The Influences of Moisture Content,Bulk Density and Impurity Removal Rate on Weight Conversion Ratio between Wet Paddy and Dry Paddy

本研究完成濕穀含水率、容重量及去雜率對濕乾穀折算率的影響 探討，在不增加公糧業者濕穀收購作業負擔的原則下，研究建立一套 合理且客觀的濕乾穀折算率的作業模式。此方法的採用將不會增加目 前各濕穀收購點的工作量。 折算率換算公式的建立分別採用二因子(含水率及容重量)以及 三因子(含水率、容重量和濕穀去雜率)進行換算的。由於今年度(105 年)收穫時受到異常氣候影響，一期作受颱風影響，二期作則遇到連 日陰雨及颱風影響，導致部分地區折算率的相關性降低。也造成部分 地區和農會現行之折算表有所差異。而相關性則以各縣市>北中南東 分區>全部不分區，證明每個濕乾穀折算率換算公式適用範圍不宜過 大。 比較去除雜質的方法，風選去雜方式較優於篩網去雜方式，由於 風選去雜作業時間較短，對於濕穀水分含量變化影響較不顯著，考慮 時間消耗與工作量，風選去雜可廣泛應用於濕穀的收購過程。This research accomplishes to investigate the influences of moisture content, bulk density and impurity removal rate on weight conversion ratio between wet paddy and dry paddy. Without increasing the working burden of rice drying center that purchases wet paddy to be public paddy. Through this research a reasonable and objective weight conversion ratio of wet paddy to dry paddy had been established in different areas. The research also designs a feasible method to remove the impurity of wet paddy. The method will not increase the workload in a wet paddy acquisition operation. The developed weight conversion ratio equations uses two factors (moisture content and bulk density) and three factors (moisture content, bulk density and wet paddy impurity removal percentage) separately. During the experimental period, the quality of harvested paddy has been significantly affected due to abnormal climate. The first crop of paddy in that year was affected by the typhoon. The second crop of paddy was affected by heavy rain and the typhoon. The abnormal climate during the harvesting season, the correlations of the conversion rate in some areas are relatively low. In some of areas the conversion ratio of this study is different with the recommended ratio by the Agriculture and Food Bureau. The values of determination coefficients of small areas are higher than in big areas. It proves that the actual weight conversion ratio should be calculated in a local area specifically. The comparison of the methods to remove the impurity, the air-blow method is much better than the screen method. Due to the short operation time period in an air-blow method, there is no significant influence on the moisture content change of wet paddy. Concerning the time consumption and working loading, the air-blow method can be widely applied in the wet paddy acquisition process.謝誌 i 摘要 ii Abstract iii 圖目錄 viii 表目錄 xi 符號表 xiii 第一章 前言 1 1.1 研究動機 1 1.2 研究目的 2 第二章 文獻探討 3 2.1 稻米品種、產量 3 2.2稻穀之交易與乾燥 4 2.3 稻米物性檢測 5 2.3.1 含水率檢測 5 2.3.2 稻穀容重量 6 2.3.3 成品率 8 2.3.4 夾雜率 9 2.3.5 風選機除雜率與終端速度 11 第三章 材料與方法 13 3.1 實驗材料 13 3.1.1 樣本來源 13 3.1.2 濕穀進入乾燥中心流程 15 3.1.3 取樣步驟 16 3.2 實驗方法 18 3.2.1 建立去雜技術 18 3.2.2 成品率測量 20 第四章 結果與討論 24 4.1 取得樣本分布 24 4.1.1 樣本取得分布 24 4.1.2 高濕稻穀含水率量測 26 4.1.3 地域性影響 28 4.2 去雜方式的影響探討 35 4.3 容重量的影響探討 39 4.4 成品率分析 41 4.4.1 成品率換算 41 4.4.2 成品率與含水率 43 4.4.3 容重量 46 4.4.4 去雜率 50 4.5 濕穀折算率之換算公式 53 4.6 與農糧署現行折算表差異 59 第五章 結論與建議 67 5.1 結論 67 5.2 建議 68 參考文獻 70 附錄一 75 附錄二 9