - m. „,

shtg .rvf-K f / uPftJ

c is the specific gravity of dry gas, kg / nm; 7yl specific weight of i-ro component,%, ToNaO 0.084 - the specific weight of water vapor, kg / nm. Thus, the essence of the method is as follows. Before passing the tested gas to the black capillary gas, the functional dependence of the pressure loss DP-j and iR on the flow rate of dry (any) calibration gas is determined. In this case, the flow rate of the dry calibration gas is not necessary to fix, since further calculations require knowledge of the value of the quantity. / K., (-) consl, defined by its “) d from the slope of the dependence P –fCAPj). Provided, r zUJ Further, the wet pelvis is passed through a capillary perv1 and recorded uPg, cooled at the outlet of this capillary, the condensed moisture is separated, absorbed residual moisture (moisture of a saturated moist gas), passed through, the expanded gas through the second capillary and recorded here LR analysis of dry gas is carried out on the components upon its exit from the second capillary (with insufficient capacity of the capillaries, gas is taken for analysis up to the first capillary; when using automatic gas analyzers, the removal of gas the analysis is performed after the second capillary), the specific gravity of the dry gas is calculated and the moisture content is determined from the above plot. PRI me R. Dry argon was used as the test gas, which was deposited in a moisture sensor at the saturation temperature tg, and then passed through the device shown in the drawing. Preliminarily, dry gases were passed through capillaries and found dependencies for the following gas: aprcwa 1,784 kg / nm5; 1,968 kg / nm; and nitrogen1.25 kg / nm and hydrogen with a pH of 0f09 kg / nm. At the same time, the gas pressure losses in capillaries 2 and 3 were recorded at V different flow rates of these gases. The data are given in, table 1. . T and l and ts and And

Continuation of table 1

f) - the number of divisions on the flowmeter installed in front of the device for recording the relative flow rate of dry calibration gases. From the data of table 1 we can conclude that for the same consumption of dry calibration gas, the ratio:

DRA

LR.

10 After that, a valuable gas was passed through the device wet (ar. Gon) and the generated humidity was determined by temperature, saturated, and the desired one according to (16). The results of the research are given in table 2. 2: humidity gTable2

for, determined by the temperature of the saturated moist gas (argon); gas humidity determined by the proposed method; . and A, the otgoi, respectively, is an absolute and relative error in determining the moisture content, which is caused, in all likelihood, by the inaccuracy of determining the temperature of the saturated moist gas. In this way, it is possible to determine not only the content of water vapor 6 of any gas, but also its content. vapors of another substance, if instead of TpQ o, in dependence (16), we substitute the value of the specific weight of the pa) s of this b

Thus, the proposed method for determining the moisture content of a gas allows the determination of the moisture content of the gas continuously, since the values of DRS H P, the continuous transmission of gas through the device, can be recorded continuously; analysis of dry gas (gas at the exit from the second capillary), and other computational operations can also be performed continuously. ...

Claims (2)

1.Berliner M.A. Measurement of humidity, M., Energia, 197s3, pp. 206-209. 2. Handbook of dust and zoleulavlivanyu. Ed. A.A.Rusanova, M., Energy 1975, pp. 34-35 (prototype).