Sökning: "Helena Håkansson"

Visar resultat 6 - 10 av 10 avhandlingar innehållade orden Helena Håkansson.

1. 6. Process modelling based on data from an evaporation and a CTMP process : Analysis of energy efficiency and process variability

   Författare :Daniel Ekbåge; Lars Nilsson; Helena Håkansson; Per Engstrand; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CTMP; process modelling; evaporation; energy efficiency; Miljö- och energisystem; Environmental and Energy Systems;

   Sammanfattning : The manufacture of pulp and paper is an energy intensive process configured of several unit processes that shape a network of flows of wood chips, chemical pulp, mechanical pulp, paperboard, steam and other important components. Improved energy efficiency supports sustainability of the process and the products. LÄS MER

3. 7. Process modelling in pulp and paper manufacture : Application studies with aspects of energy efficiency and product quality

   Författare :Daniel Ekbåge; Lars Nilsson; Helena Håkansson; Birgitta Engberg; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CTMP; freeness; process modelling; board machine; multiple effect evaporator; Miljö- och energisystem; Environmental and Energy Systems;

   Sammanfattning : The manufacture of pulp and paper is an energy intensive process configured of several unit processes that shape a network of flows of wood chips, chemical pulp, mechanical pulp, board and other important components. Improved energy efficiency supports sustainability of the process and the products. LÄS MER

4. 8. Fenton Pre-treatment of a Birch Kraft Pulp for MFC preparation

   Författare :Pia Hellström; Helena Håkansson; Anette Heijnesson Hultén; Magnus Paulsson; Monica Ek; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Microfibrillated cellulose; Fenton chemistry; carbonyl groups; surface charge; total charge; Enzymatic hydrolysis; Tensile strength; z-directional strength; Chemical Engineering; Kemiteknik;

   Sammanfattning : The potential to use acidic hydrogen peroxide in the presence of ferrous ions (Fenton’s reagent) as a pre-treatment when producing microfibrillar cellulose (MFC) from a fully bleached birch (Betula verucosa) kraft pulp was investigated and the properties of the produced MFC was compared to the properties of a MFC produced with enzymatic pre-treatment with a monocomponent endoglucanase (FiberCare® R). The mechanical treatment to MFC was performed in a laboratory colloid mill or in a pilot high-pressure homogeniser and the pre-treated pulps as well as the produced MFCs were chemically and morphologically characterised. LÄS MER

5. 9. On calcium-related problems in kraft pulping of Eucalyptus dunnii

   Författare :Vijaya Lakshmi Vegunta; Olena Sevastyanova; Helena Håkansson; KTH; []
   Nyckelord :Fiber- och polymervetenskap; Fibre and Polymer Science;

   Sammanfattning : Kraft pulping is the most widely used pulping process for producing chemical pulp today. It has been in use for more than 130 years. LÄS MER

7. 10. On the Process Development of an ECF Light Bleaching Sequence for the Production of High Quality Softwood Kraft Pulp and Low AOX Formation

   Författare :Sara Starrsjö; Juha Fiskari; Mikael Lindström; Olena Sevastyanova; Maria Boman; Peter Sandström; Mittuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemical Engineering; Natural Science; Chemical Pulping; Softwood; Kraft Pulp; Bleaching; ECF light bleaching; Chlorine Dioxide; AOX formation; Delignification; Bleachability;

   Sammanfattning : The aim of this work is to contribute to the process development of the ECF light bleaching sequence Q(OP)D(PO) by providing a better understanding of the bleaching of softwood kraft pulp. There are few published studies on this type of sequence, and more knowledge is needed on how to reduce environmental impact, improve cost-effectiveness and ensure a high pulp quality. LÄS MER