REACTOR WITH PLATE-SHAPED CATALYTIC MEMBRANE FOR DIRECT CONVERSION OF MICROALGAE INTO BIOFUELS

Abstract

In the present invention, a reactor (2) for direct conversion of microalgae in a growth medium into biofuels, prevents energy consumption, reduce operating costs, reduce thermal stress, and provide simultaneous separation of polar and nonpolar compounds and salts is disclosed. The reactor (2) subject to the present invention comprises at least one compartment (1) containing a plate-shaped catalytic membrane (3) and two cells, a warm water inlet (5), a warm water outlet (6), a wet microalgae inlet (7), a liquid products and unconverted wet algae outlet (8).

Claims

1. A reactor (2) with a plate-shaped catalytic membrane (3) for conversion of microalgae in a growth medium into biofuels characterized by comprising, at least one compartment (1) comprising a plate-shaped catalytic membrane (3) which directly converts microalgae into biofuel and separates products and/or raw materials in a reaction medium and two cells (4), a warm water inlet (5), wherein warm water with a temperature between 80 C.-90 C. enters through, a warm water outlet (6), wherein warm water with a temperature between exits through, a wet microalgae inlet (7), wherein wet microalgae enter through, a liquid products and unconverted wet algae outlet (8), wherein wet microalgae exit through.

2. The reactor (2) according to claim 1, the reactor (2) comprises one compartment (1).

3. The reactor (2) according to claim 1, the reactor (2) comprises two compartments (1) having a first compartment (9) and a last compartment (10).

4. The reactor (2) according to claim 3, the reactor (2) further comprises at least one intermediate compartment (11) between a first compartment (9) and a last compartment (10).

5. The reactor (2) according to claim 1-4, the warm water inlet (5) and the liquid products and unconverted wet algae outlet (8) are located in the upper right corner of the reactor (2), and the wet algae inlet (7) and warm water outlet (6) are located at the lower-left corner of the reactor (2) to create reverse flow when number of compartments is odd.

6. The reactor (2) according to claim 1-4, the warm water inlet (5) and the liquid products and unconverted wet algae outlet (8) are located in the lower right corner of the reactor (2), and the wet algae inlet (7) and warm water outlet (6) are located at the lower-left corner of the reactor (2) to create reverse flow when number of compartments is even.

7. The reactor (2) according to claim 1, wherein the surface of the membrane is covered with catalysts.

8. The reactor (2) according to claim 7, wherein the catalysts is alumina-silica supported nickel catalyst.

9. The reactor (2) according to claim 1, wherein the wet microalgae comprise a solid content between 2-10% in the growth medium.

10. The reactor (2) according to claim 9, wherein the growth medium comprises sea water and f/2 medium.

11. The reactor (2) according to claim 10, wherein f/2 medium comprises trace metals, vitamins, Na.sub.2SiO.sub.3.Math.9H.sub.2O, NaH.sub.2PO.sub.4.Math.H.sub.2O and NaNO.sub.3.

12. The reactor (2) according to claim 1, wherein the microalgae is Nannochloropsis oculata (N. oculata).

13. Working method of the reactor (2) according to claim 2 characterized by comprising the following steps: i. Entrance of the wet microalgae to one of the cells (4) through wet microalgae inlet (7), wherein the wet microalgae comprise a solid content between 2-10% in the growth medium, ii. At the same time, entrance of warm water with a temperature between 80 C.-90 C. to the cell (4) through warm water inlet (5) in order to bring the reaction temperature to the desired point, iii. After the entry of wet microalgae to the compartment (1), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, iv. The passing of water, polar products and salt to the other cell (4) through the membrane inside the compartment (1), v. After the end of the reaction, exit of liquid products and unconverted wet algae through the liquid products and unconverted wet algae outlet (8), vi. At the same time, exit of warm water through the warm water outlet (6).

