Search for dissertations about: "pre-treatment"

Showing result 16 - 20 of 341 swedish dissertations containing the word pre-treatment.

2. 16. Mild Steam Explosion of Wood and Forest Residues in the Perspective of a Materials Biorefinery

   Author : Joanna Wojtasz-Mucha; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Steam explosion; Forest residues; Pre-treatment; Soda cooking; Kraft cooking; Autohydrolysis; Biorefinery; Local properties; Hot water extraction;

   Abstract : The main objective of this work was to explore the prospects of using mild steam explosion as a pretreatment step in a forest based material biorefinery. During the steam explosion saturated steam is applied to the biomass at elevated pressure leading to an autohydrolysis of the lignocellulosic tissue, which is followed by a rapid pressure discharge, disintegrating and opening up the structure. READ MORE

4. 17. Pre-Extraction of Wood Components Mild hydrothermal methods for a future materials biorefinery

   Author : Joanna Wojtasz-Mucha; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; spruce; forest residues; pre-treatment; Biorefinery; soda cooking; hot water extraction; steam explosion; autohydrolysis; birch; kraft cooking;

   Abstract : Today there is an increasing urgency in discovering new, and more sustainable, replacements for fossil-based materials and chemicals. The biorefinery concept is promising in this context in that it relies on transforming biomass into a spectrum of commercial products. Wood is the primary bioresource in Scandinavia. READ MORE

5. 18. Fenton Pre-treatment of a Birch Kraft Pulp for MFC preparation

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

   Abstract : 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. READ MORE

6. 19. When and why is pre-treatment of substrates for anaerobic digestion useful?

   Author : My Carlsson; Hinrich Uellendahl; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Waste Science and Technology; Avfallsteknik;

   Abstract : Anaerobic digestion (AD) plays a key role in the recovery of renewable energy, in the form of biogas, and nutrients from waste materials. Pre-treatment of AD substrates has the potential to improve process performance in terms of increased methane yield and solids reduction, but pretreatments are not yet widely implemented into full-scale AD systems. READ MORE

7. 20. Energy-metabolic aspects of ischemia and pre-treatment: studies in porcine myocardium

   Author : Katarina Ahlström; Göteborgs universitet; []
   Keywords : myocardial ischemia; adenosine; preconditioning; carbon monoxide;

   Abstract : The focus of this thesis is to clarify mechanisms involved in protective pre-treatment of ischemia by carbon monoxide (CO) and ischemic preconditioning (IP), so that new pro-tective therapies can be designed. This is studied in heart muscle, where the clinical gain would ultimately be to be able to prolong the period during a threatened myocardial infarction where permanent injury can be prevented. READ MORE