Enhanced practical photosynthetic CO2 mitigation

• US 6,667,171 B2
• Filed: 07/18/2001
• Issued: 12/23/2003
• Est. Priority Date: 07/18/2000
• Status: Expired due to Term

• Current Assignee: Ohio University
• Original Assignee: Ohio University
• Inventors: Kremer, Gregory G., Vis-Chiasson, Morgan L., Bayless, David J.
• Primary Examiner(s): Redding, David A.
• Application Number:
  US09/908,369
• Publication Number:
  US 20020072109A1
• Time in Patent Office: 888 Days
• Field of Search: 422/168, 422/186, 435/292.1, 435/297.1, 435/297.2, 435/297.4
• US Class Current: 435/292.1
• CPC Class Codes: B01D 2251/95 Specific microorganisms
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/84 Biological processes
• CPC Class Codes: C12M 21/02 Photobioreactors culturing algae A01G33/00, A01H4/001, C12N1/12
• CPC Class Codes: C12M 25/02 Membranes; Filters filters or filtration in general B01D24/00-B01D41/00
• CPC Class Codes: C12M 29/02 Percolation
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/59 Biological synthesis; Biological purification

Abstract

This process is unique in photosynthetic carbon sequestration. An on-site biological sequestration system directly decreases the concentration of carbon-containing compounds in the emissions of fossil generation units. In this process, photosynthetic microbes are attached to a growth surface arranged in a containment chamber that is lit by solar photons. A harvesting system ensures maximum organism growth and rate of CO₂ uptake. Soluble carbon and nitrogen concentrations delivered to the cyanobacteria are enhanced, further increasing growth rate and carbon utilization.

Claims

1. An apparatus for removing a carbon-containing compound from a flowing gas stream, said apparatus comprising:

(a) at least one substantially immobile membrane mounted in said gas stream;

(b) a plurality of photosynthetic microbes, selected from the group of algae and cyanobacteria, on said membrane;

(c) a water and nutrient delivery device including a liquid-conveying conduit having at least one opening near a top edge of said at least one membrane for delivering water and nutrients in the conduit near the top edge of the membrane, wherein the membrane permits water and nutrients to flow through the membrane by capillary action; and

(d) means for changing a pressure of the water front a microbe-sustaining pressure, wherein water and nutrients are supplied to the microbes without substantial removal of microbes from the membrane, to a microbe-removing pressure, wherein at least water is applied to the membrane to remove at least some of the microbes from the membrane.

2. An apparatus in accordance with claim 1, further comprising means for cooling the gas upstream of the membrane.

3. An apparatus in accordance with claim 2, wherein the temperature of the gas near said membrane is less than about 75 degrees Centigrade.

4. An apparatus in accordance with claim 1, wherein the temperature of said gas near the membrane is less than about 75 degrees Centigrade.

5. An apparatus in accordance with claim 1, wherein the temperature of said gas is greater than about 50 degrees Centigrade.

6. An apparatus in accordance with claim 1, wherein the water and nutrient delivery device comprises at least one liquid-conveying conduit having at least one opening adjacent the membrane near the top edge of the membrane for injecting the liquid into the membrane.

7. The apparatus in accordance with claim 6, wherein the means for changing a pressure further comprises means for varying the pressure over time between the microbe-sustaining pressure and the microbe-removing pressure.

8. An apparatus in accordance with claim 1, further comprising means for illuminating said photosynthetic microbe with a light source for a period of time.

9. An apparatus in accordance with claim 6, wherein said light source includes fiber optics.

10. The apparatus in accordance with claim 1, wherein said cyanobacteria is Cyanidium.

11. The apparatus in accordance with claim 1, wherein said cyanobacteria is Nostoc.

12. The apparatus in accordance with claim 1, wherein said membrane is a polyester.

13. The apparatus in accordance with claim 1, wherein said membrane is tetraflouroethylene.

15. The apparatus in accordance with claim 1, wherein the water and nutrient delivery device further comprises at least one nozzle spaced from the membrane near the top edge of the membrane for spraying the water and nutrients onto the membrane across a gap between the nozzle and the membrane.

14. An apparatus for removing carbon dioxide from a flowing gas stream, said apparatus comprising:

(a) at least one substantially immobile membrane mounted in said gas stream;

(b) a plurality of photosynthetic microbes selected from the group of algae and cyanobacteria on said membrane;

(c) means for illuminating said photosynthetic microbe for a period of time;

(d) a water and nutrient delivery device including at least one liquid-conveying conduit seating against the membrane near a top edge and openings in the conduit for injecting water and nutrients in the conduit into the top edge of the membrane, wherein the water and nutrients flow at least through the membrane by capillary action; and

(e) means for changing a pressure of the water from a microbe-sustaining pressure, wherein water and nutrients are supplied to the microbes without substantial removal of microbes from the membrane, to a microbe-removing pressure, wherein at least water is applied to the membrane to remove at least some of the microbes from the membrane.