Sökning: "Per Engstrand"

Visar resultat 1 - 5 av 29 avhandlingar innehållade orden Per Engstrand.

  1. 1. Wood and fibre mechanics related to the thermomechanical pulping process

    Författare :Jan-Erik Berg; Per Engstrand; Per A. Gradin; Tomas Björkqvist; Mittuniversitetet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Acoustic emission; Chips; Compression tests; Defibration; Disc refiners; Energy consumption; Fibre structure; Force sensors; Fracture; Impact strength; Mathematical analysis; Moisture content; Picea abies; Refining; Stiffness degradation; Strains; Temperature; Thermomechanical pulping; Velocity; Chemical engineering; Kemiteknik;

    Sammanfattning : The main objective of this thesis was to improve the understanding of some aspects on wood and fibre mechanics related to conditions in the thermomechanical pulping process. Another objective was to measure the power distribution between the rotating plates in a refiner. LÄS MER

  2. 2. Distributions Of Fiber Characteristics As A Tool To Evaluate Mechanical Pulps

    Författare :Sofia Reyier Österling; Per Engstrand; Hans Höglund; Olof Ferritsius; Rita Ferritsius; Hans Ersson; Per Gradin; Mittuniversitetet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Fiber; fibre; fiber characteristics; fiber dimension; fiber properties; mechanical pulp; FiberLab; raw data; distribution; fiber wall thickness; BIN; bonding ability influence; bonding indicator; bonding ability; fiber width; fibrillation; collapse resistance; laboratory sheet; fiber analyzer; optical analyzer; TMP; CTMP; SGW; sheet model; prediction; fiber characterization; hydrocyclone; fractionation; kernel density estimation; KDE; diffusion mixing; acoustic emission; F0.90; Norway spruce; Picea abies;

    Sammanfattning : Mechanical pulps are used in paper products such as magazine or news grade printing papers or paperboard. Mechanical pulping gives a high yield; nearly everything in the tree except the bark is used in the paper. This means that mechanical pulping consumes much less wood than chemical pulping, especially to produce a unit area of printing surface. LÄS MER

  3. 3. Beyond averages – some aspects of how to describe a heterogeneous material, mechanical pulp, on particle level

    Författare :Olof Ferritsius; Birgitta A. Engberg; Per Engstrand; Mats Rundlöf; Øyvind Weiby Gregersen; Mittuniversitetet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Visualisation; Uniformity; Distributions; Independent common factors; Weighted fibre length; Fibre bonding; Fibrillation; Curl; Wall thickness; Particle analyser characterisation; Raw material; CTMP; Process configuration; Sampling accuracy;

    Sammanfattning : For a more profound understanding of how a process works, it is essential to have a relevant description of the material being processed. With this description, it will be easier to evaluate and control processes to produce more uniform products with the right properties. LÄS MER

  4. 4. Improved energy efficiency in mill scale production of mechanical pulp by increased wood softening and refining intensity

    Författare :Erik Nelsson; Per Engstrand; Birgitta A. Engberg; Rodger Beatson; Mittuniversitetet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER;

    Sammanfattning : This thesis focuses on the electric energy efficiency of single stage double disc refining for production of printing grade mechanical pulp from Norway spruce wood chips. The thesis is based on the hypothesis, that more energy efficiency refining can be attained by balanced increases of wood softening and refining intensity. LÄS MER

  5. 5. Evaluation of two hydrocyclone designs for pulp fractionation

    Författare :Rasmus Andersson; Mikael Lindström; Per Engstrand; Kristofer Gamstedt; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Chemical engineering; Kemiteknik;

    Sammanfattning : The process conditions and fractionation efficiency of two hydrocyclone designs, a novel and a conventional conical design, were evaluated. The novel design comprised a modified inlet section, where the pulp suspension had to pass a narrow ring-shaped opening, and a very compact fractionation zone. LÄS MER