Slow-flow thin-layer photobioreactor

Abstract

The utility model relates to the technical field of microalgae photobioreactors, and discloses a slow flow thin layer type photobioreactor which comprises a supporting frame and a water tank container installed on the supporting frame, the water tank container is arranged in an inclined mode, and a plurality of baffles which are arranged in a staggered mode are arranged in the water tank container in an array mode in the extending direction. Through cooperation of the baffles which are arranged in the water tank container and are arranged in a staggered mode, the flowing track of algae liquid is in an S shape, the flowing path of the algae liquid is greatly increased, and the retention time of the algae liquid in the water tank container is prolonged; the flow velocity required for maintaining the algae liquid with the same thickness is obviously smaller than that required when the baffle plates are not arranged, so that the energy consumption caused by overhigh flow velocity can be reduced, and the energy consumption can be greatly reduced by adjusting the distance between the two adjacent baffle plates and the width of the water tank reactor.

Description

Technical Field

[0001] The utility model relates to the technical field of microalgae photobioreactor, and in particular to a slow-flow thin-layer photobioreactor. Background Art

[0002] Microalgae have been proven to contain a variety of nutrients and have great development potential in health products, aquatic bait, degradable plastics and biofuels. Currently, there are two main microalgae cultivation modes: open and closed. Runway pools and ponds are open. When culturing algae liquid, the liquid layer thickness is relatively high (for example, in runway pools, the liquid layer thickness is generally 10-30cm). The attenuation of sunlight when passing through the algae liquid is very serious, resulting in low density of the algae liquid. There are problems such as the large volume of algae liquid required to produce unit dry weight of microalgae biomass and high mixing energy consumption cost. Pipeline and flat-plate photobioreactors, as closed culture systems, have higher culture densities, but also have the problem of excessive mixing energy consumption.

[0003] In response to the problems of low density and high energy consumption in microalgae cultivation, some researchers have developed thin-layer reactors. Due to the short light path (low liquid layer thickness) of thin-layer photobioreactors, the density of algae liquid can reach 1.5-5.0g / L. Therefore, the volume of algae liquid required to produce unit weight of algae powder is smaller. Compared with pipeline reactors and flat-plate reactors, thin-layer reactors use the gravity of the algae liquid for flow mixing, and the mixing energy consumption may be reduced to a lower level. However, the flow rate of the thin-layer reactors currently developed is generally between 0.2 and 0.8 meters per second. The energy consumption in this flow rate range is 4-5 times that of the raceway pool, and the energy consumption per unit volume is about 23.5-58.2w / m 3 This energy consumption range is close to that of flat-plate reactors. Therefore, it is still necessary to significantly reduce its mixing energy consumption. In addition, the thin-layer reactors currently developed are all single-layer structures with low output per unit area. For the relevant content of the above-mentioned thin-layer photobioreactor, please refer to: Journal of Guangdong Ocean University_Development of thin-layer self-flowing photobioreactor and evaluation of microalgae cultivation effect_Chi Qinglei.

[0004] Based on the above, the present invention proposes a slow-flow thin-layer photobioreactor. Utility Model Content

[0005] In order to solve the problems mentioned in the above background, the present invention provides a slow-flow thin-layer photobioreactor.

[0006] In order to achieve the above technical purpose, the technical solution adopted in this utility model is as follows.

[0007] A slow-flow thin-layer photobioreactor comprises a support frame and a water tank container mounted on the support frame. The water tank container is arranged obliquely, and a plurality of staggered baffles are arranged in an array along an extension direction in the water tank container.

[0008] Furthermore, the water tank containers are arranged in multiple layers in the vertical direction, and in two adjacent layers of water tank containers, the lowest point of the upper water tank container is connected to the highest point of the lower water tank container.

[0009] Furthermore, the flow rate of the culture solution in the water tank container is less than or equal to 1 m / s.

[0010] Furthermore, the flow rate of the culture solution in the water tank container is 0.05-0.1 m / s.

[0011] Furthermore, an artificial light source is arranged on the support frame, and the artificial light source is located below the water tank container.

