Representative application of LNG-fuelled ships: a critical overview on potential GHG emission reductions and economic benefits

The shipping industry is the primary and most significant mode of international cargo transportation. The ship must comply with strict rules regarding reducing greenhouse gas (GHG) emissions as a dominant transportation mode. Liquified Natural Gas (LNG) is the primary alternative fuel option for several shipping companies. In essence, many studies recommend LNG as a transitional and alternative fuel because its emission characteristics are cleaner than other fossil fuels. Several previous investigations have been carried out to develop an action plan for integrating the use of LNG as a ship fuel. However, there have been few discussions on the estimation of GHG emission reduction and the economic efficiency of a representative LNG-fuelled ship. The recent progress on LNG-fuelled ships is systematically reviewed to summarize the pathways and highlight the core technological concepts, technical issues, current LNG-fuelled ship applications, and future outlooks regarding integrating LNG energy resources into ship power systems to measure GHG emission reductions and cost savings estimations. The report will discuss the current development in the maritime sector and the effects of the macroeconomic scale. The result reveals that future research on ship-based LNG energy systems will probably concentrate on integrating new energy source generating strategies with existing ship power systems to improve energy efficiency. Several potential research areas for future outlook were also discussed to anticipate future challenges

Design Improvement Using Topology Optimization for the Structural Frame Design of a 40 Ft LNG ISO Container Tank

LNG ISO tank containers are a solution for bulk liquefied natural gas (LNG) delivery to the outer islands of Indonesia that are not connected to the gas pipeline network. The design of an ISO tank frame must consider two critical parameters, strength/rigidity and weight saving, which affect the operational performance of the distribution process. The current investigation aims to numerically optimize the design of the structural frame of a 40 ft LNG ISO tank for a mini LNG carrier operation using a topology optimization framework. Two design solutions are used in the topology optimization framework: reducing the strain energy and mass retained. Mass retained was selected as the objective function to be minimized, which was assumed to be 60–80%. The proposed frame design is tested using three operational loading scenarios, including racking, lifting, and stacking tests based on the ISO 1496 standard. The convergence mesh tests were initially evaluated to obtain the appropriate mesh density in the finite element analysis (FEA). The simulation findings show that the topology optimization method of the frame design resulted in an improved design, with an increase in the strength-to-weight saving ratio. A promising result from the optimization scenario demonstrates weight savings of about 18.4–37.3%, with experienced stress below the limit criteria. It is found that decreasing mass retained causes a significant stress increase in the structural frame and ISO corner castings, especially in the stacking load. The critical recommendation in the frame design of the LNG ISO tank can be improved by eliminating the saddle support and bottom frame and increasing the thickness of the vertical frame