Explosion Safety of a Methanol Dual Fuel System Enclosure on a Small Marine Diesel Engine: A Mixed Methods Evaluation of Whether a Retrofit Solution Can Achieve Regulatory Compliance by Including Field Experiments
Typ
Examensarbete på grundnivå
Program
Affärsutveckling och entreprenörskap 180 p.
Publicerad
2024
Författare
Eriksson, Adam
Hartikka, Joel
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The growing interest in environmentally friendly propulsion arrangements in shipping is driven by international conventions that impose increasingly stringent environmental requirements for airborne emissions. Methanol is a cleaner burning fuel than conventional petroleum-based alternatives, enabling compliance with the most stringent emission regulations for Particulate Matter (PM), Sulphur and Nitrogen Oxides (SOx and NOx). In order to capitalize on these environmental benefits for small-scale applications, the Gothenburg-based company ScandiNAOS has niched in on this segment of the market when it was felt that such solutions were lacking. To this end, ScandiNAOS has developed an aftermarket solution for converting engines to methanol dual fuel operation. However, installation of this kit on commercial vessels requires the solution to meet applicable national and international regulatory requirements in this area.
This work aims, in collaboration with ScandiNAOS, to determine whether an enclosure of the methanol components included in this solution for installation on a Volvo Penta D16 meets the new requirements developed for low-flashpoint fuels. The study addresses Det Norske Veritas (DNV) class rules as they are considered to be comprehensive. Methanol leakage should normally be contained and collected by double-jacketed fuel lines, but that other solutions providing the same level of safety are largely acceptable within the framework of alternative design. Such solutions require interpretation of the rules. ScandiNAOS's enclosure is interpreted as an extension of this double jacket, transitioning on the inside to conventional single-walled components. Because of the specific explosion risks associated with a methanol leakage, there are requirements for Ex certified electrical equipment, such as electrically controlled injectors, that the ScandiNAOS design does not meet. Due to non-compliance with a direct interpretation of the rules, demonstration of good safety in case of a gas explosion originating from the enclosure is paramount. To prove this safety, field experiments such as compressed air leakage tests and explosion tests are conducted to measure, among other things, explosion pressures from gas explosions at various temperatures and degrees of saturation. The explosion tests are complemented by analytical and computer-aided calculations for the same conditions. The experiments identified the main leakage points as the sealing surfaces between the enclosure components, which contributed to the original rendering of the design being able to withstand a maximum of 0.2 bar gauge pressure.
Based on subjective assessment of compliance with applicable class rules and experimental findings, the design is considered approvable as long as the enclosure is sealed for the maximum expected fuel pressure of 7 bar. In addition, the risks of sparking must be reduced. A number of corrective measures are presented in order to remedy the deficiencies that are deemed to constitute an obstacle to approval, but an assessment is made that there are good conditions for
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approval and that the design as such should be suitable for installation on more engine models than the one concerned in this study. The enclosure would then constitute a complement to existing solutions by broadening the application of methanol operation to engines in the smaller size segment and further securing methanol as an environmentally friendly alternative for shipping.
Beskrivning
Ämne/nyckelord
DF-metanolmotorer , metanolläckage , explosionsrisker , trycktäta kapslingar , tryckmätningar , explosionsberäkningar , eftermonteringslösningar , alternativ design , maritima regelverk och klassregler , DF methanol engines , methanol leakage , explosion risks , pressure tight enclosures , pressure measurements , explosion calculations , retrofit solutions , alternative design , maritime regulations and class rules