초록 ▼

In order to provide a pressure-swing-adsorption oxygen production process which can maintain the product recovery at a high level while enhancing the oxygen productivity and reducing the unit power consumption, a pressure recovery step is carried out in which communication is provided between an out

In order to provide a pressure-swing-adsorption oxygen production process which can maintain the product recovery at a high level while enhancing the oxygen productivity and reducing the unit power consumption, a pressure recovery step is carried out in which communication is provided between an outlet end of an adsorption column which has completed an adsorption step and an outlet end of an adsorption column which has completed a regeneration step, and in which gas remaining in the adsorption column which has completed the adsorption step is collected within the adsorption column which has completed the regeneration step; and simultaneously with the pressure recovery step, a gas mixture which has approximately the same composition as feed gas mixture is introduced into at least one of the adsorption column which has completed the adsorption step and the adsorption column which has completed the regeneration step through the inlet end thereof.

대표청구항 ▼

[ What is claimed is:] [1.] A process for producing oxygen by means of a pressure swing adsorption separation in a plurality of adsorption columns packed with zeolite as adsorbent, an adsorption step carried out at a relatively high pressure and a regeneration step carried out at or below atmospheri

[ What is claimed is:] [1.] A process for producing oxygen by means of a pressure swing adsorption separation in a plurality of adsorption columns packed with zeolite as adsorbent, an adsorption step carried out at a relatively high pressure and a regeneration step carried out at or below atmospheric pressure are repeated alternately and sequentially, whereby oxygen and nitrogen are separated from a feed gas mixture principally containing oxygen and nitrogen, and oxygen gas is produced, the process comprising the steps of:(a) introducing the feed gas mixture into a feed-gas-mixture inlet of a first adsorption column of packed zeolite, which is capable of selectively adsorbing nitrogen in the feed gas mixture, thereby allowing primarily adsorption of nitrogen, while withdrawing oxygen, which is less adsorbable, from a product-oxygen-gas outlet of the first adsorption column as a product oxygen gas, this step being continued until a mass transfer zone of nitrogen reaches the vicinity of the product-oxygen-gas outlet of the first adsorption column;(b) depressurizing the first adsorption column to a pressure between an adsorbing pressure and a regenerating pressure of the first adsorption column by cocurrently taking out a gas in the mass transfer zone of the first adsorption column, the gas having an oxygen concentration lower than that of the product oxygen gas and higher than that of the feed gas mixture, from the product-oxygen-gas outlet of the first adsorption column, the gas thus taken out by this step of depressurization being guided to a product-oxygen-gas outlet of a second adsorption column undergoing step (e) for repressurization;(c) further depressurizing the first adsorption column by countercurrently evacuating it through the feed-gas-mixture inlet thereof by a vacuum pump, thereby allowing the adsorbed nitrogen to be desorbed;(d) countercurrently purging the first adsorption column by guiding a product oxygen gas produced in another adsorption column undergoing step (a) to the product-oxygen-gas outlet of the first adsorption column so as to be supplied to the first adsorption column, whereby the desorption of the adsorbed nitrogen by the evacuation using the vacuum pump is further promoted;(e) pressurizing the first adsorption column by countercurrently supplying the product-oxygen-gas outlet of the first adsorption column with a gas in a mass transfer zone of an adsorption column other than the first adsorption column, the gas having an oxygen concentration lower than that of a product oxygen gas and higher than that of a feed gas mixture of the adsorption column other than the first adsorption column, and at the same time by cocurrently supplying the feed-gas-mixture inlet of the first adsorption column with the feed gas mixture;(f) further pressurizing the first adsorption column with a portion of a product oxygen gas from an adsorption column other than the first adsorption column; and(g) performing steps (a) through (f) in each of the plurality of adsorption columns in a phased sequence.