SELECTION OF ALTERNATIVE MARINE FUEL TECHNOLOGY BASED ON LITERATURE REVIEW BY APPLYING APPROPRIATE MULTI-CRITERIA DECISION-MAKING METHOD

The use of alternative fuel in ships can help alleviate high carbon emissions and adverse environmental consequences produced by the maritime industry. Due to the complexity of assessing many performance factors and lack of information, it is challenging for decision-makers to select the best sustainable alternative energy source for shipping from various options. Nevertheless, alternative energy decisions can be supported, and contradicting impacts can be analyzed with MCDM methodologies. This study focuses on applying decision-making processes for sustainable energy development concerns. A systematic review of published papers in the Scopus database on alternative fuel technologies and MCDM approaches from 2001 to 2021 has been conducted. All the selected articles were sorted by application area and process. In classifying the scientific journal articles and in-depth analysis, a SWOT analysis of MCDM techniques is offered. Convincing data support the conclusion that MCDM methods help decision-makers select appropriate fuel technology and are widely utilized in practice.

Energy Transition and Climate Change in Decision-Making Processes

Humans have been using fossil fuels for centuries, and the development of fossil fuel technology reshaped society in lasting ways [...]

R&D on Surrogate Kernel Fabrication in Support of Reaktor Daya Eksperimental (RDE) Project

R&D program on HTGR fuel to support the RDE project has been outlined and is aimed to develop national capabilities on nuclear fuel technology. The external sol-gel technology has been adopted for the fabrication of kernels. Laboratory scale work has been ongoing at the Center for Nuclear Fuel Technology (PTBBN) BATAN to study various parameters involved in the process of kernel fabrication including tuning of parameters related to droplet formation (feed flow rate, vibrator frequency, NH3 gas flow rate), optimizing chemical formulation in broth preparation, various treatments in aging, washing, drying process, and thermal treatment for densification of kernels. In this early stage, zirconium precursors were used to manufacture surrogate kernels of ytrria-stabilized zirconia. The steps for kernel fabrication include chemical formulation of broth and droplet casting, aging-washing-drying of gel microspheres, calcination and sintering, and characterization of sintered kernels (surface morphology, density, diameter/sphericity, solid phase). Stable cast of droplets from 1 mm nozzle diameter was optimized by adjusting feed flowrate at 30 ml/min, viscosity at 45-60 cP, and vibrating frequency at 100 Hz. Presolidification of gel skin was optimized at a working NH3 flow rate of 3.5 - 4 L/min. Addition of urea with mole ratio urea/metal 2.5/1.0 gave the most preferable results based on SEM examination for crack and morphological structure. Control the opaqueness of the sol can be done by portioning addition of urea, where a portion of urea was added at decomposing temperature around 85°C, while another portion was added at a lower temperature. Addition of urea has a desirable effect on crack reduction during heat treatment of gel microspheres. Increase in metal concentration results in an increase in kernel diameter when other sol-to-gel conversion parameters were kept unvaried. Phase determination by X-Ray Diffractometer indicates that solid phase for ceria-stabilized zirconia prepared with precursor composition of 16% yttrium in zirconium-yttrium sol results in yttria-stabilized zirconia 8YSZ with cubic phase.

Emission of typical pollutants (NOX, SO2) in the oxygen combustion process with air in-leakages

Oxygen combustion, being an alternative to air combustion, is distinguished in a variety of modern coal management technologies by quick and easy removal of CO2 from the combustion process, which is the key merit of this oxy-fuel technology. The laboratory work conducted so far has not directly addressed the issue of air in-leakages in the oxy-fuel system. The previous studies showed that air in-leakages in the combustion system (both under the air and oxygen regime) occur and affect the combustion process. However, there are no direct research studies on the volume of air in-leakages and their impact on the individual stages of combustion, including the emission of gaseous pollutants. This article focuses on the assessment of the impact of air in-leakages on NOx and SO2 emissions for a single-stage coal-dust combustion system. Moreover, these studies were supplemented with measurements on the rate of devolatilisation of volatile matters and, in particular, on the rate of nitrogen compounds released from fuel. The obtained results of combustion in the oxy-fuel atmosphere with the following air in-leakage levels: 10, 15 and 20% were compared to combustion conditions in the air. Air in-leakages in the oxygen combustion system create an additional flow of oxygen and nitrogen appearing in the combustion area, which affects the course of pollutants and their emission. The conducted studies have shown that when adequate tightness of the combustion system is provided, it contributes to the reduced emission of nitrogen compounds.