System for detecting content of all components in process gas at outlet of methane synthesis reactor

The invention belongs to the technical field of methane production equipment, and particularly relates to a system for detecting the content of all components in process gas at an outlet of a methane synthesis reactor, which comprises a sampling cooler, a sample gas separation tank and an online chromatographic analyzer; a sample gas flowmeter, a sample gas total flow regulating valve, a sample gas pressure gauge and a sample gas thermometer are arranged on a gas inlet pipeline of the sampling cooler, a cooling water flow control valve is arranged on a cooling circulating water feeding pipeline of the sampling cooler, and an outlet pipeline of the sampling cooler is connected with the sample gas separation tank; and a gas outlet pipeline of the sample gas separation tank is provided with an on-line chromatographic analyzer, a second pressure gauge, a second thermometer and a second flowmeter. The invention also provides a detection method using the full-component content detection system. The content of each