Low dew point pressure swing adsorption nitrogen plant and process flow

Abstract

The invention provides a low-dew-point pressure swing adsorption nitrogen generation device and a process flow. The low-dew-point pressure swing adsorption nitrogen generation device comprises a compressor, a liquid separation tank, two adsorption towers and a dust removal buffer, wherein a pressure equalizing pipeline and a blowing pipeline are arranged between outlets of the two adsorption towers, and an exhaust pipeline is arranged between the inlets of the two adsorption towers; a nitrogen generation carbon molecular sieve bed layer and an adsorption drying bed layer capable of adsorbing water vapor are arranged in the adsorption tower from top to bottom; the inlet end of the dust removal buffer is connected with a gas conveying pipeline; the outlets of the two adsorption towers are connected with the gas conveying pipeline correspondingly through a first gas outlet pipeline and a second gas outlet pipeline; the exhaust pipeline is connected with an unloading silencer; the unloading silencer is positioned between a first regenerated gas unloading valve and a second regenerated gas unloading valve; the inlets of the two adsorption towers are communicated with the liquid separation tank correspondingly through a first gas inlet pipeline and a second gas inlet pipeline. In the invention, the whole process flow is simplified, and the equipment and valves are saved and reduced; furthermore, the desorbed gas is skillfully used as the regenerated gas for drying, and the utilization efficiency of the compressed air is improved.

Description

technical field [0001] The invention belongs to the field of nitrogen used in petrochemical, chemical, oil and gas fields, etc., and specifically relates to a low dew point pressure swing adsorption nitrogen production device and a process flow. Background technique [0002] In existing operations, nitrogen is separated from compressed air by using carbon molecular sieves through the PSA (Pressure Swing Adsorption) separation process. However, due to the poor water absorption capacity of carbon molecular sieves, the water content of the obtained nitrogen Larger, its pressure dew point is generally greater than -10°C, and under most working conditions, the pressure dew point of nitrogen is required to be low, for example, in LNG projects, the pressure dew point is required to be -70°C. For this reason, in order to produce nitrogen with a low dew point that meets the requirements, the current PSA nitrogen production process is to add a dryer before the nitrogen production devi...

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Problems solved by technology

[0003] However, in this process, because the compressed air needs to be dried through the dryer first, and then the impurity media such as oxygen and carbon dioxide are absorbed by the adsorption tower, there are two processes of regenerative dryer and PSA nitrogen production, with many equipment and long process. Moreover, the regeneration gas in the desorption process of PSA nitrogen production cannot be shared with the dryer, which will consume a certain amount of raw material gas, which is not conducive to energy saving and high production costs.

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