Continuous generation device and preparation method for low-temperature air

The invention belongs to the technical field of refrigeration equipment and particularly relates to a continuous generation device for low-temperature air. The continuous generation device comprises a high-pressure air supply unit, a dehumidification unit, a second-stage depressurization and refrigeration unit and a circulation unit, wherein the high-pressure air supply unit, the dehumidification unit and the second-stage depressurization and refrigeration unit are sequentially connected in series, and the circulation unit is connected with the dehumidification unit and the second-stage depressurization and refrigeration unit. The dehumidification unit is provided with a dehumidification inlet, a dehumidification outlet, a circulation inlet and a circulation outlet, wherein the circulation inlet and the circulation outlet are matched with the circulation unit. The high-pressure air supply unit is connected with the dehumidification inlet of the dehumidification unit. The second-stage depressurization and refrigeration unit is composed of a plurality of parallel capillary tubes and cooling parts outside the capillary tubes, wherein one ends of the capillary tubes are connected with the dehumidification outlet of the dehumidification unit, refrigeration outlets are formed in the other ends of the capillary tubes, and the cooling parts are provided with inlets and outlets. The circulation outlet of the dehumidification unit is connected with the inlets of the cooling parts, and the outlets of the cooling parts and the circulation inlet of the dehumidification unit are connected with the circulation unit. According to the continuous generation device, the low-temperature air with the temperature being minus 75 DEG C can be obtained, the cost is just one tenth that of nitrogen refrigeration, and therefore the cost is greatly lowered, and the economic benefit is improved.