Integrated process for gasifying and combusting a carbonaceous fuel

Claim 1

An integrated gasification/combustion process for sulfur and nitrogen-bearing carbonaceous fuels wherein a flue gas is produced having a reduced content of sulfur-based and nitrogen-based compounds, comprising: a. gasifying a first portion of said carbonaceous fuel in a gasification reactor in the presence of air to produce a hot char-containing carbon monoxide-rich fuel gas having a low Btu content; b. introducing a sulfur capturing material into the gasification reactor so that the gasifying of said carbonaceous fuel is carried out in the presence of said sulfur capturing material whereby a substantial portion of the sulfur in the first portion of said carbonaceous fuel is captured by said sulfur capturing material; c. passing the hot char-containing carbon monoxide-rich fuel gas produced in the gasification reactor through a heat exchanger in indirect heat exchange relationship with a heat exchange fluid to cool the fuel gas to a temperature less than about 1000° F.; d. introducing the cooled char-containing carbon monoxide rich fuel gas passing from the heat exchanger into a combustion zone within a vapor generating furnace; e. introducing a second portion of said carbonaceous fuel into the combustion zone of the vapor generating furnace; f. combusting the second portion of said carbonaceous fuel together with said cooled char-containing carbon monoxide-rich fuel gas within the combustion zone of the vapor generating furnace in the presence of at least sufficient additional air to substantially complete combustion whereby a hot flue gas is produced having a reduced emission of nitrogen oxide pollutants; g. introducing a sulfur capturing material into the combustion zone of the vapor generating furnace so that the combustion of the second portion of said carbonaceous fuel is carried out in the presence of said sulfur capturing material whereby a substantial portion of the sulfur in the second portion of said carbonaceous fuel is captured by said sulfur capturing material; and h. passing the flue gas generated in the combustion zone of the vapor generating furnace by combusting the second portion of said carbonaceous fuel together with said cooled carbon monoxide-rich fuel gas therein through a particulate collecting apparatus so as to remove therefrom a substantial portion of the sulfur capturing material with the sulfur captured therein so as to produce a flue gas having a low content of sulfur-based and nitrogen-based pollutants.