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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Kylvattenkemikalier i länsvattnet ifrån världshandelsflottan : En approximativ beräkningsmodell för årliga utsläpp av kylvattenkemikalier ifrån världshandelsflottan

Karlsson, Joel, Moe, Karl January 2015 (has links)
Fartyg använder sig av stora dieselmotorer för framdrift och för att producera elektricitet ombord. Motorerna samt diverse kringsystem har behov av kylning och till detta används kemikaliebehandlat vatten i ett slutet kylsystem. Vid tömning och läckage från systemet tenderar det kemikaliebehandlade vattnet att hamna med länsvattnet. Länsvattnet genomgår en reningsprocess innan det pumpas överbord. Denna reningsprocess är inte utformad för att avskilja kemikalier och dessa tenderar att hamna i havet. I arbetet har en beräkningsmodell tagits fram för att kunna approximera den mängd kylvattenkemikalier som årligen släpps ut ifrån världshandelsflottan. Information om kylvattenkemikalierna har inhämtats via Kemikalieinspektionen samt MSB RIB gällande deras miljöpåverkan och toxicitet. Resultatet visar att en beaktansvärd mängd kemikalier potentiellt kan hamna i havet årligen. Några av kemikalierna beskrivs som giftiga för vattenlevande organismer och akvatiska system. Samt att kemikalierna även kan anrikas i naturen och vara cancerframkallande. / Shipping vessels use large diesel engines for propulsion and for producing electricity. The engines as well as various peripheral systems need to be cooled and for this; chemically treated water in a closed cooling system is used. During leakage and the emptying of the cooling water system, the chemically treated water tends to end up with the bilge water. Bilge water undergoes a purification process before it is pumped overboard. The purification process is not designed to separate chemicals therefore these tend to end up in the sea. A model has been developed for approximating the amount of cooling water chemicals annually emitted from the world merchant fleet. Information regarding the cooling water chemicals has been taken from the Swedish Chemicals Agency and the Swedish Civil Contingencies Agency on its environmental impact and toxicity. The results show that a considerable amount of chemicals can potentially end up in the sea annually and that some of the chemicals described as toxic to aquatic organisms, toxic to aquatic systems, are enriched in nature and may be carcinogenic.
2

Relating the Formation Mechanisms and Kinetic Stability of Complex Shipboard Emulsions to the Physical and Chemical Properties of Model Surfactant-Oil-Water-Salt Systems

Cole R Davis (11113473) 22 July 2021 (has links)
<p>Emulsions are advantageous in many applications including healthcare, food science, and detergency due to their ability to disperse one fluid in another, otherwise immiscible fluid. For the same reason, emulsions are also problematic when mixtures of oil and water are undesirable like in industrial wastewater pollution and fuel systems. Whether an emulsion is desirable or not, both benefit from understanding the fundamental relationship of emulsion formation and stability to the physical and chemical properties of the oil-water-surfactant mixture. This work identifies the formation and stability mechanisms of model emulsion systems through the perspective of emulsion prevention for applications in shipboard wastewater (bilge water) treatment. Although experiments in this study were designed to model bilge water systems, their fundamental approach makes them practical for many different applications like food science, pharmaceuticals, and detergency.</p> <p>The impact of salts on emulsion formation and stability to coalescence were studied to understand how emulsions stabilized by ionic surfactant behave in saltwater environments. Droplet size analysis revealed that emulsion stability to coalescence improved with salt concentration. Through interfacial tension and zeta potential measurements, it was found that the addition of salt promoted close surfactant packing and faster surfactant adsorption kinetics at the oil-water interface. This aided in preventing coalescence and created conditions favorable for the formation of a stable Newton black film. Extended DLVO calculations were used to model the interaction energy between droplets and suggested that hydration forces play an important role in stabilizing these systems. These emulsions were then studied under dynamic ageing conditions to observe the impact of motion on emulsion stability. While statically aged emulsions were stable to coalescence, dynamic ageing induced coalescence (increased droplet size) or emulsified the oil droplets (decreased droplet size) depending on the surfactant concentration and energy input during ageing.</p> Formation mechanisms and stability of spontaneous emulsion systems were also investigated. Low molecular weight oils (e.g., toluene, xylenes, and cyclohexane) were found to spontaneously emulsify with nonylphenol polyethoxylated (NPE) and sodium dodecylbenzene sulfonate (SDBS). NPE emulsions spontaneously emulsified via diffusion and micelle swelling and displayed limited stability due to Ostwald ripening. SDBS emulsions also spontaneously emulsified with toluene but only in saltwater environments. As the concentration of salt in the aqueous phase increased, the spontaneity of these emulsions also increased. These systems were analyzed using the hydrophilic lipophilic difference (HLD) theory to evaluate its efficacy for predicting the conditions favorable for spontaneous emulsification. Limitations and practicality of using the HLD model for these systems were also explored.
3

Installation Marinfloc : En redogörelse för installationen av en ny länsvattenseparator ombord på Calmare Nyckel

