Trace amounts of co and co in a high-concentration gas 2 Quantitative analysis method

Abstract

The invention discloses a trace amount of CO and CO in high-concentration gas 2 The quantitative analysis method, through the online monitoring of the elution window of the high-concentration gas behind the chromatographic separation column and combined with the switching of the two-position valve position, can realize the timely and simple adjustment of the high-concentration gas cutting program, which solves the problem of high concentration of the chromatographic column after years of use. The disadvantages caused by the difficulty of determining the concentration gas elution window; the repeatability of trace gas analysis is also improved by using forward blowing instead of back blowing. This process is very suitable for samples with high concentrations of hydrogen chloride, chlorine and sulfur hexafluoride, which are harmful to some chromatographic columns, online reaction columns, or detectors of GC. It is suitable for both laboratory analysis and industrial processes. analyze.

Description

Technical field [0001] The present invention belongs to CO and CO 2 The field of detection technology involves the quantitative analysis of trace amounts of CO and CO in high concentration gases using gas chromatography 2 method. Background [0002] In production and quality control, trace amounts of CO and CO in high concentration gases 2 Quantitative analysis is a common problem, and the use of gas chromatography (GC) is a very effective means. However, high concentrations of gases can sometimes saturate the detector suitable for trace gas detection, or inhibit the detection signal of other co-existing trace gases, or cause damage to subsequent separation columns, or damage to in-line reaction columns introduced to improve the sensitivity of trace gas detection. In order to deal with the drawbacks or possible brought about by this high concentration of gas, there are usually two ideas to guide the solution of the problem, one is to separate the high concentration of background ...

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Problems solved by technology

[0003] The above-mentioned GC techniques and methods have solved some problems to a certain extent, but disadvantages have been found in practical work: (1) In order to cut the high-concentration background gas out of the GC detection system, all of them are pre-processed in the chromatographic column without exception. After separation, the operation of switching the valve position is used to realize the operation, and the timing (time) of this operation is very important, and this moment is generally determined by the instrument manufacturer at one time according to the specific use status of the chromatographic column at that time. The method of building an intermediate detection system to obtain this moment is either at the cost of trial and error that bears some kind of damage, or at the expense of the inconvenience of setting up an ad hoc detection system, which causes great inconvenience to the tester; more troublesome What is interesting is that the conversion moment is not fixed, it is closely related to the specific type of chromatographic column and the length of use, etc. It changes gradually with the increase of the use time of the chromatographic column, and the change is greater after the replacement of the chromatographic column. The timing of this conversion must be adjusted in time, and this "notification" is generally issued by an experimental accident of "behindsight", and the adjustment of this conversion time is as difficult as its first acquisition

(2) High-concentration background gas is generally discharged from the chromatographic column and detection system by backflushing. Backflushing will cause two disadvantages. One is that backflushing will bring turbulent fluctuations to the airflow flowing in the chromatographic column, thereby affecting Because of the movement of the substances flowing out of the chromatographic column due to high-concentration gases in the chromatographic column, it will eventually affect the retention time of the separation and the repeatability of the chromatographic peak area. Second, backflushing is not conducive to maintaining the uniformity of the stationary phase inside the chromatographic column, thus Affect its performance and life

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