Krebs & Sisler has developed a CO2 separation and recycling method called Enhanced Photosynthesis and Photocatalysis Water Treatment/Biomass Growth Process.

The technology is described in US Patent No. 8,673,615. The suburban Chicago energy research firm says it complements the O2/CO2 combustion and condensing boiler system of its US Patent No. 6,907,845 which separates and recovers CO2 and all other combustion-generated exhaust gases.

In O2/CO2 combustion, oxygen is diluted with CO2 for temperature control of the fuel oxidant used to combust coal, petroleum coke or natural gas. Excluding the nitrogen that is present in air-fired combustion enables cost-free recovery of both the condensate and the CO2 from a condensing boiler. The condensate and CO2 are pumped into deep and slowflowing water channels, saturated in the visible light spectrum of light-emitting diodes (LEDs). A photocatalyst mineralizes organic and inorganic compounds for absorption into a cynobacterial biomass like Spirulina. The absorption of minerals in the growing biomass concurrently purifies the flowing water.

These processes will operate at high efficiency with no harmful emissions or effluents into the environment, Krebs & Sisler says. They will also produce a carbohydrate and protein-rich biomass useful for fuel, fertilizer, animal feed or a human food supplement.

Inventor Bill Krebs says the firm is now developing a combination coal, rotary kiln, O2/CO2 combustion condensing boiler that will have cost, efficiency and emission advantages. Krebs says air-fired plants operate at an average 34 percent fuel efficiency. By comparison, the firm’s O2/CO2 combustion method combined with a condensing boiler can more than double plant fuel efficiency, reducing both the fuel and oxygen requirements by half, Krebs says.