Abstract: Method and apparatus to prevaporize and premix liquid and/or gaseous fuels with air in two stages at two different temperatures prior to combustion. The invention is directed to the entry of a finely atomized liquid fuel, such as No. 2 diesel, into an inlet end of an annular chamber. Air is mixed with finely atomized liquid fuel, preferably generated by a small flow number liquid fuel nozzle, in a first chamber of the annular chamber at a first (relatively high) temperature for a relatively long residence time. The air and liquid fuel is moved into a second chamber of the annular chamber where a secondary hotter air is injected into the annular chamber by a plurality of staggered high velocity jets to prevaporize and premix the combined fuel and air mixture at a second higher temperature, but for a shorter time. The intense prevaporization and premixing make the mixture suitable for entry into a combustor, but without the need to add water or steam to keep pollutant emissions low.