Tubular Photobioreactors are one of the most used technologies for microalgae production in closed systems.
Ideal for the production of high-value and high-quality products and the production of strains that require a strict control of temperature, or that produce volatile compounds.
The tubes arrangement versatility is an asset for optimal cost-effective production. For instance, it can be designed to act as a solar collector (Unilayer Horizontal Tubular PBR) or provide the highest amount of photosynthetic area using the minimum implantation surface (Multilayer Horizontal Tubular PBR).
A4F has a large experience optimizing this production technology, for different algae species, location, environmental characteristics and type of product / applications of our Customers.
Fluid flow dynamics: reduction of the reactor zero velocity areas/dead volumes.
Fluid flow dynamics: constant velocity along all the PBR piping extension (> 100 m long).
Optimized global mass and energy balance: O2, CO2, nutrients mixing, thermoregulation through internal coils.
Energetic optimization for cost-effective production: efficient circulation pumps.
Improved culture management via parameter control, analysis and fast response: adjust culture circulation velocity, pH, temperature.
MULTILAYER HORIZONTAL TUBULAR PBR
This configuration comprises several layers of tubes disposed horizontally and parallel to the ground, which means that it has a higher volume to area ratio. This configuration is the most common in the microalgae sector, and has been used for several years in A4F. This configuration allows more flexibility to vary the ratio light/cell and decrease the photo-inhibition effect.
Ideal for applications with artificial illumination as only or additional energy source, since the area available for artificial light exposure is high, compared to an unilayer configuration.
Higher ratio volume/area
More flexibility to vary the ratio light/cell
Temperature is more easily controlled, which might represent an advantage in extreme heat environments
Degassing less critical => higher volume for oxygen build-up
UNILAYER HORIZONTAL TUBULAR PBR
A PBR system developed as an optimization of the multilayer for most applications. Its special configuration comprises one sole layer of tubes disposed horizontally and parallel to the ground, which maximizes the available radiation per cell, enabling a very high photosynthetic efficiency; this configuration allows a maximization of the volumetric productivity and consequently higher culture concentrations and a more robust culture; another direct impact of its higher volumetric productivity is the decrease in harvesting costs due to the lower total volume of the culture
Ideal for cultures growing exclusively with solar radiation
Lower ratio volume/area
Lower amount of water and inorganic nutrients required => reduction of CAPEX and OPEX
Higher concentration of the biomass => Better culture conditions and quality => higher annual productivity
FLAT PANEL PHOTOBIOREACTOR (FP-PBR)
This closed photobioreactors offer a solution to improve contamination control and achieve higher volumetric productivities.
Within closed systems, the most versatile and economic system for the cultivation of microalgae is the flat panel PBR constituted by a disposable transparent LDPE film enclosed within a metal frame.
Lower capital investment (compared to other closed systems)
Easiness of operation possible to produce different microalgae (robust and fragile strains)
Flexibility and the capacity to be scaled-up
No civil construction required aside from a levelled and compacted site
GLASS PANEL PHOTOBIORECTOR (GP-PBR)
A4F’s has developed a special GP-PBR design indicated for very delicate species, where a sterilization process and a complete sealed system is required; this GP is made of glass and high grade stainless steel.
This closed photobioreactor offers a complete solution to contamination control and achieve higher volumetric productivities.
Indicated for GMO species production and species highly sensitive to other organisms.
Ability to significantly reduce the exposure to other contaminant organisms trough its sealed configuration
Ability to sterilize the materials contacting the culture
Ability to produce high sensitive species with a higher performance
Easiness of operation and the capacity to be scaled-up
Continuous design optimization since 2010 by A4F for cost effective microalgae production considering energetic costs, productivity enhancement and weather specific conditions, such as high rainfall or sand storms.
This improved cascade raceway, deployed in 2014 in the scope of BIOFAT FP7 project, comprises two parallel-sloped ramps with opposite inclination. After this photosynthetic flow path, the culture flows into a covered tank and pumped back to the first sloped ramp.
Typical industrial production modules are 3.000 to 4.000 m2.
The CRW tank has the capacity to store the entire culture volume, which enables this type of raceway to be operated outdoors during high precipitation seasons with better culture management. The CRW ramps slope and pump specifications were designed to operate with a reduced film thickness, 3 to 8 cm, which allows an increase in volumetric productivity and a decrease in harvesting costs due to the lower total volume of the culture, when compared with a conventional raceway design, with water columns between 20 and 30 cm.
The CRW special configuration enables it to be operate trough the tank and also bypassing the tank, reducing considerably its energetic requirements.
Ideal for microalgae that grow in selective media and to every weather conditions.
Recommended for intensive microalgae production projects.
Lower ratio volume/area
Lower amount of water, and inorganic nutrients required => reduction of operation costs
Easier CO2 control and lower O2 build-up – better cultivation conditions => lower OPEX and higher annual productivity
Culture continuously flows through a pipe => Higher mixing efficiency and ability to control contaminants and optimized culture management
Storage capacity: capacity to protect the culture from extreme environmental conditions => Higher annual productivity and optimized culture management
Adjustable film thickness between 3 cm and 8 cm => optimized culture management
Prefabricated algae ponds that include containment walls, liner, paddle wheels, and optional control systems. Ideal for microalgae that grow in selective media and to install in areas without large climate variations or frequent storms.
Over decades the most common design used for industrial deployment or large areas (over 10 ha up to 100 ha)
Typical industrial production modules are 5.000 m2 and 1.500 m3.
Recommended for wastewater treatment applications.
Low construction costs (compared to closed systems)
Easiness of operation
Flexibility and the capacity to be scaled-up
Few to none civil construction required aside from a levelled and compacted site