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秸秆汽爆梳分分级及其生物基材料的制备
Alternative TitleAgricultural stover fractionation by steam explosion coupling with mechanical carding and preparation of biobased materials
王宁
Subtype博士
Thesis Advisor陈洪章
2014-04
Degree Grantor中国科学院研究生院
Degree Discipline生物化工
Keyword农作物秸秆   蒸汽爆破   机械梳分   生物基材料   加氢裂化
Abstract农作物秸秆组织结构的不均一性,造成了其在转化利用过程中不同功能级分之间相互干扰,限制了其作为工业原料的用途。论文针对农作物秸秆各功能级分不能清洁有效分离的问题,在蒸汽爆破技术预处理的基础上,开发了用于汽爆农作物秸秆长纤维和短纤维分离的技术和设备,建立了清洁有效的农作物秸秆分级技术,实现了农作物秸秆半纤维素、长纤维和短纤维的分离。同时,以农作物秸秆为代表的木质纤维素原料开发可循环再生的具有功能特性的生物基材料日益受到全世界各国的关注,论文研究了不同级分的功能特性,并根据不同级分的功能特性,研究了不同级分转化为生物基材料的可行性。论文取得的主要研究成果如下: (1)研究了汽爆玉米秸秆半纤维素水洗液作为可发酵性碳源发酵生产2,3-丁二醇的可行性。发现汽爆玉米秸秆半纤维素水洗液中的乙酸、糠醛和5-羟甲基糠醛浓度低,对2,3-丁二醇的发酵具有促进作用。可溶性木质素是2,3-丁二醇的发酵抑制物,活性炭脱毒后,汽爆玉米秸秆半纤维素水洗液可以作为粘质沙雷氏菌(Bacillus polymyxa S-07)发酵生产2,3-丁二醇的碳源,2,3-丁二醇的转化率为0.42 g/g糖。研究结果表明,汽爆玉米秸秆半纤维素水洗液可作为碳源发酵生产2,3-丁二醇,与纤维素作为可发酵碳源需要昂贵的酶成本相比,汽爆玉米秸秆半纤维素水洗液为2,3-丁二醇的发酵生产提供了廉价的碳源来源。 (2)建立了农作物秸秆汽爆耦合机械梳分分级技术,开发了汽爆秸秆长纤维与短纤维的分离设备。与纤维的传统水力筛分相比,纤维分级过程中不需要水环境,是一种清洁有效的分离技术,汽爆玉米秸秆含水量在纤维饱和点(27.62%)时最适合长纤维与短纤维的分离。长纤维主要由纤维细胞构成,纤维细胞含量高达70%(面积百分百比),纤维细胞平均长宽分别为1.85 mm和17.02 μm,长径比为108;纤维素、半纤维素和木质素含量分别为55.17%,8.34%和23.06%;纤维素结晶度高。短纤维主要由杂细胞构成,杂细胞含量高达60%(面积百分比),纤维细胞平均长宽分别为0.72 mm和16.93 μm,长径比为43;纤维素、半纤维素和木质素含量分别为54.00%,12.88%和20.06%;纤维素结晶度低。研究结果表明,梳分机可以实现汽爆秸秆长纤维与短纤维清洁有效的分离;玉米秸秆汽爆梳分后,获得了组织结构均一,化学组成和细胞类型具有明显差异的两个级分,建立了一种清洁有效的农作物秸秆分级分离技术,解决了农作物秸秆组织结构均一性差的问题。 (3)系统研究了汽爆玉米秸秆短纤维的酶解特性,考察了短纤维同步糖化发酵生产2,3-丁二醇和短纤维酶解液加氢裂化制备低碳多元醇的可行性。 当用酶量为25 IU/gds时,短纤维48 h酶解率为62.1%,而此时长纤维酶解率仅为45.0%。短纤维酶解过程中批次补加短纤维至固液比为1:5,用酶量减少至5 IU/gds,整个体系仍然有较高的酶解率为66.42%,酶解液总糖浓度可达106.27 g/l;短纤维酶解过程中批次补加短纤维和纤维素酶至固液比为1:5,用酶量为20 IU/gds,酶解率可达85.53%,酶解液总糖浓度高达136.845 g/l。以上结果表明,在相同酶解条件下,短纤维比长纤维容易酶解;短纤维补料酶解,在较低的用酶量条件下,可以获得较高的总糖浓度。 短纤维不需要预酶解可直接与B. polymyxa S-07同步糖化发酵生产2,3-丁二醇,当固液比为1:20时,发酵液中2,3-丁二醇浓度为8.799 g/l,短纤维转化率为17.60%。短纤维酶解液可直接用于加氢裂化反应,酶解液中存在降低Ru/C催化剂活性、提高Ru/C催化剂选择性、避免有色物质生成的物质,利用酶解液直接加氢裂化,不需要添加FeS,可提高产物浓度以及1,2-丙二醇的选择性,减少有色物质的产生。 (4)论文考察了汽爆玉米秸秆长纤维与短纤维的制浆性能,提出了利用汽爆玉米秸秆长纤维制备纸浆和溶解浆,建立了长纤维碱法制备纸浆和硫酸盐法制备溶解浆的工艺。 在用碱量10%,固液比1:10,蒸煮温度120°C,蒸煮时间1 h的条件下,长纤维本色浆得率为60.27%,KMnO4值为15.22,本色浆白度20.47。利用5% H2O2,1% NaOH,0.5% MgSO4作为漂白试剂,在固液比1:10,漂白温度70°C,漂白时间60 min的条件下,长纤维本色浆一段漂白白度为65.42,二段漂白白度已达到70.25,汽爆玉米秸秆长纤维通过碱法制浆和两段碱性双氧水漂白制备的漂白浆粕性能达到了漂白碱法麦草浆国家标准的优等品的标准。以上结果表明:汽爆玉米秸秆长纤维具有良好的制浆性能和漂白性能,可以作为纤维原料制备纸浆。 汽爆玉米秸秆长纤维通过硫酸盐法制浆和两段碱性双氧水漂白制备了低甲溶解浆,其中α-纤维素含量为93.10%,戊聚糖含量为3.96%,灰分含量为0.13%,动力粘度为23.96 mPa?s,其性能满足了粘胶纤维用浆粕的要求。通过冷碱抽提和木聚糖酶的协同处理,进一步提高了溶解浆的纯度,制备得到高甲溶解浆。其中高甲溶解浆α-纤维素含量为97.10%,戊聚糖含量为2.86%,灰分含量为0.10%,制备的高甲溶解浆可以满足溶解浆下游产品醋酸纤维和硝化纤维对纤维素纯度的要求。以上结果表明:汽爆玉米秸秆长纤维可以作为纤维原料制备溶解浆,根据工艺不同,可以制备低甲溶解浆和高甲溶解浆。
Other AbstractThe structure of agricultural straw was inhomogeneous, and fractionations with different functionation were mutual interference in the conversion and utilization process, which limited its use as industrial materials. In this thesis, in order to fractionate different functional components cleanly and efficiently, a novel technology and equipment was developed to fractionate steam-exploded agricultural straw long fiber and short fiber based on the steam explosion pretreatment technology, and a clean and efficient agricultural straw component fractionation technology was established, which achieved the fractionation of agricultural straw hemicellulose, long fiber and short fiber. In addition, biobased materials with functional properties were recycled, and developing biobased materials