Analysis of drying characteristic, effective moisture diffusivity and energy, exergy and environment performance indicators during thin layer drying of tea in a convective-hot air dryer
The objective of this study is mainly to analyze the drying kinetic parameters, effective diffusivity, and thermodynamic performance indicators (energy, exergy, heat, and mass transfer coefficients) of tea under different drying conditions of different drying temperatures (DT) and thin layer thickne...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2024-04-01
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| Series: | Frontiers in Sustainable Food Systems |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fsufs.2024.1371696/full |
| _version_ | 1797217045872377856 |
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| author | Zhiheng Zeng Zhiheng Zeng Chongyang Han Qi Wang Huilin Yuan Xuefeng Zhang Bin Li |
| author_facet | Zhiheng Zeng Zhiheng Zeng Chongyang Han Qi Wang Huilin Yuan Xuefeng Zhang Bin Li |
| author_sort | Zhiheng Zeng |
| collection | DOAJ |
| description | The objective of this study is mainly to analyze the drying kinetic parameters, effective diffusivity, and thermodynamic performance indicators (energy, exergy, heat, and mass transfer coefficients) of tea under different drying conditions of different drying temperatures (DT) and thin layer thicknesses (TT). Experimental drying was conducted at drying temperatures of 70°C, 80°C, and 90°C with thin layer thicknesses of 10 mm, 15 mm, and 20 mm. The results show that a higher drying temperature and a lower thin layer thickness can increase evaporation moisture content and shorten drying time. By evaluating and comparing the fitting of five drying models adopted by the coefficient of determination (R2) and chi-square (χ2), it can be found that the logarithmic model is the best to describe drying behavior. The effective moisture diffusivity shows a positively correlated trend with the increase in DT and TT, with the value of activation energy ranging from 14.030 to 22.344 kJ mol−1 K−1. The specific moisture evaporation rate (SMER), energy efficiency, exergy efficiency, and sustainability index (SI) descend as the TT increases at all DT; the specific energy consumption (SEC) and improvement potential (IP) rate perform in an opposite manner, but the TT remains unchange. The conclusion drawn from the thermodynamic parameters is opposite to the aforementioned. As the TT increases, the heat and mass transfer coefficients show a significant decrease trend. In addition, the heat and mass transfer coefficients are given as functions of DT and TT, and further knowledge shows that the mass transfer coefficient is positively correlated with DT but the heat transfer coefficient is negatively correlated. In conclusion, this article provides new insights into the effects of drying characteristics, energy consumption characteristics and heat and mass transfer characteristics in the process of tea drying under different drying conditions, and provides certain theoretical reference bases for promoting the optimization of industrialized tea drying production machinery design and drying process optimization. |
| first_indexed | 2024-04-24T11:55:37Z |
| format | Article |
| id | doaj.art-90856eb7afd640fb939a087be4d15412 |
| institution | Directory Open Access Journal |
| issn | 2571-581X |
| language | English |
| last_indexed | 2024-04-24T11:55:37Z |
| publishDate | 2024-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Sustainable Food Systems |
| spelling | doaj.art-90856eb7afd640fb939a087be4d154122024-04-09T05:00:19ZengFrontiers Media S.A.Frontiers in Sustainable Food Systems2571-581X2024-04-01810.3389/fsufs.2024.13716961371696Analysis of drying characteristic, effective moisture diffusivity and energy, exergy and environment performance indicators during thin layer drying of tea in a convective-hot air dryerZhiheng Zeng0Zhiheng Zeng1Chongyang Han2Qi Wang3Huilin Yuan4Xuefeng Zhang5Bin Li6College of Intelligent and Manufacturing Engineering, Chongqing University of Arts and Sciences, Chongqing, ChinaCollege of Engineering, South China Agricultural University, Guangzhou, ChinaCollege of Engineering, South China Agricultural University, Guangzhou, ChinaChongqing College of Finance and Economics, Chongqing, ChinaCollege of Intelligent and Manufacturing Engineering, Chongqing University of Arts and