共查询到20条相似文献,搜索用时 187 毫秒
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以生物质成型燃料炉为对象,分别燃用玉米秸秆和木质成型燃料,分析其不同点火方式下的点火过程和熄火过程中污染物(NOx,CO)的排放规律。试验结果表明:点火过程,NOx的平均排放量比稳态时的要低,而CO的平均排放量比稳态时的要高。冷炉点火过程,燃用玉米秸秆成型燃料,CO与NOx的质量比随排烟温度呈指数关系减小,燃用木质成型燃料,CO与NOx的质量比随排烟温度呈乘幂关系减小。采用热炉点火的方式,CO的排放量降低一半左右,对于不同的燃料减排NOx要采取不同的措施。熄火过程,NOx的平均排放量很低,而CO的平均排放量是稳态的4倍左右。 相似文献
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以活性污泥混合木屑为原料制备生物质燃料,考察成型压力、物料含水率和活性污泥占比对生物质燃料的抗破碎强度和松弛密度的影响,并研究生物质燃料的燃烧特性。研究结果表明:生物质燃料的抗破碎强度和松弛密度均随着成型压力和活性污泥占比的增大而增大,物料含水率控制在15%~20%较为合适;成型压力和物料含水率对生物质燃料的抗破碎强度有显著影响,而成型压力和活性污泥占比对生物质燃料的松弛密度有显著影响;活性污泥的燃烧过程可分为水分析出、挥发分燃烧及无机盐分解3个阶段,木屑的燃烧过程可分为水分析出、挥发分析出及剩余挥发分和固定碳燃烧3个阶段;生物质燃料的燃烧过程因活性污泥占比的多少而有所差异。生物质燃料的综合燃烧性能随着木屑占比的增加而逐渐提高,活性污泥的加入可以改善生物质燃料的着火性能,合理的活性污泥混合木屑工艺和配方能够制备出燃烧性能较好的生物质燃料。 相似文献
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分别采用冷压成型和炭化成型工艺以锯末制备生物质成型燃料。冷压成型工艺主要考察原料水分、成型压力对燃料的成型性能影响。试验结果表明:原料水分为12%~16%,成型压力为60 MPa的条件下能够制得成型性能较好的生物质成型燃料,其密度与抗跌强度分别能够达到0.94 g/cm3和99%;炭化成型工艺主要考察混合料水分、无烟煤配比、J型粘结剂添加量、成型压力对燃料的成型性能影响。试验结果表明:无烟煤配比为50%、混合料水分为30%、J型粘结剂添加量为8%、成型压力为45 MPa的条件下能够制得成型性能较好的优质生物质成型燃料,其密度与抗跌强度分别为0.93 g/cm3和99.3%。 相似文献
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Jianjun DaiJohn R. Grace 《Biomass & bioenergy》2011,35(2):942-955
Successful feeding is critical to biomass utilization processes, but difficult due to the heterogeneity, physical properties and moisture content of the particles. The objectives of the present study were to find the mechanisms of blockage in screw feeding and to determine the effects of particle mean size (0.5-15 mm), size distribution, shape, moisture content (10-60%), density and compressibility on biomass particle feeding at room temperature. Wood pellets, sawdust, hog fuel and wood shavings were tested in a screw feeder/lock hopper system previously employed to feed sawdust into a pilot-scale circulating fluidized-bed gasifier. Experimental results showed that large particles, wide size distributions, large bulk densities and high moisture contents generally led to larger torque requirements for screw feeding. The “choke section” and seal plug play important roles in determining the torque requirements. 相似文献
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《Biomass & bioenergy》1999,16(3):191-198
A pneumatic fuel feeding system for wood powder fired gas turbines was incorporated at the Vienna University of Technology. One of the most important requirements of fuel feeding is a very homogeneous mass flow of wood powder. Therefore, the performance of the mechanical conveying part of the feeding system has been studied experimentally at flow rates corresponding to the operation range. Beside screw feeding, a vibrator is used to homogenize the flow rate. While the screw feeder shows large fluctuations, the vibrator conveyer reduces them considerably. The tests also show that for each flow rate a certain optimum amplitude of the vibrator exists at which the fluctuations reach a minimum. Furthermore, a linear function is observed between optimum oscillation amplitude and feeding rate. 相似文献
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Although basic investigations on wood chip material properties haven been carried out, only few studies deal with transport of wood chips, despite the fact that significant problems are commonly observed when feeding biomass in industrial applications. Within the work presented, basic bulk material properties were measured and experiments carried out with a system consisting of a hopper, agitator and a screw conveyor. The aim of this study was to investigate how three different wood chip grades and two blends of wood chips influence typical design parameters, such as mass flow and driving torque, of a biomass feeding system. The measured basic bulk properties are in good overall agreement with the literature. However, discrepancies were discovered between two standardized methods for determination of the bulk density. The results for the driving torque, mass flow and mass-related energy consumption showed that different grades of wood chips can alter these values considerably. Between two wood chip grades, a twice as high torque was recorded, while a third grade could not be fed due to jamming. One of the major findings of this study is that mixing a rather small amount of a high-fine content grade with the non-feedable grade of wood chips resulted in a blend which inhibited jamming during the screw feeding process. 相似文献
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生物质成型燃烧成本较低,且经过致密成型后的生物质燃料密度和强度都得到提高,便于运输和燃烧.生物质致密成型技术按加热温度可以分为加热成型和常温高压成型两种.应用较多的成型燃料加工机有活塞冲压式、辊模挤压式、螺旋挤压式3种形式.很多发达国家早在20世纪初就已开始研究生物质成型技术,这些国家的成型设备专业化程度高,自动化程度好,热效率高,污染小,有合理的加工工艺.但由于设备价格高、耗电高、易结渣、原料产品单一,并不适合我国.我国在生物质成型方面的研究起步较晚,目前主要的生物质成型技术包括螺旋挤压技术、活塞冲压技术和辊模挤压成型技术,但与西方发达国家相比仍有较大差距.为了进一步促进我国生物质成型燃料的发展,建议国家应不断完善对生物质成型燃料研究及生产的扶持政策;生物质成型燃料装备不仅要考虑到节能,还应该与指定的原料基地相结合;加强生物质成型机理的研究,减少设备易损件的数量,降低能耗;开发研制以生物质成型物为原料的发电、供电一体化集成设备;在设备实用性、系列化上下功夫,不断降低成本,提高技术水平. 相似文献
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为了实现进口滚丝轮的国产化,对材料的化学成分进行了分析,初定4种材料进行产品试制,根据对滚丝轮加工工艺的分析,确定采用磨螺纹工艺,根据共轨喷油器体用螺纹滚丝轮牙型特点,设计3种螺纹圆顶牙型的加工方案,经比较分析,确定采用先将螺纹磨成平顶牙型,再用成型砂轮接磨R0.1 mm圆顶的方案,确定了加工工艺参数,设计了磨削R0.... 相似文献