How It Works

摘要

Gasification differs from combustion in that it uses just 20 percent to 30 percent of the air or oxygen needed for complete fuel combustion. During gasification, the amount of air supplied to the gasifier is carefully controlled so that only a small portion of the fuel burns completely. This 'starved-air' combustion process provides sufficient heat to pyrolyze and chemically break down the balance of the fuel into producer gas, called "syngas." At the core of Nexterra's system is a fixed-bed, updraft gasifier (fig. 1). Fuel, sized 3 inches or less, is bottom-fed into the center of the gasifier. Combustion air, steam and/or oxygen are introduced into the base of the fuel pile. Partial oxidation, pyrolysis and gasification occur at 1,500-1,800 degrees F, and the fuel is converted into the syngas and non-combustible ash. The ash migrates to the base of the gasifier and is removed intermittently through an automated in-floor ash grate.