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The Algae Coil photobioreactor design in this invention consists of the following components:

  1. A vertical coil of transparent or semi-transparent tubing joined at top and bottom via a tube or tank so as to provide a system through which a solution of blue-green algae, water, nutrients and gas can circulate.
  2. A tap at the base of the photobioreactor to allow the solution to be drained off and harvested or cleaning of the photobioreactor.
  3. A gas inlet into the tubing, connected at the base of the coil, above the tap so that gas rises up through the solution in the tubular coil.
  4. A stop value on the gas inlet to prevent the algae solution flowing back up the gas inlet.
  5. A gas outlet at the uppermost point of the photobioreactor.
  6. A method of temperature control for the photobioreactor via a heat exchanger, controlling the temperature of the gas to the gas inlet.


The tubing is in a coil shape so as to maximize the exposure of the gas from the inlet to the blue-green algae solution and thus maximize the removal of greenhouse gases. It also aids in increasing the amount of light available to the blue-green algae.

The pipe connected to the gas inlet should come from a height above the bioreactor. A stop value should also be part of the gas inlet in the event that if the gas flow ceases the Algae solution does not flow into the inlet.

Gas coming in the inlet causes the solution to circulate from the bottom up to the top through the coil, without the need of a pump. It also aids in cleaning the tubing due to the scouring action of the gas bubbles rising through the tubing.

The Algae Coil bioreactor is not limited to flue or exhaust gases and may use atmospheric air. In this case, air will need to be pumped into the gas inlet.

The tubular coil may be made into various shapes depending on materials available and desired exposure to light. Other than a cylinder, the coil can be a cone, oval cylinder, cuboid, tetrahedron, pyramid or a flat horizontal coil shape.

The gas should be cooled or heated by a separate system so as to maintain a temperature suitable for the blue-green algae growing in the photobioreactor. This would typically be below 30 degrees Celsius. For example: a temperature control system using a heat exchanger, which has a gas or water filled coil wrapped around the pipe leading to the gas inlet, and a temperature sensor before the gas inlet to the photobioreactor.

It is preferred that a tank, rather than a tube be used in the centre of the coil, so
as to increase the volume of the blue-green algae solution in the photobioreactor.
The cone shape coil is preferred to maximize light to the blue-green algae solution.

Refer to the drawings on the design page for more detail on the invention.