A novel control strategy with an anode variable geometry ejector for a SOFC-GT hybrid system. (15th December 2022)

• Record Type: Journal Article
• Authors: Chen, Jinwei; Hu, Zhenchao; Lu, Jinzhi; Zhang, Huisheng; Weng, Shilie
• Is Part Of: Energy. Volume 261:Part B(2022)
• Publication Date: 2022-12-15
• Subjects: Solid oxide fuel cell-gas turbine -- Anode variable geometry ejector -- System control -- Small-scale load step -- Large-scale load step; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2022.125281
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: A novel control strategy was developed with an anode variable geometry ejector for a solid oxide fuel cell-gas turbine (SOFC-GT) system. The anode inlet temperature was controlled by combining two modes to achieve a greater controllable range: anode variable geometry ejector adjusting and after-burner fuel valve adjusting. Two tests were carried out under small-scale and large-scale load steps. The results indicate that all controlled variables can be effectively kept around set-point. Moreover, the critical parameters are kept within safe ranges, including steam-to-carbon ratio higher than 2.0, peak temperature gradient below 10 K/cm, peak time-dependent temperature gradient below 3 K/min, and surge margin higher than 15%. The developed novel control strategy can maintain almost constant SOFC spatial temperature. The spatial temperature variation is within 2.50 K under 5% load step, and within 14.30 K under 30% load step. Besides, the novel control strategy can keep the system efficiency at a high level (more than 63.21%) during the load tracking. Compared with the conventional control strategy with a fixed geometry ejector, the results demonstrated that the novel control strategy can significantly improve the system performance, especially the transient behaviors of after-burner fuel rate, turbine inlet temperature, and system efficiency. Highlights: Control strategy with anode variable geometry ejector is developed for a SOFC-GT hybrid system. Seven variables are controlled by eight PI controllers. Anode inlet temperature is controlled by combining two control modes. Control capability is tested under small-scale and large-scale load steps. Developed control strategy ensures safe and efficient operation.