| dc.description.abstract | This study aims to investigate protonic ceramic fuel cell (PCFC) combined with micro gas turbine (MGT) and Organic Rankine Cycle (ORC) hybrid systems with external reformer fueled by various fuels. Five optimized system configuration has analyzed in this study using ethanol, methanol, ammonia, propane, and octane. The fuel type selection was determined based on its reforming temperature level. The idea of each optimized system configuration is mainly focus on flue gas utilization as primary heat source for reformer component so the hydrogen production can be optimized. The combine heat and power (CHP) system is also been evaluated in present study as the representation of system flexibility. Next, several parameters such as air and fuel flow rate, fuel utilization factor (Uf), and anode off-gas recycling ratio (AOGR) are also analyzed. Thermolib is employed to build the system with input parameters obtained from references.
The results in ammonia system (configuration 3) show most outstanding system performance compared with other configuration. The maximum system energy and exergy efficiency achieved is 81.44% and 77.24%, respectively with a total exergy destruction of 36.62 kW which is the lowest exergy destruction percentage, with only 22.76% of exergy destroyed across the whole cycle from its initial exergy input. The CHP system proven can enhanced the overall system energy efficiency for up to 85.55% for ammonia system. Meanwhile, the exergy efficiency tends to decrease by 2% for all system configuration using CHP system compared with ORC system. The ammonia system heat recovery steam generator (HRSG) exergy efficiency is the highest up to 68.5%.
The parameter variation results reveal that when the AOGR ratio increases, so does the PCFC power output. It is fundamentally related to massive hydrogen flowing into the anode. In contrast, when turbine inlet temperature and combustor reactant decrease, correspondingly decreases MGT power output. The results indicate that the increase in fuel cell power is dominant than the decrease of MGT power; hence, system efficiency increases as the AOGR ratio grows. Furthermore, installing AOGR can keep a PCFC-MGT-ORC hybrid system working at maximum power under various Uf variations.
The investigation of Uf variations reveals that this parameter is critical in energy distribution into PCFC, MGT, and ORC, in which cell power output increases but MGT power output drops as Uf increases. The results also show that a hybrid PCFC-MGT-ORC system can generate maximum power at low Uf with a high AOGR rate, and a hybrid system can produce peak power at high Uf without AOGR.
This work enables the scientific community by (i) determining an appropriate configuration in a PCFC-MGT-ORC hybrid system using various fuels, (ii) understanding system flexibility based on heat or power demand, (iii) understanding the effect of anode-off gas recycling (AOGR) on system performance, and (iv) selecting a reasonable fuel, S/C, Uf, air flow rate, fuel flow rate. | en_US |