Industrial photobioreactor with precise and intelligent control system

Abstract

Industrial photobioreactor with precise and intelligent control system is designed for cultivation of various algae species on an industrial scale for production of human and pharmaceutical grade algae. The device has high efficiency and productivity in terms of quantity, quality and growth rate, in terms of production of various algae, in the electrical part, all parameters and effective factors are controlled precisely and intelligently through analysis of sensor data, and in the mechanical part, the steel half-funnel aeration system and diffuse aeration and airlift removal. Effective factors for increasing the efficiency of the electrical part include a precise and intelligent online control system for light, temperature, pH parameters, appropriate aeration strategy, beneficial growth stresses, and the addition of nutrients (CO2). Effective factors for increasing the efficiency of the mechanical part include ease of construction, operation, and maintenance, uniform rotation and agitation of the culture medium, facilitating the release of oxygen produced by photosynthesis from the tanks, continuous operation, long life of the device components, and elimination of shear stresses to prevent damage to algae. Some existing devices are not industrial, but rather research-based and not economically viable.

Description

Description of the invention Title of the invention Industrial photobioreactor with precise and intelligent control system Technical background of the relevant invention Agriculture - Mechanics - Electronics Technical problem and stating the objectives of the invention High performance in closed systems (photobioreactors) in terms of quantity, quality and speed of algae cultivation requires creating conditions for precise and intelligent control of light, temperature, pH parameters, appropriate aeration strategy and addition of nutrients (CO2 and creating two growth phases with beneficial stresses...) in the photobioreactor, which requires a completely advanced device to carry out the complex process of algae growth well. In addition to the necessity of controlling effective growth factors, the release of oxygen from photosynthesis from the tanks, the elimination of shear stresses to prevent damage to algae, the appropriate volume of algae growth tanks to create high productivity, ease of construction, operation and maintenance are also important. Without having a suitable algae cultivation system with the ability to adjust to cultivate different algae species and precise control and creating ideal intelligent conditions between all growth parameters in the photobioreactor device, it is not possible to achieve the desired result and high performance. For example, the amount of CO2 injection based on increasing concentration is necessary for the algae growth period, but the lack of intelligent control of CO2 injection causes changes in the pH level, which is harmful to algae growth.Also, in addition to the need to precisely control the amount and duration of light exposure to the photobioreactor, the interaction of other factors, including pH, concentration, aeration, temperature, etc., is very important. Therefore, because none of the parameters and processes of algae growth are independent of each other and affect each other, the lack of control of one of the parameters alone can prevent algae growth or destroy biomass. The lack of a suitable solution will be one of the problems and challenges of the photobioreactor device, which has been resolved in the claimed device. The objectives of the invention and construction of the aforementioned device are stated as follows: Lack of a comprehensive and complete industrial device that can achieve high performance. The inventive and design method reduces the cost of producing the photobioreactor device and increases productivity. The design of the device makes it easy to manufacture, operate, and maintain. All environmental and process parameters (including photosynthesis, oxygen release, and beneficial stresses...) are present in this device. The device can be adjusted to grow various types of algae. Precise and intelligent control of all factors affecting algae growth has a direct impact on the quality and speed of algae production. The design of the mechanical and electronic parts increases the performance and productivity of the photobioreactor in terms of quantity and quality of algae production. Continuous operation of the device without the need to stop algae production. Large tanks and uniform and gentle mixing of the culture medium increase the quality and speed of growth. Aeration system with a steel half-funnel eliminates airlift and eliminates harmful stresses. The device has the ability to increase the volume of the culture medium by increasing the number of cylinders with an integrated control system. Objective: The main purpose of this invention is to design and manufacture an industrial photoreactor device with a precise, adjustable and intelligent control system for all environmental and process factors, in addition to increasing the achievement of growth in terms of quantity, quality and speed, providing conditions for the growth of various algae species and having greater performance and productivity. The device is also designed with high-volume tanks and a completely isolated environment for human and pharmaceutical grades. In existing methods, performance and productivity are low and achieving a high growth rate per unit volume per time is