This study performs energetic and exergetic comparisons between the steam methane reforming and steam methanol reforming technologies combined with HT-PEMFC and a carbon capture/liquefaction system for use in hydrogen-fueled ships. The required space for the primary fuel and captured/liquefied CO2 and the fuel cost have also been investigated to find the more advantageous system for ship application. For the comparison, the steam methane reforming-based system fed by LNG and the steam methanol reforming-based system fed by methanol have been modeled in an Aspen HYSYS environment. All the simulations have been conducted at a fixed Wnet, electrical (475 kW) to meet the average shaft power of the reference ship. Results show that at the base condition, the energy and exergy efficiencies of the methanol-based system are 7.99% and 1.89% higher than those of the methane-based system, respectively. The cogeneration efficiency of the methane-based system is 7.13% higher than that of the methanol-based system. The comparison of space for fuel and CO2 storage reveals that the methanol-based system requires a space 1.1 times larger than that of the methane-based system for the total voyage time, although the methanol-based system has higher electrical efficiency. In addition, the methanol-based system has a fuel cost 2.2 times higher than that of the methane-based system to generate 475 kW net of electricity for the total voyage time.

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The primary focus of this research was an assessment of the external carbon source (RCS5, RCS15, and TPA5) as environmentally friendly, alternative of the carbon sources in the denitrification process. These alternative carbon sources (RCS5, RCS15, and TPA5) demonstrated the same grade of biodegradability and denitrification rate. The nitrogen removal efficiencies of RCS5, RCS15, and TPA5 in field application test were 77.4%, 58.7%, and 62.4%, respectively. The application of the alternative carbon sources (RCS5, RCS15, and TPA5) to sewage from K, N and S-STP facilities reduced the cost of an alternative carbon source more than 55.4% when compared with methanol application.