Sciences, Chongqing, ChinaCollege of Intelligent and Manufacturing Engineering, Chongqing University of Arts and Sciences, Chongqing, ChinaCollege of Intelligent and Manufacturing Engineering, Chongqing University of Arts and Sciences, Chongqing, ChinaThe objective of this study is mainly to analyze the drying kinetic parameters, effective diffusivity, and thermodynamic performance indicators (energy, exergy, heat, and mass transfer coefficients) of tea under different drying conditions of different drying temperatures (DT) and thin layer thicknesses (TT). Experimental drying was conducted at drying temperatures of 70°C, 80°C, and 90°C with thin layer thicknesses of 10 mm, 15 mm, and 20 mm. The results show that a higher drying temperature and a lower thin layer thickness can increase evaporation moisture content and shorten drying time. By evaluating and comparing the fitting of five drying models adopted by the coefficient of determination (R2) and chi-square (χ2), it can be found that the logarithmic model is the best to describe drying behavior. The effective moisture diffusivity shows a positively correlated trend with the increase in DT and TT, with the value of activation energy ranging from 14.030 to 22.344 kJ mol−1 K−1. The specific moisture evaporation rate (SMER), energy efficiency, exergy efficiency, and sustainability index (SI) descend as the TT increases at all DT; the specific energy consumption (SEC) and improvement potential (IP) rate perform in an opposite manner, but the TT remains unchange. The conclusion drawn from the thermodynamic parameters is opposite to the aforementioned. As the TT increases, the heat and mass transfer coefficients show a significant decrease trend. In addition, the heat and mass transfer coefficients are given as functions of DT and TT, and further knowledge shows that the mass transfer coefficient is positively correlated with DT but the heat transfer coefficient is negatively correlated. In conclusion, this article provides new insights into the effects of drying characteristics, energy consumption characteristics and heat and mass transfer characteristics in the process of tea drying under different drying conditions, and provides certain theoretical reference bases for promoting the optimization of industrialized tea drying production machinery design and drying process optimization.https://www.frontiersin.org/articles/10.3389/fsufs.2024.1371696/fullteadrying kineticsthin layer thicknessdrying temperatureeffective moisture diffusivitythermodynamic |
| spellingShingle | Zhiheng Zeng Zhiheng Zeng Chongyang Han Qi Wang Huilin Yuan Xuefeng Zhang Bin Li Analysis of drying characteristic, effective moisture diffusivity and energy, exergy and environment performance indicators during thin layer drying of tea in a convective-hot air dryer Frontiers in Sustainable Food Systems tea drying kinetics thin layer thickness drying temperature effective moisture diffusivity thermodynamic |
| title | Analysis of drying characteristic, effective moisture diffusivity and energy, exergy and environment performance indicators during thin layer drying of tea in a convective-hot air dryer |
| title_full | Analysis of drying characteristic, effective moisture diffusivity and energy, exergy and environment performance indicators during thin layer drying of tea in a convective-hot air dryer |
| title_fullStr | Analysis of drying characteristic, effective moisture diffusivity and energy, exergy and environment performance indicators during thin layer drying of tea in a convective-hot air dryer |
| title_full_unstemmed | Analysis of drying characteristic, effective moisture diffusivity and energy, exergy and environment performance indicators during thin layer drying of tea in a convective-hot air dryer |
| title_short | Analysis of drying characteristic, effective moisture diffusivity and energy, exergy and environment performance indicators during thin layer drying of tea in a convective-hot air dryer |
| title_sort | analysis of drying characteristic effective moisture diffusivity and energy exergy and environment performance indicators during thin layer drying of tea in a convective hot air dryer |
| topic | tea drying kinetics thin layer thickness drying temperature effective moisture diffusivity thermodynamic |
| url | https://www.frontiersin.org/articles/10.3389/fsufs.2024.1371696/full |
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