Reflux condenser method

Patent metadata

Field	Value
Publication number	US-10471371-B2
Application number	US-201715590407-A
Country	US
Kind code	B2
Filing date	May 9, 2017
Priority date	Jan 25, 2008
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

Methods, apparatus, and processes are provided for a condenser including flowing a vapor stream including formaldehyde into a tube bundle in a vertical upflow reflux condenser, where a tube in the tube bundle has a length to outside diameter ratio of greater than about 170:1, flowing a cooling fluid on a shell-side of the vertical upflow reflux condenser to condense at least a portion of the vapor stream, where the condensed portion of the vapor stream forms a wetted tube internal surface area on each tube in the generally upright tube bundle; and maintaining the vapor stream velocity at a rate that provides a liquid residence time where formaldehyde condensed on the wetted internal surface area of each tube can react with water to form methylene glycol, removing at least sixty percent (60%) of formaldehyde from the vapor stream fed to the condenser.

First claim

What is claimed:

1. A method of operating a condenser, comprising:
flowing a vapor stream including formaldehyde and water into a generally upright tube bundle in a vertical upflow reflux condenser, where a tube in the tube bundle has a length to outside diameter ratio of greater than about 170:1;
flowing a cooling fluid on a shell-side of the vertical upflow reflux condenser to condense at least a portion of the vapor stream, where the condensed portion of the vapor stream and the vapor stream flow counter currently within the tube in the tube bundle and the condensed portion of the vapor stream forms a wetted tube internal surface area on each tube in the generally upright tube bundle;
promoting methylene glycol formation by providing the wetted tube internal surface area for reacting formaldehyde and water to form methylene glycol; and
maintaining the vapor stream velocity at a rate that provides a liquid residence time where formaldehyde condensed on the wetted internal surface area of each tube can react with water to form methylene glycol, removing at least sixty percent (60%) of formaldehyde from the vapor stream fed to the condenser.

2. The method of claim 1 , where flowing the vapor stream into the generally upright tube bundle includes flowing the vapor stream at an exit velocity to form the wetted internal surface area on each tube in the generally upright tube bundle.

3. The method of claim 2 , where the method includes collecting a portion of the condensed portion of the vapor stream exiting the tube bundle on a top tubesheet positioned at a top of the tube bundle, where condensed liquid flows down the internal surface area of each tube in the tube bundle.

4. The method of claim 3 , including flowing the liquid reflux countercurrent to the vapor stream.

5. The method of claim 1 , where the vapor stream velocity is about 8.5 feet per second (2.59 meters per second) or less.

6. The method of claim 1 , where the vapor stream velocity is about ninety percent (90%) or less of a calculated critical flooding velocity at an inlet of the tube bundle.

7. The method of claim 1 , where the method includes removing at least about eighty percent (80%) formaldehyde from the vapor stream fed to the condenser.

8. The method of claim 1 , where the method includes removing at least about eighty-five percent (85%) formaldehyde from the vapor stream fed to the condenser.

9. The method of claim 1 , where the liquid residence time is at least about 0.5 seconds.

Assignees

• Dow Technology Investments Llc

Inventors

• Conneway Fred A
• Rhodes Ii Clyde L
• Szul John F

Classifications

• B01D5/0063 Primary

  Reflux condensation · CPC title

• B01D5/0012

  Vertical tubes · CPC title

• B01D3/04

  pipe stills · CPC title

• C07D301/32

  Separation; Purification · CPC title

• C07C31/20

  Dihydroxylic alcohols · CPC title