Stirred tank reactor

Patent metadata

Field	Value
Publication number	US-9815033-B2
Application number	US-201414762414-A
Country	US
Kind code	B2
Filing date	Jan 29, 2014
Priority date	Jan 30, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

The invention relates to a stirred tank reactor for gas-liquid mass transfer in a slurry. The reactor includes a reactor tank ( 1 ) having a first volume (V 1 ), a drive shaft ( 2 ) that extends vertically in the reactor tank, a motor ( 3 ) for rotating the drive shaft ( 2 ), a main impeller ( 4 ) which is a downward pumping axial flow impeller attached to the drive shaft ( 2 ) to create a main flow pattern in the reactor tank, and a gas inlet ( 5 ) arranged to supply gas into the reactor tank ( 1 ) to be dispersed to the liquid. The reactor includes a mechanical gas sparging apparatus ( 6 ) comprising a dispersion chamber ( 7 ) having a second volume (V 2 ) which is substantially smaller than the first volume (V 1 ) of the reactor tank ( 1 ), the dispersion chamber being arranged coaxial with the drive shaft ( 2 ), and the gas inlet ( 5 ) being arranged to feed gas into the dispersion chamber ( 7 ), and mixing means ( 8, 9, 10, 11, 12 ) arranged within the dispersion chamber ( 7 ) for mixing the gas into liquid by dispersing the gas to fine bubbles before the bubbles enter the main flow pattern. The mixing power per unit volume inside the dispersion chamber ( 7 ) is significantly larger than the mixing power elsewhere in the reactor.

First claim

The invention claimed is:

1. A stirred tank reactor for gas-liquid mass transfer in a slurry, including
a reactor tank having a first volume,
a drive shaft that extends vertically in the reactor tank,
a motor for rotating the drive shaft,
a main impeller which is a downward pumping axial flow impeller attached to the drive shaft to create a main flow pattern in the reactor tank, the main impeller having a first diameter,
a gas inlet arranged to supply gas into the reactor tank to be dispersed to the liquid, and
a gas sparging apparatus, characterized in that the gas sparging apparatus is mechanical and comprises
a dispersion chamber comprising a wall defining a hollow inner space inside the wall, an upper end which is upwardly open and a lower end which is downwardly open, said dispersion chamber having a second diameter which is smaller than the first diameter of the main impeller, said dispersion chamber having a second volume which is greater than 0% of and less than 10% of the first volume of the reactor tank, and said dispersion chamber being arranged coaxial with the drive shaft, and the gas inlet being arranged to feed gas into the dispersion chamber, and
mixing means arranged within the dispersion chamber for mixing the gas into liquid by dispersing the gas to fine bubbles before the bubbles enter the main flow pattern,
whereby the mixing power per unit volume inside the dispersion chamber is significantly larger than the mixing power elsewhere in the reactor.

2. The reactor according to claim 1 , characterized in that the dispersion chamber is located below the main impeller.

3. The reactor according to claim 1 , characterized in that the dispersion chamber is located above the main impeller.

4. The reactor according to claim 1 , characterized in that the mixing means comprises a mixing element attached to the drive shaft.

5. The reactor according to claim 4 , characterized in that the mixing element comprises an auxiliary impeller attached to the drive shaft to be rotatable with it and located in the inner space of the dispersion chamber.

6. The reactor according to claim 1 , characterized in that the dispersion chamber is attached to the bottom or to the side wall of the reactor tank to be stationary.

7. The reactor according to claim 6 , characterized in that the mixing element comprises baffles attached to the wall of the dispersion chamber in the inner space of the dispersion chamber.

8. The reactor according to claim 1 , characterized in that the dispersion chamber is attached to the drive shaft to be rotatable with it.

9. The reactor according to claim 5 , characterized in that the dispersion chamber and the auxiliary impeller are attached to each other.

10. The reactor according to claim 9 , characterized in that the dispersion chamber is attached to the main impeller.

11. The reactor according to claim 10 , characterized in that the dispersion chamber is attached to the main impeller below the main impeller.

12. The reactor according to claim 1 , characterized in that the dispersion chamber is attached to the main impeller below the main impeller to be rotatable with it; and that the mixing element comprises baffles attached to the wall of the dispersion chamber in the inner space of the dispersion chamber, and a stator element attached to the bottom of the reactor tank, the stator element being arranged coaxially in relation to the dispersion chamber.

13. The reactor according to claim 1 , characterized in that for creating the main flow pattern the reactor comprises two main impellers, a lower main impeller attached to the lower end of the drive shaft and an upper main impeller attached to the drive shaft at a distance above the lower main impeller, and that the dispersion chamber is attached to the drive shaft or to the lower main impeller above the lower main impeller.

14. The reactor according to claim 1 , characterized in that the dispersion chamber is attached to the bottom or to the side wall of the reactor tank; that the mixing means comprises an auxiliary drive shaft that extends through the side wall or the bottom of the reactor tank to the inner space of the dispersion chamber, a second motor for rotating the auxiliary drive shaft; and that the mixing means comprises an auxiliary impeller attached to the auxiliary drive shaft and located in the inner space of the dispersion chamber.

15. The reactor according to claim 14 , characterized in that the rotation axis of the auxiliary drive shaft is substantially vertical.

16. The reactor according to claim 14 , characterized in that the rotation axis of the auxiliary drive shaft is substantially horizontal.

Assignees

• Outotec Finland Oy

Inventors

• Latva-Kokko Marko
• Ritasalo Teemu
• Vaarno Jussi

Classifications

• B01F2215/0463

  Numerical power values · CPC title

• B01F7/186

  Operations & Transport · mapped topic

• B01F2003/0468

  Operations & Transport · mapped topic

• B01F7/22

  Operations & Transport · mapped topic

• B01F3/04517

  Operations & Transport · mapped topic