Abstract: A method and apparatus for producing clean, sweet, fuel gas for use in a combustion process and for producing other useful products by processing a waste stream from digestion of lignocellulosic material. Essentially, the waste stream is partially oxidized to form hot gases and molten salts. The hot gases and molten salts are then cooled using a quench liquor to form quenched gas and carbonate liquor. Particles are removed from the quenched gas to form a raw fuel gas, preferably by subjecting the quenched gas to a multi-step fume reduction process which includes heat extraction from the quenched gas to reduce particulate load and water content of the quenched gas to form a low fume fuel gas. H2S is removed from the low fume fuel gas using an H2S removal process which is more selective for H2S than it is for CO2, the removing step forming clean, sweet, fuel gas and acid gases.

Abstract: An improved floor for a recovery boiler furnace having a flat floor has a number of tubes in the floor immediately adjacent each of the sidewalls of the furnace oriented at an oblique angle to horizontal. A method of replacing the floor is provided as well.

Abstract: An improved floor for a recovery boiler furnace having a flat floor has a number of tubes in the floor immediately adjacent each of the sidewalls of the furnace oriented at an oblique angle to horizontal. A method of replacing the floor is provided as well.

Abstract: A spout for channeling smelt from a boiler through an opening in the walls of the boiler comprises a jacket having an inner wall and an outer wall. The outer wall is spaced a distance away from the inner wall and the jacket has one end insertable into the opening of the wall. The jacket defines a trough for carrying smelt from the boiler. An inlet communicates with the jacket for delivering a water flow to the jacket between the inner wall and the outer wall. An O-shaped tube communicates with the jacket at the inserted end of the jacket for receiving the water flow from between the inner wall and the outer wall of the jacket. An outlet communicates with the O-shaped tube near the inserted end for channeling the water flow from the O-shaped tube and out of the spout. A vacuum is used near the outlet for insuring a proper low pressure drop.