Air exchange and mixing of the rector medium are very important parameters
in a PBR. The PBR developed at SDSU has a porous membrane dividing the
plenum and the reactor medium that contains the algae. Air from the
plenum is forced through the porous membrane. Air moving through the
reactor medium can be used to bring nutrients like carbon dioxide and remove
products of photosynthesis like oxygen from the algae growth medium. The
air flow also can be used to mix the reactor medium bringing nutrients to
the algae and moving the algae from the interior of the reactor to the exterior
and back again. The following figures show the bubble movement and
mixing in a experimental bubble chamber.
 Experimental setup to test bubbling through porous membrane into the bubble column |
 Air bubbling through the bubble chamber |
 Saw dust placed in bubble chamber rising to top with no air flow |
 Saw dust disperses (mixing)) throughout bubble column with air flow |