【作者】 罗光恩；

【导师】 倪吾钟； 石伟勇；

【作者基本信息】 浙江大学 ， 植物营养学， 2011， 博士

【摘要】 随着各类资源的不断消耗,作为产量巨大和可再生的生物质资源逐渐引起各界的重视,并被认为是未来公认的潜在能源性物质和资源性物质。新鲜生物质一般具有较高的含水量,特别是作为未来生物质利用重心的水生生物质,其含水量更大。而当前各类资源化处理过程中,生物质中的高含量水分将带来高额操作成本或处理操作工艺及路线限制,成为生物质再利用的重要限制性因素之一。故而,本论文开展了针对高含水量生物质的资源化利用处理工艺的实验,并期于未来可以在实际中得到商业化运用。通过实验及分析得到以下主要结论：(1)结合当前热门的生物质处理工艺—水热处理和高含水量生物质的较高含水量这一特点,提出一套针对高含水量生物质的亚临界水热处理工艺,即不添加水,直接对这类高含水量生物质进行加压升温处理。通过初探性试验可以表明,该工艺可以将生物质中的各组分降解转化形成相应的单体。通过水热处理可以增值回收得到氨基酸、蛋白质和单糖等物质以及生物原油等可以在化学工业再利用物质。而该工艺具有以下特点：免除了其他处理技术中需要烘干等高成本工艺,并可以多元化利用处理得到的产物。(2)通过响应面分析了不同添加水含量对水热资源化利用生物质的影响。试验表明,水热过程中的水分添加量对水热资源化转化过程具有重要的影响。而当生物质的水分含量达到85%以上,则可以采用不添加水的水热处理工艺直接进行处理。(3)选取了不同来源的三种生物质废弃物：蔬菜废弃物、水生生物质以及水生生物质和花鸟市场的花枝废弃物的两组分混合生物质原料作为高含水量木质纤维类生物质的模型物,研究其在423-553 K处理温度和0-60 min处理停留时间内的水热转化效果。实验结果表明：在所设置的处理温度和处理停留时间内,三种生物质材料发生不同程度降解转化。木质纤维素类生物质中的主要组分纤维素和半纤维素均发生降解转化,而且它们的降解量随着处理温度的升高和处理停留时间的增加而增加。由于水热体系中存有再浓缩现象,故在没有酸碱等催化剂存在的情况下,于本试验设置温度范围内是无法完全降解生物质材料中的纤维素和半纤维素组分的。相比之下,木质素在水热体系降解转化所需的温度更高,本试验中,只在553 K温度和较长的处理时间下才表现降解现象。此外,通过固体产物的资源化分析表明,由于固体产物中具有较高含量的腐殖酸类物质和氮磷钾等养分含量,可以作为有机肥料施用于土壤改造和地力提升等工程。而残留在固体产物中少量纤维组分有利于进一步提升固体产物作为有机肥料的品质。处理温度和处理停留时间对资源化回收蛋白质、氨基酸和单糖及生物原油等影响不同,故在实际操作中应当针对具体的目的物质,进行具体参数设置。在多元化探讨水热降解产物利用的研究表明,水热处理得到的液体产物还具有较强的抗氧化性和一定的抑菌性,在提取这些抗氧化性物质和抑菌性物质后,可用于相关行业的药品制备,并为高产值资源化利用液体产物提供了新的途径。(4)通过动力学试验分析比较了常规热解和水热处理高含水量生物质的降解转化过程。结果表明：水热处理可以在较低温度下对纤维素等组分进行降解转化。水热体系中,生物质在473-553 K处理温度范围内的计算得到的表观活化能为90 KJ/mol,要明显低于常规热解条件下于相同温度区间内计算得到的活化能值130～116 KJ/mol,这也表明了在较低处理温度下,水热技术更合适于木质纤维类生物质的降解及在利用转化。更多还原

