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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

Techniques for characterization and quantification analysis of foulant deposition in Alfa Laval’s high-speed separators : A literature study

Benaya, Mwansa, Dahlén, Henrik, Axelsson, Emil, Liljekvist, Cassandra, Nordell, Maja January 2022 (has links)
Alfa Laval is a global company that provides solutions, products, and services for industry, such as high-speed separators for marine and food-application. Foulant deposition on the stainless-steel surfaces of Alfa Laval’s high-speed separators has shown to result in lowering of the separation efficiency. In this report, a literature study was conducted to present research documenting the use of analytical techniques for characterization and quantification of oil and dairy foulant deposition on stainless-steel surfaces. The focus of the research was oil foulant deposition and dairy foulant deposition on stainless steel surfaces. The following techniques were examined; NMR, AFM, SEM, XPS/ESCA, EDS/EDX and RBS, ToF – SIMS, EPMA, TGA, Fluorescent Microscopy, and HTGC.  The various techniques were evaluated from their applicability on fouling deposits of Alfa Laval’s high-speed separators and the settings of interest for each technique were also presented. This study also presented possible surface coatings of stainless-steel to impede the initial foulant deposition.  In conclusion, the surface coatings that were found were polyethyleneimine with TiO2 on an epoxy resin surface on the surface, and electronless nickel with embedded polytetrafluoroethylene nanoparticles to reduce surface energy. From the found techniques, the techniques may demonstrate information about specific properties, like chemical composition e.g., and may be suitable for individual use. However, to obtain a general picture of the foulants deposited onto the surface, several of these techniques could be combined, like RBS & EDS. Further research on which techniques are most complementary in identifying, characterizing, and quantifying foulant deposition would be of interest.
2

Membrane Distillation for Leachate Treatment with Fenton Pre-Coagulation Treatment Process

Chung, Kyung Sun 03 February 2020 (has links)
Landfill leachate is considered as a complex wastewater with various organic and inorganic species which must meet strict discharge standards before its release. Due to such high concentration of diverse pollutants, leachate is low in biodegradation; therefore, a proper usage of physicochemical treatments is required. In this study, membrane distillation (MD) has been used along with Fenton treatment process for pre-coagulation to achieve an effective removal of contaminants. MD is a technology derived with vapor pressure difference across the hydrophobic membrane which traps the feed-wastewater vapor at the entrance of the hydrophobic side before permeation. In order to modify and assist in membrane technology's common drawback, which is dealing with foulants, Fenton oxidation is coupled in the leachate treatment process. Fenton is reserved to be the most effective for leachate treatment and is widely used due to its simple operation and low costs. Fenton oxidation was able to lessen the chemical oxygen demand (COD) concentration of leachate up to 55% while increasing the conductivity and reducing the concentration of NH4-N. The membrane flux and volume had a significant increase with a use of lower COD leachate after Fenton treatment coupled with MD. / Master of Science / Landfilling has been recognized as a principal disposal process of municipal solid wastes globally over the past decades, and this disposal method has been one of the leading concerns for a continuous production of landfill leachate. Leachate is considered as a complex wastewater with a variety of organic and inorganic species which must meet strict discharge standards before its release. Due to such high concentration of diverse pollutants, leachate is low in biodegradation; therefore, a proper usage of physicochemical treatments is required. In this study, membrane distillation (MD) has been used along with Fenton treatment process for pre-coagulation to achieve an effective removal of contaminants. MD is a technology derived with vapor pressure difference across the hydrophobic membrane which traps the feed-wastewater vapor at the entrance of the hydrophobic side before permeation. MD has several advantages which include reduced operating temperature compared to conventional distillation processes, fewer requirements of membrane cleaning, and lower operating hydraulic pressure than other conventional pressure-driven membrane processes such as reverse osmosis (RO). This technology has a common drawback along with other membrane-required technologies which is dealing with foulants. For a reduction in membrane fouling, Fenton oxidation is coupled in the leachate treatment process. Fenton is reserved to be the most effective for leachate treatment and is widely used due to its simple operation and low costs.

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