@phdthesis{MoralesHenriquez2009, author = {Morales Henr{\´i}quez, Carlos Javier}, title = {W/O Emulsions : formulation, characterization and destabilization}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-6068}, school = {BTU Cottbus - Senftenberg}, year = {2009}, abstract = {This work refers to water in oil emulsion formulation, characterization and destabilization. These topics were studied in order to generate knowledge that could be used as a base for the treatment of highly stable W/O emulsions. Two types of emulsions were studied: synthetics and naturals; the last ones come from the crude oil production process of different Venezuelan regions. In this book, chapters 1 and 2 give an introduction to the research area and the theoretical background related with it, respectively. In chapter 3, the effect of surfactant content, water content, HLB value, alcohol content, salinity, emulsion volume, and mixing properties on water in paraffin emulsion stability was studied. Emulsion stability was determined by the amount of water and oil separated after 30 days. After finishing the variables scans, the most appropriate formulation conditions were established, and a formulation protocol was defined. Emulsion density and apparent viscosity were measured, and viscosity was modeled by the Power Law considering both shear rate and water content. Chapter 4 deals with emulsion characterization. Although some particle sizing devices have gained a lot of popularity, none of them is able to distinguish between drops and solids, and few are able to handle viscous oily samples. In this chapter the use of optical microscopy, enhanced by the use of digital video capabilities and image analysis software, to characterize oil production wastes is discussed. Several thousands of particles were counted and their projected areas were measured. A discussion is given about the different corrections required in order to extract the most reliable information from the image, overcoming some of the drawbacks of this kind of measurements. A new technique the so-called cross-linked method was developed to offer unique features like the determination of the fraction of droplets that exist in the form of non-coalesced agglomerates. When cross-linked with the results obtained by standard ASTM procedures, it is calculated the amount of disperse phase that exists in the form of submicron droplets or large free water drops that are usually not sampled for microscope slides. Chapters 5 and 6 deal with emulsion destabilization. In chapter 5, a variety of materials were used to investigate their applicability as so-called collector materials, to improve the destabilization and separation of water in oil emulsions stabilized by a non-ionic surfactant. The emulsion destabilization degree was determined by the amount of water and oil separated after centrifugation. The recovery of both phases was strongly dependent on the nature of the material, material/emulsion ratio, particle size, and contact time. By varying conditions, it was possible to increase the water separation from 0 (without material) up to 95\%. In chapter 6, the effect of a DC electric field on W/O emulsions was evaluated. Electric field magnitude, water content, cell size, electrode design, and electrode coating were considered. Emulsion destabilization was improved by combining electric field, collector material and centrifugation. A comparison is given about the emulsion characteristics in terms of microscopy between both, synthetic and crude oil emulsions.}, subject = {Wasser-in-{\"O}l-Emulsion; W/O Emulsionen; Emulsionsformulierung; Emulsionscharakterisierung; Emulsionsdestabilisierung; Kollektormaterial; W/O Emulsions; Emulsion formulation; Emulsion characterization; Emulsion destabilization; Collector material}, language = {en} } @phdthesis{Saulich2008, author = {Saulich, Katja}, title = {Reaktionskinetische Experimente zur Lipase-katalysierten Hydrolyse von Raps{\"o}l in Wasser-in-{\"O}l-Emulsionen}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-5975}, school = {BTU Cottbus - Senftenberg}, year = {2008}, abstract = {Mit zunehmender Knappheit an Energieressourcen und den daraus resultierenden hohen Energiekosten entwickelt sich ein Bedarf, energieintensive Verfahren der produzierenden Industrie durch Verfahren geringeren Energiebedarfs und h{\"o}herer Produktselektivit{\"a}t zu ersetzen. In der stoffumwandelnden Industrie kommen als Substitutionsverfahren biokatalytische Prozesse in Frage. Als Voraussetzung f{\"u}r eine kommerzielle Anwendung von Enzymprozessen ist ein quantitatives und qualitatives Verst{\"a}ndnis der grundlegenden physikalischen und chemischen Ph{\"a}nomene, die diesen Prozessen obliegen, notwendig. Die Hydrolyse von {\"O}len und Fetten ist ein Beispiel, bei dem die Produkte neben dem technisch etablierten Verfahren alternativ biokatalytisch herstellbar sind. Zur Reaktorauslegung sowie f{\"u}r eine optimale Prozessf{\"u}hrung ist die Kenntnis der Reaktionskinetik notwendig. Die Kinetik dieser heterogenen Reaktion wird maßgeblich durch Qualit{\"a}t und Quantit{\"a}t der Phasengrenzfl{\"a}che sowie dem Enzymverhalten (Aktivit{\"a}t, Stabilit{\"a}t) w{\"a}hrend der Reaktion bestimmt. Diese Arbeit besch{\"a}ftigt sich mit der ph{\"a}nomenologischen Beschreibung der Reaktionskinetik auf der Basis von kinetischen Untersuchungen f{\"u}r die biokatalytische Hydrolyse von Raps{\"o}l in einer w/o-Emulsion (25 Vol.-\% w{\"a}ssrige Phase). Dabei galt es, den Reaktionsfortschritt (Fourier-Transformations-Infrarot(FTIR)-Absorptionsspektroskopie) und die Phasengrenzfl{\"a}che (Photonendichtewellen(PDW)-Spektroskopie) in hoher zeitlicher Aufl{\"o}sung zu messen sowie Einfl{\"u}sse wie Temperatur, pH-Wert, Substratverh{\"a}ltnis und R{\"u}hrergeschwindigkeit auf das Enzymverhalten zu bestimmen. Mit dem Ziel, eine wirtschaftliche Lipasekonzentration absch{\"a}tzen zu k{\"o}nnen, wurden zudem Kenntnisse bez{\"u}glich des Lipase- und Fetts{\"a}ureverhaltens an der Grenzfl{\"a}che mittels der Pendant-Drop-Methode w{\"a}hrend der Reaktion gewonnen.}, subject = {Raps{\"o}l; Wasser-in-{\"O}l-Emulsion; Hydrolyse; Lipase; FTIR; Reaktionskinetik; PDW-Spektroskopie; Pendant-Drop; Lipase; FTIR; Reaction kinetics; PDW-Spectroscopy; Pendant-Drop}, language = {de} }