【Abstract】 With the continuous consumption of various resources, the large amounts and renewable biomass resources are gaining public attention and regarded as the potential energy of the future material and resource material. General speaking, fresh biomass material has a higher water content, especially as the focus of future biomass utilization of aquatic biomass, among which the water content is much greater. The inherently high moisture content of biomass is the disadvantage for many treatment processed, because prior drying bring about high operating costs. Thus, water content is one of the important limiting factors that affect the treatment process of biomass. Therefore, this dissertation work is carried out encompassed resource re-utilization technology of the high water content biomass, and aimes at supporting the commercial re-utilization of high water content biomass. Via experiment and analysis, the following conclusions were obtained:(1) Hydrothermal treatment attracts many interest for its effectively, environmental benign on organic matter treatment. Considering the characteristics of hydrothermal treatment, which inducing decomposition in the water, and the higher water content in fresh biomass, we proposed to treat those biomass by using hydrothermal process, in which the high moisture content could be used advantageously to produce commercially viable valued-added matters without prior drying or other expensive chemicals. A prep-experiment that the high moisture biomass was hydrothermally treated directly without adding a external water, which was different from prior hydrothermal process, was carried out. The results showed that this process can degrade the biomass into its corresponding monomer. After hydrothermal decomposition of the biomass, value-added matters like amino acids, proteins, disaccharides and bio-crude could be recovered through the liquid product.(2) Effects of different watenfeed ratio on the hydrothermal conversion of biomass into resource were tested by response surface experiment. The results showed that the adding water amount during hydrothermal process had great effect on the value-added matters recovery and the biomass hydrothermal decomposition, and too low adding water amounts had a disadvantage effect on the biomass decomposition. As for the hydrothermal process without adding external water, it was recommended that higher than 85% moisture content is appropriate for directly hydrothermal conversion of the high moisture content of biomass.(3) Vegetable waste, aquatic biomass and two component mixture of waste biomass materials (aquatic biomass and bird market squid material) were selected as three different sources of high moisture content biomass waste model. These three biomass were hydrothermal treated under the 423-553 K of reaction temperature and reaction residence time of 0-60 min to view hydrothermal treatment effects. The results show that:in the set processing temperature and reaction residence time, all the three kinds of biomass materials could happen degradation reaction. The main components of cellulose and hemicellulose in lignocellulosic biomass could be split into their units successfully, and the amount of hemicellulose and cellulose decomposition was increased with the elevated reaction temperature and reaction retention time as set in this experiment, so did the amount of solid product. However, because there is existed a phenomenon of re-concentrated during hydrothermal process, it was very different to completely decompose the cellulose and hemicellulose components in the biomass without the presence of a catalyst such as acid and alkali, especially in subcritical water condition. The conversion of lignin in hydrothermal process usually needed a higher temperature, and in this experiment, only in the 553 K of reaction temperature with a longer retention time, the lignin appeared degradation phenomena. Thus, there still existed certain amounts of fiber in solid product. These residue lignocelluloses could benefit solid product, which contain a certain amounts of humus and nutrient fertilizer like N, P, K and other mineral nutrients, to re-use as a organic fertilizer to increase soil fertilizer via increasing the soil carbon content and buffering power of the soil. Moreover, reaction temperature and retention time had a great effect on the resource recovery of protein, amino acids and simple sugars from the biomass and constituents of the bio-crude oil. thus in practice, it was very important to set the hydrothermal condition according to the matter recycling targets. In addition, strong antioxidant and antimicrobial activity of liquid product obtained after hydrothermal treatment was also provided a new way to value-added re-utilization of the product in medicine and health products industries.(4) Kinetic experiments of pyrolytic and hydrothermal decomposition of lignocellulose were carried out to analyze and compare the biomass conversion process during the two thermo chemical treatment. The results showed that:a lower reaction temperature was needed for the lignocellulose biomass decomposition in hydrothermal treatment than that of the pyrolysis treatment. In the temperature range of 473-553 K, the calculated apparent activation energy 90 KJ/mol for hydrothermal treatment, significantly lower than the apparent activation energy of 130-116 KJ/mol calculated in the same temperature range of conventional pyrolysis, which also shows that at lower reaction temperature, hydrothermal technology was more appropriate to decompose the lignocellulosic biomass for re-utilization.更多还原