not possible, therefore, designing a device with ease of construction, operation and maintenance is another goal. A description of the state of the prior art and the history of developments related to the claimed invention. Photobioreactors are devices used to grow and cultivate algae. Algae is a type of single-celled plant without roots and stems that reproduces and grows in water along with other conditions. This plant has existed since the beginning of the world and still exists today and is considered an intelligent plant. Algae is a product that is used in various pharmaceutical, food, cosmetic and health industries and is a rich source of lipids, vitamins and secondary metabolites. Astronauts use it as food on their journeys. The largest habitat of microalgae is in the seas and oceans, which is difficult to extract and separate in the seas, so microalgae are grown and produced in open systems (ponds) and closed systems (photobioreactors) to be produced and harvested in a more convenient and convenient way. The production volume in open systems is greater than in closed systems, but the possibility of contamination is greater due to the lack of sanitary conditions, and the product produced cannot be used in the food and pharmaceutical industries due to its low quality and unsanitary conditions.Also, in open systems, there is a lot of water loss (evaporation) in the ponds and they require more water resources than closed systems. The low quality of the product produced in the open system due to the settling of microalgae and the need for a lot of space are other disadvantages. Closed systems have many advantages and the product obtained will be more acceptable. Of course, the existing closed systems are not economical and the production volume in them is very small and they are mostly of a study and laboratory nature and sometimes have drawbacks that make designing a comprehensive system with high efficiency and performance a necessity. Photobioreactor models that use light (sun or artificial) as a photosynthesis accelerator have been built, but they have no industrial application, and are mostly for study and research purposes. Their shortcomings, including difficulty and complexity in construction, small volume of culture medium, and lack of precise and intelligent control of effective growth factors, have led to a decrease in performance and productivity (economic unprofitability). Existing photobioreactors, which are made as horizontal tubes, have some problems such as lack of precise control of pH along the long path of the tubes, lack of oxygen produced by photosynthesis in the tubes, which causes inappropriate culture conditions and slow and stop growth of microalgae or biomass is destroyed in general. The possibility of microalgae sticking to the walls inside the tubes, which will also be difficult to clean, was mentioned. The settling of microalgae due to the long length of the tubes or lack of turbulence and uniform rotation causes the formation of a sediment layer and lack of penetration of light and photosynthesis, and over time, the settled part is destroyed by inappropriate chemical and microbial processes, and other algae also have problems, and as a result, the final product cannot be used. Therefore, preventing sedimentation in the photobioreactor is very necessary. The alleged photobioreactor device has been designed in mechanical and electronic parts by conducting various simulations and tests. In the mechanical part, high-volume vertical cylinders have been used. The invention of a steel half-funnel and diffuse aeration of the cylinders, in addition to eliminating airlift, prevents shear stresses from entering the algae cells. The steel half-funnel provides uniform and gentle rotation and agitation of the culture medium liquid in the cylinder, provides conditions for photosynthesis and CO2 retention, and facilitates the exit of O2. In the electronic part, using sensors and the device panel, all environmental conditions and processes for the growth of different algae species are controlled accurately, intelligently, and automatically. The set of measures taken in the design of the alleged device increases the performance and productivity of algae growth in terms of quantity and quality per unit volume per time. Providing a solution to an existing technical problem along with an accurate, sufficient, and integrated description of the invention Microalgae are photosynthetic microorganisms used in the food, pharmaceutical, dyeing, and aquaculture and livestock industries. A plant without roots, stems, branches, and leaves that grows in water through photosynthesis. Algal biomass consists mainly of lipids, proteins, carbohydrates, and pigments, and the range of products is very diverse. Microalgae are considered the most valuable biological material on earth and have high reproductive power. For example, chlorella contains the highest amount of chlorophyll among all known plant species. Due to its rich and complete content, this algae compensates for possible deficiencies in the diet by providing protein, fiber, vitamins, mineral elements, etc. Chlorella is a single-celled freshwater algae and is easily cultivated in large quantities. This algae contains about 30% protein, 15% fat, 30% carbohydrates, and 5% minerals. Under suitable conditions, up to 50% of the dry weight of this algae is protein and 5.8% is fat.Chlorella proteins contain all the essential amino acids, so they are used as food in space travel. A photobioreactor is a closed system containing a biologically active