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標題: | 農業廢棄物生產食品與糠醛之製程開發及程序評估 Processes Design and Evaluations for Producing Food and Furfural from Agricultural Wastes |
作者: | Chin-Heng Wang 王志恒 |
指導教授: | 萬本儒(Ben-Zu Wan) |
關鍵字: | 農業廢棄物,食用級葡萄糖液,糠醛,程序設計,經濟分析,碳足跡, agricultural wastes,food-grade glucose,furfural,process design,economic analysis,carbon footprint, |
出版年 : | 2018 |
學位: | 博士 |
摘要: | 本論文是有關農業廢棄物轉化為食品級葡萄糖液與工業級糠醛的製程開發、程序設計、經濟分析及二氧化碳排放評估。台灣核能研究所已開發出一套成熟的試驗級農業廢棄植物前處理程序,經稀酸浸泡及蒸氣爆裂程序後,可生產出結構鬆軟之纖維素固渣以及稀酸木糖液。本研究利用這些固渣及木糖液繼續開發兩製程,第一項製程,是以廢稻稈纖維素固渣為原料,由酵素水解反應製備食用級葡萄糖溶液。由於氣候變遷導致全球糧食減產,有需要發展程序因應可能發生的糧荒問題。該研究重點在於提升反應效率,以及減少和控制溶液中毒性副產物質(甲酸、羥甲基糠醛、糠醛)含量,以生產具足夠熱量的食用級葡萄糖液。研究發現,纖維固渣的酵素水解反應有質傳阻力問題,能藉由反應器底部的研磨增加反應速率。另外發現,纖維固渣中的酸在水解反應時會催化毒性副產物的生成,藉由新研發的固渣浸泡程序,可有效減少毒性物質產量。綜合上述的改善,本研究已發展出程序,能生產出含103.5 g/L(即每公升有414大卡熱量)符合食用標準的葡萄糖溶液,做為未來糧食短缺之用。本研究所研發的第二項製程,是利用蒸氣爆裂程序所生產的稀酸木糖液,用以生產工業級糠醛。首先是以純木糖為原料在批次反應系統下收集數據研究木糖生成糠醛及副產物的反應動力式,發現不鏽鋼反應器腐蝕釋出之鉻三價離子會與硫酸共催化而加快木糖轉化速率。本研究已詳細探討硫酸、鉻離子、及氯化鈉共催化木糖生成糠醛的反應機制,及觸媒濃度對反應速率之影響。後續研究以廢木片生產之工業級稀酸木糖液為原料進行生產糠醛,發現木片木糖液中的雜物會降低糠醛的生成速率及選擇率,已嘗試分析雜物,並探討對反應速率定量影響。基於研究所得知之木片木糖液各反應速率方程式,本研究已設計一具蒸氣出料口的CSTR反應器,反應程序中產生的糠醛可迅速蒸發流出反應器,由降低反應系統中糠醛濃度來降低副反應從而提升產率。程序最適化後,經濟評估顯示糠醛生產成本為1.65 USD/公斤,略低於市場價格,已顯示該製程具經濟效益的可能性。二氧化碳排放評估顯示,本研究開發的糠醛製程與生產石油化學品製程的二氧化碳排放相比,較具環保優勢。 Processes development, design, economic evaluation, and CO2 emission evaluation for producing food and furfural from agricultural wastes are studied. The researches continue the pilot-plant pretreatment process developed by INER (Institute of Nuclear Energy Research), in which agricultural wastes are pretreated in a dilute sulfuric acid solution and subsequently undergo steam explosion to produce cellulose-rich solid and xylose-rich liquid. Therefore, two major subjects have been studied in this research. One is developing processes for manufacturing food-grade glucose solution through enzymatic hydrolysis of the cellulose-rich solids. The motivation is from growing concern that climate change may cause a food shortage. Producing food from agricultural waste may offer an alternative for overcoming the catastrophe. It has been found in this research that there is a considerable mass transfer resistance for hydrolysis reaction of cellulose-rich solids. It can be reduced by adding glass beads for grinding the solid during the reaction in an impeller-stirred batch reactor. A soaking process for the cellulose-rich solids has been developed for an effective reduction of the generation of undesired byproducts. The resulting food-grade glucose solution is within food regulatory limits and can provide 414 kilocalories per liter. The other major subject studied in this research is catalyst improvement and process development for producing furfural from xylose-rich sulfuric acid solution from steam explosion process. The reaction kinetics and rate equations of converting pure xylose to furfural and the side products in sulfuric acid solution are studied first. It has been found that furfural production can be improved in the presence of chromium(III) ion and sodium chloride. For producing furfural from xylose solution produced from wood-chip from steam explosion process, the impurities in the solution decrease furfural production rate and the selectivity significantly. Therefore, a reactor system which can alleviate the consecutive side reaction rate of furfural degradation has been designed for improving furfural yield. The optimized processes for producing furfural from the xylose-rich solution from wood chip can have economic advantage and are environmentally friendly. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/72247 |
DOI: | 10.6342/NTU201803329 |
全文授權: | 有償授權 |
顯示於系所單位: | 化學工程學系 |
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