基于毛竹废弃物的成型燃料制备及水热炭特性研究
发布时间：2018-11-11 17:37
【摘要】：本论文以资源广泛,燃烧清洁的毛竹废弃物为原料,采用正交实验优化热压成型工艺,制备优质毛竹成型颗粒燃料;采用水热炭化技术制备优质毛竹水热炭燃料,基于无模式函数多重扫描速率法,研究了毛竹及水热炭燃烧特性及动力学;同时为探索毛竹水热炭化原理,以模化物微晶纤维素为原料,探究pH值对生物质水热炭化的影响规律。(1)采用热压成型工艺制备毛竹成型颗粒燃料,研究了粒径、含水率、预热温度、成型压力对毛竹成型颗粒燃料的影响,并以松弛密度、耐久度为指标,在单因素实验基础上,采用正交试验对毛竹成型颗粒燃料制备工艺参数进行了优化。结果表明:当粒径小于0.38 mm,含水率为15%,预热温度为125℃,成型压力为20 MPa时,成型效果最好,此时成型颗粒的松弛密度为1.110 g/cm3,耐久性为0.955,可达到欧美国家成型颗粒燃料的标准。该工艺的优化设计为毛竹废弃物制备成型颗粒燃料工艺参数的选择提供了参考。(2)对毛竹进行水热炭化处理制备水热炭,对毛竹原料及其水热炭进行燃烧实验,采用升温速率为10、20、40 K/min,基于无模式函数多重扫描速率法(FWO、KAS、FR法),研究了毛竹及水热炭燃烧特性及动力学。结果表明:升温速率提高,样品挥发分燃烧和固定碳燃烧阶段均向高温区转移,着火性能下降,燃尽温度提高;水热炭较原料挥发分含量降低,固定碳含量升高;水热温度越高,热值越大,能量产率越低,水热温度为260℃,水热时间为30 min的水热炭燃料燃料性能最佳。FWO、KAS法活化能结果相近,FWO法模型最优。采用大于230℃水热温度制备的燃料,燃烧时反应能力增强,反应速率增大。(3)为初步探索毛竹水热炭化原理,以生物质模化物微晶纤维素为原料,以柠檬酸、碳酸氢钠和氢氧化钠配置pH值为3.0、4.0、5.0、6.0、7.0、8.0、9.0、10.0、11.0的溶液,在温度220℃,时间4 h条件下研究反应溶液pH值对微晶纤维素水热炭化的影响规律。通过元素分析分析了pH值对水热炭理化特性的影响,并结合范式图综合分析pH值对微晶纤维素水热炭化反应进程的影响,利用扫描电子显微镜观察水热炭表观形貌。结果表明:水热炭产率和固碳率随酸性的增强而减弱,pH为3.0时,产率及固碳率最小,分别为35.5%、41.82%,热值达到最大,为19.11 MJ/kg,pH为3时制备的水热炭的芳香性最好,pH为11时制备的水热炭的亲水性最强,碱性和中性水热炭芳香性、亲水性相似,不同pH条件的炭化进程均以脱水反应为主;扫描电镜结果显示酸性水热炭炭微球粒径随酸性增强而逐渐变小,纤维素在碱性条件下炭微球粒径均匀度较好。
[Abstract]:In this paper, high-quality bamboo pellet fuel was prepared by optimizing hot pressing process by orthogonal experiment, which was made from bamboo wastes with extensive resources and clean combustion. Hydrothermal carbonization technology was used to prepare high quality bamboo hydrothermal carbon fuel. The combustion characteristics and kinetics of Phyllostachys pubescens and hydrothermal carbon were studied based on the modeless function multiple scanning rate method. At the same time, in order to explore the principle of hydrothermal carbonization of Phyllostachys pubescens, the effect of pH value on biomass hydrothermal carbonization was studied by using microcrystalline cellulose as raw material. (1) the particle size and moisture content of bamboo pellet fuel were prepared by hot pressing molding process. The influence of preheating temperature and forming pressure on the pellet fuel of bamboo molding was studied. Based on the single factor experiment, the parameters of preparation technology of bamboo pellet fuel were optimized by orthogonal test, taking the relaxation density and endurance as the index. The results show that when the particle size is less than 0.38 mm, the moisture content is 15%, the preheating temperature is 125 鈩，
本文编号：2325632
[Abstract]:In this paper, high-quality bamboo pellet fuel was prepared by optimizing hot pressing process by orthogonal experiment, which was made from bamboo wastes with extensive resources and clean combustion. Hydrothermal carbonization technology was used to prepare high quality bamboo hydrothermal carbon fuel. The combustion characteristics and kinetics of Phyllostachys pubescens and hydrothermal carbon were studied based on the modeless function multiple scanning rate method. At the same time, in order to explore the principle of hydrothermal carbonization of Phyllostachys pubescens, the effect of pH value on biomass hydrothermal carbonization was studied by using microcrystalline cellulose as raw material. (1) the particle size and moisture content of bamboo pellet fuel were prepared by hot pressing molding process. The influence of preheating temperature and forming pressure on the pellet fuel of bamboo molding was studied. Based on the single factor experiment, the parameters of preparation technology of bamboo pellet fuel were optimized by orthogonal test, taking the relaxation density and endurance as the index. The results show that when the particle size is less than 0.38 mm, the moisture content is 15%, the preheating temperature is 125 鈩，
本文编号：2325632
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