a combustion furnace such as oxidizer, gaseous fuels, and nitrogen diluent,
respectively. After oxidation of the fuel, the resulting combustion CO 2 returns to
the photobioreactor (mass integration) partially or totally, integrating the process
globally.
Table 5 Challenges facing bio-oxycombustion technology
R&D challenges to integrated
bio-oxycombustion systems scale-up
Comments
Photobioreactor design
Aspects associated with engineering, maintenance,
economics, and microalgae species are the key to the
construction of industrial photobioreactors for oxygen
production
Collection of photobioreactor exhaust
gases
Closed photobioreactors would be potentially suitable
equipment for the oxygen supply and VOCs
generation. For the removal mainly of the
accumulated O 2 , it would be necessary to design a
degassing zone equipped with valves to control the
flow and pressure of the gaseous fluid
Humidity of the photobioreactor
exhaust gases
The gaseous phase of photobioreactor contains water
vapor. When recovering exhaust gases, water should
be removed in a separate unit to not interfere in the
combustion
Pre-heating of the gases for injection
After removal of humidity, gases can be cooled; it
would be necessary to do their pre-heating for
injection into the burner system so as to avoid system
thermal efficiency reduction
Injection site in the furnace
The injection zone must be defined so as to optimize
energy utilization potential of O 2 and VOCs
Concentration of O 2 and VOCs
The bio-oxycombustion system requires high loads of
the substances released from the photobioreactor
exhaust gases. The photobioreactors currently
available are not able to meet this demand, due to the
lack of an ideal configuration
Process integration
Due to technical barriers of oxycombustion, process
integration should be taken into account in order to
balance the cost of CO 2 capture, oxygen, and fuel
supply and to improve energy performance
Process life cycle analysis
Although bio-oxycombustion eliminates N 2 from flue
gas and presents a potential increase in thermal
efficiency, issues related to GHG emissions, more
specifically CO 2 , and energy consumption must be
properly addressed, in order to reduce the
environmental impact over its entire life cycle
Economic impacts
Microalgae-based processes are currently
economically viable only on the fine chemicals
production. It is necessary to develop new
technological routes to the potential bulk chemical
production
286
I. Aguiar Severo et al.
respectively. After oxidation of the fuel, the resulting combustion CO 2 returns to
the photobioreactor (mass integration) partially or totally, integrating the process
globally.
Table 5 Challenges facing bio-oxycombustion technology
R&D challenges to integrated
bio-oxycombustion systems scale-up
Comments
Photobioreactor design
Aspects associated with engineering, maintenance,
economics, and microalgae species are the key to the
construction of industrial photobioreactors for oxygen
production
Collection of photobioreactor exhaust
gases
Closed photobioreactors would be potentially suitable
equipment for the oxygen supply and VOCs
generation. For the removal mainly of the
accumulated O 2 , it would be necessary to design a
degassing zone equipped with valves to control the
flow and pressure of the gaseous fluid
Humidity of the photobioreactor
exhaust gases
The gaseous phase of photobioreactor contains water
vapor. When recovering exhaust gases, water should
be removed in a separate unit to not interfere in the
combustion
Pre-heating of the gases for injection
After removal of humidity, gases can be cooled; it
would be necessary to do their pre-heating for
injection into the burner system so as to avoid system
thermal efficiency reduction
Injection site in the furnace
The injection zone must be defined so as to optimize
energy utilization potential of O 2 and VOCs
Concentration of O 2 and VOCs
The bio-oxycombustion system requires high loads of
the substances released from the photobioreactor
exhaust gases. The photobioreactors currently
available are not able to meet this demand, due to the
lack of an ideal configuration
Process integration
Due to technical barriers of oxycombustion, process
integration should be taken into account in order to
balance the cost of CO 2 capture, oxygen, and fuel
supply and to improve energy performance
Process life cycle analysis
Although bio-oxycombustion eliminates N 2 from flue
gas and presents a potential increase in thermal
efficiency, issues related to GHG emissions, more
specifically CO 2 , and energy consumption must be
properly addressed, in order to reduce the
environmental impact over its entire life cycle
Economic impacts
Microalgae-based processes are currently
economically viable only on the fine chemicals
production. It is necessary to develop new
technological routes to the potential bulk chemical
production
286
I. Aguiar Severo et al.