Method for desulfurization, denitrifaction, and oxidation of carbonaceous fuels

摘要

A method for desulfurization, denitrification, and oxidation, of carbonaceous fuels including a two stage oxidation technique. The carbonaceous fuel, containing ash, along with an oxygen-containing gas is introduced into a first stage partial oxidation unit containing a molten ash slag maintained at a temperature of about 2200 DEG -2600 DEG F. A flux may also be introduced into the first stage partial oxidation unit for the purpose of increasing the basicity and maintaining the viscosity of the molten ash slag at a value no greater than about 10 poise. The carbonaceous fuel is gasified, and sulfur is chemically bound and captured in the molten ash slag. Since the first stage is operated in a gasification mode (reducing atmosphere), essentially all of the nitrogen in the fuel is converted to diatomic nitrogen, which results in low nitrogen oxide emissions upon final combustion. The first stage is also designed to physically remove a major portion of the fuel ash, the ash leaving the system as a molten slag. The combustible gas derived from partial oxidation (gasification) is directed along a substantially horizontal path to a second stage oxidation unit for final combustion. The sulfur-containing molten slag is removed to a water-sealed quench system or indirect water cooled system for disposal.