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Biodiesels are a hot topic and this includes the diesel replacement rapeseed methyl ester (RME). However, there is some concern because some metals may accelerate the degradation of RME. RME also causes corrosion of some metals. Copper, which accelerates degradation the most, can be found in engine system. Therefore, the aim of this Master’s thesis was to evaluate the corrosion of copper and different copper alloys in RME. In the experimental part, evaluation was made by analyzing water content, concentration of formic acid, acetic acid and propionic acid, metal concentrations in the fuel, oxidative stability (time until degradation with Rancimat method), macroscope of metallic surface and surface analysis by FTIR. The studied alloys included copper, brass, and aluminum alloyed with 3.2 weight % copper. A stable period for copper corrosion was observed through the copper levels in the fuel. The stable period was confirmed to be related to the properties of the material. Most likely, a protective layer consisting of corrosion products was formed on the copper surface. Formic acid and free water addition increased corrosion and prevented a stable period. Salt formation was observed when decreasing copper and acid levels and was confirmed by FTIR analysis on exposed copper. Brass accelerated the aging of B100 fuel, but to a less extent than pure copper and indicated a stable period. Aluminum did not accelerate the aging of B100 fuel in this experiment. The evaluation method proposed for copper involved measuring copper concentration as an indicator for when the corrosion has passed by the stable period. In these bench scale experiment which used 250 ml B100 and 40 cm2 area copper, the threshold was 5 mg Cu/kg B100. This method may potentially also be used for copper alloys. The knowledge that there is a stable period can be used in field tests (engines) to understand the behaviour of corrosion of copper and to design a stable window. Important to remember is that coppe, Validerat; 20150807 (global_studentproject_submitter)

As an element in the Coast Guard's compliance strategy for decreasing greenhouse gases (GHG), and increasing the use of alternative fuels, the USCG Research & Development Center tested 100 percent biodiesel (B100), a renewable alternative diesel fuel, on a USCG 49' Buoy Utility Stern Loading (BUSL). B100 derived from Waste Vegetable Oil (WVO) was obtained from a local supplier, and fuel quality was monitored throughout the test. Prior to operational testing, a materials audit for compatibility with B100 was performed on the fuel-wetted components on the three diesel engines (two main propulsion engines and one generator), and incompatible components were replaced with suitable substitutes. Break-in testing was conducted before the start of operational testing to ensure no B100 compatibility issues remained. Engine exhaust emissions were not measured, but were estimated though an analysis of previous studies on similar engines. Operational testing was conducted over a one-year period starting in March 2013. During this time, the BUSL carried out typical missions in its normal eastern Long Island Sound operating area. Engine performance data were collected and analyzed, along with crew observations of boat performance and maintenance. Details of the testing, and the conclusions and recommendations are included in the report., The original document contains color images.