14. Working method of the reactor (2) according to claim 3 characterized by comprising the following steps: i. Entrance of the wet microalgae to one of the cells (4) through wet microalgae inlet (7), wherein the wet microalgae comprise a solid content between 2-10% in the growth medium, ii. At the same time, entrance of warm water with a temperature between 80 C.-90 C. to the cell (4) through warm water inlet (5) in order to bring the reaction temperature to the desired point, iii. After the entry of wet microalgae to the first compartment (9), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, iv. The passing of water, polar products and salt to the other cell (4) through the membrane inside the first compartment (9), v. At the same time, the passing of the biofuels produced by the untransformed wet microalgae into the cell (4) in the last compartment (10), vi. In the last compartment (10), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, vii. The passing of water, polar products and salt to the other cell (4) through the membrane inside the last compartment (10), viii. Exit of liquid products and unconverted wet algae through the liquid products and unconverted wet algae outlet (8), ix. Exit of warm water through the warm water outlet (6).

15. Working method of the reactor (2) according to claim 4 characterized by comprising the following steps: i. Entrance of the wet microalgae to one of the cells (4) through wet microalgae inlet (7), wherein the wet microalgae comprise a solid content between 2-10% in the growth medium, ii. At the same time, entrance of warm water with a temperature between 80 C.-90 C. to the cell (4) through warm water inlet (5) in order to bring the reaction temperature to the desired point, iii. After the entry of wet microalgae to the first compartment (9), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, iv. The passing of water, polar products and salt to the other cell (4) through the membrane inside the first compartment (9), v. At the same time, the passing of the biofuels produced by the untransformed wet microalgae into the cell (4) in the intermediate compartment (11), vi. In the intermediate compartment (11), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, vii. The passing of water, polar products and salt to the other cell (4) through the membrane inside the intermediate compartment (11), viii. After that, the passing of the biofuels produced by the untransformed wet microalgae into the cell (4) in the last compartment (10), ix. In the last compartment (10), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, x. The passing of water, polar products and salt to the other cell (4) through the membrane inside the last compartment (10), xi. Exit of liquid products and unconverted wet algae through the liquid products and unconverted wet algae outlet (8), xii. Exit of warm water through the warm water outlet (6).

16. Working method of the reactor (2) according to claim 13-15, wherein the microalgae is Nannochloropsis oculata (N. oculata).

17. Working method of the reactor (2) according to claim 13-15, wherein the surface of the membrane is covered with catalysts.

18. Working method of the reactor (2) according to claim 17, wherein the catalysts is alumina-silica supported nickel catalyst.

19. Working method of the reactor (2) according to claim 13-15, wherein the wet microalgae comprise a solid content between 2-10% in the growth medium.

20. The reactor (2) according to claim 19, wherein the growth medium comprises sea water and f/2 medium.

21. The reactor (2) according to claim 20, wherein f/2 medium comprises trace metals, vitamins, Na.sub.2SiO.sub.3.Math.9H.sub.2O, NaH.sub.2PO.sub.4.Math.H.sub.2O and NaNO.sub.3.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1. Front view of the reactor (2) with one compartment.

[0017] FIG. 2. Front view of the reactor (2) with two compartments.

[0018] FIG. 3. Isometric view of the reactor (2) with more than two compartments.

[0019] FIG. 4. Front view of the reactor (2) with more than two compartments.

[0020] FIG. 5. Right view of the reactor (2) with more than two compartments.

[0021] FIG. 6. Left view of the reactor (2) with more than two compartments.

[0022] FIG. 7. Top view of the reactor (2) with more than two compartments.

[0023] FIG. 8. Bottom view of the reactor (2) with more than two compartments.

DESCRIPTIONS OF REFERENCES IN DRAWINGS

[0024] 1. Compartment [0025] 2. Reactor [0026] 3. Plate-shaped catalytic membrane [0027] 4. Cell [0028] 5. Warm water inlet [0029] 6. Warm water outlet [0030] 7. Wet algae inlet [0031] 8. Liquid products and unconverted wet algae outlet [0032] 9. First compartment [0033] 10. Last compartment [0034] 11. Intermediate compartment.

DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention relates to a reactor (2) with plate-shaped catalytic membrane (3) for direct conversion of microalgae in a growth medium into biofuels which prevents energy consumption, reduce operating costs, reduce thermal stress, and provide simultaneous separation of polar and nonpolar compounds and salts. The growth medium varies according to the type of algae. In an embodiment of the invention, the growth medium comprises sea water and f/2 medium. Said f/2 medium comprises trace metals, vitamins, Na.sub.2SiO.sub.3.Math.9H.sub.2O, NaH.sub.2PO.sub.4.Math.H.sub.2O and NaNO.sub.3. Said micro algae may be Nannochloropsis oculata (N. oculata).

[0036] In the present invention, a reactor (2) comprises at least one compartment (1) containing a plate-shaped catalytic membrane (3) which directly converts microalgae into biofuel and separates products and/or raw materials in a reaction medium and two cells (4), a warm water inlet (5) wherein warm water with a temperature between 80 C.-90 C. enters through, a warm water outlet (6) wherein warm water with a temperature between 80 C.-90 C. exits through, an wet microalgae inlet (7) wherein wet microalgae enter through, a liquid products and unconverted wet algae outlet (8) wherein liquid products and unconverted wet algae exit through. The plate-shaped catalytic membrane (3) converts microalgae into biofuel and separates products and/or raw materials in the reaction medium. Since the top of the plate-shaped catalytic membrane (3) is covered with the developed catalysts, it is used both for the reaction and for the separation of polar products and salt. The compartment (1) comprises a plate-shaped catalytic membrane (3) and two separate cells (4) in which the reaction products and the raw material, microalgae, in the environment decompose. The number of compartments (1) varies according to the amount of water in the growth medium of the algae, production capacity and reaction time. Thus, due to the parameters mentioned above (reaction time etc.), the reactor may have only one compartment or two compartments or more than one intermediate compartments (11) between the first compartment (9) and the last compartment (10). Especially, the number of compartments, which comprises a plate-shaped catalytic membrane (3) and two cells (4), is determined according to the reaction time to achieve a minimum of 96% algae conversion. The reactor (2) has a system using the plate-shaped catalytic membrane (3) infrastructure, and according to conventional methods, microalgae can be converted into biofuels such as sustainable jet fuel by using heterogeneous catalysts directly in low temperature and atmospheric pressure conditions in growth medium without harvesting and drying, and in-situ reaction of the products in water thanks to the membrane. The reactor (2) subject to the present invention is suitable for the use of microalgae grown in sea water and fresh water, and in fact, the salt in the sea water increases the microalgae transformation. The surface of the membranes is covered with catalysts synthesized using easily available, non-toxic and inexpensive materials. Said catalyst is alumina-silica supported nickel catalyst. Because of this ingredient, it is inexpensive and non-toxic.

[0037] In an embodiment of the invention, the reactor (2) comprises a compartment (1) containing a plate-shaped catalytic membrane (3) and two cells (4), a warm water inlet (5) wherein warm water with a temperature between 80 C.-90 C. enters through, a warm water outlet (6) wherein warm water with a temperature between 80 C.-90 C. exits through, an wet microalgae inlet (7) wherein wet microalgae enter through, a liquid products and unconverted wet algae outlet (8) wherein liquid products and unconverted wet algae exit through. Working method of the reactor (2) with one compartment comprises the following steps: [0038] i. Entrance of the wet microalgae to one of the cells (4) through wet microalgae inlet (7), wherein the wet microalgae comprise a solid content between 2-10% in the growth medium, [0039] ii. At the same time, entrance of warm water with a temperature between 80 C.-90 C. to the cell (4) through warm water inlet (5) in order to bring the reaction temperature to the desired point, [0040] iii. After the entry of wet microalgae to the compartment (1), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, [0041] iv. The passing of water, polar products and salt to the other cell (4) through the membrane inside the compartment (1), [0042] v. After the end of the reaction, exit of liquid products and unconverted wet algae through the liquid products and unconverted wet algae outlet (8), [0043] vi. At the same time, exit of warm water through the warm water outlet (6).

