The present invention relates to a method for treating green liquor in a green liquor treatment arrangement, wherein the method comprisesadding (101) a flocculation agent to green liquor to form flocculated green liquor,supplying (102) the flocculated green liquor to a clarifying vessel for separating flocculated green liquor into flocculated matter and clear green liquor,removing (103) flocculated matter through a sludge outlet, andremoving (104) clear green liquor from the clarifying vessel, wherein the method further comprisesmeasuring (201) a flocculation of the green liquor, wherein said measuring takes place after adding the flocculation agent but before supplying the flocculated green liquor to the clarifying vessel. The invention also relates to a green liquor treatment device.

The present invention relates to a mixing assembly for controlling mixing of green liquor and a flocculation agent, the mixing assembly comprising a mixing vessel (20) having a first end and a second end, a vessel inlet (21) for supplying liquor and flocculation agent to the mixing vessel in a vicinity of the first end, a vessel outlet (22), a stirring device (31) that is rotatably arranged in the vicinity of the first end for mixing the liquor and flocculation agent by stirring, wherein the mixing vessel (20) has a length from a center of the vessel inlet to a center of the vessel outlet, and the mixing vessel also has a maximum width that is perpendicular to the length, and wherein said length is at least 1.5 times the maximum width. The invention also relates to a method for controlling flocculation of green liquor.

An improved continuous process for production of cellulose from glass-like feedstock, which includes: (i) cooking of comminuted grass-like feedstock in white liquor which contains 0.5-2.0% w/w NaOH and 0.5-25.0% w/w NaCl at 95-100? C.; (ii) bleaching process of the brown cellulose in the white liquor of the same composition with oxygen (O.sub.2) and chlorine (Cl.sub.2) at 70-100? C., yielding bleached cellulose pulp; where, (iii) lignin and other side-products are separated by continuous electrolysis, where the white liquor is regenerated, together with O.sub.2 and Cl.sub.2 for the bleaching purpose, thereby closing the cycle of the process.

A method of increasing chemical efficiency of chemical additives in a papermaking system includes the steps of providing thick stock pulp comprising soluble lignin, process water, and at least about 2% by weight of cellulosic fiber based on total weight of thick stock pulp, and adding at least one laccase enzyme and at least one organic polymer to the thick stock pulp to reduce the amount of soluble lignin therein. The organic polymer is chosen from cationic polymers, non-ionic polymers and combinations thereof.

A smelt shattering apparatus includes an inlet orifice, an outlet orifice, and a fluidic pathway between the inlet orifice and the outlet orifice. A convergence divergence zone is located between the inlet orifice and the outlet orifice. In one illustrative construction, a first separable section includes the inlet orifice, and a second separable section includes the outlet orifice and a divergence zone of the convergence divergence zone. In some constructions, there may be a second outlet orifice in fluidic communication with the inlet orifice. To provide uniformity over the multiple shatter jets, the first outlet orifice may have a cross-sectional dimension and the second outlet orifice is located a distance of between about 4 and about 10 times of the cross-sectional dimension from the first outlet orifice.

Techniques for growing crystalline calcium carbonate solids such that the crystalline calcium carbonate solids include a volume of 0.0005 mm.sup.3 to 5 mm.sup.3, include a slaker to react quicklime (CaO) and a low carbonate content fluid to yield a slurry of primarily slaked lime (Ca(OH).sub.2); a fluidized-bed reactive crystallizer that encloses a solid bed mass and includes an input for a slurry of primarily slaked lime, an input for an alkaline solution and carbonate, and an output for crystalline calcium carbonate solids that include particles and an alkaline carbonate solution; a dewatering apparatus that includes an input coupled to the crystallizer and an output to discharge a plurality of separate streams that each include a portion of the crystalline calcium carbonate solids and alkaline carbonate solution; and a seed transfer apparatus to deliver seed material into the crystallizer to maintain a consistent mass of seed material.

The invention relates to a method for producing an oil rich fraction (OF) from primary feedstock (FS) that comprises water, first salt, second salt, and biomass. The feedstock (FS) is provided to a first reaction zone (Z1) of a conversion reactor (100), where it is allowed to react at a temperature of at least 350 C. in a pressure of at least 160 bar to form converted primary feedstock. The method comprises separating from the converted primary feedstock a first salt rich fraction (SF1), a second salt rich fraction (SF2), and an oil rich fraction (OF). The method comprises withdrawing the oil rich fraction (OF) from the first reaction zone (Z1) and withdrawing the first salt rich fraction (SF1) and the second salt rich fraction (SF2) from the conversion reactor (100). In the method the first salt rich fraction (SF1) comprises at least some of the first salt dissolved in the water, the second salt rich fraction (SF2) comprises at least some of the second salt in solid form, and at least one of the first salt and the second salt is a salt capable of catalysing the reaction of the biomass of the primary feedstock (FS) with the water of the primary feedstock (FS) to produce the oil rich fraction (OF). A device for the same.

A process for recausticizing green liquor in a sulphate or Kraft process for wood pulp production, in which a green liquor consisting of an aqueous solution of sodium carbonate as the major component and sodium sulphide is admixed with calcium oxide in a slaker and undergoes a reaction in a recausticizer to form an aqueous suspension containing sodium hydroxide and calcium carbonate as the major components, which suspension is filtered on a first filter and subsequently, after dilution with water in a dilution vessel, is fed over further filters two or three times and filtered to separate solids suspended therein, characterized in that after a first separation of calcium carbonate as the major component and calcium oxide as the minor component, carbon dioxide is added to the aqueous suspension at least during dilution in a dilution vessel and in particular in the dilution vessel (s) upstream of a second and/or a third filter.

Techniques for converting a portion of a carbonate to hydroxide include receiving an alkaline carbonate solution that includes between 0.1M (moles per liter of solution) to 4.0M hydroxide and between 0.1M to 4.1M carbonate; reacting, in a slaking process, quicklime (CaO) and a low carbonate content fluid to yield a slurry of primarily slaked lime (Ca(OH).sub.2); and reacting the Ca(OH).sub.2 slurry and the alkaline carbonate solution to grow calcium carbonate (CaCO.sub.3) crystal aggregates of 0.0005 mm.sup.3 to 5 mm.sup.3 in volume in a fluidized-bed reactive crystallizer.

The invention is related to improved polysulfide production process wherein a specific second filtration process (F.sub.x) is installed before the polysulfide reactor (R.sub.c). According to the inventive method a cross flow filter (F.sub.x) is used as the second filtration process reaching astonishing low levels of residual solids in the white liquor as well as extended availability of the second filtration process. The subsequent polysulfide reactor, either in form of an electrolytic cell or in form of a bed of active carbon, could then also be operated at increased availability. The invention increases the production volume of polysulfide and the retentate from the cross filtering process may be bled out continuously to a process position ahead of a first filtering or clarification stage, capturing most of the increased content of lime mud particles in the retentate and causing less disturbance of the process with a minimum of tanks and pumps.