Gasification

The gasification reaction in the BioMax is fully automated via a proprietary control algorithm that has been developed and refined through thousands of hours of operational testing in the lab and the field. The energy stored in the feedstock by the photosynthesis process is released for conversion to other forms of energy by means of computer controlled thermochemical reactions in the downdraft gasifier. The raw feedstock moves down through the gasifier, as the feedstock and char are consumed below it by the gasification process.

The feedstock enters through the top of the downdraft gasifier. The control system will call for dry feed to be added on top of this flaming pyrolysis zone automatically when system temperatures reach required levels. As the feedstock particles approach the flaming pyrolysis zone, they are heated and dried, losing their moisture as steam. This steam and the gasification air that is automatically delivered travel quickly to the flaming pyrolysis zone below. As the feedstock particles travel further downward, they are heated to pyrolysis temperatures and begin to emit pyrolysis vapors. The combustion gases and residual tar vapors then travel down to the char oxidation zone, along with the char formed in the flaming pyrolysis zone.

In the char oxidation zone, secondary air is added by computer control to oxidize the char, producing carbon dioxide and heat. In the steady-state condition of the gasifier, the temperatures of the char oxidation zone are moderated by the endothermic reactions of steam and char to form hydrogen and carbon monoxide, as well as, carbon dioxide reacting with char to form carbon monoxide. These temperature-moderating reactions increase faster at the higher temperatures of this zone. The hot char and ash surfaces, along with free radicals present in this zone catalyze the destruction of the residual tar vapors.