[0044] In another embodiment of the invention, the reactor (2) comprises two compartments (1) which are a first compartment (9) and a last compartment (10), a warm water inlet (5) wherein warm water with a temperature between 80 C.-90 C. enters through, a warm water outlet (6) wherein warm water with a temperature between 80 C.-90 C. exits through, a wet microalgae inlet (7) wherein wet microalgae enter through, a liquid products and unconverted wet algae outlet (8) wherein liquid products and unconverted wet algae exit through. Working method of the reactor (2) with two compartment comprises the following steps: [0045] i. Entrance of the wet microalgae to one of the cells (4) through wet microalgae inlet (7), wherein the wet microalgae comprise a solid content between 2-10% in the growth medium, [0046] ii. At the same time, entrance of warm water with a temperature between 80 C.-90 C. to the cell (4) through warm water inlet (5) in order to bring the reaction temperature to the desired point, [0047] iii. After the entry of wet microalgae to the first compartment (9), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, [0048] iv. The passing of water, polar products and salt to the other cell (4) through the membrane inside the first compartment (9), [0049] v. At the same time, the passing of the biofuels produced by the untransformed wet microalgae into the cell (4) in the last compartment (10), [0050] vi. In the last compartment (10), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, [0051] vii. The passing of water, polar products and salt to the other cell (4) through the membrane inside the last compartment (10), [0052] viii. Exit of liquid products and unconverted wet algae through the liquid products and unconverted wet algae outlet (8), [0053] ix. Exit of warm water through the warm water outlet (6).

[0054] In another embodiment of the invention, the reactor (2) comprises at least three compartments (1) which are a first compartment (9), a last compartment (10) and at least one intermediate compartments (11), a warm water inlet (5) wherein warm water with a temperature between 80 C.-90 C. enters through, a warm water outlet (6) wherein warm water with a temperature between 80 C.-90 C. exits through, an wet microalgae inlet (7) wherein wet microalgae enter through, a liquid products and unconverted wet algae outlet (8) wherein liquid products and unconverted wet algae exit through. Working method of the reactor (2) with at least three compartments comprises the following steps: [0055] i. Entrance of the wet microalgae to one of the cells (4) through wet microalgae inlet (7), wherein the wet microalgae comprise a solid content between 2-10% in the growth medium, [0056] ii. At the same time, entrance of warm water with a temperature between 80 C.-90 C. to the cell (4) through warm water inlet (5) in order to bring the reaction temperature to the desired point, [0057] iii. After the entry of wet microalgae to the first compartment (9), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, [0058] iv. The passing of water, polar products and salt to the other cell (4) through the membrane inside the first compartment (9), [0059] v. At the same time, the passing of the biofuels produced by the untransformed wet microalgae into the cell (4) in the intermediate compartment (11), [0060] vi. In the intermediate compartment (11), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, [0061] vii. The passing of water, polar products and salt to the other cell (4) through the membrane inside the intermediate compartment (11), [0062] viii. After that, the passing of the biofuels produced by the untransformed wet microalgae into the cell (4) in the last compartment (10), [0063] ix. In the last compartment (10), reacting wet microalgae on the plate-shaped catalytic membrane (3) surface, [0064] x. The passing of water, polar products and salt to the other cell (4) through the membrane inside the last compartment (10), [0065] xi. Exit of liquid products and unconverted wet algae through the liquid products and unconverted wet algae outlet (8), [0066] xii. Exit of warm water through the warm water outlet (6).

[0067] In another embodiment of the invention, when number of compartments is odd, the warm water inlet (5) and the liquid products and unconverted wet algae outlet (8) are located in the upper right corner of the reactor (2), and the wet algae inlet (7) and warm water outlet (6) are located at the lower-left corner of the reactor (2) to create reverse flow. On the other hand, when number of compartments is even, the warm water inlet (5) and the liquid products and unconverted wet algae outlet (8) are located in the lower right corner of the reactor (2), and the wet algae inlet (7) and warm water outlet (6) are located at the lower-left corner of the reactor (2) to create reverse flow. Reverse flow provides to enable heat transfer to take place and to contribute to the reduction of thermal stress.

