A solution for measuring a suspension which contains wood fibres. The consistency of the suspension is changed in a consistency range. Optical radiation is directed at the suspension and the intensity of optical radiation interacted with the suspension is measured at different consistencies in the consistency range. The maximum intensity of the optical radiation is determined within the consistency range. At least one of the following properties of the suspension are determined based on the determined maximum intensity: kappa number, brightness.

The invention concerns an online method and system for monitoring properties of an aqueous stream of an industrial process. The method comprises providing an initial aqueous stream originating from said process, the aqueous stream containing solid matter exhibiting a first settling behavior; adding modifying agent to the initial aqueous stream at an addition rate sufficient to provide a modified aqueous stream containing solid matter exhibiting a second settling behavior different from the first settling behavior; conducting a sample of the initial aqueous stream or modified aqueous stream, any combination stream comprising the modified aqueous stream or any substream of the modified aqueous stream batchwise from a sampling point to a settling vessel having a volume; and measuring the settling behavior of the solid matter in the sample locally in the settling vessel as a function of time. The invention can be used for efficient monitoring and, optionally, controlling the degree of agglomeration of pulp and paper or board manufacturing processes.

A sample of an aqueous stream is conducted to an optical measurement device. A hydrophobic dye is added. The sample is fractionated into fractions according to particle size or mass. Fluorescence intensity values and light scattering intensity values for the fractions are measured. Fluorescence intensity values of the fractions are added together thus obtaining a sum of the fluorescence intensity values. Light scattering intensity values of the fractions are added together, thus obtaining a sum of the light scattering intensity values. A hydro-phobicity density of the particles in the sample, is calculated by dividing the sum of the fluorescence intensity values with the sum of the light scattering intensity values. A concentration of hydrophobic contaminants in the aqueous stream is monitored and controlled based on the calculated hydrophobicity density of the particles in the sample.

The invention regards a measuring device, comprising a conductor body (7), for detecting the degree of fiber concentration and/or steam point (SP) of a fiber pad (33) being pulped, during use of the device (3), in a grinding gap (15) between refiner discs (11, 13) of a refiner (1). The conductor body (7) exhibits a first electric contact surface (17) adapted to provide electrical contact with a second electric contact surface (19) for transferring an electric current via the fiber pad (33) material. The invention also regards a method for detecting the degree of fiber concentration and/or steam point (SP) of a fiber pad (33). The method comprises the steps of mounting of the conductor body (7) to one of the refiner discs (13), grinding the fiber pad (33) material between the refiner discs (11, 13), detecting alteration of the conductivity and/or electrical resistivity of the fiber pad (33) material, and adjusting inflow of water and/or fiber material from said detected alteration.

A method to determine vapor phase corrosion load in paper and board manufacturing system is disclosed. The method allows optimizing oxidative biocide content in aqueous solutions, suspensions and slurries in the paper and board manufacturing system. The method is based on determination of redox values (rH) of the system during determined time period. A correlation between rH values exceeding a predetermined rH threshold values and corrosion load provides an estimate of increased or decreased corrosion load and allows timely changes to biocide dosage.

A system and method are provided for predictive control of brown stock treatment at a pulp mill. Various online sensors generate output signals representative of actual values for respective process characteristics, each of which are directly or indirectly affected by adjustments to corresponding process variables. A controller uses the output signals or associated measurement data to dynamically set target values for the process characteristics based on a predicted impact of control responses for corresponding process variables. The controller further generates control signals to actuators associated with the respective process variables based on detected variations between the respective actual values and target values. Exemplary brown stock washing control systems may optimize various types of brown stock washing configurations, including for example vacuum drum washers, compaction baffle washers, chemiwashers, direct displacement washers and wash presses. Cloud-based analytics and machine learning may also be implemented to improve the control algorithms over time.

A method of determining a property of a heterogeneous medium in motion comprising at least two phases is provided. A light beam is made small in relation to a part of the medium for which a property is to be determined and the bandwidth of the measurement signal is sufficiently high for distinguishing time periods for the measurement signal which are related to the part of the medium for which a property is to be determined. By using the measurement signal for determining the property of the part of the medium for which a property is to be determined for time periods for the measurement signal which are related to that part of the medium, and determining the property by a mathematical calculation using the measurement signal corresponding to that part of the medium, the properties of individual parts of the medium can be determined.

With a water, particulate and fibre mixture, a method of quantifying fibre content may include providing a sample of the mixture, filtering the sample to produce a particulate and fibre mixture, burning the particulate and fibre mixture to produce a fibre sample, and dissolving the fibre sample to produce a fibre solution. The fibre solution may be analyzed to determine an elemental content of the fibre solution. The elemental content may be compared to a known elemental content to estimate the fibre content.

An arrangement for determining concentration of at least two sample components in solution of at least three components comprises a refractometer as a first instrument for measuring refractive index data as a first quantity of the first sample component. In addition the arrangement comprises a second physical quantity measuring device for measuring second physical quantity as a second quantity data of the second sample component, such as a device for measuring conductivity. The second physical quantity is advantageously essentially independent on said refractive index, but is more strongly dependent on at least concentration of at least one second sample component of said solution. Further the arrangement comprises a data processing unit for determining said concentration of at least two sample components by using said refractive index data and second quantity data in an additive way after a variable substitution performed by said data processing unit on the refractive index data.

An apparatus for optically measuring fluidal matter having fluid as medium and particles non-dissolved in the medium wherein the apparatus comprises a measurement chamber, which is configured to contain the fluidal matter, and a nozzle. The nozzle receives flowable matter and emits a jet of the flowable matter towards or fromwards an optical detector which is associated with the measurement chamber and receives optical radiation from the fluidal matter in the measurement chamber.