Carbon dioxide trapping and purifying device system and method thereof

The invention provides a carbon dioxide trapping and purifying device system and a method thereof. The device system comprises a smoke cooler, a steam-water separation device, a PSA concentration tower, a gas concentration unit, a TSA drying tower, a precooler, a liquefaction device, a flash evaporation device and a rectification device which are connected in sequence, and impurity gas outlets of the flash evaporation device and the rectification device are respectively and independently connected with the precooler. According to the device system provided by the invention, four carbon dioxide products with different concentrations can be respectively extracted from four different positions of the PSA concentration tower, the TSA drying tower, the flash evaporation device and the rectification device according to different requirements on the concentrations of the carbon dioxide products; compared with a traditional mode of extracting a carbon dioxide product at a rectifying tower, the method has the advantag