[0068] The plate-shaped catalytic membrane (3) in the reactor (2) comprises two separate cells (4) from each other. Wet microalgae enter one of the cells (4) at the end points through wet microalgae inlet, wherein the wet microalgae comprise a solid content between 2-10% in the growth medium. At the same time, warm water with a temperature between enters the cell (4) of the last compartment (10) in order to bring the reaction temperature to the desired temperature levels. The flow of wet microalgae and warm water enter the compartments (1) in reverse directions. In the first compartment (9), wet microalgae enter the reactor (2), the wet microalgae react on the surface of the plate-shaped catalytic membrane (3). After the entry of wet microalgae in the first compartment (9), water, polar products and salt pass to the next cell (4) through the membrane inside the compartments (1). At the same time, the biofuels produced by the wet microalgae pass into the cell (4) in the next compartment (1). Here, the reaction on the plate-shaped catalytic membrane (3) surfaces the separation of the products with the membrane continues. This process continues in proceeding cells (4) until the number of microalgae is highly reduced. The reactor (2) is a continuous process and not a batch process. The reactor (2) must be continuously fed with microalgae in the growth medium, which is the raw material of the process, and warm water within the above-mentioned temperature range.

[0069] The cell wall of Nannochloropsis oculata (N. oculata) microalgae is composed of cellulose. Therefore, catalysts have been synthesized to have acidic properties. The synthesized catalysts act as a bifunctional catalyst because both functions perform the hydrolysis reaction and break the carbon-carbon bonds in the lipid structures emerging from the microalgae structure as a result of the hydrolysis reaction. Thus, with the hydrolysis reaction, the lipids/proteins that emerged from the cell (4) by breaking down with the microalgae cell (4) walls were broken on the catalyst surface and converted into products, such as biofuel or biochemical with different carbon distribution. Microalgae, whose sizes vary between 3-6 m, cannot penetrate into the pores of the catalysts; thus, reactions occur on the surface of the catalyst particles in the first stage. As the production of biofuels/biochemicals from microalgae without harvesting and drying within the scope of the invention takes place on heterogeneous catalysts covered membrane, it is another important feature that the limitations arising from mass transfer are reduced as compared to batch reactors.

[0070] GC/MS and HPLC analyzes of the products obtained at the exit of the reactor (2) were performed. GC/MS and HPLC results are shown in Table 1 and Table 2.

TABLE-US-00001 TABLE 1 GC-MS analysis results of non-polar products obtained from the reactor (2). Non-polar products Peak Area (%) C.sub.9H.sub.12 (Benzene, 1,3,5-trimethyl) 30.1 C.sub.14H.sub.30 (Tetradecane) 5.5 C.sub.16H.sub.34 (Hexadecane) 13.3 C.sub.20H.sub.42 (Eicosane) 10.2 C.sub.18H.sub.38 (Octadecane) 12.7 C.sub.18H.sub.36O.sub.2 (Hexadecenoic acid, ethyl ester) 16.5 C.sub.20H.sub.40O.sub.2 (Octadecanoic acid, ethyl ester) 11.8

TABLE-US-00002 TABLE 2 HPLC analysis results of polar products obtained from the reactor (2). Polar products Concentration (mg/L) Glucose 145 Glycerol 81 Arabinose 36

[0071] According to Table 1 and Table 2, the carbon distribution of the output products ranges from C9 to C20, and most products are linear. Obtained fatty acids and their esters also show that there are transesterification reactions occurring. The points to be considered during the use of the reactor (2) subject to the invention are as follows: [0072] The temperature of each compartment (1) in the reactor (2) should be at least 80 C. and maximum 150 C. In the preferred embodiment of the invention, the reaction temperature should be 80 C. Membranes withstand temperatures of 120 C. and above. However, the product distribution will vary, as carbon fractures will be higher above 80 C. [0073] Microalgae in the growth medium, which is the raw material of the process, and warm water in the above-mentioned temperature range should be fed to the reactor (2) [0074] Each compartment (1) in the reactor (2) should be brought to steady state conditions. [0075] The control of the obtained product should be followed by taking a sample every three hours by GC-MS. [0076] Plate-shaped catalytic membranes (3) in the reactor (2) should be checked every 3-5 years.

REFERENCES

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