TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: The method further comprises desorbing by vacuum or decompressing to realize regeneration and recycling of the absorbing agent. An operating period comprises , absorbing: opening a raw material gas output valve and a product gas tank input valve, pouring the material gas in an inlet end of a first absorbing tower and then absorbing in which the product gas flows in from an outlet end of the absorbing tower and then enters into a product gas tank, where parameter conditions include - 80-120 degrees C and a pressure of 0.1-1 MPa; equalizing the pressure in the absorbing tower whose vacuum is pumped in advance; reversely decompressing the absorbing tower to air atmosphere after equalizing the pressure, reversely pumping the vacuum and regenerating the absorbing agent in the tower, where the parameter conditions include a vacuum degree of 0.1-0 MPa and a temperature for pumping vacuum of 80-150 degrees C; and charging the first absorbing tower for a first time by the tower which has been used to absorb after the vacuum is pumped by the absorbing tower, and then finally charging the first absorbing tower by the product gas to the operating pressure, thus finishing an operating period, where the parameter conditions include a temperature of - 80-120 degrees C and a pressure of 0.1-1 MPa. The continuous production is realized by absorbing by one of the four absorbing towers; pumping vacuum by one of the absorbing towers; and equalizing pressure by two of the absorbing towers to realize the continuous production. The method comprises when absorbing by the first absorbing tower, pumping vacuum by the fourth absorbing tower and rapidly equalizing the pressure by the second and third absorbing towers; when finishing absorbing by the first absorbing tower, stopping pumping vacuum by the fourth absorbing tower; equalizing pressure of the first absorbing tower by the fourth absorbing tower, where the first absorbing tower after being equalized enters into the stage of reversely decompressing and pumping vacuum; and at the moment, rapidly charging the third absorbing tower by the product gas and then entering into the absorbing stage and, after the absorption is finished, charging the first absorbing tower which has been used to pump vacuum by the third absorbing tower and then finally charging the first absorbing tower by the product gas, so that the first absorbing tower enters into the absorbing stage again.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The absorbing agent is an orifice modified 4A, 5A zeolite molecular sieves, and carbon molecular sieve. The orifice modified 4A, 5A zeolite molecular sieves and carbon molecular sieve contain micro pores having a pore diameter of 0.3-0.5 nm.