medium, which is stable with light, energy, heat and nutrients. The main advantage of these closed systems is the reduction of the risk of algae contamination and, more importantly, the precise control of the conditions under which the algae are grown. Different types of algae require different conditions for growth. These conditions can be implemented more precisely in closed systems. Photobioreactors provide a closed culture environment that is safe from invasion and competition from other microorganisms and the conditions under which the microalgae are cultivated are effectively controlled. In addition, a wider variety of microalgae species can be cultivated in such closed environments. It should also be noted that the most important feature of reactors is their ability to limit contamination. Compared to open-air cultivation systems, the amount of biomass produced in photobioreactors is higher, the duration of microalgae cultivation is reduced, and the products produced in them have higher acceptance and acceptability in the market.In addition, photobioreactors are more flexible in selecting the type of microalgae species used, meaning that multiple microalgae species can be cultivated with a photobioreactor. Several factors influence the growth of algae and, consequently, the higher biomass productivity. Algae require light and nutrients at a certain temperature to grow. High light intensity, high oxygen levels and suboptimal temperatures negatively affect growth. The extent to which these factors affect depends on the algae species. Some grow well at low temperatures and low light intensity (e.g. Chlamydomonas nivalis), while others (e.g. Chlorella sorokiniana) are adapted to higher irradiance. To ensure good growth, the pH must be precisely regulated and the amount of carbon available to the algae must remain above a certain threshold. Another factor that needs to be regulated for continued algae growth is the amount of O2 available as a byproduct of photosynthesis. High concentrations of oxygen (O2) above 4% (about 2 nanomolar) can completely stop photosynthesis due to the competing activity of the oxygenase enzyme RuBisCO (ribulose bisphosphate carboxylase oxygenase). To avoid this problem, oxygen (O2) must be constantly monitored online and extracted from the culture medium inside the cylinders. Temperature regulation is important for all of the previously mentioned factors. High temperatures can reduce photosynthetic activity, or change the solubility of gases in the algae culture medium, and consequently negatively affect the creation of cultivation and growth conditions and reduce overall performance. In the experiments and studies conducted, the effect of light on cell growth and pigment capacity was investigated. To achieve this, two sets of experiments were conducted. The first group was exposed to light continuously for 24 hours and the second group was exposed to light for 12 hours. The effect of light on the growth of algae culture was tested in two modes: continuous light cycle and discontinuous light cycle (12 hours light / 12 hours dark) with and without aeration to maximize the amount of pigment. The results obtained can be seen in the algae growth curve (Figure 1). The best mode is the light and dark cycle with aeration. Comparing the concentrations of the two experimental groups, it was observed that the 12-hour light / 12-hour dark cycle was more efficient than the 24-hour light cycle. Also, appropriate light intensity is of great importance, which affects photosynthetic activity, thus having a specific effect on growth rate. According to the experiment, the concentration of chlorophyll and carotenoids doubled in the 12-hour light / 12-hour dark cycle. In addition, high light density is another important point. Also, high cell density, limitation and low light density cause low growth rate. The highest pigment capacity was observed in the third experiment with a 12-hour light / 12-hour dark cycle. In the second experiment; the pigment capacity is higher than in the first experiment. The aeration problem in the first experiment caused the death of the algae cells; therefore, the number of viable cells decreased and the pigment capacity reached the lowest value in the first experiment. The third experiment was performed with aeration and a 12-hour light / 12-hour dark cycle, the amount of chlorophyll and carotenoids doubled. In addition to light, the availability of a carbon source is essential for photosynthesis. Without carbon dioxide, no algal cell would be able to produce products such as carbohydrates (via glucose), fatty acids, and amino acids via the Kelvin cycle. The amount of carbon in the photobioreactor system is linked to the pH of the algal growth medium through a series of acid-base balances. When CO2 dissolves in the algal culture medium and undergoes a series of reactions, carbonic acid (H2CO3) forms bicarbonate ions (HCO3) and carbonate ions (CO3). The amount of freely dissolved CO2 and the equilibrium concentration of all three types of reactions are the keys to controlling the pH of the solution. The important point is that during the algal growth process, various interactions occur that are very important in maintaining the quality and growth of the algal. Just controlling one or two parameters is not enough and all the effective growth factors must be in ideal and balanced states. These conditions are only possible with the help of intelligent control. For example, light causes photosynthesis and changes the pH of the environment. Controlling the pH is