Browsing NTNU Open by Author "Ruwoldt, Jost"
Now showing items 1-14 of 14
-
A critical update of experimental techniques of bulk and interfacial components for fluid characterization with relevance to well fluid processing and transport
Simon, Sebastien Charles; Ruwoldt, Jost; Sjøblom, Johan (Journal article; Peer reviewed, 2020)The present article reviews techniques to address central flow assurance and separation issues. It is our purpose to update the need for extended information in order to draw adequate conclusions about the reason for ... -
Asphaltene fractionation based on adsorption onto calcium carbonate: Part 3. Effect of asphaltenes on wax crystallization
Ruwoldt, Jost; Subramanian, Sreedhar; Simon, Sebastien Charles; Oschmann, Hans-Jörg; Sjøblom, Johan (Journal article; Peer reviewed, 2018)Asphaltenes fractionation procedures were developed and tested in two preceding articles (doi: https://doi.org/10.1016/j.colsurfa.2016.02.011, doi: https://doi.org/10.1016/j.colsurfa.2016.11.035), and asphaltene fractions ... -
Characterization and assessment of wax and wax inhibitors systems in microfluidic oil-in-water coalescence experiments
Dudek, Marcin Jan; Ruwoldt, Jost; Øye, Gisle (Journal article; Peer reviewed, 2022)During produced water treatment, one of the key underlying phenomena affecting separation performance is coalescence between oil droplets. These processes can be affected by several factors, including chemical composition ... -
Effect of Low-Molecular-Weight Alcohols on Emulsion Stabilization with Lignosulfonates
Ruwoldt, Jost; Øye, Gisle (Peer reviewed; Journal article, 2020)Lignosulfonates are biobased surfactants and specialty chemicals, which are described as water-soluble polyelectrolyte macromolecules that are generated during the sulfite pulping of lignocellulose biomass. Due to their ... -
Influence of Wax Inhibitor Molecular Weight on Solution Crystallization and Rheology of Monodisperse Waxes
Kurniawan, Muh; Ruwoldt, Jost; Norrman, Jens; Paso, Kristofer Gunnar (Peer reviewed; Journal article, 2021)Molecular weight fractionation via stepwise precipitation or chain scission is performed on four pour point depressant polymers to study the pour point reduction mechanism. An homologous series of model oils is prepared ... -
Influence of wax inhibitor molecular weight: Fractionation and effect on crystallization of polydisperse waxes
Ruwoldt, Jost; Kurniawan, Muh; Sørland, Geir; Simon, Sebastien Charles; Sjøblom, Johan (Journal article; Peer reviewed, 2019)The influence of wax inhibitor molecular weight on wax crystallization was investigated in three steps: (1) Wax inhibitor fractionation via stepwise precipitation or ultrasonic disintegration, (2) characterization of ... -
Inhibitor-wax interactions and PPD effect on wax crystallization: New approaches for GC/MS and NMR, and comparison with DSC, CPM, and rheometry
Ruwoldt, Jost; Sørland, Geir; Simon, Sebastien Charles; Oschmann, Hans-Jörg; Sjøblom, Johan (Journal article; Peer reviewed, 2019)Three pour point depressants (PPDs) with different chemistries, and extracted asphaltenes were studied in their influence on wax crystallization in a model system. A new procedure for nuclear magnetic resonance (NMR) was ... -
Inhibitor-Wax Interactions and Wax Crystallization: New Experimental Approaches and Techniques
Ruwoldt, Jost (Doctoral theses at NTNU;2018:410, Doctoral thesis, 2018)Issues related to wax crystallization are one of the major challenges faced during crude oil production. Wax inhibitors and pour point depressants (PPD) are in common use for wax prevention, as they can delay gelling and ... -
Lignosulfonate Salt Tolerance and the Effect on Emulsion Stability
Ruwoldt, Jost; Planque, Juliette; Øye, Gisle (Peer reviewed; Journal article, 2020)In this article, we adapted and compared methods to assess lignosulfonates for technical applications. Salt-induced agglomeration and precipitation were studied via mechanical separation and subsequent UV spectrometry. The ... -
Lignosulfonates in Crude Oil Processing: Interactions with Asphaltenes at the Oil/Water Interface and Screening of Potential Applications
Simon, Sebastien Charles; Saadat, Marzieh; Ruwoldt, Jost; Dudek, Marcin; Ellis, Ross J.; Øye, Gisle (Peer reviewed; Journal article, 2020)The goal of this article is to test the potential application of lignosulfonates (LSs) in crude oil production and processing. Three LS samples of varying hydrophobicity and average molecular weight were considered. First, ... -
Non-linear dependency of wax appearance temperature on cooling rate
Ruwoldt, Jost; Kurniawan, Muh; Oschmann, Hans-Jörg (Journal article, 2018)The Wax Appearance Temperature (WAT) is usually the first parameter to consider, when assessing whether paraffin wax contained in the crude oil can become an issue during production. As such, correct determination of the ... -
Viscoelastic properties of interfacial lignosulfonate films and the effect of added electrolytes
Ruwoldt, Jost; Simon, Sebastien Charles; Øye, Gisle (Peer reviewed; Journal article, 2020)New evidence is presented, which confirmed interfacial gelling of lignosulfonates in presence of di- and trivalent cations. In this article, the viscoelastic properties of lignosulfonate films at the water-xylene interface ... -
Viscoelastic properties of interfacial lignosulfonate films and the effect of added electrolytes
Ruwoldt, Jost; Simon, Sebastien Charles; Øye, Gisle (Peer reviewed; Journal article, 2020)New evidence is presented, which confirmed interfacial gelling of lignosulfonates in presence of di- and trivalent cations. In this article, the viscoelastic properties of lignosulfonate films at the water-xylene interface ... -
Wax-Inhibitor Interactions Studied by Isothermal Titration Calorimetry and Effect of Wax Inhibitor on Wax Crystallization
Ruwoldt, Jost; Simon, Sebastien Charles; Norrman, Jens; Oschmann, Hans-Jörg; Sjøblom, Johan (Journal article; Peer reviewed, 2017)Isothermal titration calorimetry is applied to investigate the interactions of polymeric pour-point depressants (PPDs) or asphaltenes with macrocrystalline wax in a model oil system. This represents a novel approach to ...