Wood pulping process including pulping wood to produce a pulping effluent or liquor. Pre-concentrating the liquor in a pre-concentration unit produces concentrated liquor, a contaminated condensate and a non-contaminated condensate. Directing the concentrated liquor to a multi-effect train of forced circulation solids concentrators that further concentrating the concentrated liquor to form a highly concentrated liquor. Directing the contaminated condensate produced by the pre-concentration unit to a steam stripper and stripping gases therefrom and in the process producing a contaminated vapor stream. Utilizing the contaminated vapor stream and its thermal energy to power the forced circulation solids concentrators of the multi-effect train.

The disclosure provides methods and compositions for reducing the viscosity of black liquor. Also provided are methods of inhibiting deposition of scale and methods of processing black liquor. In some embodiments, the compositions include a carboxylate-containing polymer and an inorganic salt. In some embodiments, the compositions include a carboxylate-containing polymer, an inorganic salt, and a surfactant.

The method in a recovery boiler comprises estimating the first melting temperature T.sub.0 of the fly ash depositing on heat transfer surfaces, the estimating being based on potassium (K) content of the fly ash; measuring or estimating the temperature T.sub.ss of superheated steam; evaluating a temperature difference T.sub.D1 between the first melting temperature T.sub.0 and the temperature T.sub.ss of the superheated steam, the temperature difference T.sub.D1 providing an estimate of the risk of corrosion; and selecting a control action for influencing the temperature difference T.sub.D1. Alternatively or additionally, the method comprises estimating the sticky temperature T.sub.STK of the fly ash depositing on heat transfer surfaces, the estimating being based on potassium (K) and chlorine (Cl) contents of the fly ash; measuring or estimating the temperature T.sub.FG of the flue gases; evaluating a temperature difference T.sub.D2 between the sticky temperature T.sub.STK and the temperature T.sub.FG of the flue gases; the temperature difference T.sub.D2 providing an estimate of the risk of plugging; and selecting a control action for influencing the temperature difference T.sub.D2.

Wood pulping process including pulping wood to produce a pulping effluent or liquor. Pre-concentrating the liquor in a pre-concentration unit produces concentrated liquor, a contaminated condensate and a non-contaminated condensate. Directing the concentrated liquor to a multi-effect train of forced circulation solids concentrators that further concentrating the concentrated liquor to form a highly concentrated liquor. Directing the contaminated condensate produced by the pre-concentration unit to a steam stripper and stripping gases therefrom and in the process producing a contaminated vapor stream. Utilizing the contaminated vapor stream and its thermal energy to power the forced circulation solids concentrators of the multi-effect train.

Some embodiments of the present invention relate to a method for reducing the concentration of reactive silica in a first composition comprising adding a first amount of a calcium salt and a second amount of a magnesium salt to the first composition to form a solid silicate composition comprising one or more silicates, wherein the first composition comprises an aqueous solution; and a significant portion of the reactive silica in the first composition is converted to one or more silicate in the solid silicate composition.

The disclosure provides methods and compositions for reducing the viscosity of black liquor. Also provided are methods of inhibiting deposition of scale and methods of processing black liquor. In some embodiments, the compositions include a carboxylate-containing polymer and an inorganic salt. In some embodiments, the compositions include a carboxylate-containing polymer, an inorganic salt, and a surfactant.

Compositions and methods for the removal and prevention of scale in pulp mills in a continuous and real-time process. More particularly the composition includes one or more chelating ligands, one or more copolymers, and one or more surfactants. The scale removing composition is added to the black liquor stream in pulp and paper processes to remove scaling, such as scaling from calcium carbonate, from surfaces in contact with the black liquor stream, such as in digestors and evaporators.