necessary, which can be done in several ways (light, CO2, or adding acidic or basic substances, etc.).) is performed, where the best method is selected by intelligent control to achieve maximum performance. According to studies, the decrease in average light intensity is one of the problems of algae growth in photobioreactors. Light absorption decreases proportionally with the increase in biomass, especially in dense cultivations, therefore, a more efficient way to provide light for algae growth must be found. Therefore, the appropriate light intensity should be increased proportionally with the increase in algae biomass. Sunlight is abundant and free, so natural light is often used for large-scale microalgae cultivation, resulting in significant cost savings. However, sunlight inevitably varies due to climate, diurnal cycle, and season. The photon flux density (PFD) of sunlight on a sunny summer day is approximately over 2000 micromoles / m2 / s. However, microorganisms that use photosynthesis can only achieve a maximum efficiency of converting 8–10% of solar energy into biomass. In addition, the quality of the light spectrum is an important factor in algae cultivation. Although sunlight covers a wide spectrum, only the sunlight in the range of 400–700 nm, which is approximately equal to the visible spectrum, is photosynthetically active radiation. Photosynthetically active radiation comprises about 50% of sunlight. The portion of sunlight that is not photosynthetically active radiation is the main cause of temperature increase in the culture medium. In addition, photosynthetically inactive radiation at certain frequencies (e.g., ultraviolet radiation) is lethal to cells. The distribution of light intensity is very non-uniform due to absorption and scattering in the culture medium, and the attenuation of radiation depends on the wavelength of light, cell concentration, photobioreactor geometry, and distance from the light source or medium. In some cases, when the microalgae culture density reaches more than 10 g / L in the reactor, light can only penetrate a few millimeters, therefore, the growth rate of algal cells decreases significantly as the light penetration into the cell decreases. If the light intensity exceeds a critical value and reaches a saturation level, the light inhibits the growth of algae in the reactor. On the other hand, if the light intensity is lower than the level required for growth, its growth is limited by light and the cultivation becomes inefficient. Based on the growth rate (period), the reactor can be divided into three successive zones. First, the zone of strong light, which has a negative effect on the growth rate, extends from the exposed wall to the point where the incoming light energy is just enough to maximize algae growth. Second, the zone of weak light, which extends to the point where the light is just enough to sustain algae survival (no growth occurs).Third, the dark zone, where the algal cell growth rate is negative due to limited light availability. If the light intensity is higher than the allowable limit, the growth rate will be negative; therefore, this condition should be avoided as much as possible. Negative growth due to high light may be reversible or irreversible, depending on the light intensity and the duration of exposure of the microalgae to this light intensity. In the low light zone, photosynthetic activity decreases. As the light intensity increases in this zone, the growth rate increases. The amount of light that microalgae cells receive is critical to their photosynthetic efficiency and overall productivity, as mentioned in growth systems due to various conditions there is a limitation of light and maximum productivity cannot be achieved. When cultures become dense with cells during the growth period and its concentration increases, microalgae (cells) begin to shade each other, so light cannot reach all cells and the second problem of light limitation is due to the decrease and changes in light (sun) radiation during the day, if the aeration rate and algae recirculation are increased, the algal cells receive little light due to the high speed and the cells are exposed to light without saturation and on the other hand high aeration rate and creating more turbulence while increasing energy and costs, there is a possibility of damaging the cells and reducing growth. To achieve greater performance and solve the problem, control light and aeration according to the growth period, so that the amount of light increases in proportion to the growth of cells and the increase in concentration, and if necessary, use artificial light (LED) in different "light / dark" modes in addition to sunlight. Also, when algae are exposed to excessive radiation, it will be very useful to prevent damage by increasing aeration to an extent that does not damage the cell to reduce the number of photons that reach the photosystem. The solution used in the claimed device is to use a half-funnel and diffuse aeration in the culture medium cylinders with fine bubbles to create turbulence and uniform mixing and intelligent control of the amount of aeration and the end of the growth period. Another approach to engineering algae is to use wavelengths outside the usual wavelengths. The photosynthetically active radiation region in a reactor (PBR) is 700 to 400 nm, but there are certain types of algae that absorb light in the 750 to 700 nm region. In algae, the pigments chlorophyll a and b are very strong light receptors for photosynthesis. Their light absorption spectra are