[0012] Furthermore, the lowest point of the bottom water tank container is connected to the aeration tank, and an aeration net and a measuring instrument are provided on the aeration tank, and the measuring instrument is used to measure the pH value, temperature value and dissolved oxygen content of the aeration tank;

[0013] A suction pump is provided at the liquid outlet end of the aeration tank, a connecting pipeline is provided at the liquid outlet end of the suction pump, a gas-liquid mixing tank is provided at the end of the connecting pipeline, the height of the gas-liquid mixing tank is higher than the top water tank container, and the highest point of the top water tank container is connected to the gas-liquid mixing tank through a liquid inlet pipe.

[0014] Furthermore, the suction pump is a peristaltic pump or a diaphragm pump.

[0015] Furthermore, a pressurized ventilation pipeline is provided at the bottom of the aeration tank, a pressurized pump is provided at the end of the pressurized ventilation pipeline, a normal pressure ventilation pipe is provided on the side of the gas-liquid mixing tank, and an air pump is provided at the end of the normal pressure ventilation pipe.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] In the present solution, by cooperating with a number of baffles arranged in a staggered manner in the water tank container, the flow trajectory of the algae liquid is made S-shaped, which greatly increases the flow path of the algae liquid and prolongs the residence time of the algae liquid in the water tank container. Compared with the case where no baffles are set, the flow rate required to maintain the same thickness of algae liquid is significantly smaller than the flow rate required when no baffles are set. Such a setting can reduce the energy consumption caused by excessive flow rate. Furthermore, referring to the specific implementation method, it can be seen that the energy consumption can be greatly reduced by adjusting the distance between two adjacent baffles and the width of the single-sided reactor.

[0018] Furthermore, the water tank container is set at an angle so that the flow of microalgae is completed by relying on the force of its own gravity on the inclined surface of the water tank container, reducing the dependence on the pump to provide the algae liquid flow rate. In addition, the design of the multi-layer water tank container can improve the space utilization of the entire reactor, increase the output while having a higher culture density, and further reduce the energy consumption per unit volume of the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of this utility model;

[0020] Figure 2 This is a top view of the algae liquid flow path in a reactor with a single-layer water tank container.

[0021] The reference numerals in the accompanying drawings are:

[0022] 1. Water tank container; 2. Aeration net; 3. Support frame; 4. Normal pressure ventilation pipe; 5. Gas-liquid mixing tank; 6. Connecting pipeline; 7. Suction pump; 8. Measuring instrument; 9. Aeration tank; 10. Pressurized ventilation pipeline; 11. Baffle. DETAILED DESCRIPTION

[0023] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined practical purpose, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0024] Reference Figure 1 A slow-flow thin-layer photobioreactor comprises a support frame 3 and a water tank container 1 installed on the support frame 3. Preferably, the water tank container 1 is provided with multiple layers in the vertical direction and each layer of the water tank container 1 is arranged obliquely. Specifically, in two adjacent layers of the water tank container 1, the lowest point of the upper water tank container 1 is connected to the highest point of the lower water tank container 1.

[0025] An artificial light source is arranged on the support frame 3, and the artificial light source can be an LED light panel. The artificial light source is located below the water tank container 1, and provides light source for the microalgae in each layer of the water tank container 1 by irradiating the artificial light source upward. This bottom irradiation method can reduce the loss of light in the light path and improve the utilization rate of the light source.

[0026] The lowest point of the bottom water tank container 1 is connected to the aeration tank 9, and the aeration tank 9 is provided with an aeration net 2 and a measuring instrument 8. The measuring instrument 8 is used to measure the pH value, temperature value and dissolved oxygen content of the aeration tank 9, which can be realized by the existing technology and will not be elaborated.

[0027] A suction pump 7 is provided at the liquid outlet end of the aeration tank 9. The suction pump 7 can be a peristaltic pump or a diaphragm pump or the like. A connecting pipe 6 is provided at the liquid outlet end. A gas-liquid mixing tank 5 is provided at the end of the connecting pipe 6. The height of the gas-liquid mixing tank 5 is higher than the top water tank container 1. The highest point of the top water tank container 1 is connected to the gas-liquid mixing tank 5 through a liquid inlet pipe.

