Abstract: There is provided a process for chemically pretreating reclaimed cellulose fibres to be used in the production of moulded bodies from regenerated cellulose, wherein the pretreatment includes one stage, in which stage acid metal removal and acid oxidative bleaching are carried out together. Advantages include that the propensity of the regenerated cellulose to clog when flowing in a tube and through a nozzle is reduced. This is believed to be an effect of an efficient metal removal. The need for additional bleaching steps and/or metal removing steps is reduced or even eliminated. A one-stage method is more efficient, faster and less costly compared to a multi-stage method according to the prior art. From an environmental perspective, acidic metal removal is preferred over removal by chelating agents such as EDTA.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A process is modeled by a dynamic model, handling time dependent relations between manipulated variables of different process sections (10A–D) and measured process output variables. Suggested input trajectories for manipulated variables for a subsequent time period are obtained by optimizing an objective function over a prediction time period, under constraints imposed by the dynamic process model and/or preferably a production plan for the same period. The objective function comprises relations involving predictions of controlled process output variables as a function of time using the process model, based on the present measurements, preferably by a state estimation procedure. By the use of a prediction horizon, also planned future operational changes can be prepared for, reducing any induced fluctuations. In pulp and paper processes, process output variables associated with chemical additives can be used, adapting the optimization to handle chemical additives aspects.

Abstract: A process is modeled by a dynamic model, handling time dependent relations between manipulated variables of different process sections (10A-D) and measured process output variables. Suggested input trajectories for manipulated variables for a subsequent time period are obtained by optimizing an objective function over a prediction time period, under constraints imposed by the dynamic process model and/or preferably a production plan for the same period. The objective function comprises relations involving predictions of controlled process output variables as a function of time using the process model, based on the present measurements, preferably by a state estimation procedure. By the use of a prediction horizon, also planned future operational changes can be prepared for, reducing any induced fluctuations. In pulp and paper processes, process output variables associated with chemical additives can be used, adapting the optimization to handle chemical additives aspects.