US 5,689,974 A · Method and apparatus for pre-purification for air cryogenic separation plant

Abstract

The present invention offers a pre-purification method and apparatus for an air cryogenic separation plant for removing water vapor and carbon dioxide from feed air, which is able to operate at high air temperatures without the use of special installations such as pre-cooling equipment or demoisturizers to replace freon refrigerators or water spray cooling columns. One aspect of the present invention is a pre-purification method for an air cryogenic separation plant which continuously purifies feed air using a plurality of reciprocally-used adsorption columns 5a, 5b filled with adsorbents for adsorption removal of water vapor and carbon dioxide from the feed air. The method includes an adsorption step, a depressurization step, a heating step, a cooling step, and a repressurization step, whereof the adsorption step for adsorption removal of impurities is performed by feeding pressurized feed air at a temperature of 10.degree..about.45.degree. C. into an adsorption column filled with water adsorbent and carbon dioxide adsorbent arranged respectively in that order from the air entrance, at a superficial velocity of 5.about.40 cm/s. Another aspect of the present invention is a pre-purification apparatus for an air cryogenic separation plant having adsorption columns 5a, 5b filled with water adsorbent and carbon dioxide adsorbent arranged respectively in that order from the air entrance, wherein the weight ratio of the water adsorbent to the total amount of adsorbents is 0.4.about.0.7.

Claims16

Dependent claims

A pre-purification method for an air cryogenic separation plant which continuously purifies feed air by being provided with a plurality of reciprocally-used adsorption columns filled with adsorbents for adsorbing impurities such as water vapor and carbon dioxide from said feed air;

said pre-purification method for an air cryogenic separation plant comprising:
a) an adsorption step wherein pressurized feed air is fed into an adsorption column and impurities are removed from said feed air;
b) a depressurization step wherein the pressure inside said adsorption column is reduced to approximately atmospheric pressure;
c) a heating step wherein purge gas which does not contain impurities is fed into said adsorption column in order to heat-regenerate said adsorbent, wherein said heating is performed at a heating temperature within the range of 100.degree..about.250.degree. C., and the purge gas ratio of said purge gas to said feed air is within a range of 20.about.60%;
d) a cooling step wherein the inside of said adsorption column is cooled to an adsorption operation tempaerature by means of said purge gas;
and
e) a repressurization step wherein the adsorption column is repressurized;
wherein said adsorption step is performed by feeding pressurized feed air at a temperature of 10.degree..about.45.degree. C. and a superficial velocity of 5.about.40 cm/s into said adsorption column which has been filled with water adsorbent and carbon dioxide adsorbent arranged so that said water adsorbent is closer to an air entry side of said adsorption column.

5 more elements

A pre-purification apparatus for an air cryogenic separation plant which continuously purifies feed air by being provided with a plurality of reciprocally-used adsorption columns filled with adsorbents for adsorbing impurities such as water vapor and carbon dioxide from said feed air;

said pre-purification method for an air cryogenic separation plant comprising:
a) an adsorption step wherein pressurized feed air is fed into an adsorption column and impurities are removed from said feed air at a temperature within the range of 20.degree..about.80.degree. C.;
b) a depressurization step wherein the pressure inside said adsorption column is reduced to approximately atmospheric pressure;
c) a heating step wherein purge gas which does not contain impurities is fed into said adsorption column in order to heat-regenerate said adsorbent;
d) a cooling step wherein the inside of said adsorption column is cooled to an adsorption operation tempaerature by means of said purge gas;
and
e) a repressurization step wherein the adsorption column is repressurized;
wherein said adsorption column is loaded with water adsorbent and carbon dioxide adsorbent arranged so that said water adsorbent is closer to an air entry side of said adsorption column, and the weight ratio of said water adsorbent with respect to all of the adsorbents is within the range of 0.4.about.0.7 and wherein said plurality of adsorption columns are provided in a switching system means having a duration of a switching period consisting of said adsorption step a) and the regeneration steps b).about.e) within a range of 2.about.12 hours.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus for pre-purification for air cryogenic separation plant

Life of this patent

Method and apparatus for pre-purification for air cryogenic separation plant

Life of this patent

Abstract

Claims16