different, so chlorophyll a and b overlap each other's absorption strengths. Microalgae cell growth involves three cellular processes: photosynthesis, photorespiration, and dark respiration. Microalgae use and release light energy for photosynthesis. Oxygen, which is released as a byproduct of photosynthesis, accumulates in the culture medium and can lead to toxicity of the culture medium and threaten the survival of microalgae. Under adverse conditions, high temperatures combined with limited dissolved oxygen exacerbate the adverse effects. It is used as a carbon source in microalgae cultivation. It cannot be used directly, as the microalgae can only use it in the liquid phase. If the amount in the liquid phase is too low, it can be a limiting factor for growth (for example, when air is used as the feed gas and mixing in the photobioreactor is insufficient or when the length of the tubular photobioreactor is too long). It must be present in appropriate concentrations to avoid limiting cell growth. It is therefore appropriate that the partial pressure should be greater than 0.2 kPa (for example, 0.076 mol / m3, which is equivalent to 3 mg / L). Since the partial pressure in the atmosphere is 0.04 kPa, pure air (with a content of 0.035% by volume) is not sufficient to supply the gas, and a rich gas mixture is required. On the other hand, high concentrations of carbon dioxide can lead to a decrease in the pH of the culture, which leads to a decrease in the growth of some algae cells. Therefore, it is very important to maintain the pH level within the appropriate range. The optimal pH level depends on the type of algae species.For example, 1% to 4% relative to air is suitable for salina species. In general, the CO2 consumption rate and photoreceptors of each algae are different. Maximum photosynthetic efficiency is usually achieved when the concentration is in the range of 1% to 5% by volume. Also, for microalgae cultivation, a suitable space for gas exchange is considered in the cylindrical tank of the culture medium, which increases the mass exchange in the photobioreactor. The important point here is that the control of each parameter in terms of increasing or decreasing the effective growth factors is not independent and affects each other. Therefore, balancing and optimizing all conditions to achieve maximum performance requires intelligent and online control of all algae growth conditions. The intelligent control is able to estimate the duration of the algae growth period based on the daily growth graph based on the set program of the selected algae species and send the necessary alarms in case of problems. Algae growth is affected by the pH of the environment. The pH can be controlled by adding acid or base to the environment. However, the pH of the environment is usually lowered by distributing carbon dioxide gas in the culture medium. After dissolving in the medium, it turns into carbonic acid, bicarbonate and carbonate, which causes the release of ions ( ) and consequently reduces the pH of the environment. Most microalgae species have an optimal pH range of 7.8 to 8.2, although they can also be grown in a pH range of 7 to 9. However, some species can tolerate unfavorable conditions at more acidic or alkaline values. It is important to maintain the pH of the culture medium within the optimal range to prevent the culture from being destroyed due to the disruption of cellular processes due to low or high pH. As a result, the concentration of DCD is a critical factor affecting the pH of the culture. Since solubility depends on pH, DCD is the result of a balance between consumption by microalgae cells and mass transfer from the gas phase to the liquid phase. In general, the solubility in water is low. (1650 ppm at 25 °C in pure water) In addition, it is a factor of pH changes in the culture medium. This is due to the equilibrium. Also, the effect of pH changes on the solubility coefficient is significant. Studies show that at pH less than 4.5, most of the carbon is inorganic, while the ratio of bicarbonate ( ) is about 5.6. At pH equal to 3.8, almost all of the carbon is in the bicarbonate form.When the pH reaches about 1 / 4, the bicarbonate ratio decreases and becomes equal to the carbonate ratio (). At pH above 12, most of the inorganic carbon will be in the form of carbonate. Microalgae can rapidly utilize bicarbonate ions in the reactor, and some species are even able to utilize carbonate ions. Therefore, availability for microalgae growth at high pH values ​​becomes problematic. In such conditions, the pH during cultivation must be controlled to enhance uptake by the microalgae. Addition to the culture medium not only provides but also acts as a factor in controlling the pH of the medium. As the amount of carbon dioxide increases, the pH decreases. On the other hand, during the photosynthesis process, microalgae consume it, resulting in an increase in the pH of the environment. The pH of a solution indicates the concentration of ions in the solution. The relationship between pH and ion concentration is a logarithmic relationship (PH = -Log [ ). This equation indicates two points: First, whenever the pH of a solution decreases, the concentration of ions in the solution increases and the solution becomes acidic. The second point is that since the relationship between the pH of a solution and the concentration of ions is a logarithmic relationship, if the pH number decreases by one unit, the concentration of ions increases by ten units. In simpler terms, the pH number indicates the degree of