Norsker et al. (2011) calculated the cost for outdoor production of microalgae
biomass in tubular photobioreactor and concluded that € 4.15 is the price for
producing 1 kg of dry weight biomass, in a 100-ha plant. On the other hand, Grima
(2009) found a cost of € 25 per kg of dry weight, in a horizontal tubular PBR of
4000 L. However, according to these authors, it is possible to reduce this cost up to
€ 0.5 per kg, through of process optimization.
2.2.4 Scaling-up
The scale-up of a tubular photobioreactor is not so simple in an open system,
because it requires scaling-up of both the solar receiver and the airlift device. In
principle, the volume of the solar receiver may be increased by increasing the
diameter and the length of the tube. However, an increase in tube length can result
in unacceptable concentrations of dissolved oxygen along the tubes. For this reason,
in practice, only the tube diameter may be varied (Grima et al. 2001). Any change
in tube diameter would imply a change in the light/dark cycle inside of photobioreactor. These cycles can improve the biomass productivity due to the ability of
some species to store light energy to maintain their metabolism in the absence of
light (Maroneze et al. 2016). Thus, the geometry of the PBR must be optimized
according to the species used.
Grima et al. (2001) concluded that for Phaeodactylum tricornutum, the optimal
photobioreactor (0.2 m
3 ) configuration and operations conditions were as follows: a
solar receiver tube of 0.06 m diameter, 80 m long, connected to a 4 m tall airlift.
Although not having a simple scaling-up, the tubular PBR is already quite widespread in large scale.
Table 2 Biomass productivities in tubular PBRs
Microalgae
Photobioreactor
Total
volume (L)
Productivity
(g/L/d)
References
Porphyridium
cruentum
Airlift tubular
200
1.5
Camacho et al.
(1999)
Phaeodactylon
tricornutum
Airlift tubular
200
1.2
Fernández et al.
(2001)
Phaeodactylon
tricornutum
Airlift tubular
200
1.9
Grima et al.
(2001)
Phaeodactylon
tricornutum
Helical tubular
75
1.4
Ugwu et al.
(2002)
Haematococcus
pluvialis
Parallel tubular
25,000
0.05
Olaizola (2000)
Nannochloropsis
gaditana
Fence-type
tubular
340
0.59
San Pedro et al.
(2014)
14
M. M. Maroneze and M. I. Queiroz
biomass in tubular photobioreactor and concluded that € 4.15 is the price for
producing 1 kg of dry weight biomass, in a 100-ha plant. On the other hand, Grima
(2009) found a cost of € 25 per kg of dry weight, in a horizontal tubular PBR of
4000 L. However, according to these authors, it is possible to reduce this cost up to
€ 0.5 per kg, through of process optimization.
2.2.4 Scaling-up
The scale-up of a tubular photobioreactor is not so simple in an open system,
because it requires scaling-up of both the solar receiver and the airlift device. In
principle, the volume of the solar receiver may be increased by increasing the
diameter and the length of the tube. However, an increase in tube length can result
in unacceptable concentrations of dissolved oxygen along the tubes. For this reason,
in practice, only the tube diameter may be varied (Grima et al. 2001). Any change
in tube diameter would imply a change in the light/dark cycle inside of photobioreactor. These cycles can improve the biomass productivity due to the ability of
some species to store light energy to maintain their metabolism in the absence of
light (Maroneze et al. 2016). Thus, the geometry of the PBR must be optimized
according to the species used.
Grima et al. (2001) concluded that for Phaeodactylum tricornutum, the optimal
photobioreactor (0.2 m
3 ) configuration and operations conditions were as follows: a
solar receiver tube of 0.06 m diameter, 80 m long, connected to a 4 m tall airlift.
Although not having a simple scaling-up, the tubular PBR is already quite widespread in large scale.
Table 2 Biomass productivities in tubular PBRs
Microalgae
Photobioreactor
Total
volume (L)
Productivity
(g/L/d)
References
Porphyridium
cruentum
Airlift tubular
200
1.5
Camacho et al.
(1999)
Phaeodactylon
tricornutum
Airlift tubular
200
1.2
Fernández et al.
(2001)
Phaeodactylon
tricornutum
Airlift tubular
200
1.9
Grima et al.
(2001)
Phaeodactylon
tricornutum
Helical tubular
75
1.4
Ugwu et al.
(2002)
Haematococcus
pluvialis
Parallel tubular
25,000
0.05
Olaizola (2000)
Nannochloropsis
gaditana
Fence-type
tubular
340
0.59
San Pedro et al.
(2014)
14
M. M. Maroneze and M. I. Queiroz