Process and device for biological treatment of a suspension in a bioreactor with integrated hydraulic bottom layer removal

• US 20050126997A1
• Filed: 07/06/2004
• Published: 06/16/2005
• Est. Priority Date: 12/11/2003
• Status: Active Grant

• Current Assignee: Linde-KCA-Dresden GmbH
• Original Assignee: Linde-KCA-Dresden GmbH
• Inventors: Matthias, Herms, Buechner, Thomas, Langhans, Gerhard
• Granted Patent: US 7,300,584 B2
• Time in Patent Office: Days
• US Class Current: 210/629
• CPC Class Codes: C02F 2303/12 Prevention of foaming
• CPC Class Codes: C02F 3/2873 with internal draft tube circulation
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel

Abstract

A process and a device for biological treatment of a suspension in a bioreactor (2) are described. To circulate the suspension, at least some of the suspension is routed through a vertically aligned guide zone (5) so that a vertical flow of the suspension is produced. To control sediment problems, it is suggested that by feeding a fluid, especially a free liquid jet, via at least one nozzle (11), a horizontal flow is superimposed on the vertical flow in the vicinity of the bottom of the bioreactor (2), by which a spiral flow to the central outlet area of the bioreactor (2) is produced (FIG. 1).

Claims

1. In a process for biological treatment of a suspension in a bioreactor that has a central outlet area near the bottom and in which to circulate the suspension, at least some of the suspension is routed through a vertically aligned guide zone so that a vertical flow of at least a portion of the suspension is produced, which flow extends into the vicinity of the bottom of the bioreactor or proceeds from the vicinity of the bottom of the bioreactor, the improvement comprising feeding at least one horizontal jet of fluid superimposing on the vertical flow in the bottom part of the bioreactor, so as to establish a spiral flow to the central outlet area of the bioreactor.

2. A process according to claim 1, wherein the jet of fluid is fed into the bioreactor at a flow velocity of 10 to 15 m/s.

3. A process according to claim 1, wherein the jet of fluid is fed into the bioreactor at a volumetric flow rate of 300 to 600 m³/h.

4. A process according to claim 1, wherein in the bottom part of the bioreactor at the bioreactor wall, the spiral flow has a flow velocity of about 0.5 m/s.

5. A process according to one of claims 1, wherein the jet of fluid is fed into the bioreactor at an offset angle to radial flow of 40 to 50°

.

6. A process according to claim 1, wherein the fluid is fed into the bioreactor at angle of 0 to 10°

downward from the horizontal.

7. A process according to claim 6, wherein the fluid is fed into the bioreactor at angle of >

0 to 10°

.

8. A process according to claim 1, comprising withdrawing suspension from the bioreactor and recycling said suspension into the bioreactor via a nozzle as said at least one horizontal jet of fluid.

9. A process according to claim 1, wherein the jet of fluid is fed into the bioreactor via several nozzles distributed on the periphery of the bioreactor in the vicinity of the bottom.

10. A process according to claim 9, wherein the nozzles are supplied with a jet of fluid, at different times.

11. A process according to claim 9, wherein the nozzles are operated with a common pump and are successively supplied from said common pump by means of cyclic switching.

12. A process according to claim 8, wherein the suspension is suctioned off from the center of the bottom of the bioreactor.

13. A process according to claim 8, wherein fluid that is suctioned off from the bioreactor is fed into the bioreactor in part or in a time sequence via at least one upper nozzle to form a jet of fluid, the nozzle is provided in the area of the suspension fill level such that the surface of the suspension and/or the top scum floating on the surface of the suspension is forced into rotary flow.

14. A process according to claim 13, wherein the jet of fluid from the at least one upper nozzle is fed into the fermentation reactor via nozzles that are located tangentially on the periphery of the tank.

15. A process according to claim 14, wherein the upper nozzles are supplied from the same pump as the nozzles located in the vicinity of the bottom.

16. A device for biological treatment of a suspension comprising a bioreactor for receiving the suspension, a vertically aligned guide means in the interior of the bioreactor that extends into the vicinity of the bottom region of the bioreactor for circulating the suspension, and further comprising at least one nozzle for feeding a fluid into the bioreactor in the vicinity of the bottom of the bioreactor.

17. A device according to claim 16, wherein said at least one nozzle is supplied with the suspension via a pump and a feed line connected to the interior of the bioreactor.

18. A device according to claim 16, wherein several nozzles are distributed in the vicinity of the bottom on the periphery of the bioreactor.

19. A device according to claim 18, wherein the nozzles are connected to a common pump.

20. A device according to claim 18, wherein the nozzles are arranged with a tilt angle against the horizontal of 0 to 10°

.

21. A device according to claim 18, wherein the nozzles are arranged with a tilt angle against the horizontal of >

0 to 10°

.

22. A device according to claim 17, wherein the bioreactor bottom has an incline from the edge of the tank to the center of 10 to 20°

.

23. A device according to claim 17, wherein the feed line connected to the interior of the bioreactor is additionally connected to at least one upper nozzle that is located in the top region of the bioreactor in the area of the suspension fill level.

24. A device according to claim 23, wherein the at least one upper nozzle is located tangentially on the periphery of the tank.

25. A device according to claim 23, wherein the at least one upper nozzle is connected to the same pump as the nozzle that is located in the vicinity of the bottom of the bioreactor.