Process and device for air separation and steam generation in a combined system

Patent metadata

Field	Value
Publication number	US-9435229-B2
Application number	US-201313750015-A
Country	US
Kind code	B2
Filing date	Jan 25, 2013
Priority date	Jan 26, 2012
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

The disclosed process and apparatus provide for air separation and steam generation in a combined system that comprises a steam system ( 10 ) and an air separation plant ( 9 ), wherein a feed air stream ( 1 ) is introduced into a multistage air compression system ( 101, 102, 103 ) having n stages (n>=3) and compressed to a first high pressure that is equal to the final pressure of the air compression system, and, at this final pressure, is introduced ( 8 ) into the air separation plant ( 9 ). An intercooler is arranged between an i-th stage ( 102 ) (1<=i<n) and an i+1-th stage ( 103 ) of the air compression system; there, the feed air stream ( 4 ) is cooled in indirect heat exchange with a feed water stream ( 11 ).

First claim

The invention claimed is:

1. An integrated process for air separation and steam generation in a combined system comprising a steam system ( 10 ) and an air separation plant ( 9 ), said process comprising:
introducing a feed air stream ( 1 ) into a multistage air compression system ( 101 , 102 , 103 ) having n stages, wherein n is greater than or equal to 3, and at least a first part of the feed air stream is compressed to a first high pressure that is equal to the final pressure of the air compression system, and, at this final pressure, is introduced ( 8 ) into the air separation plant ( 9 ),
removing the feed air stream ( 3 ) from an i−1-th stage ( 101 ) of the air compression system, wherein i is greater than 1 and i is less than n, and introducing the feed stream, without intercooling, into an i-th stage ( 102 ) of the air compression system,
removing the feed air stream ( 4 ) at an outlet temperature Tout(i) from the i-th stage ( 102 ) of the air compression system and introducing the feed air stream at this temperature into an intercooler ( 202 ) which is arranged between said i-th stage ( 102 ) and the subsequent i+1-th stage ( 103 ) of the air compression system,
cooling the feed air stream ( 4 ) in the intercooler ( 202 ) by indirect heat exchange with a heat carrier stream ( 311 ),
coupling heat from the heat carrier stream ( 312 ) heated in the intercooler ( 202 ) into the steam system ( 10 ), wherein the heat carrier stream is used directly as feed water in the steam system or the heat of the heat carrier stream is coupled by indirect heat exchange into the steam system,
introducing the feed air stream into a further cooler ( 300 ) positioned downstream of the intercooler and upstream of the last stage of the air compression system, and
introducing at least said first part of the feed air stream ( 7 ) into an aftercooler ( 203 ) downstream of the last stage ( 103 ) of the air compression system, and cooling said first part of the feed air stream ( 7 ) in said aftercooler ( 203 ) by indirect heat exchange with said heat carrier stream ( 15 ) before introducing said first part of the feed air stream ( 8 ) into the air separation plant ( 9 ), and
wherein said heat carrier stream ( 316 ), after being heated in said aftercooler ( 203 ), is introduced ( 311 ) into said intercooler ( 202 ).

2. The process according to claim 1 , wherein said further cooler ( 300 ) is constructed as a direct contact cooler and the feed air stream is cooled in the direct contact cooler ( 300 ) by direct heat exchange with cooling water ( 301 , 303 ).

3. The process according to claim 1 , wherein the air compression system is formed by a single multistage air compressor having n stages.

4. The process according to claim 1 , wherein the air compression system comprises at least two air compressors, namely one main air compressor and an aftercompressor, wherein the last stage of the air compression system is formed by the aftercompressor.

5. The process according to claim 1 , wherein the outlet temperature Tout(i) of the feed air stream ( 4 ) from the i-th stage ( 102 ) of the air compression system is between 120 and 200° C.

6. The process according to claim 5 , wherein the outlet temperature Tout(i) of the feed air stream ( 4 ) from the i-th stage ( 102 ) of the air compression system is between 130 and 170° C.

7. The process according to claim 1 , wherein the heat carrier stream ( 311 ) is heated in the intercooler ( 202 ) to a temperature of 125 to 140° C.

