SU1511664A1 - Apparatus for measuring non-methane hydrocarbons in gases - Google Patents

Abstract

The invention relates to the field of gas analysis, in particular to the analysis of non-methane hydrocarbons in the atmosphere. The aim of the invention is to improve the accuracy and reliability of the device and reduce power consumption. In the device with two flame ionization detectors (DIP), two adsorbers and three pneumatic resistances, a fourth pneumatic resistance, similar to the third one, and a tee are introduced. The tee is connected to the input of the first DIP and the outputs of the third and fourth pneumatic resistances, and their inputs are connected to the outputs of the adsorbers. 1 il.

Description

The invention relates to gas analysis and can be used to measure the concentration of non-methane hydrocarbons in the atmospheric air, in the air of industrial premises and other environments.

The purpose of the invention is to improve the accuracy and reliability of the device, as well as to reduce the power consumption.

The drawing shows the principle of the proposed device.

The device contains two flame ionization detectors 1 and 2, two regenerable adsorbers 3 and 4, two heaters 5 and 6 installed on the adsorbers, solenoid valves

7 and 8, the connecting inputs of the adsorbers with the device inlet and discharge into the atmosphere, pneumatic resistances 9 and 10 at the outputs of the adsorbers, pneumatic resistance 11 at the inlet of the flame ionization detector 2, pneumatic resistance 12 connected between the outputs of the adsorbers 3 and 4 , tee 13, electrometric amplifiers 14 at the output of detectors 1 and 2, microprocessor device 15, recording device 1b and fan 17 mounted on adsorbers 3, 4.

The device works as follows.

The analyzed air through the valves 7 and 8 alternately (in accordance with

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commands of the microprocessor device 15) goes to one of the adsorbers 3 or 4, where all hydrocarbons, except methane, are absorbed. The gas flow sample through one of the pneumatic resistances 9 or 10 and the tee 13 enters the flame ionization detector 1, where the concentration of methane is converted into an electrical signal, al. The current of the detector is amplified by one of the electrometric amplifiers 1. Amplified signal--. The residue, which corresponds to the methane concentration in the analyzed gas, is processed by the microprocessor device 15 and recorded by the device 1b.

In the first half-cycle of separation, the valve 7 passes the analyzed gas under pressure through the adsorber 3. Next, the gas flow is divided into two parts at pneumatic resistances 9 and 12. Part of the sample-gas, purified from higher hydrocarbons, containing only methane, through pneumatic resistance 12 is fed to the reverse purge of the adsorber 4 and through the solenoid valve 8 is discharged into the atmosphere. The rest of the gas flow through the pneumatic resistance 9 goes to the tee 13, and from there to the flame ionization detector 1. It is essential that in this half-cycle the gas sample from the tee 13 will go to the detector 1, but will not go through pneumatic resistance 10, since the pressure at both ends is practically equal to atmospheric pressure, on the one hand due to direct communication through tee 13 with detector 1 operating at atmospheric pressure, and on the other, due to communication through adsorber 4 and valve 8 with discharge into the atmosphere.

In the second operation cycle of the device, the analyzed air under the same pressure as in the first half cycle enters through the valve 8 to the adsorber k. Then one part of the air through the resistivity 12 is fed to the back blow of the adsorber 3 and then through the valve 7 to the atmosphere,

and the rest of the analyzed gas through the pneumatic resistance 10 and the tee 13 enters the flame ionization detector 1. In this case, the air flow

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through pneumatic resistance 9 will not flow, since the pressure at both its ends is equal to atmospheric.

Note that the consumption of the sample gas to be analyzed is. the entrance to the detector 1 is constant in both half-cycles of operation of the device due to the equality of the pneumatic resistance values 9 and 10 and the constant value of the input pressure.

The regeneration process is carried out using heaters 5 and 6 and fan 17 under the control of the microprocessor device 15 as in the prototype.

The total concentration of hydrocarbons in the analyzed gas is measured using detector 2, the signal of which is amplified by one of electrometric amplifiers k, processed by microprocessor device 15 and recorded by device 16. Using microprocessor device 15, total concentration of hydrocarbons without methane is calculated and also recorded by device 1b.

Claims (1)

Invention Formula about A device for measuring non-methane hydrocarbons in gases, containing two parallel-connected adsorbers, electromagnetic valves installed at the inputs of adsorbers, two flame-ionization detectors, the first of which is installed at the outlet of the adsorbers, and the second detector through the first pneumatic resistance is connected to the device entrance, the second pneumatic - Matical resistance included between the outputs of the adsorbers, and a third pneumatic resistance, characterized in that, increasing the accuracy and reliability of the measurement device, the fourth pneumatic resistance equal to the third one, and the tee, the output of which is connected to the INPUT of the first flame ionization detector, and the inputs are connected to the outputs of the third and fourth pneumatic resistances, the inputs of which are connected to to the outputs of the adsorbers.