Process and device for air separation by low-temperature rectification
AssigneeLinde Aktiengesellschaft
InventorHelmut Attlfellner
Life of this patent
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Abstract
An air stream is compressed and divided into a first partial stream (4) used as the feed air stream for a low-temperature air rectification system (16), and a second partial stream (5) used as an oxidation agent in a chemical reaction (6). The waste gas from the chemical reaction is work expanded (9). The first partial stream (4) is introduced into one of rectifying columns (17, 18). A liquid product stream is withdrawn from one (18) of the rectification columns, compressed (28) and vaporized against a further compressed (31, 33) process stream (15) from the low-temperature rectification. At least a portion of the mechanical energy resulting from the work expansion (9) of the waste gas of chemical reaction (6) is used for further compression (31, 33) of the process stream.
Claims18
In a process for air separation by low-temperature rectification in a rectifying column system (16) having at least one rectifying column (17, 18), comprising the following steps:
- (a) compression (3) of an air stream (1) to at least the highest pressure of that prevailing inside the rectifying column system (16);
- (b) dividing the resultant compressed air stream into a first partial stream (4) passed as feed air stream into the rectifying column system, and into a second partial stream (5) that is fed to a chemical reaction zone (6) as an oxidation agent;
- (c) work expanding (9) at least a portion of waste gas (8) resulting from said chemical reaction zone (6);
- (d) cooling (14) said first partial stream (4) to about saturation temperature and introducing resultant cooled partial stream (15) into said rectifying column system;
- (e) withdrawing a liquid product stream (27) from said rectifying column system;
- (f) increasing the pressure of the liquid product stream (27);
- (g) further compressing (31, 33;
- 231, 233) a process stream (30, 230) of said air separation by low temperature rectification to a pressure above the highest pressure occurring in rectifying column system (16);
- and
- (h) vaporizing the liquid product stream by indirect heat exchange (14) with at least a portion (35, 235) of the further compressed process stream, the improvement comprising
- (i) employing at least a portion of the resultant mechanical energy generated in work expansion (9) of waste gas (8) from the chemical reaction zone (6) in step (c) for the compression of said process stream (30;
- 230) in step (g).
In a facility for low-temperature rectification of air, said facility comprising a rectifying column system (16) having at least one rectifying column (17, 18), and
- (a) an air compressor (3) having an inlet and outlet,
- (b) a first air line (4) that leads from the outlet of air compressor (3) through a main heat exchanger (14) to said rectifying column system (16);
- (c) a second air line (5) that leads from the outlet of said air compressor (3) to a chemical reactor (6) having an inlet and outlet;
- (d) a gas turbine (9) having an inlet connected to the outlet of chemical reactor (6);
- (e) a liquid product line (27) for withdrawal of a liquid product stream from said rectifying column system (16);
- (f) means (28) to increase the pressure of the liquid product stream;
- (g) means (33,31;
- 231,233) to further compress a process stream (30;
- 230) of the facility for low-temperature rectification of air to a pressure above the highest pressure occurring in rectifying column system (16);
- and
- (h) means for vaporizing the liquid product stream by indirect heat exchange with at least a portion of the further compressed process stream, the improvement comprising
- (i) means to transfer at least a portion of the mechanical energy generated in gas turbine (9) to the means (31;
- 231) for further compressing said process stream.
Dependencies are inferred from the claim text.