8/12/2019 Foto Bioreaktor

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Fotobioreaktor

The core of the production unit is the photobioreactor, where the algae grow in a water

environment enriched with carbon dioxide and nutrients. The limiting growth factor is the incoming

light. The algae are then separated from the water; the separated water is recycled and the algae

continue to the next separation step. In this step the algae are crushed and the solid algae

membranes and other solid constituents are separated from the algae oil. The algae oil contains free

fatty acids and phosphorous that needs to be eliminated before transesterification; this is done in

the pre-treatment. After the pretreatment the crude oil is ready to be used in a regular

transesterification process for biodiesel production.

There are two main groups of systems for cultivation of microalgae, open and closed systems. The

open ponds have their surface open towards the atmosphere, while the closed photobioreactors are

closed vessels made of a transparent material allowing the light to reach the microorganisms inside.

Most of the closed systems can then be further categorized into one of the following two categories;

tubular devices or flat panels (6).

Fotobioreaktor tertutup dapat digunakan untuk kultivasi pertumbuhan mikroalga dalam jangka

waktu yang lama dibandingkan dengan kolam terbuka yang rentan terhadap kontaminan dan

beberapa patogen lainnya. The closed photobioreactor system consists of a number of transparent

reactors. The reactors are designed to maximize the absorption of the incoming light and to

minimize negative effects such as oxygen oversaturation.

Advantage:

High productivity per areal of land and per volume (5). High algae content per volume makes separation easier and cheaper, because less water per

kg dry biomass has to be removed.

Easier to prevent contamination from other microalgae, due to the fact that the system isclosed to the environment.

Small evaporative losses of water compared to open systems.

Disadvantage:

Cooling needed to prevent the system from overheating (5). Problems due to oversaturation of oxygen (5) Cleaning problems due to bio-adhesion on the inside of transparent surfaces. Expensive construction that is complex to build.

When a tubular and a flat reactor are compared with reference to the photo efficiency during

the day, it can be seen that the flat reactor suffers more from the light saturation effect. The

photo efficiency of the tubular reactor was greater due to the dilution effect caused by the

curved surface area.