produced from lignocellulose were concerned more and more. In this thesis, the characteristics of different components were studied, and the feasibility of the different fractionation converted into biobased materials was studied according to the functional characteristics of the different fractionations. The main research results obtained are as follows: (1) The feasibility of steam-exploded cornstover hemicellulose washing water as carbon source for 2,3-butanediol fermentation was studied. It was found that the concentration of acetic acid, furfural and 5-hydroxymethylfurfural (5-HMF) was low, which promoted the fermentation of 2,3-butanediol. Soluble lignin was the inhibitor for 2,3-butanediol fermentation, and after detoxification using activated carbon, steam-exploded cornstover hemicellulose washing water could be used as the carbon source for the fermentation of 2,3-butanediol by Bacillus polymyxa S-07, and the conversion rate of 2,3-butanediol was 0.42 g/g sugar. The results showed that steam-exploded cornstover hemicellulose washing water could be used as the carbon source for the fermentation of 2,3-butanediol. Compared with cellulose as fermentable carbon source requiring expensive enzyme cost, this research provided a cheap carbon source for 2,3-butanediol fermentation. (2) A novel agricultural straw fractionation technology by steam explosion coupling with mechanical carding was constructed, and the equipment (fiber fractionator) for the the fractionation of steam-exploded straw long fiber and short fiber was developed. Compared with the traditional hydraulic screening for fiber, the developed fiber frationator did not require water, and it was a clean and efficient technology. The suitable water content for the fractionation of long fiber and short fiber was the fiber saturation point (27.62%). Long fiber mainly constituted of fiber cells that were up to 70% (percentage of area). The average length and width of fiber cell was 1.85 mm and 17.02 μm respectively, and the length/width ratio was 108. The content of cellulose, hemicellulose and lignin was 55.17%, 8.34 % and 23.06% respectively, and the cellulose crystallinity was high. Short fiber was mainly composed of non-fiber cells, and the non-fiber cell content was 60% (percentage of area). The fiber cell content was low and the fiber quality was poor. The average length and width of the non-fiber cell was 0.72 mm and 16.93 μm, and the length/width was 43. The content of cellulose, hemicellulose and lignin was 54.00%, 12.88% and 20.06% respectively, and the cellulose crystallinity was low. The results showed that steam-exploded cornstover long fiber and short fiber could be fractionated by fiber fractionator cleanly and efficiently. Two different fractionations with homogeneous structure and different chemical components and cell types were obtained by steam explosion coupling mechanical carding technology. A clean and efficient fractionation technology platform of cornstover was established. This research solved the problem of the heterogeneity of agricultural straw and provided homogeneous raw materials for the conversion of cornstover. (3) The enzymatic properti
Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/15530
Collection研究所(批量导入)
Recommended Citation
GB/T 7714
王宁. 秸秆汽爆梳分分级及其生物基材料的制备[D]. 中国科学院研究生院,2014.
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