# Drying Characteristics of Chicken Manure Under a Variable Temperature Process
## 4 Conclusions  
1. In this research, single-factor experiments were employed to explore the impacts of drying temperature, air velocity, and moisture content nodes on drying time, energy consumption, and total nitrogen loss, and an orthogonal experiment was performed to analyze the comprehensive impact of different influencing factors. Additionally, the drying parameters were optimized through a combination of orthogonal and single-factor experiments.
2. By analyzing the influence of drying temperature of the second stage, air velocity, and water content nodes on drying time, energy consumption, and total nitrogen loss, we found that the optimal value of the drying temperature of the second stage was around 55 \({}^{\circ}\)C, the optimal value range of air velocity was 1.2-1.5 m/s, and the best value range of the water content node was 45-50%.
3. In the range of experimental parameters, the drying temperature in the second stage had no significant effect on total nitrogen loss during the chicken manure drying process (\(p>0.05\)). In contrast, air velocity and moisture content nodes exerted significant effects on total nitrogen loss (\(p<0.05\)), and the air velocity had significant effects on energy consumption (\(p<0.05\)).
4. From the results of the orthogonal experiment and variance analysis, the drying temperature in the second stage exhibited a significant effect on the drying performance of chicken manure under variable temperature conditions (\(p<0.05\)). However, the moisture content nodes and air velocity showed no significant effects on drying performance (\(p>0.05\)). Thus, the air velocity and moisture content nodes can be set more flexibly within the experimental temperature range. In actual production, the following optimal parameters are recommended--drying temperature in the second stage: 57.5 \({}^{\circ}\)C, air velocity: 1.2-1.5 m/s, and moisture content nodes: 45-50%.
5. The findings of this study provide a theoretical foundation for utilizing residual air exchange heat and auxiliary heat sources in chicken manure drying systems. Additionally, these results provide a basis for setting the parameters for the optimal usage phase of the auxiliary heat source.  
Conceptualization, X.K.; data curation, Q.D.; formal analysis, Z.S.; funding acquisition, L.X.; investigation, L.W.; methodology, Z.S.; resources, X.K. and L.X.; software, X.L.; supervision, T.L.; writing--original draft, X.L.; writing--review and editing, X.L. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Key Project of Science and Technology of Henan Province (242102111177) and the Natural Science Foundation of Henan (242300420475).  
Not applicable.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
Author [PERSON] was employed by the company Henan Dayong Industrial Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.