A method of treating brown stock in a brown stock washing process is provided. The method includes measuring a refractive index of a brown stock; and dosing an additive to the brown stock according to at least the refractive index of the brown stock. A system for controlling dosing of an additive to a brown stock washing process is also provided. The system includes a refractive index measurement device; a controller configured to receive data provided by the refractive index measurement device and transform the data into additive addition output instructions; and an additive delivery unit configured to receive and execute the additive addition output instructions from the controller.

The present invention provides a method of producing an improved cellulose pulp consisting of cellulose fibers of a desired length, such as cellulose fibers having a length-weighted average fiber length Lc(l)>0.6 mm and its use in cellulose pulp-comprising products, such as packaging material with improved properties.

A method of producing bleached microcrystalline cellulose which method comprises neutralizing or alkalizing an acidic microcrystalline production reaction mixture slurry, typically produced by acid hydrolysis or by electronic beam irradiation, followed by adding an oxidant to such reaction mixture. This practice of this method permits the production of microcrystalline cellulose having desirable color stability as well as compression characteristics suitable for pharmaceutical binder use from paper grade and other low purity pulps.

The invention relates to a method for reducing pulp viscosity in production of dissolving pulp. The method comprises producing cellulose pulp, whereby the obtained cellulose pulp has a cellulose content of at least 90%, and bleaching the obtained cellulose pulp. The cellulose pulp is treated after bleaching with performic acid.

Cellulosic material for the production of regenerated cellulosic fiber is disclosed. The cellulosic material comprises reclaimed cellulosic material, wherein the reclaimed cellulosic material is obtained from cellulosic material waste and has an intrinsic viscosity in a range of 170 ml/g to 280 ml/g. A process for preparing reclaimed cellulosic material for the production of regenerated cellulosic fiber is also disclosed.

A bleaching apparatus comprises a measurement chamber has a first substance, the amount of the first substance in the measurement chamber being known. A dosing unit inputs a second substance to the measurement chamber for causing a chemical reaction between the first substance and the second substance, one of the first substance and the second substance being chlorine dioxide and another of the first substance and the second substance being filtered sample from pulp slurry of a pulp process. At least one sensor performs detection of a property known to depend on the chemical reaction between the first substance and the second substance as a function of time. A data processing unit determines chemical demand of chlorine dioxide for washing loss in a bleaching sub-process on the basis of at least one value in the detected property within a known period of time after the input of the second substance.

The invention relates to a method for reducing pulp viscosity in production of dissolving pulp. The method comprises producing cellulose pulp, whereby the obtained cellulose pulp has a cellulose content of at least 90%, and bleaching the obtained cellulose pulp. The cellulose pulp is treated after bleaching with performic acid.

A method of producing bleached microcrystalline cellulose which method comprises neutralizing or alkalizing an acidic microcrystalline production reaction mixture slurry, typically produced by acid hydrolysis or by electronic beam irradiation, followed by adding an oxidant to such reaction mixture. This practice of this method permits the production of microcrystalline cellulose having desirable color stability as well as compression characteristics suitable for pharmaceutical binder use from paper grade and other low purity pulps.

A bleaching apparatus comprises a measurement chamber has a first substance, the amount of the first substance in the measurement chamber being known. A dosing unit inputs a second substance to the measurement chamber for causing a chemical reaction between the first substance and the second substance, one of the first substance and the second substance being chlorine dioxide and another of the first substance and the second substance being filtered sample from pulp slurry of a pulp process. At least one sensor performs detection of a property known to depend on the chemical reaction between the first substance and the second substance as a function of time. A data processing unit determines chemical demand of chlorine dioxide for washing loss in a bleaching sub-process on the basis of at least one value in the detected property within a known period of time after the input of the second substance.

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for determining and applying a distribution of oxidizing agents in delignification of a pulp bleaching cycle. The method obtains an incoming kappa value of an unbleached pulp slurry and a target kappa value expected for a bleached pulp slurry. A model generates a sequence kappa factor based on these values, and a total equivalent chlorine (TEC) factor from the sequence kappa factor and the incoming kappa value. Scenarios are simulated using the TEC factor, each scenario specifying a unique distribution of dosage targets for oxidizing agents and having a total consumption score for the oxidizing agents that is determined based on the dosage targets for the oxidizing agents. A scenario with the lowest total consumption score is selected, and the model applies the dosage targets of oxidizing agents for the selected scenario during the pulp bleaching cycle.