局部高水分稻谷粮堆发热温度模拟初步分析

Analysis on Temperature Variation Simulation of Local High Moisture Paddy Bulk

为模拟粮堆局部粮食水分偏高引起发热霉变,在实验室条件下将含水量13.5%的稻谷粮堆中心点加入含水量22.3%的高水分稻谷,在25~30℃室内环境储藏39 d。实验结果表明:储藏过程中高水分稻谷温度不断攀升形成发热点,在第9~11天,各温度监测点相继达到最高值,发热点的物理中心点也是温度最高点,最高温度43.8℃,升温速率为2.893℃/d。距离中心点越远,温度越低,随储藏时间延长,各点温度呈线性增长。发热点形成后,降温缓慢,中心点最高降温速率0.572℃/d。经39 d储藏,各温度监测点水分由实验开始时的22.3%降到14.8%~16.4%,霉菌总数由实验开始时的3.2×10^(4)cfu/g升高到7.0×10^(6)~2.5×10^(7)cfu/g。

To simulate heating mould caused by the relatively high moisture content of grain in the stored grain bulk,paddy with 22.3%moisture content(w.b.)was added to the center point of the paddy bulk with 13.5%moisture content(w.b.)under laboratory conditions at 25~30℃for 39 days.The result indicated that,in the process,the temperature with high moisture content paddy bulk increased constantly.Finally,a hot spot was formed.During the 9th to 11th days,each temperature monitoring point reached the maximum value successively and the highest temperature in the hot spot was at the physical center of the hot spot.The highest temperature was 43.8℃,and the heating rate was 2.893℃/d.The further away from the center of the hot spot,the lower the temperature was.The temperature at each point increased linearly with the extension of storage time.After the formation of the hot spot,the temperature dropped slowly,and the maximum cooling rate at the central point was 0.572℃/d.After storage of 39 days,the water content at each temperature monitoring point decreased from 22.3%at the beginning of the experiment to 14.8%~16.4%,and the total number of mold increased from 3.2×10^(4)cfu/g to 7.0×10^(6)~2.5×10^(7)cfu/g.