acidity or alkalinity of a solution. Solutions with a pH between 0-7 are acidic solutions and solutions with a pH between 7-14 are basic solutions. PH equal to 7 indicates a neutral solution. (It has neither acidic nor basic properties) Temperature is the main factor in the photocatalytic reaction. It also affects the chemical equilibrium of the species, gas solubility and pH. The optimum temperature for microalgae cultures is generally between 20 and 24 °C, and most algae can tolerate water temperatures between 16 and 35 °C. The growth rate of cells decreases when the temperature is lower than 16 °C. Also, temperatures above 35 °C are lethal to some species. In summer, temperature control methods include the use of opaque sheets for shading, spraying water on the bright surface of the reactor when the temperature of the culture medium exceeds a certain value, overlapping the tubes, temperature regulation through food, etc. The first aspect of any aeration system is the creation of gas bubbles in a liquid medium. The number and size of the bubbles for distribution are determined by a variety of interacting factors, including the type of sparger (or diffuser) through which the gas is pumped, the gas flow rate or rate of flow used, and the properties of the liquid phase. Various types of sparger systems can be used for gas injection, the most common of which is perforated metal. The larger the number and size of holes in the diffuser or the porous plate used, the greater the surface area for gas exchange with the liquid due to the production of smaller bubbles in large numbers, and the more uniform the fluid flow or turbulence in the photobioreactor. Using the equation for the rate of increase of bubbles with small sizes and its effect on the density, viscosity and acceleration of the liquid, it is observed that the residence time of bubbles with small sizes in the photobioreactor increases. Therefore, the bubbles have more time to transfer mass to the surrounding fluid. On the other hand, with smaller bubbles, shear stress is also reduced. Also, by properly designing the aeration system with small bubbles for mixing and creating turbulence, a lower volumetric flow rate of air will be required, which also saves energy consumption. Computational Fluid Dynamics (CFD) is known as a subset of fluid mechanics. In this field, we use numerical solution methods to analyze various fluid mechanics problems. The tools used for this purpose are introduced as CFD software. Today, software in this field is able to simulate the most complex engineering problems well. Among CFD software, ANSYS is used more than others in the industry. Experience has also proven that the validity of the results obtained from ANSYS is very high if the principles of simulation are followed. The results of these simulations can provide significant insight into the behavior of prototype systems virtually. CFD software can be used to study many factors that affect fluid flow for bioreactor design, including: superficial gas velocity, gas holdup, bubble diameter, column geometry, light diffusion, and pressure. However, to produce an accurate hydrodynamic model in a photobioreactor, several factors need to be considered, including mesh resolution and the selection of the most appropriate model (smooth or turbulent) in multiphase flows such as air and water. Simulation of fluid interactions and modeling in bubble column photobioreactors is a complex engineering topic. The dynamic bubble system, whose behavior and characteristics change over time, has different flow and motion regimes that indirectly affect all aspects of performance in bioreactor design. Understanding the complexity of fluid dynamics in a bubble column reactor is very important for the application of the reactor in biotechnology-related industries and processes. It is important to understand the effect of hydrodynamics on the amount of production rate during transfer processes such as oxygen transfer between phases, nutrient mixing and its effect on the acidity and alkalinity of the mixture. To achieve an ideal design with higher performance and efficiency, a steel half-funnel with aerated diffuser has been used to produce very fine bubbles and uniform turbulence and rotation. Photobioreactor design requirements for algae growth: Algal growth systems must meet certain basic criteria to allow for the growth of algal products. Adequate light exposure is required to effectively activate photosynthesis, facilitate CO2 and O2 mass transfer for photosynthesis / respiration, provide water for intracellular solutions, provide appropriate pH conditions, maintain the necessary salts and minerals for osmotic conditions, maintain a stable temperature range (typically 20-30°C) and provide all the necessary elements including precise amounts of nitrogen, phosphorus, iron and other trace elements and free from any substances detrimental to cell growth, in addition to providing all of these requirements to prevent sedimentation with adequate aeration for mixing and fluid agitation for cell growth. Cultures must be mixed to provide adequate light to the cells, gas exchange, and avoidance of stratification (and formation of dead flow zones) that can lead to cell settling and death. Adequate aeration and agitation to prevent shear damage to the algal cells are important issues, and are complex in many ways, and optimal conditions are difficult to achieve. Therefore, designing a photobioreactor system, taking these aspects into account, is of great importance in ensuring the highest possible