Method for detecting content of carbon dioxide in natural gas

Abstract

The invention discloses a method for detecting content of carbon dioxide in natural gas. The technical scheme is as follows: the content of the detected component of carbon dioxide is used on a GDX-502 packed column so as to obtain good separation effect and present special signals, the signals are detected by a helium ion detector (HID) and form an obvious absorption peak, and experiments show that the peak area of the formed carbon dioxide content and the content thereof are in direct proportion, therefore, the peak area of the carbon dioxide in standard gas and the content thereof are made in standard work curve, then steel cylinders with sample natural gas are connected to gas chromatography through a special stainless steel tube and a needle valve for detection so as to obtain relevant peak area, and finally, the carbon dioxide standard curve well prepared is invoked, an instrument can directly read and calculate the content of the carbon dioxide in the sample natural gas through an external standard method. The method is used for detecting the content of the carbon dioxide in the natural gas, and has the advantages of being simple in sampling, convenient in operation, rapid in analysis speed, high in detection accuracy, and low in method detection limitation.

Description

technical field [0001] The invention relates to a method for detecting impurities in gas, in particular to a method for detecting carbon dioxide content in natural gas. Background technique [0002] Natural gas is a high-quality energy source with large reserves, convenient transportation, low cost, clean and ash-free, high calorific value and low environmental pollution from combustion products. Therefore, it is an ideal source of urban gas. Judging from the trend of energy utilization in the world, the use of natural gas as the main source of town gas has become the current development direction. In my country, for more than a decade, all cities with good conditions, such as Tianjin, Chengdu, Beijing, etc., have successively sent natural gas from adjacent oil and gas fields to urban areas through pipelines as a source of gas for towns. [0003] The main component of natural gas is methane (CH 4 ), among various hydrocarbon molecules, its ratio of carbon atoms to hydrogen...

AI Technical Summary

Problems solved by technology

In the existing domestic natural gas standards, it is proposed that the quantitative index of carbon dioxide should not exceed 3% (volume fraction), but they are all detected by the thermal conductivity detection device TCD, and the detection repeatability of the thermal conductivity detection device TCD is poor, and low content Carbon dioxide can hardly be detected, so that it cannot provide real quality control for the pipeline transportation of natural gas; at the same time, long-term sample injection detection leads to the accumulation of carbon dioxide on the analytical column, and this long-term accumulation will contaminate the tested samples, making the The detection of samples loses its accuracy and true meaning; however, it is not necessarily thorough when dealing with these accumulations, and the operation is cumbersome, which is not conducive to the popularization of detection methods, etc.

Images