2013-05-162024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/665635摘要：本計畫將利用計算流體力學進行纖維原料解聚前處理反應器中渣料與酸液混合流動的模擬分析。纖維原料解聚前酸水解處理程序包含了室溫混酸與高溫高壓酸水解兩個步驟。目前已有之反應器已有良好之成效，為擴大推廣既有之實驗成果，反應器容積須增加為現行研究中使用的15倍大，以達到商業操作之經濟規模。 由於纖維原料前處理程序涉及固體原料與酸液在反應器內的混和效率，將反應器直接放大時將不可避免地遇到反應器中渣料沉積的問題。尤其在混和液攪動的過程中，固液比些微的提高就將導致混合液粘性大幅提升，因而造成均勻混和的困難。另外，攪拌葉設計、攪拌速率、高溫高壓反應器的蒸氣入口位置選擇等因素也同樣影響反應器中混和液的行為與酸水解反應。 為克服以上反應器放大時的問題，我們將使用計算流體力學模擬，以提供對反應器中混和液的粘性、壓力等物理性質的預測，以探討反應器中渣料與酸液的均勻混和程度，進而推估反應速率與成效，並與實驗數據比較及驗證。計算結果可用於提升最終產物品質、分析在不同固液比下混和液的流動行為、最佳化反應器設計與了解反應器放大時流體之行為。 <br> Abstract: Computational fluid dynamic (CFD) simulations are applied to predict flow characteristics in both mixer and screw conveyor reactor designs for the diluted acid pretreatment process of biomass. The pretreatment process designed in this project includes a room-temperature diluted acid pretreatment and a high-temperature high-pressure acid hydrolysis which is performed in a reactor up-scaled 15 times in volume from reactors employed in current studies. At both stages, well-mixed slurry is desirable to evenly distribute acid on biomass, prevent buildup on the walls of the reactor, and provides a uniform final product. Slurry containing a high concentration of biomass solids exhibits a high viscosity, which poses unique mixing issues within the reactor – the viscosity increases significantly with a small increase in solid fractions and also varies with temperature. And factors such as design of screw flight, operating speed, choice of steam inlet in high-temperature reactor affect the motion of slurry and hence the reaction rates as well. CFD simulations will be used in this project to provide prediction of flow patterns obtained over a wide range of viscosities. Similarly, pressure distributions under various screw flight design and operating parameters, which may affect reaction rates and performance greatly, will also be analyzed. Experimental data or literature values will be compared to validate CFD results. Parametric study will be also conducted and summarized to provide useful tools for pretreatment reactor designs.計算流體力學纖維原料水解Computational Fluid DynamicsBiomass Hydrolysis