Advantages of vertical systems

Higher output and lower costs when using a vertical system design for PBR’s

In recent years, the fundamental question of vertical or horizontal system design has become increasingly dominant when considering a new PBR reactor system. Reactors with horizontal orientation and vertically stacked tubes have been widely used in the past. Depending on the application, these were either helix or fence reactors. In such systems, the algae solution is always pumped from the bottom to the top in horizontal arrangements.

More recently, the proven system design using vertically oriented tubes has been implemented more and more. This is understandable, since the system structure requires no pumps at all. Instead, the algae solution is driven through the photobioreactor by the airlift principal: by using CO2 that is injected into the system at the bottom of every second tube.

This pump free operation has two major economic advantages:

1. Significantly reduced costs: No pumps are required, no infrastructure is necessary to support them and no energy is needed for the pumps during active operation. Therefore, the elimination of pumps comes with the elimination of a large amount of fixed and variable costs.
2. Significantly increased productivity in comparison to traditional reactors with horizontally oriented tubes of the same volume: A key factor for this increase lies in the way the algae are more carefully transported in a reactor without a pump. A pump, is powered by a propeller, which rotates at high speeds. This leads to high shear stress within the pump system, which affects the algae organisms. In contrast, with vertical PBRs, the algae are treated gently and with their conservation in mind. The results can be clearly seen in the algae output.

You can find out more about the economic advantages of vertically oriented PBRs and other developments within glass photobioreactos in our e-book. You can download it here for free: “How using a PBR with high end glass components makes algae cultivation more economically viable”.