SU1012099A1 - Method of quantitative determination of gases diluted in liquid - Google Patents

Abstract

A method for determining the amount of dissolved gases in liquids by transferring them into a carrier gas stream passed under pressure through a porous diaphragm and liquid, characterized in that, in order to improve the accuracy and performance of the analysis, the pressure of the carrier gas stream is changed in pulsatory mode.

Description

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The invention relates to the analysis of a substance, in particular to the determination of gases dissolved in liquids, primarily in metallurgical and other melts, and can be used in metallurgy for the determination of gases directly in liquid metals. There is a method according to which a carrier gas is introduced through a hollow shaft rapidly rotating inside a liquid with ribs for mixing the liquid and dispersing the supplied gas. However, this method is technically difficult to implement, especially in the case of purging melts that destroy the structural materials. Closest to the invention is the method of bubbling the entire volume of liquid with carrier gas bubbles under Pressure through a diaphragm with holes or a porous diaphragm according to which a liquid is placed in a vessel with a bottom made in the form of a diaphragm. The carrier gas is injected under the diaphragm at a given pressure (flow rate); 2. However, in this case, the released gases are strongly diluted with a carrier gas and the measurement accuracy of their amount is insufficient. In addition, it is not possible to fabricate a diaphragm with absolutely identical holes. Therefore, if the pressure of the carrier gas under the diaphragm is small, which corresponds to a small flow rate, then the carrier gas enters the liquid only through a few of the largest openings. It degasses a limited portion of the liquid and mixes it poorly. This leads to prolonged and incomplete degassing, t With an increase in the pressure of the carrier gas, its bubbles begin to emerge from most of the holes in the diaphragm. In this case, the liquid rapidly degasses but an increase in pressure leads to an increase in the flow rate of the carrier gas, and as a result of this, to a decrease in the accuracy of the analysis. The purpose of the invention is to improve the accuracy and productivity of the analysis. The goal is achieved by the fact that, according to the method, the delays in the transfer of gases dissolved in liquids into a flow of carrier gas, passed under pressure through a porous diaphragm and liquid, the pressure of the flow: the carrier gas is pulsed. This ensures that carrier gas bubbles exit the entire surface of the diaphragm without increasing its flow rate. The drawing schematically shows a device for implementing the proposed method. The device includes a gas-carrier cylinder 1, a pressure relay 2, a fine adjustment valve 3, a pipeline 4 with an electronic valve 5 placed on it, a diaphragm 6 installed in the vessel 7. The method is carried out as follows. The flow of carrier gas from cylinder 1 is controlled by means of a pressure switch 2 and a fine adjustment valve 3. Block pipe 4 in front of diaphragm 6 with electronic valve 5. At the same time, carrier gas accumulates in the pipeline in front of the valve or in a special storage tank. The pressure of the carrier gas is increasing. Having opened the valve for a short time, the carrier gas is vented through the diaphragm 6 and the valve 5 is immediately closed in order to accumulate the next portion of carrier gas under pressure. The process is repeated as many times as necessary with the automatic control of the solenoid valve 5. The pressure in front of the valve 5 and the time during which the valve is closed is determined experimentally so that, when bleeding off, the carrier gas goes through most of the orifices in the diaphragm. The total flow rate of the carrier gas does not increase, and the efficiency of liquid degassing increases due to splitting the flow into a large number of bubbles, i.e., the liquid-gas interface increases and the efficiency of mixing by the liquid bubbles increases. Gas analyzers that are not sensitive to pressure fluctuations in a carrier gas flow, such as an analyzer AH 7560, are used to measure the amount of gases emitted. For example, analyzer AH 7560. Example. The content of carbon dioxide in a water-alcohol solution is determined by purging with nitrogen with an increased flow rate of 30 ml / min on a glass porous filter with a diameter of 40 mm sintered from 1 mm particles. The results of the analysis of the method carried out are tabulated.

Thus, as can be seen from the table, an increase in accuracy is achieved.

by 10% and an increase in productivity by 5 times.

Claims (1)

METHOD FOR DETERMINING THE NUMBER OF GASES DISSOLVED IN GAS LIQUIDS by transferring them into a carrier gas stream> passed under pressure through a porous diaphragm and a liquid, characterized in that, in order to increase the accuracy and productivity of the analysis, the pressure of the carrier gas stream is changed in a pulsating mode. »0 * ··· · * · ** · ··· * · * · ·· * · ***** · * < Eve about ov in about vvvvv · · “· aoooooo in“ ooo in her® eee oev wow ooo oo in ev ev · in eee “ I T X 1 Ι · ί · 4 »* * · * · * · * ·. 11 u I w 11 p and 1 ipnnshk :: SU,. ,, 1012099