**5. Conclusions**

A CFD simulation model for the coupled membrane reactor was developed by replacing the water vapor with a mixture of hydrogen and oxygen on the feed side, adding the energy source term on this side and adding a mass source term on both sides of the membrane, respectively, and the validity of the model was verified. The effects of the sweep gas flow rate, methane content and inlet temperature on the performance of membrane reactor were investigated when coupled with the methane combustion reaction. It is found that the coupling of methane combustion and water splitting can significantly improve the hydrogen generation capacity of the membrane reactor. Under certain conditions, the average hydrogen yield with methane combustion can be increased to three times, compared to the hydrogen yield without the methane combustion reaction. The methane conversion decreases with the increase in the sweep gas flow rate and methane content, while the trend of the hydrogen yield is opposite. In order to ensure the hydrogen yield of the membrane reactor, the methane needs to be excessive. Due to the limited oxygen permeability of the membrane reactor, when the methane is excessive, the hydrogen yield only increases slightly with the increase in the methane content or sweep gas flow rate. Increasing the inlet gas temperature can increase the membrane temperature, methane conversion, oxygen permeation rate and hydrogen yield.

**Author Contributions:** Conceptualization, T.Z. and C.C.; methodology, T.Z.; software, T.Z.; validation, T.Z.; investigation, T.Z.; writing—original draft preparation, T.Z.; writing—review and editing, T.Z. and H.Y.; visualization, T.Z.; supervision, H.Y. and C.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China, grant number U1832113.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data that support the findings of this study are available from the corresponding author upon reasonable request.

**Conflicts of Interest:** The authors declare no conflict of interest.