8. The process according to claim 1 , wherein a second part ( 13 ) of the feed air stream is removed from the air compression system at a second, medium pressure which is lower than the first, high pressure, wherein the second part is branched off from the feed air stream downstream of the intercooler ( 202 ) or downstream of the further cooler ( 300 ).

9. The process according to claim 1 , wherein the intercooler ( 202 ) and/or the aftercooler ( 203 ) is constructed as a helically coiled tube-bundle heat exchanger.

10. The process according to claim 1 , wherein the intercooler ( 202 ) and/or the aftercooler ( 203 ) is constructed as a plate heat exchanger.

11. The process according to claim 1 , wherein the heat carrier stream ( 15 ) is formed by a water stream.

12. The process according to claim 1 , wherein the steam system ( 10 ) is a steam power plant.

13. The process according to claim 12 , wherein the steam power plant is an oxyfuel power plant or an integrated gasification combined cycle power plant.

14. An integrated apparatus for air separation and steam generation with a combined system, said apparatus comprising:
a steam system ( 10 ) and an air separation plant ( 9 ),
a multistage air compression system ( 101 , 102 , 103 ) having n stages, wherein n is greater than or equal to 3 for compressing a feed air stream ( 1 ) to a first, high pressure that is equal to the final pressure of the air compression system,
means for introducing ( 8 ) the compressed feed air stream at the final pressure into the air separation plant ( 9 ),
means for removing the feed air stream ( 3 ) from an i- 1 -th stage ( 101 ) of the air compression system for introduction, without intercooling, into the i-th stage ( 102 ) of the air compression system, wherein i is greater than 1 and i is less than n,
means for removing the feed air stream ( 4 ) at an outlet temperature Tout(i) from a stage ( 102 ) of the air compression system and means for introducing the feed air stream ( 4 ) at outlet temperature Tout(i) into an intercooler ( 202 ) which is arranged between said i-th stage ( 102 ) i+1-th stage ( 103 ) of the air compression system, wherein the intercooler ( 202 ) is constructed for cooling the feed air stream ( 4 ) by indirect heat exchange with a heat carrier stream ( 311 ),
means for coupling heat from the heat carrier stream ( 312 ), heated in the intercooler ( 202 ), into the steam system ( 10 ), wherein the heat carrier stream is used directly as feed water in the steam system or the heat of the heat carrier stream is coupled by indirect heat exchange into the steam system,
means for introducing the feed air stream into a further cooler ( 300 ) downstream of the intercooler and upstream of the last stage of the air compression system,
means for introducing at least a first part of the feed air stream ( 7 ) into an aftercooler ( 203 ) downstream of the last stage ( 103 ) of the air compression system and before introduction of the first part of the feed air stream into the air separation plant ( 8 ), which aftercooler is constructed for cooling the at least the first part of the feed air stream by indirect heat exchange with the heat carrier stream ( 15 ), and
means for introducing the heat carrier stream ( 316 ), after being heated in the aftercooler ( 203 ), into the intercooler ( 202 ).

15. An integrated process for air separation and steam generation in a combined system comprising a steam system ( 10 ) and an air separation plant ( 9 ), said process comprising:
introducing a feed air stream ( 1 ) into a multistage air compression system ( 101 , 102 , 103 ) having n stages, wherein n is greater than or equal to 3, and at least a first part of the feed air stream is compressed to a first high pressure that is equal to the final pressure of the air compression system, and, at this final pressure, is introduced ( 8 ) into the air separation plant ( 9 ),
removing the feed air stream ( 3 ) from an i−1-th stage ( 101 ) of the air compression system, wherein i is greater than 1 and i is less than n, and introducing the feed stream, without intercooling, into an i-th stage ( 1

Assignees

• Linde Ag

Inventors

• Alekseev Alexander
• Goloubev Dimitri

Classifications

• F25J2230/06

  Adiabatic compressor, i.e. without interstage cooling · CPC title

• F25J2205/34

  as evaporative cooling tower to produce chilled water, e.g. evaporative water chiller [EWC] · CPC title

• F25J2205/70

  Heating the adsorption vessel · CPC title

• F25J2230/04

  Compressor cooling arrangement, e.g. inter- or after-stage cooling or condensate removal · CPC title

• F25J2205/32

  as direct contact cooling tower to produce a cooled gas stream, e.g. direct contact after cooler [DCAC] · CPC title