Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger
Abstract
:1. Introduction
2. Materials and Methods
2.1. Material
2.2. Equipment Description and the Working Principle
2.3. Experimental Design and Data Acquisition
2.4. Assumptions
- (1)
- The fluxes were in the steady flow state.
- (2)
- The heat loss on the FGP was neglected.
- (3)
- The influence of moisture content variations on the hot air velocity was neglected.
- (4)
- The temperature and the relative humidity of ambient air in the experimental period were considered to be constant at 8 °C and 85%, respectively.
2.5. Theoretical Analysis
2.5.1. Thermal Analysis
2.5.2. Thermal Efficiency
2.5.3. Specific Heat Consumption
2.5.4. Heat Loss Characteristics
2.5.5. Far Infrared Wavelength
2.5.6. Drying Kinetics
3. Results and Discussions
3.1. The Drying Performance of the Drying System
3.2. Heat Recycled Performance of the RA
3.3. Heat Loss Characteristics of the Drying System
3.4. The Thermal Efficiency of the Drying System
3.5. The Thermal Performance of the Drying System
4. Conclusions
- (1)
- The optimized variable-temperature drying process for corn industrial drying was ascertained to be Tair of 76.5 °C in the first drying cycle, Tair of 95.2 °C in the second and third drying cycles and Tair of 100.3 °C in the fourth and fifth drying cycle.
- (2)
- There was 2650.11 MJ of thermal energy that was recycled by RA, and the far infrared wavelength of the RA was found to vary from 7.53 um to 8.32 um, indicating that the RA could enhance the drying performance of the whole drying system.
- (3)
- The total energy consumption and specific heat consumption of the corn for the optimized drying process were ascertained to be 48,803.99 MJ and 7290.269 kJ/kg, respectively, which showed a better drying performance than the two analyzed constant-temperature drying processes.
- (4)
- The thermal efficiency of the optimized drying process for the DC was higher than that of the two analyzed constant-temperature drying processes. The variation range of ηDC for the optimized drying process was found to be 6.81–41.71%.
- (5)
- Only 384.74 kW of thermal energy was used to evaporate the moisture from the wet corn material, which should be further improved.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Components | Power (kW) |
---|---|
Data acquisition (DA) | 0.75 |
Hoist (HST) | 5.5 |
Conveyor belt (CB) | 1.5 |
Induced draft fan (IDF) | 30 |
Discharging device (DD) | 1.5 |
Parameters | Value/Method | Units | |
---|---|---|---|
Dryer | Loading capacity | 50 | t |
Drying capacity | 5.5 | t/h | |
Cycling time of the dryer | 90 | min | |
Total air volume of the induced draft fan | 17,585–30,774 | m3/h | |
Total pressure of the induced draft fan | 1500–2149 | Pa | |
Diameter of the flue gas pipeline | 200 | mm | |
Heat exchanger | Heat exchanger type | Shell and tube type | - |
Material | Stainless steel | - | |
Number of pipes | 253 (11 columns and 23 rows) | - | |
Pipe arrangement | Staggered | - | |
Pipe space | 120 | mm | |
Size of pipe (length × diameter × thickness) | 1800 × 50 × 1.5 | mm |
Parameters | Flue Gas Valve Openings α/° | |||||
---|---|---|---|---|---|---|
15 | 30 | 45 | 60 | 75 | 90 | |
va m·s−1 | 2.72 | 2.68 | 2.65 | 2.62 | 2.60 | 2.59 |
2.70–2.74 | 2.66–2.69 | 2.63–2.68 | 2.59–2.64 | 2.58–2.61 | 2.57–2.62 | |
vfg m·s−1 | 5.68 | 7.26 | 9.21 | 11.83 | 15.35 | 20.47 |
5.21–6.85 | 5.96–9.32 | 7.65–11.32 | 9.75–13.25 | 14.32–18.63 | 17.96–23.2 | |
Tfg,in °C | 336.6 | 462.5 | 632.3 | 795.6 | 936.5 | 1024.3 |
296.3–362 | 428.6–486.8 | 601.5–663.8 | 765.8–816.3 | 904.8–968.9 | 987.6–1086.3 | |
Tfg,out °C | 77.3 | 82.6 | 96.3 | 105.6 | 115.6 | 128.5 |
74.3–80.2 | 79.8–83.9 | 92.1–99.6 | 100.3–108.9 | 112.3–119.6 | 121.6–132.3 | |
Tfg,0 °C | 62.2 | 65.3 | 73.9 | 78.5 | 82.2 | 85.6 |
57.9–64.8 | 62.3–69.2 | 69.8–76.1 | 77.2–81.9 | 80.2–85.6 | 83.6–89.3 | |
Tair °C | 32.6 | 56.4 | 76.5 | 86.2 | 95.2 | 100.3 |
30.6–35.2 | 54.2–58.9 | 73.5–79.6 | 82.1–89.3 | 92.6–99.8 | 97.6–105.9 | |
Tr °C | 65.2 | 73.5 | 84.2 | 96.3 | 98.8 | 105.6 |
63.2–69.8 | 71.6–75.6 | 82.6–87.9 | 93.6–98..3 | 95.6–102.3 | 101.6–109.6 | |
kg·h−1 | 155.4 | 188.7 | 206.5 | 275.4 | 334.8 | 425.6 |
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Li, B.; Zeng, Z.; Zhang, X.; Zhang, Y. Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger. Appl. Sci. 2021, 11, 2772. https://doi.org/10.3390/app11062772
Li B, Zeng Z, Zhang X, Zhang Y. Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger. Applied Sciences. 2021; 11(6):2772. https://doi.org/10.3390/app11062772
Chicago/Turabian StyleLi, Bin, Zhiheng Zeng, Xuefeng Zhang, and Ye Zhang. 2021. "Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger" Applied Sciences 11, no. 6: 2772. https://doi.org/10.3390/app11062772
APA StyleLi, B., Zeng, Z., Zhang, X., & Zhang, Y. (2021). Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger. Applied Sciences, 11(6), 2772. https://doi.org/10.3390/app11062772