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 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 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.

Embodiments of the present disclosure include a system, method, and apparatus comprising a direct steam generator configured to generate saturated steam or superheated steam and combustion exhaust constituents. A CONVAPORATOR Unit (CU) can be fluidly coupled to the direct steam generator. The CU can be configured to route the saturated steam or superheated steam and combustion exhaust constituents through a condenser portion of the CU via a condenser side steam conduit and can be configured to condense the super-heated steam or saturated steam to form a condensate. A separation tank and water return system can be fluidly coupled to a condenser side condensate conduit of the condenser portion of the CU. The separation tank and water return system can be configured to separate the combustion exhaust constituents from the condensate. An evaporator portion of the CU can be fluidly coupled with the separation tank and water return system via an evaporator side condensate conduit. The evaporator portion can be configured to evaporate the condensate from the separation tank and water return system via heat transfer between the condenser portion and evaporator portion to form steam. A turbine can be fluidly coupled with the evaporator portion of the CU via an evaporator side steam conduit.

Embodiments of the present disclosure include a system, method, and apparatus comprising a direct steam generator configured to generate saturated steam or superheated steam and combustion exhaust constituents. A CONVAPORATOR Unit (CU) can be fluidly coupled to the direct steam generator. The CU can be configured to route the saturated steam or superheated steam and combustion exhaust constituents through a condenser portion of the CU via a condenser side steam conduit and can be configured to condense the super-heated steam or saturated steam to form a condensate. A separation tank and water return system can be fluidly coupled to a condenser side condensate conduit of the condenser portion of the CU. The separation tank and water return system can be configured to separate the combustion exhaust constituents from the condensate. An evaporator portion of the CU can be fluidly coupled with the separation tank and water return system via an evaporator side condensate conduit. The evaporator portion can be configured to evaporate the condensate from the separation tank and water return system via heat transfer between the condenser portion and evaporator portion to form steam. A turbine can be fluidly coupled with the evaporator portion of the CU via an evaporator side steam conduit.

Embodiments of the present disclosure include a system, method, and apparatus comprising a direct steam generator configured to generate saturated steam or superheated steam and combustion exhaust constituents. A CONVAPORATOR Unit (CU) can be fluidly coupled to the direct steam generator. The CU can be configured to route the saturated steam or superheated steam and combustion exhaust constituents through a condenser portion of the CU via a condenser side steam conduit and can be configured to condense the super-heated steam or saturated steam to form a condensate. A separation tank and water return system can be fluidly coupled to a condenser side condensate conduit of the condenser portion of the CU. The separation tank and water return system can be configured to separate the combustion exhaust constituents from the condensate. An evaporator portion of the CU can be fluidly coupled with the separation tank and water return system via an evaporator side condensate conduit. The evaporator portion can be configured to evaporate the condensate from the separation tank and water return system via heat transfer between the condenser portion and evaporator portion to form steam. A turbine can be fluidly coupled with the evaporator portion of the CU via an evaporator side steam conduit.

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 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 method of recovering wood pulping chemicals from black liquor produced in a wood pulping process where the process entails burning the black liquor in a recovery boiler to form ash containing high levels of carbonate as well as sodium, potassium and chloride. The ash is dissolved to form a dissolved ash solution that is directed to a first stage crystallization unit that concentrates the dissolved ash solution and which results in the precipitation of sodium sulfate and sodium carbonate. Thereafter the concentrated dissolved ash solution is directed to a second stage crystallization unit which adiabatically cools the concentrated dissolved ash solution to form a glaserite slurry and a purge stream that is rich in chloride. In order to reduce the tendency of sodium carbonate and burkeite to crystallize in the second stage crystallization unit and to encourage pure glaserite to crystalize in the crystallizer, the method entails mixing a sulfate source, such as sodium sulfate or sulfuric acid, to the concentrated dissolved ash solution upstream of the crystallizer.