Systems and methods for algae cultivation

Abstract

The present invention relates to a method for utilizing waste materials for cultivating algae, comprising the steps of forming a mixture comprising spent seawater and algae; spraying the mixture into a carbonation reactor pressurized with carbon dioxide; and removing the algae from the reactor and flowing the algae into a photobioreactor for cultivating algae. The present invention also relates to a system for cultivating algae, comprising at least one carbonation reactor pressurized with carbon dioxide and equipped with means for spraying the mixture comprising spent seawater and algae into the reactor, and at least one photobioreactor for cultivating the algae obtained from the carbonation reactor. The spent seawater is obtained from the production of precipitated calcium carbonate.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates generally to systems and methods for utilizing waste materials for algae cultivation. [Background technology]

[0002] Algae are considered a promising future biofuel feedstock because they have a faster growth rate than terrestrial plants, can grow on unproductive land, can utilize poor quality water, can remove pollutants from wastewater, and can sequester carbon dioxide.

[0003] Despite this potential, large-scale production of biofuels from algae remains uncertain, primarily due to a lack of process feasibility and the fact that it has proven to be capital and energy intensive.

[0004] It has been reported that integrating algal biofuel production with industrial or power plants may help increase the feasibility of the process, utilizing waste and by-products as a cheap source of carbon dioxide and nutrients for growing algae. Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore an object of the present invention to provide an improved system and method for disposing of algae cultures to waste. [Means for solving the problem]

[0006] In one aspect, the present invention provides a method for producing a pharmaceutical composition comprising: forming a mixture comprising spent seawater and algae; spraying the mixture into a carbonation reactor pressurized with carbon dioxide, which dissolves in the spent seawater and induces algae growth; removing the algae from the reactor; flowing the algae into a photobioreactor for algae cultivation; A method for culturing algae, comprising: The method is characterized in that the spent seawater is obtained from the production of precipitated calcium carbonate.

[0007] Advantageously, spent seawater has high levels of dissolved calcium ions which act as a natural facilitator for dissolving carbon dioxide, thus increasing the rate of carbon dioxide dissolution in the spent seawater, thereby increasing the concentration of bicarbonate ions which the algae consume as carbon building blocks. Additionally, the present invention utilizes a waste product (i.e., spent seawater) obtained from the production of precipitated calcium carbonate.

[0008] In one embodiment, the carbonation reactor is pre-filled with carbon dioxide to a pressure of up to 2 bar.

[0009] In one embodiment, the spent seawater may be supplemented with nutrients.

[0010] Preferably, the algae is of the genus Chlorella.

[0011] Typically, the algae accumulates at the bottom of the carbonation reactor, forming an algal column.

[0012] Typically, the algae flows out of the bottom of the carbonation reactor through an outlet and into a photobioreactor for algae cultivation.

[0013] Advantageously, in the cultivation of Chlorella spp., the use of spent seawater resulting from precipitated calcium carbonate production as a growth medium has consistently been shown to positively impact the growth profile of the algae strain by 35% (without carbon dioxide) and 39% (with carbon dioxide) compared to the use of regular seawater as a growth medium under the same conditions.

[0014] In one aspect, the present invention provides a method for producing a pharmaceutical composition comprising: at least one carbonation reactor pressurized with carbon dioxide and including means for spraying a mixture comprising spent seawater and algae into the reactor, the carbon dioxide dissolving in the spent seawater and causing algae growth to form an algae plume within the reactor and accumulate at the bottom; and At least one photobioreactor for cultivating the algae obtained from the carbonation reactor A system for cultivating algae, comprising: The system is characterized in that the spent seawater is obtained from the production of precipitated calcium carbonate.

[0015] In one embodiment, the carbonation reactor is pre-filled with carbon dioxide to a pressure of up to 2 bar.

[0016] In one embodiment, the carbonation reactor further comprises a valve located at the bottom configured to control the outflow of algae into the photobioreactor.

