Green liquor clarification comprising filtering of a flowing suspension containing solids, wherein the suspension is brought into contact with a first filter unit (4), said 5 filter unit (4) comprising one or several filter elements (12) comprising one or several filter bodies (3) having filter channels (33) within the filter bodies (3) with a filtering layer (32), a part of the suspension is forced to pass through the filtering layer (32) from a first/inner surface (32A) to a second/outer surface (32B) of the filtering layer (32) forming a filtrate while the solids substantially remains in a residual part of the suspension forming a slurry and where the filtering layer (32) is made of a membrane material with pores, said pores having a pore size of 0.1-10 micrometer, more preferred 0.1-5 micrometer and most preferred 0.2-1.0 micrometer.

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.

A method and a liquor filter, in which liquor filter sealing medium is fed via a sealing medium channel (3) into an innermost sealing zone formed by an innermost sealing member (1), an outer seal (2) and the space between them at a causticizing plant of a chemical pulp mill. The sealing medium used is an alkaline sealing liquid and/or gas, which does not substantially dilute the liquor being filtered. Advantageously the sealing medium is filtrate from the liquor filter and/or gas taken from the interior of the liquor filter.

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.

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.

Green liquor clarification comprising filtering of a flowing suspension containing solids, wherein the suspension is brought into contact with a first filter unit (4), said 5 filter unit (4) comprising one or several filter elements (12) comprising one or several filter bodies (3) having filter channels (33) within the filter bodies (3) with a filtering layer (32), a part of the suspension is forced to pass through the filtering layer (32) from a first/inner surface (32A) to a second/outer surface (32B) of the filtering layer (32) forming a filtrate while the solids substantially remains in a residual part of the suspension forming a slurry and where the filtering layer (32) is made of a membrane material with pores, said pores having a pore size of 0.1-10 micrometer, more preferred 0.1-5 micrometer and most preferred 0.2-1.0 micrometer.

The present invention relates in general to a process for removing mercury from a mercury-containing flue gas using dregs from a Kraft pulp mill green liquor clarifier. The dregs are washed with water to produce a particulate carbon slurry which is activated with hydrobromic acid and injected into a mercury-containing flue gas to oxidize and adsorb the mercury at temperatures less than about 900 F. A slurry of sodium hydroxide and calcium carbonate, optionally also obtained from Kraft mill waste, is injected into the hot flue gas to absorb and remove CO.sub.2, SO.sub.2, and SO.sub.3.

Systems and methods are disclosed herein for proactive intervention in an industrial process involving a defoamer composition. Learning models are iteratively trained using historical input data sets comprising directly measured variables from the industrial process and correlations between combinations of the input data and respective process states. For a current input data set associated with the industrial process, and responsive to detected process attributes, an intervention event is determined with respect to at least a first defoamer component in a current composition. Models are utilized to predict, responsive to the intervention event, changes in target values within a specified range of target values for other components in the current composition and/or for directly measured variables as corresponding with a specified process state. Automatic control is performed for respective actuators to produce a new defoamer composition, and as needed to other actuators for the directly measured variables.

According to an example aspect of the present invention, there is provided a method of replacing with sodium make-up chemicals sodium losses caused by outflows in a pulp mill which employs a kraft process for producing cellulosic pulp, wherein the pulp mill includes a unit for conversion of sulphurous compounds, which is fed with sulphurous substances of the kraft process to convert said sulphurous substances into oxidized sulphurous compounds, said method comprising using sodium sulphate possibly together with other sodium salts as the main make-up chemical, to achieve an essentially sodium hydroxide free feed of sodium make-up chemicals, and at least a part of the sulphur contained in the sodium sulphate make-up chemical being used for producing oxidized sulphurous compounds in said unit for conversion of sulphurous compounds.

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.