An Interactive Tool for Outdoor Computer Controlled Cultivation of Microalgae in a Tubular Photobioreactor System

Abstract

This paper describes an interactive virtual laboratory for experimenting with an outdoor tubular photobioreactor (henceforth PBR for short). This virtual laboratory it makes possible to: (a) accurately reproduce the structure of a real plant (the PBR designed and built by the Department of Chemical Engineering of the University of Almería, Spain); (b) simulate a generic tubular PBR by changing the PBR geometry; (c) simulate the effects of changing different operating parameters such as the conditions of the culture (pH, biomass concentration, dissolved O2, inyected CO2, etc.); (d) simulate the PBR in its environmental context; it is possible to change the geographic location of the system or the solar irradiation profile; (e) apply different control strategies to adjust different variables such as the CO2 injection, culture circulation rate or culture temperature in order to maximize the biomass production; (f) simulate the harvesting. In this way, users can learn in an intuitive way how productivity is affected by any change in the design. It facilitates the learning of how to manipulate essential variables for microalgae growth to design an optimal PBR. The simulator has been developed with Easy Java Simulations, a freeware open-source tool developed in Java, specifically designed for the creation of interactive dynamic simulations.

Photobioreactor Design for Improved Energy Efficiency of Microalgae Production

“…Dormido et al (2014) reported that each 3,000-L PBR unit in the Almeria facility has thirty seven 90-degree elbows and these are the major fittings.…”

“…The PBR units (Figure 2.16) are used to produce the lutein-rich, wild-type, mesophile microalgae strain Scenedesmus almeriensis (Sanchez et al, 2008;Acien et al, 2012). This facility consists of 10 tubular fence-type PBRs laid parallel to the ground (Dormido et al, 2014). Each the airlift column is for heat exchange, degassing and nutrient addition (Acien et al, 2012).…”

“…Pure CO2 is supplied on demand as minute bubbles at the beginning of the tubular solar receiver for pH control purposes (Dormido et al, 2014). The complete system, including data acquisition and control software, were designed and built by the Department of Chemical Engineering at the University of Almeria (Almeria, Spain) (Dormido et al, 2014). The capital cost of the 10-unit PBR is estimated at $8/L (in 2014 $) .…”

“…The plant located in Almeria (Spain) consists of 10 PBR units of 3,000 L each. Each of the 3,000-L units of the Almeria PBR facility shares a single air blower connected to the airlift column to mix the culture and strip the photosynthetically-generated oxygen, but each module uses its own centrifugal pump to circulate the culture around the array of tubes (Dormido et al, 2014). The total specific power consumption of the air blower and centrifugal pump for a 3,000-L unit in the Almeria facility was reported by Acien et al (2012) to be 11 kWh m -3 day -1 .The total specific power consumption of the air blower and centrifugal pump for a 3,000-L unit in the Almeria facility as calculated using the assumptions and specifications found in the literature (see Tables 3.3, 3.4, and 3.5) was 20 kWh m -3 day -1 (Table 4.5).…”

“…To cool the PBR, water is pumped through a heat exchanger coil in the airlift column (Acien et al, 2012). Pure CO2 is supplied on demand as minute bubbles at the beginning of the tubular solar receiver for pH control purposes (Dormido et al, 2014). The complete system, including data acquisition and control software, were designed and built by the Department of Chemical Engineering at the University of Almeria (Almeria, Spain) (Dormido et al, 2014).…”