Hybrid photobioreactor for microalgae cultivation and atmospheric carbon dioxide capture

Abstract

This invention relates to a hybrid photobioreactor device capable of facilitating the occurrence of light-dark reactions in a sequential process within a single system. This is done to increase biomass production of microalgae / cyanobacteria cultures, with real-time monitoring of growth parameters. This device is functionally divided into five components: 1) a closed flat-panel bioreactor unit; 2) a light source platform unit; 3) a microalgae culture suspension transfer pump unit; 4) a dark-tube bioreactor unit made of opaque material where the dark reactions occur; and 5) a data logger module to monitor photosynthesis parameters. The ratio of the microalgae culture residence time in the light-panel bioreactor, where the light reactions occur, to the residence time in the dark-tube bioreactor, where the dark reactions occur, is adjusted to achieve effective and efficient operating conditions to support microalgae growth.

Description

[0001] Description

[0002] HYBRID PHOTOBIOREACTOR FOR MICROALGAE CULTIVATION AND ATMOSPHERIC

[0003] CARBON DIOXIDE CAPTURE

[0004] Invention Engineering Field

[0005] This invention relates to a device and method for photosynthetic microalgae cultivation used to increase biomass production while capturing atmospheric carbon dioxide ( C02 ) gas in an isothermal farming mode that allows for real-time monitoring and control of operational parameters , successive treatment of dark and light photosynthesis reactions in one system, and regulation of photon flux density from a light source field so as to result in increased microalgae biomass productivity as well as the rate of carbon dioxide ( C02 ) gas removal capacity and the optimum rate of 02 gas formation at certain photon flux density conditions .

[0006] Background of the Invention

[0007] Microalgae biomass is globally in high demand among various industries because it is a source of various important chemical compounds ( such as various fatty acids , phycobiliproteins , carotenoids , various vitamins , various amino acids , carbohydrates ) for functional foods , pharmaceuticals , poultry feed, fish feed, cosmetics , and even bioenergy . On the other hand, industrial activities increase greenhouse gas emissions ( one o f which is C02 ) , which leads to global warming and consequently climate change . This poses a challenge regarding how to create a microalgae cultivation system that can produce maximum biomass while simultaneously reducing C02 emissions through photosynthesis . Closed cultivation systems using photobioreactors are designed to convert light energy into desired bioproducts . Photobioreactor systems are more advantageous for microalgae cultivation than open systems due to their superior ef ficiency in removing C02 , a key component of the photosynthesis process . In addition, the photobioreactor system has higher productivity and maximum biomass concentration, reduces the risk of low contamination, low water mass loss (evaporation) and easier process control.

[0008] Technological inventions related to photobioreactors have also been disclosed, as contained in United States Patent No. US5162051A, dated November 10th, 1992, entitled "Photobioreactor" , which discloses a photobioreactor for cultivating photosynthetic microorganisms. The patent describes a number of baffles installed within the photobioreactor tank, forming a hollow space that allows light to enter through openings in the tank wall. However, the invention still has shortcomings and differences, namely: the atmospheric FCB in this proposed patent has the light source located on the top (outside) of the flat-panel photobioreactor .

[0009] Another invention, as disclosed in the World Intellectual Property Organization patent, No. WO 2015 / 147661 Al, dated October 1st, 2015, entitled " Photobi oreactor for C02 Bio-Sequestration with Immobilized Biomass of Algae or Cyanobacteria" , discloses a photobioreactor and a process for producing and harvesting microalgae involving a microalgae culture vessel that is at least partially transparent to allow light to enter the vessel. At least a portion of the parent vessel is coated with a transparent conductive oxide (TOO) layer. The TOO layer is transparent to visible light, which is necessary for algae growth, but is opaque to infrared light, thus reducing the thermal heating load in the photobioreactor. However, the aforementioned invention still has weaknesses and limitations, including the use of an immobilized microalgae / cyanobacteria cultivation system that requires an alginate gel support material to enable the immobilization of the microalgae culture; this material is expensive. In addition, the patent requires the use of a fairly expensive TCO coating.

[0010] Also disclosed in invention number S00201911868, "Microalgae Photobioreactor with Transparent PVC Tubular Tubes, " is an open- air microalgae photobioreactor with transparent polyvinyl chloride (PVC) tubing, which is less expensive and more durable. The tubing serves as a medium for the microalgae to receive sunlight for photosynthesis, allowing rapid microalgae growth. A feed tank, or plastic drum, is used to mix the nutrients and supply the C02 needed by the microalgae , thus improving their growth rate . Furthermore , within the feed tank is a micro-hydroelectric turbine connected to a generator to supply electricity to LED lights used for lighting at night . However, the invention does not yet disclose whether real -time observations can be made .

