本研究以平板型熱擴散塔為主題，針對具變出料質量分率對熱擴散塔提煉重水效率改善之研究。本文之理論模式主要探討利用分離變數法配合正交展開方法，求得平板型熱擴散塔之解析解研究。雖然解析解的計算過程比傳送公式較為繁複，但其理論數學之模擬結果與實驗結果比較卻更為精確。同時，本研究亦針對不同的操作參數：進料質量流率、進料濃度分率及進料位置和設計參數：改變長寬比、傾斜角、板距及固定操作成本下之板距，以期能提升熱擴散塔之分離效果。 本文首先推導進料質量流率、進料濃度分率、出料質量分率及進料位置之平板型熱擴散塔的分離度公式；接著，探討變出料質量分率、改變長寬比及傾斜角度對平板型熱擴散塔之影響；而後，推導了含有變出料質量分率的板距公式，並比較在固定操作成本與無固定操作成本下之板距的分離度變化。最後，藉由文獻資料中之實驗數據來驗證本研究理論分析之可靠性結果是相當吻合。由此可以證明，改善平板型熱擴散塔之操作參數和設計參數有助於提高重水之分離效果。 Heavy water enrichment in laminar counter-flow flat-plate thermal-diffusion columns has been studied theoretically. The phenomena of mass transfer through a thermogravitational thermal-diffusion column with uniform wall temperature, one heated and the other one cooled, has been investigated by using an orthogonal expansion technique in extended power series. The method of solution is based on the Sturmian theory and requires only positive eigenvalues for enriching section and negative eigenvalues for stripping section during the derivation of the top and bottom product concentrations. The analytical results are represented graphically and compared with those obtained from the transport equation by the previous investigators as well as with the experimental results. The agreement of theoretical predictions in the present study with those calculated from experimental results obtained from the previous investigations is pretty good. Moreover, as compared to the experimental results, the accuracy of the theoretical predications in the study is better than that calculated by the transport equation. The effects of operating parameters (feed rate, feed concentration, product flow-rate and feed position), and design parameters (aspect ratio, inclined angle, plate spacing and plate-spacing under the considerations of fixed operating expense) on the separation efficiency enrichment have also been discussed.
