| 基于㶲分析法的粮食逆流干燥系统能效评价与试验 |
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| 引用本文： | 马兴灶,方壮东,李长友.基于㶲分析法的粮食逆流干燥系统能效评价与试验[J].农业工程学报,2017,33(22):285-291. |
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| 作者姓名： | 马兴灶 方壮东 李长友 |
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| 作者单位： | 1. 岭南师范学院机电工程学院,湛江 524048;华南农业大学工程学院,广州 510642;2. 华南农业大学工程学院,广州,510642 |
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| 基金项目： | 国家自然科学基金（31371871；31671783），广东省科技计划项目（2014B020207001），湛江市非资助科技攻关计划项目（2017B01095）。 |
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| 摘 要： | 为客观、合理地评价粮食逆流干燥系统的能效,实现粮食高效节能干燥,该文基于?分析法,从气流状态变化考察逆流连续式干燥工艺系统的能量利用程度。结果表明:在试验条件下,干燥机内各干燥段能量利用效果较好。在高温和低温干燥段,排气和干燥室热损失率最高分别不超过6.68%、11.09%和21.26%、9.37%,热效率和?效率不低于83.02%、68.1%和69.37%、56.22%;在冷却段,由于粮温比风温高,风对稻谷有明显的降温去水作用。而系统的平均热效率和?效率为80.24%和64.52%,表明系统能量匹配效果较好,稻谷的平均单位热耗量为2 944.6 k J/kg,与国标≤7 400 k J/kg相比,节能达到60.2%,节能效果明显。研究结果为干燥工艺设计、探索节能的途径和制定粮食干燥系统能效评价标准提供参考。
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| 关 键 词： | 节能 干燥 系统分析 粮食 能效评价 分析法 |
| 收稿时间： | 2017/8/18 0:00:00 |
| 修稿时间： | 2017/11/9 0:00:00 |
Energy efficiency evaluation and experiment on grain counter-flow drying system based on exergy analysis |
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| Ma Xingzao,Fang Zhuangdong and Li Changyou.Energy efficiency evaluation and experiment on grain counter-flow drying system based on exergy analysis[J].Transactions of the Chinese Society of Agricultural Engineering,2017,33(22):285-291. |
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| Authors: | Ma Xingzao Fang Zhuangdong and Li Changyou |
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| Institution: | 1. College of Electro-mechanical and Engineering, Lingnan Normal University, Zhanjiang 524048, China; 2. College of Engineering, South China Agricultural University, Guangzhou 510642, China;,2. College of Engineering, South China Agricultural University, Guangzhou 510642, China; and 2. College of Engineering, South China Agricultural University, Guangzhou 510642, China; |
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| Abstract: | Grain drying is not only restrained by human operation behavior, but also influenced by a lot of objective factors, such as environmental factors, grain physical properties, and grain flow characteristics, as well as the processing technology and geometry of the dryer. In order to objectively and rationally evaluate the energy efficiency of the drying system, and realize the high efficiency and energy saving of grain drying, based on the heat and mass balance calculation of drying system, as well as the evaluation method of thermal efficiency and exergy efficiency, the energy utilization degree of counter-flow continuous drying process system was investigated under the change of airflow condition. The test results showed that the energy utilization effect of each drying segment in the dryer was better under the experimental condition. In high temperature drying segment, the exhaust gas heat loss and heat loss of drying chamber were not higher than 6.68% and 11.09%, respectively, and the thermal efficiency and exergy efficiency were not less than 83.02% and 68.1%, respectively. In low temperature drying segment, the exhaust gas heat loss and heat loss of drying chamber were not higher than 21.26% and 9.37%, respectively, and the thermal efficiency and exergy efficiency were not less than 69.37% and 56.22%, respectively. In cooling segment, due to that the grain temperature was higher than air temperature, which meant that the air had obvious cooling and dehydration effect on the grain. The average thermal efficiency and exergy efficiency of drying system were 80.24% and 64.52% respectively, which showed that the energy matching effect during grain drying process was good. The heat loss of drying chamber initially was 1.86% while 21.26% in later stage. The corresponding thermal efficiency of drying chamber reduced from 89.09% to 69.37%. The exergy efficiency of drying chamber reduced from 72.55% to 56.22%, which indicated that the energy consumption of grain drying not only had subjective exergy, but also contained objective exergy, and the evaluation of drying process and dryer energy utilization efficiency could not just stay on the subjective thermal efficiency, and should consider the effect of objective energy. Test showed that the average unit heat consumption of grain was 2944.6 kJ/kg, and compared with the national standard, which was less than 7400 kJ/kg, the highest energy saving could reached 60.2%. At the same time, the grain temperature was raised slowly with the moisture content decreasing during grain drying, and the highest temperature did not exceed 38.0℃, close to or below the glass transition temperature of grain, which showed that with the reasonable design of the grain drying process, the drying quality of grain could be better ensured. The results provide an analytical reference to improve grain drying efficiency and explore the ways of energy saving drying, as well as provide reference to design the grain drying process system and establish energy efficiency evaluation standard for grain drying. |
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| Keywords: | energy conservation drying system analysis grain energy efficiency evaluation experimental study |
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