SU1065734A1 - Gas volume determination method - Google Patents

Abstract

A METHOD FOR DETERMINING A GAS VOLUME, including creating a pressure differential in a measured flow of the test mixture, separating a gas from the mixture in with measuring the parameters of the mixture and gas before and after creating a differential pressure, and then determining the volume of the gas that differs. y and so that, in order to increase the total crush of the instantly mixed mixture with a current of forms of accuracy of determination due to the release of gas from the gas – liquid mixture, the measured flow is divided into the main and auxiliary ones, the first of which is expanded the released gas is withdrawn from the oncoming stream, the differential pressure is generated in the auxiliary flow, and the gas volume is calculated from the flow volume of the gas-liquid mixture that is to be measured; volumetric flow rate after degassing; gas pressure at the withdrawal point after instantaneous expansion; gas pressure at the point of entry into the auxiliary stream; constant coefficient.

Description

The invention relates to a measurement technique, in particular to the measurement of the gas content of a gas-liquid mixture.

A known method for measuring the volume of gas contained in a moving mixture of liquid and gas is that a sample of the liquid is placed in a press, compressed and a volume of gas contained in it 1 is determined by changing the volume of liquid.

However, when a liquid sample is taken, its flow is disturbed and the gas content in the liquid changes, which. affects measurement accuracy.

The closest to the present invention is a method for measuring the volume of gas contained in a moving mixture | Liquid and gas, which consists in using the dependence of the volume of gas on the pressure change by creating a moving mixture on the measured section of the differential pressure and simultaneously measuring the value of the pressure and the volume of the mixture to after throttling, substitution of the obtained values in the formula and the determination of some value for the change in gas volume at the measured points; kak 2J.

However, in this method there is practically no possibility of complete. releasing the contained gas and gas-liquid mixture on the stream, therefore, changes in the gas volumes at the measured points to determine the desired value are distorted. This significantly reduces the measurement accuracy. Measuring the volume of gas contained in a moving gas-liquid mixture by creating a pressure differential in its path leads to a decrease in the capacity of the measuring section due to the fact that the pressure drop of the moving gas-liquid mixture causes a sharp increase in pressure loss in the pipeline.

The purpose of the invention is to improve the accuracy due to the complete release of gas from the gas-liquid mixture.

The goal is achieved by the fact that according to the method, which includes creating a pressure drop in the measured flow of the test mixture, separating out the gas from the mixture and measuring the parameters of the mixture and gas before and after creating the pressure drop, then measuring the volume of gas is divided into the main and auxiliary in the first of which instantaneous expansion of the test mixture is carried out, the released gas is withdrawn to the auxiliary flow, the pressure drop is created in the auxiliary flow, and the volume of gas is calculated from pho rmule

Q: Q

cm Q.iijp;

where the volumetric flow rate of the studied gas-liquid mixture;

Q is the volumetric flow rate after degassing;

P-, is the gas pressure at the outlet point after instantaneous expansion;

P is the gas pressure at the point of entry into the auxiliary stream; jb is a constant coefficient.

3 of the proposed method, by dramatically expanding the gas-liquid mixture in the expansion chamber, creating the possibility of completely releasing gas from the mixture and venting the released gas from this into the injector, due to the pressure differential between them, a significant increase in the measurement accuracy and a sharp decrease in the pressure differential over the measured section, an increase its throughput, as well as by measuring the pressure of the released gas in the expansion chamber, is obtained by the value of the elasticity of the saturated. vapor moving gas-liquid mixture.

The flow rate of released gas from the expansion chamber to the injector is determined by the formula

(I

and the gas factor in the main flow

. then the volume of gas in the moving gas-liquid mixture is

"R Sc" f

(The solutions of equations (1) - (3) together obtain the required volume of gas, depending on the measured parameters.