productivity. In the design of photobioreactors, light penetration and distribution, along with proper mixing and mass transfer, are among the critical conditions for algae growth. Various designs of vertical tubular photobioreactors at different scales are being investigated for algae cultivation. A photobioreactor is a bioreactor that uses a light source to provide photonic energy into the reactor. A photobioreactor refers to a closed system that has no direct exchange with the surrounding environment. These photoreactors are constructed of transparent vertical tubes to allow light to penetrate the reactor. A distributor (diffuser and half-stainless steel funnel) is located at the bottom of the reactor that breaks the gas into small bubbles, the gas distribution in this way provides good overall mixing that improves mass transfer and also the removal of products produced by photosynthesis. Photobioreactors have several major advantages over open systems: Reduces the possibility of contamination and allows algae cultivation to be carried out in a single crop. Provide better control of conditions such as pH, temperature, light, concentration, etc. They cause less waste. They prevent water evaporation. It allows access to higher cell concentrations. The following are considered in the design of the photobioreactor. The reactor should allow for the cultivation of a variety of common algae species. Uniform light should be provided to the culture medium and mass transfer should be rapid and present. Photobioreactor design according to drawings: Simulation, design of drawings and technical calculations of the photobioreactor device were carried out in ANSYS and SolidWorks software, and the device control panel was carried out using AutoCAD and Siemens TiaPortal software. The mechanical and electronic parts of the photobioreactor device (Figure 1) include: 1-Structure: The structure of the device is designed from steel sheets and cans with a thickness of 1.5 mm, which are assembled on each other by welding and bolts. 2- Retaining structure: The culture medium cylinders are secured to the structure by holding structures, and to move each cylinder, all we need to do is unfasten the holding structure. 3- Vertical cylindrical tanks of culture medium: The culture medium containers are glass cylinders with a diameter of 28 cm and a height of 180 cm, each with a volume of 110 liters and are divided into two sections: 100 liters of culture medium and 10 liters of empty space for the release of gases resulting from photosynthesis. 4- Steel half-funnels and aeration diffusers: The half-funnel and aeration diffuser (Figure 2) has the following parts: 4-1 A half-steel funnel with a 5-centimeter glass cylinder inside and sealed with glue. 4-2 3 mm thick silicone gaskets used to seal the diffuser and half funnel. 4-3 Diffuse plate made of steel with many and very fine holes, designed with software calculations and simulation. The diffusion plate is capable of producing small bubbles in large numbers and creating uniform mixing and turbulence of the culture medium through aeration in the culture medium cylinders. 4-4 Diffuser end plate that connects to the air pipe and air pump. 5- Fixed cylinder doors: The fixed door of the cylinders is made of steel and is designed to prevent the entry of dirt and dust and to protect the glass cylinder. Also, the fixed door has a gas outlet pipe, a place to install sensors and an opening door. The fixed door is sealed with adhesive. 6- Cylinder opening doors: An opening door that is placed on a fixed door and is used to access the inside of the cylinders. 7- Cylinder outlet pipe: Various gases are produced as a result of photosynthesis, which are collected in the empty space of the cylinders and are discharged through the cylinder's outlet pipe and can also be collected. 8- Air pump: An air pump with an adjustable output flow rate of 5 to 15 liters per minute and a pressure of 25 kPa for the aeration system, the electrical supply of which is adjusted via an intelligent control panel according to the required air volume. 9- HEPA filter: The HEPA filter is used before diffusion and in the aeration path to prevent fine particles and dust from entering the culture medium. 10- Dosing pump to send nutrients to the culture medium: A dosing pump is used to inject the required amount of nutrients. 11- Nutrient reservoir: A 4-liter stainless steel nutrient tank that is charged based on the type of algae being cultivated. 12- CO2 tank: A 10-liter CO2 gas tank with a pressure control manometer and a solenoid valve at its outlet to open and close the CO2 gas path. The solenoid valve outlet is connected to the aeration pipe. The solenoid valve is electrically powered and controlled through the device panel. 13- Manometer 14- Solenoid valve 15- Air communication pipes 16-Nutrient tubes 17- Precise and intelligent control system panel: The control panel is made of metal or compact plastic resistant to sunlight. There are electrical protection equipment, PLC equipment, input and output terminals and HMI in the panel. Through the HMI of the intelligent control panel, the PLC software can be adjusted and the operating status of the device is displayed. 18- Sensors: Salinity, concentration, pH, temperature, light, CO2, and O2 sensors are installed one each on top of the cylinders and send the measured data online to the control panel. 