Abstract: A radial turbine impeller includes a turbine wheel module including a first surface and a second surface being mutually opposite in the axial direction of the radial turbine impeller. The radial turbine impeller includes blade modules attached to the turbine wheel module. Each blade module is a single piece of material and includes a body portion and blades connected to the body portion and protruding in the axial direction from the body portion. At least the first surface of the turbine wheel module is provided with one or more annular grooves opening in the axial direction and containing the body portions of the blade modules so that, in each of the grooves, the blade modules are successively in the circumferential direction. The radial turbine impeller further includes a securing system for keeping the body portions of the blade modules in the one or more grooves.

Abstract: A method of recovering energy from waste liquors from cellulose pulp processes produces high quality superheated steam, a savings in material costs is achieved, and the utilization factor of the pulp mill is improved (that is the number of shutdowns for service is reduced). A main stream of waste liquor from cellulose pulp processing is divided into first and second streams. The first stream is combusted in the recovery boiler to produce steam and the steam is fed to a superheating boiler. The second stream of waste liquor is gasified outside the recovery boiler to produce a combustible gas and an inorganic fraction. The inorganic fraction is not fed to the recovery boiler, but is separately recovered. The combustible gas is burned in the superheating boiler to superheat steam produced from combusting the first stream of waste liquor, the combustible gas providing substantially the only source of fuel for superheating the steam in the superheating boiler.

Abstract: Combustion gas is fed to a furnace, preferably a recovery boiler for combusting black liquor from cellulose pulp processing, through a gas nozzle disposed in association with a wall of the furnace. The nozzle has a longitudinal axis of elongation, an exterior, and a hollow interior. Cooling gas is directed into contact with the nozzle exterior, and typically also the furnace wall where the nozzle engages the furnace wall. The cooling gas typically moves in a direction substantially perpendicular to the longitudinal axis of the nozzle (e.g. at a velocity of between 10-30 m/sec), and cools the nozzle. Combustion gas passes through the nozzle hollow interior and enters the furnace facilitating combustion of black liquor within the furnace. Desirably the cooling gas is redirected and enters the nozzle interior as the combustion gas. The nozzle may be further cooled by cooling fins or studs on a portion of the nozzle exterior impacted by cooling gas.

Abstract: Method of recovering energy from waste liquors from pulp processes, wherein the waste liquor is burned in a waste liquor recovery boiler and energy is recovered from the flue gases by producing saturated or partially superheated steam in the recovery boiler. According to the invention, a portion of the waste liquor is gasified in a gasifying reactor in order to produce combustion gas. The combustion gas is burned in a separate superheating boiler, in which the steam produced in the recovery boiler is superheated.