Backward-Facing Step

• US 20110136212A1
• Filed: 12/04/2009
• Published: 06/09/2011
• Est. Priority Date: 12/04/2009
• Status: Active Grant

• Current Assignee: Aurora Algae, Incorporated (Reliance Industries Limited)
• Original Assignee: Aurora Algae, Incorporated (Reliance Industries Limited)
• Inventors: Rice, David, Parsheh, Mehran, Radaelli, Guido
• Granted Patent: US 8,748,160 B2
• Time in Patent Office: Days
• US Class Current: 435/257.1
• CPC Class Codes: C12M 21/02 Photobioreactors culturing algae A01G33/00, A01H4/001, C12N1/12
• CPC Class Codes: C12M 23/18 Open ponds; Greenhouse type or underground installations
• CPC Class Codes: C12M 27/02 Stirrer or mobile mixing elements
• CPC Class Codes: C12M 29/14 Pressurized fluid
• CPC Class Codes: C12M 41/00 Means for regulation, monitoring, measurement or control, e.g. flow regulation controlling or regulating chemical, physical or physicochemical processes B01J19/0006; heating or cooling apparatus for laboratory use B01L7/00; electro optical investigation of individual particles, flow cytometers G01N15/14; automatic analysis G01N35/00; controlling or regulating in general G06N
• CPC Class Codes: C12M 41/26 of pH
• CPC Class Codes: C12M 41/34 of gas
• CPC Class Codes: C12M 41/36 of biomass, e.g. colony counters or by turbidity measurements electrooptical investigation of individual particles G01N15/14, flow cytometers G01N15/1404

Abstract

Systems, methods and media for carbonation of fluid in an algae cultivation pond via the use of backward-facing steps are disclosed. In a first aspect, a method for initiating carbonation of a fluid flow in an algae cultivation pond is disclosed. Fluid flow is initiated over a backward-facing step in the algae cultivation pond. A backflow region is generated in the fluid flow downstream of the backward-facing step. Carbon dioxide is provided to the backflow region.

Claims

1. A method for initiating carbonation of a fluid flow in an algae cultivation pond, the method comprising:

initiating fluid flow over a backward-facing step in the algae cultivation pond;

generating a backflow region in the fluid flow downstream of the backward-facing step; and

providing carbon dioxide to the backflow region.

2. The method of claim 1, wherein the backflow region corresponds to a closed flow loop.

3. The method of claim 1, wherein the backflow region interfaces a dividing streamline.

4. The method of claim 1, wherein the backflow region is bounded by a reattachment region of a boundary layer associated with the backflow region.

5. The method of claim 4, wherein providing carbon dioxide to the backflow region includes providing carbon dioxide in the reattachment region.

6. The method of claim 1, wherein the carbon dioxide is provided to the backflow region at a rate ranging from approximately 2.2 to approximately 2.9 standard cubic feet per hour per meter of a channel width associated with the backflow region.

7. A system for initiating carbonation of a fluid flow in an algae cultivation pond, the system comprising:

a step forming a portion of a pond bed of an algae cultivation pond; and

a gas diffuser coupled to the pond bed of the algae cultivation pond downstream of the step, the diffuser configured to introduce carbon dioxide in gas form into the fluid flow.

8. The system of claim 7, wherein a position of the diffuser is based on a height of the step.

9. The system of claim 7, wherein a ratio between a downstream distance between the diffuser and the step and a height of the step ranges between 5 and 10.

10. The system of claim 8, wherein the height of the step ranges from five centimeters to thirty-five centimeters.

11. The system of claim 7, wherein the diffuser is coupled to a source of carbon dioxide, the carbon dioxide in gas form.

12. The system of claim 7, further comprising a jet circulation system configured to initiate circulation of the fluid flow in the algae cultivation pond.

13. The system of claim 7, further comprising a paddle wheel configured to initiate circulation of the fluid flow in the algae cultivation pond.

14. A system for initiating carbonation of fluid in an algae cultivation pond, the system comprising:

a step forming a portion of a pond bed of the algae cultivation pond; and

a nozzle coupled to a pressurized fluid source, a carbonation source and the step, the nozzle configured to generate a jet of carbonated fluid from the pressurized fluid source and the carbonation source.

15. The system of claim 14, wherein the jet of carbonated fluid initiates circulation of the fluid in the algae cultivation pond.

16. The system of claim 14, wherein the position of the nozzle downstream of the step is based on a height of the step.

17. The system of claim 14, wherein the nozzle is coupled to the step.

18. The system of claim 14, wherein an outlet of the nozzle is oriented such that the jet of carbonated fluid is discharged in a direction of bulk fluid flow in the algae cultivation pond.

19. The system of claim 14, wherein an outlet of the nozzle is oriented such that the jet of carbonated fluid is discharged at an angle to bulk fluid flow in the algae cultivation pond.

20. A system for initiating carbonation of fluid in an algae cultivation pond, the system comprising:

a step forming a portion of a pond bed of the algae cultivation pond;

a carbonation input coupled to the pond bed of the algae cultivation pond downstream of the step, the carbonation input configured to release carbon dioxide into the fluid flow;

a pH sensor;

a processor; and

a computer-readable storage medium having embodied thereon a program executable by the processor to perform a method for adjusting a concentration of carbon dioxide in the algae cultivation pond, wherein the computer-readable storage medium is coupled to the processor, the processor executing instructions on the computer-readable storage medium to;

measure a pH associated with the fluid in the algae cultivation pond via the pH sensor; and

initiate the release of carbon dioxide from the carbonation input based on the measured pH.

21. The system of claim 20, wherein the computer-readable storage medium is further configured to:

measure a flow velocity of the fluid in the algae cultivation pond; and

adjust a position of the gas diffuser based on the measured flow velocity.