Multi-criteria evaluation and optimization of a new multigeneration cycle based on solid oxide fuel cell and biomass fuel integrated with a thermoelectric generator, gas turbine, and methanation cycle

Abstract

Recently, due to increasing concerns about the reduction of fossil energies reserves and environmental crises, the development of more efficient and low-emission systems has become necessary. An alternative energy system should be able to improve the efficiency of energy production, have a reasonable investment cost and be environmentally friendly. The current research developed a multi-criteria evaluation method of a new multigeneration cycle (MGC) based on a solid oxide fuel cell (SOFC) and biomass fuel. In the planned MGC, the SOFC is fed by syngas from the biomass gasification process. To reduce environmental hazards, a fraction of the carbon dioxide was recycled for reutilization in the aforementioned process. A gas turbine and a thermoelectric generator (TEG) were employed to produce electrical energy and an absorption chiller was embedded to produce cooling. The output heat of the fuel cell was utilized for heating purposes. A part of the electricity produced was feed into the electrolysis cycle to produce hydrogen. Excess hydrogen was combined with carbon dioxide released from the MGC in a synthesis cycle to reduce pollutant emissions by producing methane. A thermodynamic-conceptual, exergoeconomic and environmental evaluation of the MGC was developed. The optimization based on the genetic algorithm to maximize performance and minimize the cost of the MGC was also developed. The results obtained from the optimization indicate that the proposed MGC can compete with most biomass-driven systems. Besides, the amount of carbon dioxide released can be significantly reduced compared to conventional coal, natural gas and petroleum-driven power plants.