Waste Combustion Gases and Algae

Abstract

The poor match between continuous combustion and algal farming that has diurnal discontinuities and seasonal variations poses almost impossible problems for joining them for efficient and economical removal of carbon dioxide from waste gas. Nevertheless, the waste heat and high concentrations of carbon dioxide can benefit a factory that makes products such as biodiesel using algae. Keys to low initial investment, reasonable labor costs, and efficient operations are very inexpensive photobioreactors, self-actuation of gassing and addition of nutrient medium with sun valves, and provisions for weather emergencies and climatic changes. A major recommendation is mounting the photobioreactors on land that need not be leveled or graded. This reduces cost of land acquisition and site preparation to a minimum. Thin, transparent, very wide plastic bags can be fabricated to have a gassing system and an overflow for harvesting of the algal suspension that are integral to the bag thus eliminating much of the accessory piping. Both the flow rate of gas and nutrient medium may depend on sun valves that respond to the intensity of sunlight and that eliminate the need for human operators to stop flows at night and to adjust them during the day.