Condenser-reboiler system and method

Patent metadata

Field	Value
Publication number	US-10048004-B2
Application number	US-201615285545-A
Country	US
Kind code	B2
Filing date	Oct 5, 2016
Priority date	Jan 29, 2014
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

A system and method for the concurrent condensation of a nitrogen-rich vapor and vaporization of an oxygen-rich liquid in a distillation column based air separation unit is provided. The disclosed system includes a condenser-reboiler heat exchanger located between a lower pressure column and a higher pressure column and configured to condense a nitrogen-rich vapor from the higher pressure column and partially vaporize an oxygen-rich liquid from the lower pressure column. Within the condenser-reboiler heat exchanger, the nitrogen-rich vapor flows in an upward direction such that any non-condensables present in the nitrogen-rich vapor will accumulate proximate the upper portion or top of the condenser-reboiler modules where they can be easily removed through venting.

First claim

What is claimed is:

1. A condensation and vaporization system for an air separation unit comprising:
one or more condenser-reboiler modules having a housing defining a top, a bottom, one or more lateral sides, an upper portion, and a lower portion, the one or more condenser-reboiler modules disposed within a lower pressure column and configured to receive a condensing medium at a condensing inlet disposed at the top of the housing, an oxygen-rich liquid from the lower pressure column at an oxygen-rich liquid inlet disposed proximate the top of the housing, and further defining a condensate outlet proximate the bottom of the housing and an oxygen-rich effluent outlet disposed proximate the bottom of the housing;
a shell and tube heat exchanger disposed in the one or more condenser-reboiler modules and comprising two opposed tube sheets, a cylindrical shell connecting the two opposed tube sheets, an inlet conduit centrally and vertically disposed within the shell configured to direct the condensing medium from the condensing inlet to a location proximate a bottom of the cylindrical shell and a plurality of tubes extending between the two opposed tube sheets, the shell and tube heat exchanger configured to partially vaporize the oxygen-rich liquid flowing within the plurality of tubes thereby forming an oxygen-rich effluent and condense the condensing medium within the cylindrical shell forming a condensate;
wherein the condensing medium enters the one or more condenser-reboiler modules at the condensing inlet, traverses through the inlet conduit and is released within the shell and tube heat exchanger in the condenser-reboiler modules at the bottom of the cylindrical shell and flows in an upward and radially outward direction within the cylindrical shell;
wherein non-condensables present in the condensing medium accumulate at the outer surfaces of the plurality of tubes and proximate the upper portion; and
one or more vents disposed proximate the upper portion or top of the housing for the one or more condenser-reboiler modules and configured to remove the accumulated non-condensables proximate the outer surfaces of the plurality of tubes.

2. The system of claim 1 wherein the heat exchanger is a downflow heat exchanger and the oxygen-rich liquid inlet is disposed proximate the top of the housing for the one or more condenser-reboiler modules and the oxygen-rich effluent outlet is disposed proximate the bottom of the condenser-reboiler module.

3. The system of claim 1 wherein the condensate outlet is disposed proximate the bottom of the housing for the one or more condenser-reboiler modules and concentrically around the condensing medium inlet.

4. The system of claim 1 wherein the condensate outlet is disposed proximate the bottom of the housing for the one or more condenser-reboiler modules and proximate the lateral side or peripheral edges of the housing.

5. The system of claim 1 further comprising a distributor structure centrally disposed in a lower portion of the housing for the one or more condenser-reboiler modules and configured to radially distribute the flow of the condensing medium to disperse the condensing medium to the condensing surfaces.

6. The system of claim 1 wherein the condensing medium inlet is disposed at the top or the lateral side of the housing and directed via a conduit to the bottom of the housing for the one or more condenser-reboiler modules where the condensing medium is released.

7. The system of claim 1 further comprising a non-condensable recovery system coupled to the one or more vents and configured to purify and recover the removed non-condensables.

8. The system of claim 1 wherein the condensing medium is a nitrogen-rich vapor.

9. The system of claim 1 wherein the condensing medium is an air vapor.

Assignees

• Shelat Maulik R
• Chakravarthy Vijayaraghavan S
• Kwark Sang Muk
• Praxair Technology Inc

Inventors

• Shelat Maulik R
• Chakravarthy Vijayaraghavan S
• Kwark Sang Muk

Classifications

• F25J3/04412

  in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column · CPC title

• F25J3/04884

  Arrangement of reboiler-condensers · CPC title

• F25J2250/02

  Bath type boiler-condenser using thermo-siphon effect, e.g. with natural or forced circulation or pool boiling, i.e. core-in-kettle heat exchanger · CPC title

• F25J5/005 Primary

  in a reboiler-condenser, e.g. within a column · CPC title

• F25J2290/44

  Particular materials used, e.g. copper, steel or alloys thereof or surface treatments used, e.g. enhanced surface · CPC title