Ask for advice on analyzing instrument problems
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Please tell me my friends: 1. What are the gas measurement principles of mass spectrometers, chromatographic analyzers, thermal conductivity analyzers, and infrared analyzers? 2. For a mixture of carbon monoxide, carbon dioxide, hydrogen, and methane, which method can be used to accurately measure the content of these four gases? 3. What is the sensitivity of mass spectrometer, chromatograph, infrared and thermal conductivity measurements? (That is how long it takes from when they detect the gas to when the result is displayed on the DCS) Thank you very much! Looking forward to getting an answer soon!
I think the main motivation of the poster is to know how to analyze the four mixed gases of carbon monoxide, carbon dioxide, hydrogen, and methane. I think GC (gas chromatography) should be a better choice. Gas chromatography has several detectors, commonly used ones include conductivity, FIR, etc. The simple principle is to use different retention times of different gases in the gas phase column to separate and detect them separately!
CO/CO2/CH4/H2 can be measured with a gas chromatograph, and their respective components can be measured using a TCD detector and TDX-01 as a chromatographic column. The order of peaks is N2+Ar, CO, CH4, CO2. H2 can be found by difference subtraction method.
Yes, you can use a gas chromatograph to measure the concentrations of these four gases, but one thing to note is that you must use a chromatograph based on the TCD working principle, not FIR (flame ion), because you cannot use chromatography based on the FIR working principle to measure CO.
So how long does it take to measure with a chromatograph? In other words, how long is the general lag?
So what is the general lag time of chromatography? This post was last edited by Mobei Yihai on 2009-4-7 18:49 ]
The lag time of a gas chromatograph is not a certain number. The analysis time can be specifically determined based on the quantity and type of analyzed gases and the analysis method of the analyzer.
Analyze the components of the process gas at the outlet of the gasifier carbon scrubber, mainly analyzing carbon monoxide, carbon dioxide, methane, and hydrogen. How long is the lag time?
I think GC (Gas Chromatography) should be a better choice. It can achieve the best detection results. As for the reflection time, I need to consult the manufacturer.:lol
Gas chromatography analyzers are easy to use. The hysteresis is related to the length of the sampling pipeline and the sampling period of the instrument.
Gas chromatography is a better choice. According to the composition of the poster, the sample should be something like coal gas or natural gas. TCD chromatography can solve the problem. Some manufacturers have special natural gas chromatography. You can consult. This type of chromatography can be installed on site, which greatly shortens the sample transmission distance and reduces the lag time. In addition, if the composition gap is large, for example, the content of a certain component is PPM level, you should consider using FID chromatography. For small contents of CO and CO2, FID chromatography can use a methanator to convert it into methane for measurement. This is the most conventional method. Several other methods have certain problems with the sample you proposed, such as the cost of the mass spectrometer instrument. The thermal conductivity analysis instrument only has high sensitivity for hydrogen and can only analyze hydrogen in it.
This post was last edited by zlky2005 on 2015-1-5 10:25 What is the standard number of Osteni method, chromatography, and infrared gas analysis? @qugd
I cannot know these standard numbers. You can check the catalog of national standards or the compilation of some industry or professional standards.
If chromatography is used, the measurement points are well selected, and the sample gas is clean, multi-component analyzers from Wuhan Sifang and Xi'an Zhiqi can measure it, but you need to know the approximate component range of the sample gas to eliminate interference.