[0011] Another invention, numbered S 00202410068 , entitled "Carbon Capture Device Using a Microalgae Photobioreactor with Two Features , " describes a carbon / C02 capture and degradation device in the form of a photobioreactor with two main features : a modular design, allowing for easy assembly and removal , and a sel f- contained power supply in the form of a solar panel with a four- dimensional / positional air intake . This device consists of at least ( 1 ) a right panel containing a mini LED display, a right vertical TV, an inlet air blower, a C02 filter, an air sensor box, and an aerator . ( 2 ) a left panel containing a QR code , a left vertical TV, an 02 filter, an outlet air blower, a solar cell control panel , a control panel , an inverter, and a battery . ( 3 ) a main panel containing an aquarium, a di f fuser, a water sensor, and an algae hopper . ( 4 ) a bottom panel containing a bench, an outlet air blower, and an electrical outlet / plug . And there are also ( 5 ) solar cell units . This invention is characteri zed by a knockdown / modular connection feature so that it is easy to disassemble and reassemble , as well as the presence of a solar panel feature as an independent power supply for lighting at night . In addition, this tool can also be applied as a bench / seat at a bus stop . However, the invention has not been disclosed that observations can be carried out in real time as this invention proposes .

[0012] Furthermore , the proposed invention is intended to overcome the problems stated above by means of atmospheric FCB using microalgae or cyanobacteria cultures in the form of suspensions that circulate simultaneously through two types of photobioreactors ( flat panels and bubble columns ) with their respective functions in light and dark reactions in one process sequence .

[0013] Brief Description of the Invention

[0014] The main obj ective of this invention is to overcome the existing problem, namely the inef fectiveness of the photosynthesis process that occurs in conventional photobioreactor systems .

[0015] The invention is a hybrid photobioreactor system for microalgae cultivation and carbon dioxide capture where this photobioreactor system combines light and dark reactions in microalgae cultivation to make the carbon dioxide capture process more ef fective . It consists of a microalgae or cyanobacteria culture in the form of a suspension that can circulate simultaneously through a bioreactor in the form of a light panel ( 9 ) , a bioreactor in the form of a dark tube ( 6 ) , a light source panel whose photon flux density can be adj usted ( 10 ) , a circulation pump for trans ferring the culture suspension ( 8 ) , a process parameter sensor module for real-time monitoring and process control ( 14 ) which is characteri zed by a low-cost culture system in the form of a system that allows a microalgae or cyanobacteria culture suspension to simultaneously move from dark and light reactions , thereby increasing biomass productivity while capturing CO2 from the atmosphere .

[0016] Another obj ective of this invention is to homogeni ze the process of mixing CO2 contained in ambient air with microalgae or cyanobacteria biomass in the form of microalgae or cyanobacteria culture suspension ef ficiently and cheaply so that when this biomass moves to a translucent flat panel photobioreactor it will be able to undergo the maximum light reaction process in photosynthesis , and then by gravity trans ferred to a dark tube bioreactor to undergo the dark reaction in the photosynthesis process . These light and dark reactions simultaneously circulate in a controllable system .

[0017] Other obj ects and advantages and a more complete understanding of the invention are as follows as preferred embodiments and will be explained with reference to the accompanying drawings .

[0018] Short Description of Image

[0019] Figure 1 is a perspective view of the prototype of the atmospheric hybrid photobioreactor according to the present invention .

[0020] Complete Description of the Invention

[0021] The present invention will be fully described with reference to the accompanying drawings .

[0022] Referring to Figure 1 , which shows a complete detailed image of an atmospheric hybrid photobioreactor for microalgae cultivation and atmospheric carbon dioxide capture . The present invention relates to an atmospheric C02 hybrid photobioreactor ( C02 contained in the atmosphere ) for microalgae or cyanobacteria culturing, which allows light-dark reactions to occur in a sequential process within a single system) to increase the biomass production of microalgae cultures monitored in real time and allows control of process parameters . This device comprises :

[0023] 1 . Air compressor

[0024] 2 . Mi st separator A

[0025] 3 . Air Fl ow meter

[0026] 4 . C02 inlet gas sensor

[0027] 5 . Air Sparger

[0028] 6 . Dark tube bioreactor

[0029] 7 . Culture suspension fl ow meter

[0030] 8 . Culture suspension trans fer pump

[0031] 9 . Bright flat panel bioreactor

[0032] 10 . Light Source Panel

[0033] 11 . Bright flat panel bioreactor outlet hose

[0034] 12 . pH, DO, and temperature sensor probes

[0035] 13 . Mi st separator B

[0036] 14 . Headspace C02 sensor probe

[0037] 15 . Monitoring and control module 16. Data acquisition

[0038] Functionally, the 16 components are classified into 5 groups

[0039] (groups A to E, with a description of each group as follows:

[0040] A. Bright Flat Panel Bioreactor

[0041] B. Dark Tube Bioreactor

[0042] C. Circulation Pump

[0043] D. Light Source Panel

[0044] E. Monitoring and Control Panel

[0045] Berikut adalah keterangan masing-masing gugus fungsi dari f otobioreaktor hibrida atmosferik:

[0046] A. Bright Flat Panel Bioreactor Unit: This unit is part of the FCB2023 atmospheric hybrid photobioreactor. It is made of a translucent, hermetically sealed material and is tilted at a 9° angle to the unit's support base (9) to optimally receive light from the light source panel (10) , which can adjust the photon flux density for a specific residence time. This flat panel bioreactor is box-shaped with a capacity of 20% of the total working volume of the microalgae culture in the hybrid reactor. The function of this bright flat panel unit is to facilitate the light reactions in the photosynthesis process carried out by the microalgae culture within it. The flat panel unit receives microalgae culture input from the dark tube unit (6) through a hose connected to a flow meter (7) and flows to the circulation pump (8) . This hose holds approximately 10% of the total working volume of the microalgae culture in the system. The microalgae culture that has undergone light reaction in this bright flat panel unit, flows through an outlet hose (11) to the dark tube bioreactor unit (6) with the help of gravity, the output hose from the bright flat panel bioreactor (11) holds 4% of the total working volume of the microalgae culture. Thus the microalgae culture circulates from the bright flat panel bioreactor (9) and the dark tube bioreactor (6) continuously at a rate that can be adjusted as needed. B. The dark tube unit (6) : This is a part of the FCB2023 atmospheric hybrid photobioreactor. It is made of opaque material and is hermetically sealed. It contains 66% of the total working volume of the microalgae culture in this photobioreactor system. This unit is equipped with an air diffuser (5) located at the base of the tube. Air flows from the compressor (1) into the mist separator (2) to remove moisture. Its rate is regulated using a flowmeter (3) and fed to the air diffuser inlet. The function of the air diffuser (5) is to effectively agitate (advection) and diffuse atmospheric carbon dioxide (CO2) into the microalgae cells, allowing them to optimally bind CO2. Operating parameters in the dark tube such as CO2 concentration in the air stream fed into the air diffuser (5) , CO2 concentration in the air stream in the headspace, pH, temperature, dissolved oxygen (DO) concentration, are monitored in real time through a number of appropriate sensor probes (12) , which are installed on the top of this dark tube bioreactor unit (6) . The data cable is connected to the monitoring and control panel (15) by passing through the mist separator unit (14) so that data reading interference can be overcome properly.

[0047] C. Circulation pump unit (8) : is a unit that transfers microalgae culture from the dark reaction bioreactor unit (6) to the light reaction (9) whose flow rate can be adjusted using a flow meter (7) , thus making it possible to determine the residence time of the culture in the dark tube unit (6) . This stage is important in efforts to optimize the overall atmospheric system.

[0048] D. Light Source Panel Unit (10) : is a unit part of a hybrid photobioreactor made of a series of lamps that emit light at a certain wavelength to optimize the light reaction in the light panel bioreactor (9) in the photosynthesis process. This unit is very important as an energy source for the bioconversion process of inorganic compounds into microalgae biomass. The density of the photon flux produced can be adjusted according to the needs to optimize the photosynthesis process by adjusting the distance of the light source to the bright flat panel (9) .

[0049] E. The monitoring and control panel unit (15) is a unit part of the FCB2023 atmospheric hybrid photobioreactor which consists of a measurement data logger and a control data logger connected to each sensor probe (to measure the C02 concentration in the air flow entering the air diffuser (5) , the C02 concentration in the air flow in the headspace (14) after passing through the mist separator (13) , pH, temperature, dissolved oxygen (DO) concentration (12) . This real time monitoring data compilation is then connected to a computer set for data acquisition and processing (16) .

Claims

Claim1. A hybrid photobioreactor system for microalgae cultivation and carbon dioxide capture consisting of:• Atmospheric C02 input is compressed in an air compressor(1) ; then fed through a mist separator (2) with a certain flow rate regulated using a flow meter (3) to a dark tube bioreactor (6) made of opaque material through an air diffuser (5) at the base of the dark tube (6) ; this dark tube (6) is where the dark reactions in the photosynthesis process take place, the atmospheric C02 input is intended to add an inorganic carbon source to the microalgae or cyanobacteria culture cultured in the system;• The air diffuser (5) at the base of the dark tube bioreactor (6) is designed to optimize C02 absorption by microalgae or cyanobacteria cells;• Real-time monitoring is carried out on process parameters (temperature, pH, dissolved oxygen, and C02 headspace) using sensor module devices (12) and (14) which are previously passed through a mist separator (13) to eliminate measurement interference due to air humidity, which is then connected to the monitoring and control module unit (15) ;• The microalgae or cyanobacteria culture that has optimally absorbed C02 in the dark tube (6) is then transferred to the light flat panel bioreactor (9) using a circulation pump (8) at a certain flow rate using a flow meter (7) ;• The culture that has been moved into the light panel bioreactor (9) is then illuminated by a light source platform (10) whose photon flux density can be adjusted so that it can optimally undergo light reactions in the photosynthesis process; which is characterized by the dark reaction and light reaction processes taking place cyclically in a system whose reaction period can be regulated.

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