[0017] Typically, the algal pillars substantially prevent carbon dioxide from being released into the environment.

[0018] In one embodiment, the carbonation reactor further comprises at least one optical sensor for adjusting the height of the algae pillar and a pressure regulator for adjusting the pressure of carbon dioxide within the reactor.

[0019] In one embodiment, the carbonation reactor further comprises a pump mounted downstream of the atomizing means for pumping the mixture at a minimum flow rate to form small pressurized particles of the mixture that enter the carbonation reactor.

[0020] In one embodiment, the photobioreactor comprises several U-shaped low density polyethylene (LDPE) plates that serve as the body of the photobioreactor and ultraviolet lights.

[0021] In one embodiment, the photobioreactor further comprises an outlet for recirculating the algae solution.

[0022] To further explain the invention, it will be convenient to refer to the accompanying drawings, which show possible arrangements of the invention. Other arrangements of the invention are possible, and therefore the particularity of the accompanying drawings should not be understood as superseding the generality of the foregoing description of the invention. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram showing the process flow of the algae culture system of the present invention. [Figure 2] Figure 1 shows experimental results of algae growth in spent seawater (SS) compared to normal seawater under various conditions. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention discloses the use of waste materials, such as spent seawater resulting from the production of precipitated calcium carbonate, as a growth medium for algae cultivation. The spent seawater has a high level of dissolved calcium ions and exhibits a basic pH in the range of 8 to 10. Dissolved calcium ions act as a natural promoter for dissolving carbon dioxide, thus increasing the rate of carbon dioxide dissolution in the spent seawater, thereby increasing the concentration of bicarbonate ions that the algae consume as carbon building blocks. The algae utilized for cultivation are selected from the genera Parachlorella, Chlorella, Amphora, and Synechococcus. Preferably, the genus Chlorella is cultivated.

[0025] FIG. 1 illustrates a method for cultivating algae, including forming a mixture containing spent seawater and algae in a tank (104), where the tank is at a pressure of up to 5 bar. The spent seawater, a waste product from the production of precipitated calcium carbonate (102), can be further supplemented with nutrients such as nitrates, potassium, and phosphorus. The mixture is then sprayed into a carbonation reactor (106) pressurized with carbon dioxide from a carbon dioxide supply system, where the carbon dioxide dissolves in the spent seawater and induces algae growth. The carbonation reactor is pre-charged with carbon dioxide at a pressure of up to 2 bar before spraying the spent seawater and algae mixture into the reactor. The algae accumulate at the bottom of the carbonation reactor, forming an algae plume, which flows out of the bottom of the carbonation reactor through an outlet and into an algae cultivation photobioreactor (108). The temperature throughout the process is maintained at 25°C.

[0026] The photobioreactor contains several U-shaped low-density polyethylene (LDPE) panels that serve as the body of the photobioreactor. One end of the U-shaped LDPE serves as an inlet to receive algae from the carbonation reactor, and the other end serves as an outlet to recirculate the algae solution to the algae and spent seawater tanks. Both ends of the U-shaped LDPE are equipped with air spargers. The photobioreactor is also equipped with an ultraviolet light. A pump is attached to the outlet header of the photobioreactor to transport the algae solution to the algae and spent seawater tanks. Algae cultivation in the photobioreactor is carried out at atmospheric pressure.

[0027] The algae cultivation system includes at least one carbonation reactor pressurized with carbon dioxide and equipped with means for spraying a mixture containing spent seawater and algae into the reactor, where the carbon dioxide dissolves in the spent seawater, causing algae to grow and form an algae plume within the reactor, which accumulates at the bottom, and at least one photobioreactor for cultivating the algae obtained from the carbonation reactor. The spent seawater is a waste product from the production of precipitated calcium carbonate. The carbonation reactor is pre-filled with carbon dioxide at a pressure of up to 2 bar.

