Development and multiobjective optimization of a novel trigeneration system based on biomass energy

Abstract

Biomass energy can play a significant role in achieving sustainable energy production goal, as biomass is considered carbon–neutral fuel when observed from standpoint of the lifecycle. In this paper, a novel trigeneration system has been proposed, incorporating a gasification unit, a solid oxide fuel cell unit, an externally fired gas turbine module, a vapour absorption refrigeration unit, and a hot water generation unit. The proposed trigeneration system has been assessed by energy, exergy, economic and environmental analyses. Furthermore, multiobjective optimization of the proposed trigeneration system has been carried out via response surface methodology. The effects of critical decision variables on the performances of the system have been investigated. The desirability test suggests that the individual desirability value is maximum for levelized cost of electricity followed by fuel energy saving ratio, exergy efficiency of the system and environmental benefit. The combined desirability value (0.949) of the responses is also found to be in the higher side. Thus, it can be said that the setting can be useful in obtaining accurate results for all the responses combined. The proposed plant yields the optimum performance at a pressure ratio of 4.49, current density of 3228.67 A/m2, fuel utilization factor of 0.9, and oxygen utilization factor of 0.1. The results indicate that at the optimum operating condition the proposed system can achieve the maximum exergy efficiency and the fuel energy saving of 55.99% and 52.63%, respectively. The optimum values of the levelized cost of electricity and environmental benefit are estimated to be 0.079$/kWh and 39067.5 $/year, respectively.