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    Hot-water pre-extraction of hardwoods: Impact of processing on extract and pulp properties.

    機譯:硬木的熱水預提取:加工對提取物和紙漿特性的影響。

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    摘要

    The aim of this work is to further evaluate the viability of the integrated biorefinery concept. On one side the properties of hot-water extracts are studied, in order to develop a purification method that allows for further processing of the extracts. It was found that poly-DADMAC is an effective flocculant for the extracts, removing the majority of suspended particles while maintaining the sugar levels high, improving subsequent purification techniques such as filtration. The optimum pH for the effectiveness of the polymer was found to be around 4.5. The use of an inert anchoring agent, Kaolin, drastically improves the efficiency of the flocculant, reducing the treatment time in more than an order of magnitude, while the presence of indifferent electrolytes hinders its efficiency. This pre-treatment allowed for the destabilization of the colloidal suspension, lowering the turbidity from values of the order of 1200 NTU to 4 NTU over a 24-hour period.;On the other side, the effect that extraction has on fiber properties and consequent paper properties is studied and models are developed to predict and better understand them. For that two hardwood species (Acer saccharum and Eucalyptus globulus) were extracted and consequently pulped. Generally the two different species behaved differently, but in both cases it was found that extracted chips are much easier to pulp (smaller H-factors required to reach the same kappa) than non-extracted. The hemicellulose content in the pulps drops drastically from 20--22% to approximately 5%. This difference will affect all other pulp properties. In fact, with the exception of viscosity, the majority of pulp and paper properties are hindered by the hot-water pre-extraction, which also reflects in a lower total yield. The viscosity initially increases significantly, but for longer extraction periods the gain is not very significant. For eucalyptus there is also no significant gain (in hemicellulose removal) in extracting more than 90 min.;The models developed have very high correlation factors and they not only help explaining which parameters affect the different properties the most, but also provide some foresight into the fibers and laboratory handsheets properties.
    機譯:這項工作的目的是進一步評估整合的生物精煉概念的可行性。一方面,研究了熱水提取物的性質,以便開發一種純化方法,以便進一步處理提取物。發現聚-DADMAC對于提取物是有效的絮凝劑,除去大部分懸浮顆粒,同時保持高糖含量,改進了諸如過濾的后續純化技術。發現用于聚合物有效性的最佳pH為約4.5。惰性錨固劑高嶺土的使用極大地提高了絮凝劑的效率,將處理時間縮短了一個數量級以上,而無差別的電解質的存在則阻礙了其效率。這種預處理會使膠體懸浮液不穩定,在24小時內將濁度從1200 NTU降低到4 NTU;另一方面,萃取對纖維性能的影響也隨之而來。研究紙張特性并開發模型以預測和更好地理解它們。為此,提取了兩種硬木樹種(槭樹和桉樹)并制成紙漿。通常,兩個不同物種的行為不同,但是在兩種情況下,都發現與未提取相比,提取出的木片更容易制漿(達到相同κ所需的較小H因子)。紙漿中的半纖維素含量從20--22%急劇下降至大約5%。這種差異將影響所有其他紙漿性能。實際上,除粘度外,熱水預萃取會阻礙大多數紙漿和紙張的性能,這也反映出總產量較低。粘度最初顯著增加,但是對于更長的提取時間,增益不是非常顯著。對于桉樹,提取90分鐘以上也沒有明顯的收獲(去除半纖維素);建立的模型具有非常高的相關因子,不僅有助于解釋哪些參數對不同性質的影響最大,而且還提供了一些先見之明纖維和實驗室手抄紙的性能。

    著錄項

    • 作者

      Duarte, Gustavo.;

    • 作者單位

      State University of New York College of Environmental Science and Forestry.;

    • 授予單位 State University of New York College of Environmental Science and Forestry.;
    • 學科 Engineering Chemical.
    • 學位 Ph.D.
    • 年度 2010
    • 頁碼 179 p.
    • 總頁數 179
    • 原文格式 PDF
    • 正文語種 eng
    • 中圖分類
    • 關鍵詞

    • 入庫時間 2022-08-17 11:36:56

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