[0028] The carbonation reactor further includes a valve disposed at the bottom configured to control the outflow of the algae, the algae pillars being capable of substantially preventing carbon dioxide from being released into the environment through the valve.

[0029] The carbonation reactor further includes at least one optical sensor for adjusting the height of the algae pillars and a pressure regulator for adjusting the pressure of carbon dioxide within the reactor. A pump is mounted downstream of the spraying means for pumping the mixture at a minimum flow rate to form small pressurized particles of the mixture that enter the carbonation reactor.

[0030] Figure 2 shows the results of an experiment comparing algal growth in spent seawater (SS) with normal seawater under various conditions. The graph shows an increase in the daily algal growth rate from 0.41-0.43 OD (normal seawater) to 0.57-0.74 OD (SS). The dotted vertical lines indicate where algae were harvested for growth rate evaluation. The higher average daily algal growth rate in spent seawater compared to normal seawater is related to the higher concentration of bicarbonate ions present in spent seawater.

[0031] Experimental results for the cultivation of Chlorella consistently showed that using spent seawater resulting from precipitated calcium carbonate production as a growth medium positively impacted the growth profile of the algae strain by 35% (without carbon dioxide supplementation) and 39% (with carbon dioxide supplementation) compared to using regular seawater as a growth medium under the same conditions.

Claims

1. forming a mixture (104) comprising spent seawater and algae; spraying the mixture into a carbonation reactor pressurized with carbon dioxide, where the carbon dioxide dissolves in the spent seawater and induces growth of the algae; removing the algae from the reactor; flowing the algae into a photobioreactor for culturing algae (108); A method for culturing algae, comprising:

10. The method of claim 9, wherein the spent seawater is obtained from the production of precipitated calcium carbonate.

2. 10. The method of claim 1, wherein the carbonation reactor is pre-filled with carbon dioxide at a pressure of up to 2 bar.

3. 10. The method of claim 1, wherein the spent seawater may be supplemented with nutrients.

4. 2. The method of claim 1, wherein the algae is preferably of the genus Chlorella.

5. 10. The method of claim 1, wherein the algae accumulates at the bottom of the carbonation reactor to form an algae plume.

6. 10. The method of claim 1, wherein the algae flows out of the bottom of the carbonation reactor through an outlet and into the algae cultivation photobioreactor.

7. at least one carbonation reactor pressurized with carbon dioxide, comprising means for spraying a mixture comprising spent seawater and algae into said reactor, said carbon dioxide dissolving in said spent seawater and causing said algae to grow and form an algal plume within said reactor, accumulating at the bottom; and at least one photobioreactor for culturing the algae obtained from said carbonation reactor; A system for cultivating algae, comprising:

1. The system, wherein the spent seawater is obtained from the production of precipitated calcium carbonate.

8. 8. The system of claim 7, wherein the carbonation reactor is pre-filled with carbon dioxide at a pressure of up to 2 bar.

9. 8. The system of claim 7, wherein the carbonation reactor further comprises a valve disposed at the bottom configured to control the outflow of the algae into the photobioreactor.

10. 8. The system of claim 7, wherein the algal pillars substantially prevent carbon dioxide from being released into the environment.

11. 8. The system of claim 7, wherein the carbonation reactor further comprises at least one optical sensor for adjusting the height of the algae pillar and a pressure regulator for adjusting the pressure of carbon dioxide within the reactor.

12. 8. The system of claim 7, wherein the carbonation reactor further comprises a pump mounted downstream of the atomizing means for pumping the mixture at a minimum flow rate to form pressurized small particles of the mixture entering the carbonation reactor.

13. 8. The system of claim 7, wherein the photobioreactor comprises several U-shaped low density polyethylene (LDPE) sheets that serve as the body of the photobioreactor and ultraviolet lights.

14. 8. The system of claim 7, wherein the photobioreactor further comprises an outlet for recirculating the algae solution.

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