A method for controlling a chemical recovery boiler. The method includes measuring concentrations of sodium carbonate, sodium sulfide, and sodium sulfate from green liquor of the chemical recovery boiler, determining a target temperature for smelt, imaging at least an area of a char bed of the chemical recovery boiler, the area being close to a smelt spout, to obtain an image of the area, determining a measured temperature of the char bed using the image of the area. The method further includes determining that the measured temperature of the char bed is less than the target temperature for smelt, and controlling the chemical recovery boiler such that the temperature of the char bed increases. A chemical recovery boiler for the same.

A cooling shield for a liquor injection pipe of a liquor gun for supplying liquor to a combustion chamber of a recovery boiler, which has a first and a second side edge, the side edges extending in a longitudinal direction (L) of the cooling shield, and a first end edge and a second end edge extending between the side edges, the cooling shield comprising an outside shield wall, and an inside shield wall, the outside shield wall and the inside shield wall being connected along the side edges of the cooling shield, the cooling shield comprising a cooling medium space being arranged between the outside shield wall and the inside shield wall, the cooling shield comprising a cooling medium inlet and a cooling medium outlet the cooling medium inlet and the cooling medium outlet being arranged in communication with the cooling medium space.

A method for controlling carryover in a chemical recovery boiler. The method comprises feeding black or brown liquor to a furnace of the chemical recovery boiler through an injection gun to burn the black or brown liquor. The chemical recovery boiler comprises a bullnose, which narrows the furnace, and a first superheater, of which at least a part is arranged at a higher vertical level than the bullnose. The method comprises measuring information indicative of a spatial temperature distribution on a cross section of the furnace, wherein the cross section is above the injection gun and below the first superheater; determining primary information indicative of carryover using the information indicative of the spatial temperature distribution on the cross section of the furnace; and controlling a temperature of the black or brown liquor that is fed to the furnace using the primary information. In addition, a system for performing the method.

A method and apparatus for cleaning a black liquor recovery boiler, where a furnace floor of the boiler is washed by mixing wash water in a wash water pool formed on the floor by at least one mixing device in the wash water pool, and by jetting wash water towards the floor by at least one pressure washer installed into the furnace through an opening in the furnace wall.

A method and apparatus for protecting a furnace floor of a black liquor recovery boiler, where a mixture is formed by mixing material with a fluid, and the furnace floor is covered by said mixture by flowing the formed mixture onto the floor from the outside of the furnace.

A method for controlling carryover in a chemical recovery boiler. The method comprises feeding black or brown liquor to a furnace of the chemical recovery boiler through an injection gun to burn the black or brown liquor. The chemical recovery boiler comprises a bullnose, which narrows the furnace, and a first superheater, of which at least a part is arranged at a higher vertical level than the bullnose. The method comprises measuring information indicative of a spatial temperature distribution on a cross section of the furnace, wherein the cross section is above the injection gun and below the first superheater; determining primary information indicative of carryover using the information indicative of the spatial temperature distribution on the cross section of the furnace; and controlling a temperature of the black or brown liquor that is fed to the furnace using the primary information. In addition, a system for performing the method.

A method and apparatus for protecting a furnace floor of a black liquor recovery boiler, where a mixture is formed by mixing material with a fluid, and the furnace floor is covered by said mixture by flowing the formed mixture onto the floor from the outside of the furnace.

An apparatus for the destruction of a precursor material includes a steam plasma reactor having a high temperature zone and a combustion zone. The high temperature zone is adapted for hydrolyzing the precursor material, whereas the combustion zone is adapted to effect medium temperature oxidation of the reactant stream where combustion oxygen or air is injected. A quenching unit is provided at an exit end of the reactor for quenching a resulting gas stream to avoid the formation of unwanted by-products.

A method and a boiler for decreasing the amount of nitrogen oxides in flue gases of a boiler, which flue gases are generated in the combustion of fuels and air. The boiler has a water circulation system comprising superheaters and a furnace for combustion of fuel and for generating flue gases that contain nitrogen oxides, which flue gases mainly flow upwards in the furnace and further to the superheater zone and via other heat recovery surfaces of the boiler out of the boiler, and a nitrogen oxides reducing agent is introduced into the flue gases. The nitrogen oxides reducing agent is introduced into the flue gases prior to the superheater zone, after the temperature of the flue gases is decreased by at least one heat exchanger that is located upstream of the nose of the boiler and upstream of the introduction of the nitrogen oxides reducing agent.

A system comprising a plasma assisted vitrifier (8) configured to produce vitrified product. A feed pipe (4) can be fluidly connected to the plasma assisted vitrifier (8). The feed pipe (4) can be configured to deliver a feedstock into the plasma assisted vitrifier. A heated combustion air conduit (34) can be fluidly connected to the plasma assisted vitrifier (8). A spinning fiberizer can be disposed next to the plasma assisted vitrifier (8) and configured to receive the vitrified product (24). An emissions attenuation device can be fluidly connected to the plasma-assisted vitrifier (8) and configured to treat gaseous emissions generated by the plasma-assisted vitrifier (8).