The figure shows the measured section with a common inlet 1 of the gas-liquid mixture branched into the main stream 2 with the expansion chamber 3 and the auxiliary flow 4 with the injector 5 on the line with flow meters b and 7, gauges 8 and 9, shut-off members 10 and 11. The expansion chamber 2 and the injector 5 are connected by pipeline 12. In the expansion chamber 3, the main flow pipeline ends with the nozzle 13, and the injector 5 has a mixing chamber 14, a nozzle 15 and a suction chamber 16.

The method is carried out as follows.

The moving gas-liquid mixture, the flow rate Scm of which is measured by the flow meter b, is divided into main 2 and auxiliary 4 streams. The main T1OTOK. 2, the gas-liquid mixture through the nozzle 13 expands sharply in the expansion chamber 3. Under conditions of abrupt expansion, a complete and intensive release of gas from the moving gas-liquid mixture occurs. The pressure in expansion chamber 3 is measured by a pressure gauge 8. The flow of degassed liquid after chamber 3 is measured by flow meter 7. The gas evolved from the gas-liquid mixture from chamber 3 is sucked through pipe 12 by injector 5, installed HtoM on the line of auxiliary flow 4, which is connected to the main the flow in section 14. A steady flow of released gas from chamber 3 to injector 5 is provided as a result of a pressure differential (P., - Pj) between them. The pressure in the expansion chamber 3 (P) and in the injector 5 (P2 I is measured by pressure gauges 8 and 9, respectively. The value of the elastic vapor of the moving gas-liquid mixture is measured by pressure gauge 8 with shut-off members 10 and 11 closed. On the lines of the auxiliary flow 4 and gas pipeline 12.:

Example. Take the instrument readings:

the flow rate of the gas-liquid mixture QC, at the inlet of the measuring section and the liquid after the chamber 3, the expansion of QTC is 520 and 180 pressure P. and 2 in the expansion chamber 3 and all, respectively. chamber 16 of the injector 5, respectively, 1500 and -100 mm.vod.st; constant coefficient d for this device in gas-liquid mixture, selected from tabular data

is equal to 9. Therefore

flSOOO - i-lOOj

“R - 520 Qy. .

In the proposed method, the elasticity of the moving gas-liquid mixture is measured by a pressure gauge 8 with the closure bodies 10 and 11 closed. lines of auxiliary flow 4 and gas pipeline 12. For example, its value in this case is equal to P $ 13,320.

The presence of an expansion chamber ensures complete evolution of the gas contained in the gas-liquid mixture and

0 increases the performance of the pipeline in comparison with the known diaphragm, which does not allow to increase the productivity of the pipeline; since the proposed method

5 ensures the complete release of gas from the gas-liquid mixture in the expansion chamber, the accuracy of measuring the volume of gas contained in the gas-liquid mixture is higher than in the known method and is within the limits of the accuracy of existing flow meters. In addition, the proposed method provides a measurement of the elasticity of the saturated vapor of the gas-liquid bone mixture, since the expansion chamber provides for the complete release of gas contained in the gas-liquid mixture.

Claims (1)

METHOD FOR DETERMINING GAS VOLUME, including creating a pressure drop in the measured flow of the test mixture, extracting gas from the mixture with measuring the parameters of the mixture and gas before and after creating the pressure drop with subsequent determination of the gas volume, characterized in that, in order to increase the accuracy of determination for due to the complete evolution of gas from the gas-liquid mixture, the measured flow is divided into the main and auxiliary in the first of which instant expansion of the test mixture is carried out, the released gas is taken into the auxiliary flow, pressure drop is created in the auxiliary flow, and the gas volume is calculated according to the formula ^{r with} where Axis ^{is the} 'volume flow rate of the investigated6 gas-liquid mixture; βχ is the volumetric flow rate of the liquid after degassing; P-t - gas pressure at the outlet point after instant expansion; P ₂ is the gas pressure at the point of entry into the auxiliary stream; β is a constant coefficient. SU, „. 106573