Three-stage process for burning fuel containing sulfur to reduce emission of particulates and sulfur-containing gases

摘要

A three-stage combustion process is disclosed for burning a fuel containing sulfur characterized by low sulfur emission and good ash removal. The process comprises mixing the sulfur containing fuel with an additive capable of reacting with sulfur; burning the mixture in a first combustion stage with less than 75% theoretical air and at a temperature below the melting point of the ash but sufficiently high to cause reaction between the additive and any sulfur in the fuel to facilitate removal of the sulfur compounds formed; removing at least a portion of the sulfur compounds formed in the first stage; passing combustible gases from the first stage to a second stage; burning the gases in the second stage with less than 100% theoretical air at a temperature above the melting point of the ash to form a liquid slag which is removable from the second stage; and burning combustible gases from the second stage in a third stage with an excess of air to ensure complete combustion of the fuel.