Examination of the 3516 B Series diesel Engine's Material Tube Fuel Line Failure

Abstract

In this paper, an investigation was conducted to examine the non-functional fuel line components of the fuel delivery system to cylinder head number 10 in the 3516 B series diesel engine generator set. The system experienced fuel leakage at the connection between the main line and the fuel line tube after operating for 8,922 hours. This problem significantly affects engine performance and increases the risk of fire hazards in the powerhouse and surrounding areas. Therefore, the main objective of this investigation is to identify the underlying cause of the fuel line tube leak and determine the fuel tube replacement schedule. The methods used in the research include chemical composition analysis, energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and microstructure observation. Two distinct structures are visible when the microstructure of the pipe material is viewed at 200x magnification: a black pearlite structure and a white ferrite structure. SEM/EDS tests revealed erosion cavitation on the material's surface; the material's EDS testing was indicated by a box mark. The results of the research conducted in the standard fuel testing are as follows: API Gravity @ 60°F test results showed a value of 39, within the specifications from the Directorate General of Oil and Gas, which range from 31 to 42. The density was measured at 830 kg/m³ at 15°C, within the standard range of 815-870 kg/m³. The water content was 197 ppm, compared to the standard ASTM D-1744 limit of <500 ppm. The ash level was 0.003, and the fuel cleanliness was measured on 18/16/13. The chemical composition examination of the tube fuel line showed that the steel was a low alloy, with an iron (Fe) content of 98.35% and a carbon (C) content of 0.068%. It was determined that the damage to the fuel line tube was caused by cavitation, erosion, and turbulence in the fluid flow. The benefits of the research include identifying the root cause and improving the fuel line tube inspection strategy every 4,000 hours. If cavitation is found, the tube is to be immediately replaced, and replacement spare parts should be prepared to reduce engine downtime.

Keywords

• Diesel engine generating set
• Fuel leak
• Root cause
• Cavitation
• Erosion
• SEM