2014-03-152024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/665663摘要：本計畫主要的目的在於建立流體力學模型，以模擬生質物料在高溫高壓反應器中之溫度變化以及反應物產出情形。由於纖維原料處理程序涉及固體原料在反應器內的混合以及反應效率，若將反應器直接放大時將不可避免地將遇到反應器中渣料沉積以及溫度不均等問題。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將影響反應物的生成速率。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以及反應生成物組成的預測，並探討反應器中渣料的溫度均勻混和程度，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與溫度分布、以及將反應器設計最佳化。 此計畫並將由上述建立之模型探討反應器尺寸放大後反應器中混合物之流動行為、各項物質分布情形以及主反應與副反應之反應程度。此外並改變攪拌速率變動、溫度(或反應速率)分布與蒸氣入口位置選擇等操作參數探討其對系統之影響，由其中找出最佳化之可行性結果。以期能提升此反應器中反應物轉化率，提高經濟效益至可商轉之規模。 <br> Abstract: Computational fluid dynamic (CFD) simulations will be developed to predict flow and thermal characteristics in reactor designs for a biomass pretreatment process. The pretreatment process designed in this project is a high-temperature high-pressure hydrolysis which performs in a reactor up-scaled 20 times in volume from reactors employed in current studies. At this stage, well-mixed biomass slurry is delivered to the reactor and generates final product after thermal heating. The 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 and heating effects of the high pressure steam. Similarly, pressure distributions under various designs and operating parameters, which may affect reaction rates and performance greatly, will also be analyzed. Experimental data will be compared to validate CFD results. Parametric study will be also conducted and summarized to provide useful optimization tools for reactor designs.流體力學模型高溫高壓反應器Computational fluid dynamic (CFD)biomass pretreatment process