SU1080077A1 - Method of measuring hydrogen partial pressure - Google Patents

Abstract

A METHOD FOR MEASURING PARTIAL PRESSURE OF HYDROGEN IN GAS BY MEASURING THE CURRENT, Passing 1T1 of it through a sensitive element consisting of a solid proton electrolyte coated on its end surfaces with hydrogen absorbing material electrodes, characterized in that, in order to improve accuracy, before measuring electrodes They are polarized with a voltage selected from 100 to 480 mV, and crystalline sodium bisulfate is used as a solid proton electrolyte. (L 00

Description

The invention relates to electrochemical gas analysis methods and is intended to measure the partial pressure of hydrogen in gaseous mixtures, where necessary, to carry out a fast and continuous control of the composition of the gas. ; A known method for measuring the partial pressure of hydrogen in a gas mixture is based on the property of hydrogen to reduce oxides to a metal. The amount of hydrogen is judged on the reduction of metal oxide analyzed by gas by the reduction reaction. The method is based on a direct, proportional dependence of the amount of reduced metal on the amount of hydrogen and the sample being analyzed. Cl3 times. The disadvantages of this method include inertia (response time 5-10 min) and low sensitivity. The closest to the invention is a method for measuring the partial pressure of hydrogen in gases by measuring the current passing through a sensitive element consisting of a solid proton electrolyte coated with platinum electrodes P2} on its end surfaces. . . , The disadvantages of this method are that it has a high inertia, low. accuracy of measurements and low selectivity. The purpose of the invention is to improve measurement accuracy. I The goal is achieved by the method of measuring the partial pressure of hydrogen in gases by measuring the current passing through a sensitive element consisting of a solid proton electrolyte with electrodes from a material that absorbs hydrogen before its measurements. The electrodes are polarized with a voltage selected within 100.480 mV, and crystalline sodium bisulfate is used as a solid proton electrolyte. The range of polarized voltage values is limited by the following conditions: at voltages below 100 mV, a sharp drop in the current value to the level of background currents occurs; at a voltage of 480 mV, hydrogen is released at the electrodes, as a result of the electrochemical decomposition of NaHSO, which leads to a decrease in the sensitivity of the sensor, and with time to its chemical degradation. The method has limitations on both the upper and the lower limit being measured; pressures. The lower limit may be limited by the STJOBHeM of the electronic conductivity, if it is relatively large (and IO), and if it is not immeasurable, then it is due to the minimum current that the meter can measure on the equipment. . The upper limit of measurement is due to the conductivity level of the proton electrolyte on the main current carriers, since when the hydrogen pressure is too large, the current is limited not by the delivery of protons to the electrolyte, but by the speed of their transfer through the electrolyte. To implement the proposed method, a sensitive element with a solid proton crystal of sodium bisulfate electrolyte has been developed. The drawing shows a diagram of the sensing element. Electrodes 2 from a material that absorbs hydrogen are deposited on the surface of electrolyte 1. This may be SsiTb-palladium, nickel, graphite, and others. A constant voltage is applied to the electrodes 2 from the extrusion source 3 of direct current. The current flowing through the black; ee electrolyte is changed by the gauge 4. To increase the electrical water content, the crystalline bisulfate is heated by heater 5 to 90 110 ° C, while its specific electrovoreness reaches values of 0. At lower temperatures, the electrical conductivity is too low, which leads to a decrease in the limits of measurement of the sensitive element, and at more high temperatures than the crystal thermally degrades c. loss of all useful properties for this device. For example. The sensing element consists of crystalline sodium bisulfate with graphite electrodes deposited from a suspension of finely dispersed graphite in an organic binder. The crystal is heated to increase its proton conductivity and is polarized for a long time (24 hours) at a constant voltage of 450 mV. During the polarization time, the current measured by the IMT-05 instrument drops from the beginning to A in the establishment of a stationary value. The sensitive e.ent is in a vacuum of 10 -10 Torr. After polarization, an analyte gas containing hydrogen is introduced into the system. Already at

310800774

the partial pressure of the sr-torr current

increases to the new stationary sensitivity method

values of 2–10, with Pu Ju, the torus increases by 3 orders of magnitude, the provision increases to, and the selectivity with respect to

10 torr - up to 5 ,. to hydrogen.

Claims (1)

METHOD FOR MEASURING PARTIAL PRESSURE OF HYDROGEN in gases by measuring the current passing through a sensitive element consisting of a solid proton electrolyte with electrodes deposited on its end surfaces made of hydrogen absorbing material, characterized in that, in order to increase accuracy, the electrodes are polarized with voltage before measurements , selected in the range of 100 - 480 mV, and crystalline sodium bisulfate is used as a solid proton electrolyte. 1080077 2