19-LED lamps: According to plan number one, a 10-watt LED lamp is provided for each cylinder, which is supplied with electricity at the appropriate time through the control panel. Explanation of shapes, maps and diagrams Map No. 1: Main mechanical and electronic parts of the photobioreactor device Map No. 2: Half-funnel and aeration diffuser sections Image No. 1 Algae growth curve diagram A clear and precise statement of the advantages of the claimed invention over prior inventions. Various photobioreactors have been built, which are mostly used for scientific experiments and research, but the claimed device, which was invented and designed by conducting experiments and studying and researching different species of algae and acquiring relevant knowledge, resulted in the invention and design of an industrial photobioreactor. This device has industrial applications for the growth and production of algae with food and pharmaceutical grades. Precise and intelligent control of all effective growth factors with the ability to be adjusted for different species forms a comprehensive device. Various innovations in the mechanical and electrical sections, including increasing the volume of culture medium cylinders, using a half-funnel and aerated steel diffusers, and a control system panel, have increased the quantity, quality, and speed of algae growth and production. Increased productivity and performance of the device, ease of construction, operation, and maintenance are other advantages of the device. Description of at least one implementation method for implementing the invention The device in question is designed for continuous operation with a long service life, with industrial application. The main components of the mechanical part are made of steel, glass and silicon, which have a long service life. It is designed and manufactured and only requires cleaning inside the cylinders at certain periods. In the electrical part, suitable equipment with a long service life is used, and in the event of a possible breakdown, the relevant part can be replaced and repaired simultaneously with the operation of the device, and there will be no problem in the operation and overall performance of the device. All parts are manufactured according to the design drawing of the device and assembled on each other by bolts and welding. The mechanical and electronic parts control all factors affecting algae growth accurately, intelligently and automatically, and if necessary, there is also the ability to change the automatic mode to manual. The control panel of the device is programmed with PLC equipment and sensors, and can be adjusted to grow different types of algae. Due to the intelligent control, to operate the device, it is necessary to charge the device with raw materials such as suitable water, culture medium, algae cells and connect it to the power supply. Therefore, the user starts producing algae by selecting the type of control program based on the type of selected algae species, adding the necessary nutrients in the relevant tanks, and adding the selected algae species to the culture medium of the cylindrical tanks. Also, a short explanatory training and a device guide brochure will be provided to the user. Explicit mention of the industrial application of the invention This device, due to its industrial application, will be used for the production of various types of algae with human and medicinal value due to its high efficiency and performance. Also, the photobioreactor device is a closed system and produces algae with high concentration, the algae growth and production pools and ponds are open systems, which is the best way to produce several times more and increase productivity and performance, the best way is to use open and closed systems simultaneously. Therefore, this device can also be placed in open algae growth and production farms and increase algae production several times for various uses.

Claims

Complaint What is claimed: Claim 1) Industrial photobioreactor with a precise and intelligent control system, designed for all parameters of cultivation of various species of microalgae with human and pharmaceutical value in cylindrical tanks made of glass. The claimed photobioreactor accurately and intelligently controls all factors affecting the increase in yield and growth rate (quality and speed) including light, temperature, CO2, air, pH, nutrients and culture medium, useful stress period (nutrition and darkness periods). In addition to being adjustable for the growth of different species, the claimed photobioreactor can create two useful phases of growth rate through the precise and intelligent control system and useful stress periods. Also, the device is designed for the growth of photoautotrophic microorganisms using sunlight or artificial light sources to facilitate photosynthesis in cylindrical tanks of culture medium with a large volume and a half-funnel of steel aeration of the cylinders. The claimed device has high productivity and performance.The claimed device is divided into main mechanical and electronic parts, the mechanical part including the following parts: 1- Structure 2- Holding structure 3- Tanks (three) vertical glass cylinders, each with a volume of 100 liters 4- Steel half-funnels and aeration diffusers 5- Fixed cylinder doors 6- Opening cylinder doors 7- Cylinder outlet pipe 8- Air pump 9- HEPA filter 10- Dosing pump for sending nutrients to the culture medium 11- Nutrient tank 12- CO2 tank 13- Manometer 14- Solenoid valve 15- Air and nutrient communication pipes, and the electronic part including the following parts: 17- Precise and intelligent control system panel 18- Sensors 19- LED lamps.

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