Optimization of a 30 kW SOFC combined heat and power system with different cycles and hydrocarbon fuels

Solid oxide fuel cells (SOFCs) could generate power cleanly and efficiently by using a wide range of fuels. Through the recovery and utilization of the energy in the SOFC tail gas, SOFC combined heat and power (CHP) systems achieve efficient cascade utilization of fuels. In this article, an efficient 30 kW SOFC CHP system with multiple cycles is designed based on a commercial kw-level SOFC device. The energy and substances could be recycled at multiple levels in this system, which makes the system do not need external water supply anymore during working. Meanwhile, the performance, fuel applicability, flexibility and reliability of the system are investigated. Finally, an optimized operating condition is confirmed, in which the electrical efficiency is 54.0%, and the thermoelectric efficiency could reach 88.8% by using methanol as fuel. • An efficient 30 kW SOFC combined heat and power (CHP) system with multiple cycles is designed. • Under an optimized condition, the total efficiency of the system could reach 88.8% and the electrical efficiency is 54.0%. • With a reforming water recycle (RWR), the system does not require external water supply during working. • The results are verified based on a commercial SOFC CHP system in Xuzhou China, and provide improvements for this device.