Various techniques are described for enhanced combustion of hot water extraction (HWE) derived liquor. For example, the HWE derived liquor can be pre-treated prior to introduction into a combustion chamber. The pre-treatment can include subjecting HWE derived liquor to filtration to remove suspended solids, evaporation to produce a first stage concentrated HWE liquor; additional concentration to produce a second stage concentrated HWE liquor; additional filtration to remove additional suspended solids; and pre-heating to produce a preheated HWE liquor. The preheated HWE liquor can be atomized and combined with pre-heated combustion air supplied into a combustion chamber to effect combustion of the HWE derived liquor.

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 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.

An apparatus comprising a cleaning rod driven in reciprocating, axial extension (y) and retraction (x) movements upon cleaning a smelt discharge opening of a chemicals recovery boiler, wherein a linear actuator is controllable for driving the cleaning rod in the axial movements. A pivot actuation means is controllable for pivoting the cleaning rod about an axis (S) upon cleaning a smelt spout associated with the smelt discharge opening, wherein one or more sensors are arranged to provide control basis for correlation of the axial movements (x; y) with the change in pivot angle (φ) during pivoting of the cleaning rod. A method to be performed in use of the apparatus is likewise disclosed.

An apparatus comprising a cleaning rod driven in reciprocating, axial extension (y) and retraction (x) movements upon cleaning a smelt discharge opening of a chemicals recovery boiler, wherein a linear actuator is controllable for driving the cleaning rod in the axial movements. A pivot actuation means is controllable for pivoting the cleaning rod about an axis (S) upon cleaning a smelt spout associated with the smelt discharge opening, wherein one or more sensors are arranged to provide control basis for correlation of the axial movements (x; y) with the change in pivot angle (φ) during pivoting of the cleaning rod. A method to be performed in use of the apparatus is likewise disclosed.

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 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.

Processes for stabilizing toluenediamine residues are disclosed. These processes include adding a low viscosity, low boiling liquid to a toluenediamine residue composition to form a blend, and optionally, continuously monitoring the viscosity of the blend during addition of the low viscosity, low boiling liquid. The low viscosity, low boiling liquid may be added at 5% to 30% by weight based on the total weight of the blend. Further, the low viscosity, low boiling liquid may be added so that the blend has a viscosity of 10,000 cP or less throughout the temperature range of 40° C. to 95° C. Blends of toluenediamine residue compositions and low viscosity, low boiling liquids such as water, and methods of their use as a fuel are also disclosed.

Processes for stabilizing toluenediamine residues are disclosed. These processes include adding a low viscosity, low boiling liquid to a toluenediamine residue composition to form a blend, and optionally, continuously monitoring the viscosity of the blend during addition of the low viscosity, low boiling liquid. The low viscosity, low boiling liquid may be added at 5% to 30% by weight based on the total weight of the blend. Further, the low viscosity, low boiling liquid may be added so that the blend has a viscosity of 10,000 cP or less throughout the temperature range of 40° C. to 95° C. Blends of toluenediamine residue compositions and low viscosity, low boiling liquids such as water, and methods of their use as a fuel are also disclosed.

A method for obtaining information on quality of combustion of a liquor in a chemical recovery boiler. The method comprises entering a value of a first input parameter to a computational model configured to determine, based on the value of the first input parameter, a value of the quality of combustion of the liquor in the chemical recovery boiler, and at a first time, running the computational model to obtain a first modelling result. The method comprises measuring, from the chemical recovery boiler a value indicative of carryover to obtain a measurement result; comparing the first modelling result with [a] the measurement result or [b] a result derived from the measurement result, to obtain a primary comparison result; and adjusting the value of the first input parameter based on the primary comparison result to obtain an adjusted value of the first input parameter. The method comprises entering the adjusted value of the first input parameter to the computational model, and at a second time, running the computational model to obtain the information on quality of combustion of the liquor in the chemical recovery boiler.