A gas chromatograph is an analytical instrument used to determine the content of different components in a sample. The principle of gas chromatography is: after the sample solution is injected, it first enters the vaporization chamber, and then enters the chromatographic column under the transmission of the carrier gas (the carrier gas is usually nitrogen or helium), and the different components are separated in the chromatographic column. The outgoing chromatographic column is detected by a detector to obtain its content. When determining the content of a certain component in a sample, it is necessary to analyze a standard sample of known concentration, and then compare the retention time and peak area of the chromatographic peak of the standard sample with the sample to be tested to calculate the content of the target component in the sample to be tested.
The gas chromatograph is used to analyze the component content of natural gas, liquefied gas, liquefied mixed air and gas distribution, and quickly give the high calorific value, low calorific value, density, relative density, Huabai number, combustion potential and other characteristic indices of different gases. It can be widely used in gas appliance manufacturers, gas measurement and testing departments, scientific research, environmental protection and gas distribution industries. The natural gas analysis gas chromatograph adopts three carrier gas regulator valve and two-way packed column sampling system.
The gas chromatograph is mainly composed of a gas circuit system, a sample injection system, a separation system, a temperature control system and a detection and recording system.
1. Air system:
Including gas source, gas purification, gas flow rate control and measurement. To obtain a pure, stable carrier gas.
2. Sampling system:
Includes injector and vaporizer. The sampler is divided into a gas sampler and a liquid sampler, and the vaporization chamber is a device that instantly vaporizes liquid samples.
3. Separation system:
According to the difference of the distribution coefficient or adsorption coefficient of each component in the mobile phase and the stationary phase, each component is separated in the chromatographic column.
4. Temperature control system:
Control the temperature of the vaporizer, oven, and detector.
5. Detection and recording system:
Convert the concentration or mass of each component into an electrical signal and record it.