TWO-STAGE FUEL COMBUSTION TECHNIQUE AND COMBUSTOR Russian patent published in 2008 - IPC F23C10/02 

FIELD: energy.

SUBSTANCE: two-stage fuel combustion technique is achieved in the first stage through gasification and partial combustion in a boiling bed with a linked circulating, vertically oriented descending fuel gasification zone and an ascending fuel partial oxidation zone, with its coke residue at an ecologically specified low combustion temperature. In the second stage, there is re-burning of gasification products and un-burnt fuel in a torch high-temperature process in a chamber furnace. This involves a process of recovering heat expended in the first combustion stage, supplementary to energy losses, necessary for maintaining isothermality of processes in the boiling bed, and for heating air used for fuel combustion and re-burning in both reaction stages, and air from cooling materials. In the fluidizated layer, supplementary to the circulating, there is a descending transit zone for re-burning using a stream of fluidizing air with a regulated temperature of the combustible components from the merged, and at temperature of the zone output sufficient for heating the reaction air using heat recovered from the inert component of material layer. The starting end of the re-burning zone is located on the upper level of the fluidizated layer, directly in contact with the upper outer end of the ascending oxidation zone, removing layers of material from the surface with the lowest permissible content of combustible substances for any reaction mode. Part of the material is taken from the layer through the surface into the chamber furnace by reaction products and un-reacted air from the oxidation zone, and does not reach the re-burning zone. Heat recovery is achieved through a highly effective contact heat exchange between the dispersed mineral component of the material layer, which practically does not contain combustible components, and air. The air is heated before it is used in burning the combustible substances. Outside the combustion zone, transportation of combustible dispersed mineral component of the material layer, which practically does not contain combustible components, is achieved by using any transport system, including aerogravitational and pneumatic systems.

EFFECT: more economical and ecologically efficient organisation of organic fuel combustion stages.

6 cl, 4 dwg