system, temperature control, gas holdup, and a limited surface for illumination
especially at up-scaled devices in case of algal species with high demands for
illumination (Koller 2015). However, Mirón et al. (1999) affirm that such perceptions have never been substantiated and, according to their results, both bubble
column and airlift photobioreactors are more suitable to scaling-up that horizontal
PBRs.
A practical example of the difficulty of scale-up is the failure case of GreenFuel
Technologies Corporation, at Arizona in 2007. Firstly, GreenFuel designs vertical
inclined closed photobioreactors and installed pilot plant to recycle CO 2 emissions
into microalgal biomass for biofuels production. With the success of the pilot plant,
months later the company installed a photobioreactor at the same plant, but 100
times larger than its earlier test models. Due to incorrect scaling-up, the project of
millions of dollars failed, its photobioreactors turned out to be twice as expensive as
expected and the company had to fire nearly half its staff (Waltz 2009).
3.2 Flat-Plate Photobioreactors
Flat-plate photobioreactors have received much attention for microalgae biomass
production due to their large illumination surface area (Ugwu et al. 2008). In this
type of photobioreactor, a thin layer of culture is passed across a flat panel made of
a transparent material, as glass, plexiglass, or polycarbonate (Faried et al. 2017).
They can be oriented at different angles so as to modify the light intensity and use
diffused and reflected light. Agitation can be provided either by bubbling air from
its one side through perforated tube or by rotating it mechanically using a motor
(Chang et al. 2017).
Flat-panel photobioreactors feature important advantages for biomass production
of photoautotrophic microorganisms and may become a standard reactor type for
the mass production of several algal species (Sierra et al. 2008). However, the
capital and operational cost of such systems are still too high to produce microalgae
biomass as feedstock for biofuels or other low-value products with currently
available technologies (Li et al. 2014).
The construction of flat-plate reactors dates back to the early 1950s (Burlew
1953), since then, many different designs have been developed. Tredici and collaborators developed a rigid alveolar panel photobioreactor (Tredici et al. 1991;
Tredici and Materassi 1992). Pulz and Scheibenbogen (1998) proposed a flat-plate
PBR inner walls arranged to promote an ordered horizontal culture flow that was
forced by a mechanical pump. Recently, Li et al. (2014) developed a flat-panel
photobioreactor with internal bulk liquid flow and an external airlift with the purpose of developing a scalable industrial photobioreactor.
2 Microalgal Production Systems with Highlights …
21
especially at up-scaled devices in case of algal species with high demands for
illumination (Koller 2015). However, Mirón et al. (1999) affirm that such perceptions have never been substantiated and, according to their results, both bubble
column and airlift photobioreactors are more suitable to scaling-up that horizontal
PBRs.
A practical example of the difficulty of scale-up is the failure case of GreenFuel
Technologies Corporation, at Arizona in 2007. Firstly, GreenFuel designs vertical
inclined closed photobioreactors and installed pilot plant to recycle CO 2 emissions
into microalgal biomass for biofuels production. With the success of the pilot plant,
months later the company installed a photobioreactor at the same plant, but 100
times larger than its earlier test models. Due to incorrect scaling-up, the project of
millions of dollars failed, its photobioreactors turned out to be twice as expensive as
expected and the company had to fire nearly half its staff (Waltz 2009).
3.2 Flat-Plate Photobioreactors
Flat-plate photobioreactors have received much attention for microalgae biomass
production due to their large illumination surface area (Ugwu et al. 2008). In this
type of photobioreactor, a thin layer of culture is passed across a flat panel made of
a transparent material, as glass, plexiglass, or polycarbonate (Faried et al. 2017).
They can be oriented at different angles so as to modify the light intensity and use
diffused and reflected light. Agitation can be provided either by bubbling air from
its one side through perforated tube or by rotating it mechanically using a motor
(Chang et al. 2017).
Flat-panel photobioreactors feature important advantages for biomass production
of photoautotrophic microorganisms and may become a standard reactor type for
the mass production of several algal species (Sierra et al. 2008). However, the
capital and operational cost of such systems are still too high to produce microalgae
biomass as feedstock for biofuels or other low-value products with currently
available technologies (Li et al. 2014).
The construction of flat-plate reactors dates back to the early 1950s (Burlew
1953), since then, many different designs have been developed. Tredici and collaborators developed a rigid alveolar panel photobioreactor (Tredici et al. 1991;
Tredici and Materassi 1992). Pulz and Scheibenbogen (1998) proposed a flat-plate
PBR inner walls arranged to promote an ordered horizontal culture flow that was
forced by a mechanical pump. Recently, Li et al. (2014) developed a flat-panel
photobioreactor with internal bulk liquid flow and an external airlift with the purpose of developing a scalable industrial photobioreactor.
2 Microalgal Production Systems with Highlights …
21