Overview of design diagrams for solid oxide fuel cell and gas turbine hybrid systems for combined heat and power generation

The article presents a comprehensive review and classification of possible layout solutions for hybrid systems based on the integration of solid oxide fuel cells (SOFC) and gas turbines (GT). Most SOFC/GT hybrid systems use methane as a fuel due to its availability and ease of handling, unlike hydrogen. An important element of the plant design is the fuel processing subsystem. SOFC/GT systems direct part of the energy generated by the fuel cell to carry out the methane steam reforming process. Steam is produced in the anode compartment of the fuel cell, or alternatively in an external steam generator, using the heat from the gases leaving the fuel cell. Most of the designs of hybrid SOFC/GT systems presented in the literature are pressurized, the installations in them are hermetically connected, which makes it possible to achieve high and ultra-high energy efficiency with relatively low capital costs. In atmospheric hybrid systems, the units are connected via a system of heat exchangers, which makes them independent and easier to control. The article also explores more complex SOFC/ GT configurations using an organic Rankine cycle, multiple fuel cells and gas turbines, with a steam turbine, a cooling system, etc. The design and nature of the relationship between the components of a hybrid system have a significant impact on achieving performance targets based on numerical simulation of the proposed circuit solutions.