## 8 Conclusions  
An integrated WTE system based on the steam-water cycle and urea hydrolysis process of a CFPU is developed to improve the performance of WTEU, according to the previous works. In the integrated design, partial cold reheat steam of CFPU absorbs the energy from WTE boiler. Simultaneously, the heat required for partial preheated air of WTEU and its feedwater are supplied by the feedwater of CFPU. Furthermore, the heat source for the UHU is varied from the extraction steam of STs of CFPU to the outlet stream of AE in WTE boiler. The results demonstrate that the integrated WTE system could generate more electricity and a remarkable boost in its energy efficiency. Based on a 500 t/d WTEU and a 660 MW CFPU, the conventional stand-alone units and the suggested system are evaluated by thermodynamics and economics methods. In addition, the net power outputs of different integration modes are compared based on the two units. The main results are concluded as follows:  
1. When consumption rates of coal and MSW keep unchanged, the WTE system in the new configuration can generate an extra 4.25 MW of net power output and increase power generation efficiency by 10.48%. The reduction of energy loss in CON could explain the upturn in power generation of the proposed design through energy analysis.
2. System integration reduces the exergy loss of boilers, STs and CON by 0.89 MW, 1.78 MW and 0.70 MW, with the decrease of heat transfer temperature difference  
Figure 7: The net power output result of different integrated modes.  
in boilers and the reduction of the total exhaust steam flow in STs. Subsequently, the exergy efficiency of WTEU is raised by 9.92%, and the total exergy efficiency of suggested system is enhanced by 0.28%.
3. After the system integration, the DDP of WTE system is cut down from 11.39 years to 5.48 years. Its NPV is augmented from $9.60 million to $24.02 million, confirming the financial feasibility of the innovative hybrid design.
4. According to the comparison of listed integration modes, the mode with the highest net power generation is adopted in this paper. Among the compared modes, the utilized way of SH of WTE boiler has become the main factor affecting the total power output difference of the integrated system. In addition, exergy analysis results indicate that the larger heat transfer temperature difference will cause more exergy loss, reducing net power output. That's why the outlet fluid from each heat exchanger of WTEU must be mixed with the working fluid at a close temperature in the CFPU to maximize the energy output.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app12020866/s1](https://www.mdpi.com/article/10.3390/app12020866/s1)]([https://www.mdpi.com/article/10.3390/app12020866/s1](https://www.mdpi.com/article/10.3390/app12020866/s1)), Table S1: Detailed cash flows of the WTE project under the stand-alone design; Table S2: Detailed cash flows of the WTE project under the integrated design; Figure S1: Flowcharts of different integrated modes.  
Conceptualization, Y.Z. and H.C.; methodology, H.C.; software, L.W.; validation, Y.Z., H.C. and K.Z.; formal analysis, Y.Z.; investigation, L.W.; resources, Q.L.; data curation, X.G.; writing--original draft preparation, Y.Z.; writing--review and editing, Q.H.; visualization, L.W.; supervision, H.C.; project administration, Q.L.; funding acquisition, H.C. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Nature Science Fund of China, grant numbers 51806062 and U1910215, and the Open Project Program of State Key Laboratory of Clean and Efficient Coal-Fired Power Generation and Pollution Control, grant number D2021Y001.  
Not applicable.  
Data Availability Statement: Data are contained within the article.