[0028] A pressurized ventilation pipeline 10 is provided at the bottom of the aeration tank 9 , and a pressure pump is provided at the end of the pressurized ventilation pipeline 10 , through which carbon dioxide, air or flue gas is pressurized and sent into the aeration tank 9 .

[0029] A normal pressure ventilation pipe 4 is arranged on the side of the gas-liquid mixing tank 5 , and an air pump is arranged at the end of the normal pressure ventilation pipe 4 , through which carbon dioxide, air or flue gas is sent into the gas-liquid mixing tank 9 .

[0030] In a preferred embodiment, in order to reduce the flow velocity of the algae liquid, a plurality of staggered baffles 11 are arranged in an array along the extension direction in the water tank container 1. The significance of this is that the baffles 11 can slow down the flow velocity of the algae liquid, and the coordination of the plurality of staggered baffles 11 can make the flow path of the algae liquid in the water tank container 1 S-shaped, thereby greatly increasing the flow path of the algae liquid and prolonging the residence time of the algae liquid in the water tank container 1. Compared with the case where the baffles 11 are not provided, the flow velocity required to maintain the same thickness of the algae liquid is significantly smaller than the flow velocity required when the baffles 11 are not provided. Such a setting can reduce the energy consumption caused by the flow velocity.

[0031] How this utility works:

[0032] Pour algae liquid into the aeration tank 9, and then start the suction pump 7. The algae liquid in the aeration tank 9 is transported to the gas-liquid mixing tank 5 through the suction pump 7, and finally falls into the water tank container 1 at the top. The algae liquid flows along each layer of the water tank container 1, and finally flows back to the aeration tank 9, completing a cycle. This is repeated to achieve continuous flow of the algae liquid.

[0033] After the algae liquid flows steadily, the measuring instrument 8 is turned on to monitor the pH, temperature and dissolved oxygen content of the aeration tank 9 in real time;

[0034] After the algae liquid flows steadily, carbon dioxide, air or flue gas is injected into the aeration tank 9 through the pressurized ventilation pipeline 10, and carbon dioxide, air or flue gas is injected into the gas-liquid mixing tank 5 through the normal pressure ventilation pipe 4;

[0035] During the above process, when it is rainy and there is not enough sunlight, artificial light is turned on to provide light for the growth of microalgae.

[0036] Further:

[0037] For conventional thin-layer reactors:

[0038] Energy consumption P0 = Q*H*ρ*g;

[0039] Culture volume V = L*w*h;

[0040] Energy consumption per unit volume of reactor:

[0041] Substituting Q=v1*w*h into the energy consumption per unit volume of the reactor, we can get:

[0042] For this plan:

[0043] Energy consumption n =Q*H*ρ*g;

[0044] Culture volume V = L*w*h;

[0045] Energy consumption per unit volume of reactor:

[0046] Substituting Q=v2*h*L / n into the energy consumption per unit volume of the reactor, we can obtain:

[0047] Where: the length of the reactor is L, the width is w, the head is H, and the energy consumption is P (P0 is a traditional thin-layer reactor, P n is this scheme), the thickness of the liquid layer inside the reactor is h, the volume of the cultured algae liquid is V, the algae liquid flow rate is Q, the flow rate is v (v1 is the traditional thin layer reactor, v2 is this scheme), the density is ρ, and the acceleration of gravity is g;

[0048] n is the number of baffles in the single-layer water tank container in this scheme.

[0049] According to the above, the ratio of the energy consumption per unit volume of this solution to the energy consumption per unit volume of the traditional reactor is:

[0050] When the algae liquid flow rate is the same, that is, v1=v2, L / n is the distance between every two baffles. As long as it is smaller than the width w of the reactor, the energy consumption of this scheme is lower than that of the traditional thin layer reactor. In fact, the distance between the baffles can be much smaller than the width of the reactor. Therefore, this scheme can greatly reduce energy consumption.

[0051] Flow rate and liquid layer thickness test of a slow-flow thin-layer photobioreactor with a single-layer water tank container

[0052] Specific parameters of the reactor: reactor single-side length 100cm, single-side width 25cm, baffle length 20cm, each baffle interval 10cm, single-side slope 5%; reactor total length 125cm, total width 50cm, upper and lower inlet and outlet drop 10cm.