Svensson, Daniel, Szvoboda, Robin January 2016 (has links)
Ombord på Sjöfartshögskolans fartyg Calmare Nyckel, fanns en anläggning för rening av oljehaltigt vatten. Eftersom anläggningen började bli gammal och det var svårt att få tag i reservdelar, samt att nya innovativa lösningar uppkommit under senare år, önskade skolan byta ut den gamla anläggningen mot en ny från Marinfloc AB.   Författarna till denna rapport fick i uppdrag av skolan att ta fram installationsunderlag i form av ritningar, materialförteckningar samt instruktioner på hur arbetet bör genomföras. Även en analys skulle genomföras, där den gamla och den nya anläggningen jämfördes med avseende på renhet hos det separerade länsvattnet.    Syftet med projektet var att ersätta befintlig länsvattenseparator mot en ny modernare anläggning, få den besiktigad och godkänd av berörda myndigheter. Syftet med denna rapport är att redogöra för projektets genomförande, enligt projektdirektivet.   Resultatet av projektet var att Calmare Nyckel blev utrustad med en fullt fungerande, modern anläggning för rening av länsvatten. Den nya anläggningen renade länsvattnet mycket effektivt och bidrar därmed till mindre med föroreningar i världens hav. / On board the Maritime Academy vessel Calmare Nyckel, they had equipment for treatment of oily water. Since the equipment was beginning to get old, and that it was difficult to find spare parts, as well as new innovative solutions had arisen in recent years, the academy wanted to replace the old equipment with new from Marinfloc AB.   The authors of this report were assigned by the academy to provide the installation basis in form of drawings, material list and instructions on how the work should be carried out. Also an analysis would be carried out, where the old and the new equipment were to be compared with regard to the purity of the separated bilge water.   The purpose of the project was to replace the existing oily water separator with a new modern one, get it inspected and approved by authorities. The purpose of this report is to give account for the project implementation in accordance to the projects directive.   The result of the project was that Calmare Nyckel had been equipped with a full functioning, modern equipment for purification of bilge water. The new equipment purified bilge water very efficient, thereby contributing to less pollution in the world's oceans. / Installation Marinfloc
4

Traitement d’eaux huileuses par photocatalyse hétérogène : application à la dépollution des eaux de cales / Treatment of oily water by heterogeneous photocatalysis : application to the bilge water remediation

Cazoir, David-Alexandre 13 December 2011 (has links)
Afin de réduire la quantité d’hydrocarbures déversés dans le milieu marin, les navires de la flotte marchande et, depuis peu, les navires militaires sont tenus de contrôler leurs rejets huileux. Par exemple, seules les eaux de cales dont la concentration en huile (indice hydrocarbure) est inférieure à 15 ppmv peuvent être déversées en mer (Marpol 73/78). Au-delà de cette teneur, et si le stockage à bord n’est pas envisageable, un traitement avant rejet devient alors inévitable. Cependant, les traitements actuels des eaux de cales se sont avérés jusqu’ici insuffisants. La photocatalyse hétérogène, méthode largement utilisée dans le cas du traitement d’effluents gazeux et liquides, a ainsi été proposée dans ce travail. L’abattement de l’indice hydrocarbure a été suivi par analyse GC-MS. Dès lors, après avoir mis en évidence la faisabilité et les limites du procédé batch, un réacteur photocatalytique à aération diffusée (DAPR) a été développé afin de remédier au manque d’oxygène dissous de l’effluent réel. Comparativement au traitement dans le réacteur batch, une meilleure efficacité de la dégradation a été observée dans le DAPR. Cependant, l’analyse parallèle (ATD-GC-MS) de l’évolution de la composition de la phase gazeuse a montré qu’une quantité non négligeable de composés organiques volatils (COV) y étaient alors émis. Enfin, les nalcanes ont été identifiés comme étant les composés les plus réfractaires au traitement photocatalytique et le pentadécane a alors été choisi comme polluant modèle des eaux de cales pour une analyse cinétique. / In order to reduce the marine oil pollution, ships have to control their hydrocarbon dumping at sea. For example, only bilge water that has a hydrocarbon oil index less than 15 ppmv can be discharged at sea (Marpol 73/78). Otherwise, effluents have to be stored on board or treated. In this study, heterogeneous photocatalysis was proposed as an alternative method to the current treatments that are still not efficient enough. Oil removal was monitored by GC-MS analysis. Then, by demonstrating the feasibility and limitations of the batch process, we developed a diffused aeration photocatalytic reactor (DAPR). In this case, better results were obtained than in the batch reactor because the problem of the lack of dissolved oxygen in the real effluent was solved by supplying air continuously. However, volatile organic compounds were then found by monitoring (ATD-GC-MS) the evolution of the gaseous phase composition. Finally, we showed that linear alkanes were the most resistant compounds to the photocatalytic treatment and thereby, pentadecane was chosen as a model pollutant of bilge water for a kinetic study.
5

Heavy metal removal from bilge water by electrocoagulation treatment

Andrade, Milton 20 December 2009 (has links)
The purpose of this research was to observe the removal efficiency for copper (Cu), nickel (Ni), and zinc (Zn) using Electrocoagulation (EC) technique in a continuous flow reactor with a synthetic bilge water emulsion; and additionally, to discuss the operation cost of the treatment. The optimal configuration for EC treatment used combined electrodes, aluminum and carbon steel; flow rate of 1 L/min; effluent recycling and 7.5 amps; this optimal configuration achieved 99% of zinc removal efficiency, 70% of both, copper and nickel removal efficiency, and low operation costs. The current intensity did not have significance incidence on the removal efficiency. The analysis of cost per gram of removed contaminant indicated that nickel had an average cost of $1.95 per gram removed, zinc and copper had $0.60 and $0.88 per gram removed, respectively. To develop additional experiments with the EC reactor are required in order to optimize metal removal efficiency.

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