Design and thermodynamic analysis of a hybrid power plant using torrefied biomass and coal blends

• Two hybrid power plant configurations based on torrefied biomass co-gasification (TBCG) are evaluated.
• The carbon boundary points (CBPs) are found using a specific optimization algorithm.
• The pre-SOFC configuration is superior to the post-SOFC one in terms of the maximum net system efficiency.
• With regard to global warming, the post-SOFC configuration has lower specific CO2 emissions.
• The energy penalty of the post-SOFC configuration can be reduced based on heat integration design.

This study developed a clean hybrid power plant using a combination of integrated torrefied biomass co-gasification (TBCG), solid oxide fuel cell (SOFC), and calcium looping (CaL) CO2 capture. Based on pre-SOFC (Design I) and post-SOFC (Design II) configurations, thermodynamic analysis is adopted to examine the performance of hybrid power generation plants. The carbon boundary points (CBPs) for different torrefied biomass blending ratios (TBBRs) are found using specific optimization algorithms to maximize the syngas yield. From the viewpoint of energy utilization, the simulation results show that Design I is superior to Design II. However, the CO2 emissions of Design II are lower than those of Design I by 94.19%, although it has an accompanying energy penalty of 4.17%. Due to its use of the internal heat recovery approach, the energy penalty of Design II falls to 1.09%. As a whole, Design II with the heat integration design is recommended for use in hybrid power plants.