[0053] For this thin layer reactor, adding baffles according to the above parameters can obtain stable flow. The thickness of the liquid layer can be controlled by the flow rate, and its thickness can be stably maintained, while the required flow rate is significantly reduced. Compared with the traditional thin layer reactor that requires a large flow rate, this reactor can save a lot of energy consumption. The relationship between the measured flow rate and the corresponding liquid layer thickness is shown in the following table:

[0054] Table 1 Flow rate and corresponding power consumption per unit volume to maintain different liquid layer thicknesses

[0055]

[0056] According to the power and flow formula: power = flow × head × density × acceleration of gravity.

[0057] As shown in Table 1, when the liquid layer thickness is 1, 1.5, 2, 2.5, and 3 cm, the minimum power required is 0.059, 0.073, 0.103, 0.151, and 0.204 W, respectively. The corresponding culture volumes are 5.98, 8.97, 11.96, 14.95, and 17.94 L, respectively. After calculation, the input power required per unit volume is 9.9, 8.1, 8.6, 10.1, and 11.3 W / m3.

[0058] According to the reference: Journal of Guangdong Ocean University_Development of thin-layer gravity-flow photobioreactor and evaluation of microalgae cultivation effect_Chi Qinglei; it can be known that the flow rate of the thin-layer reactor without staggered baffles in traditional technology is 0.8m / s, and its culture volume is 6000L. After calculation, the input power required per unit volume is: 23.5w / m3. In comparison, the unit energy consumption of the new thin-layer photobioreactor in this scheme can be reduced by 52% to 65%.

[0059] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A slow-flow thin-layer photobioreactor, comprising a support frame (3) and a water tank container (1) mounted on the support frame (3), characterized in that: The water tank container (1) is arranged in an inclined manner, and a plurality of baffles (11) arranged in a staggered manner are arranged in an array along an extension direction in the water tank container (1).

2. A slow-flow thin-layer photobioreactor according to claim 1, characterized in that: The water tank container (1) is provided with multiple layers in the vertical direction, and in two adjacent layers of water tank containers (1), the lowest point of the upper water tank container (1) is connected to the highest point of the lower water tank container (1).

3. The slow-flow thin-layer photobioreactor according to claim 1 or 2, characterized in that: The flow rate of the culture solution in the water tank container (1) is less than or equal to 1 m / s.

4. The slow-flow thin-layer photobioreactor according to claim 1 or 2, characterized in that: The flow rate of the culture solution in the water tank container (1) is 0.05-0.1 m / s.

5. A slow-flow thin-layer photobioreactor according to claim 1 or 2, characterized in that: An artificial light source is arranged on the support frame (3), and the artificial light source is located below the water tank container (1).

6. The slow-flow thin-layer photobioreactor according to claim 2, characterized in that: The lowest point of the water tank container (1) at the bottom is connected to the aeration tank (9), and an aeration net (2) and a measuring instrument (8) are provided on the aeration tank (9). The measuring instrument (8) is used to measure the pH value, temperature value and dissolved oxygen content of the aeration tank (9); A suction pump (7) is provided at the liquid outlet end of the aeration tank (9), a connecting pipeline (6) is provided at the liquid outlet end of the suction pump (7), a gas-liquid mixing tank (5) is provided at the end of the connecting pipeline (6), the height of the gas-liquid mixing tank (5) is higher than the top water tank container (1), and the highest point of the top water tank container (1) is connected to the gas-liquid mixing tank (5) via a liquid inlet pipeline.

7. The slow-flow thin-layer photobioreactor according to claim 6, characterized in that: The suction pump (7) is a peristaltic pump or a diaphragm pump.

8. The slow-flow thin-layer photobioreactor according to claim 6, characterized in that: A pressurized ventilation pipeline (10) is arranged at the bottom of the aeration tank (9), and a pressurized pump is arranged at the end of the pressurized ventilation pipeline (10). A normal-pressure ventilation pipe (4) is arranged on the side of the gas-liquid mixing tank (5), and an air pump is arranged at the end of the normal-pressure ventilation pipe (4).

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