共查询到19条相似文献,搜索用时 796 毫秒
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介绍了一种新型秸秆燃料成型机,阐述了其基本机械结构和工作原理.为了便于分析秸秆燃料压缩成型过程中秸秆碎料形变规律,将成型机工作区域动态地划分为供料区、压紧区、压实区、成型区和保型区等五个工作分区.从秸秆碎料宏观体积、微观组织变化以及秸秆碎料的形变情况,分别探讨了每个分区秸秆碎料的形变特点.成型机压辊对秸秆碎料的挤压力过小会降低成型燃料的品质,挤压力过大则会降低秸秆成型机的寿命.通过研究挤压力与秸秆燃料密度的关系,以控制压缩比为措施设计了新型秸秆成型机的挤压力控制方案. 相似文献
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玉米秸秆成型燃料是生物质能利用的主要方式,选取具有代表性的玉米秸秆成型燃料作为试验对象,运用场发射投射电子显微镜(JEM-2100F)对其微观结构进行观察,通过对图像进行分析,压缩后的成型燃料致密程度显著增加,减少的是原生物质的孔隙率,其组织结构变得纵横叠加,且层与层之间的空隙较小,连接物无明显界线,结合紧密,断面的形成有相互牵拉的迹象;通过计算分析,玉米秸秆致密成型燃料的相对孔隙率为22.8%,因此,在燃烧过程中应增加氧气的供应量与燃料强制混合.研究为成型燃料燃烧机理的研究提供实验依据,是成型燃料燃烧设备和加工设备设计的重要理论基础和设计依据. 相似文献
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利用层流炉研究玉米秸秆粉末的快速热解特性 总被引:11,自引:2,他引:11
为了研究闪速加热条件下生物质的热解挥发特性,设计了等离子体加热高温层流炉作为实验设备。由于该设备内部的流动特性对于实验结果影响巨大,为此特别设计了一套1:1比例的透明有机玻璃冷态模拟装置,用于观察层流炉的流动状态,为热态实验参数设计提供实践指导。根据冷态研究观察结果,进行了层流炉热态实验。采用灰分示踪法测定了玉米秸秆粉末在800,850,900,950K的热解失重曲线。通过数据处理得到了玉米秸秆粉末在快速加热条件下的热解动力学方程和参数。 相似文献
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生物质秸秆成型工艺的试验研究 总被引:2,自引:1,他引:1
以节能降耗、延长设备使用寿命为出发点,以玉米秸秆和小麦秸秆为原料,对生物质秸秆的不同成型工艺进行了系统的成型试验研究,并对各种成型工艺的能耗进行了分析.结果表明:热压成型的效果最佳,在条件允许的情况下应优先选择热压成型工艺. 相似文献
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为研究生物质平模成型机的攫取成型机理,将棉花秸秆原料压缩成颗粒,通过场发射扫描电子显微镜对生物质平模成型机的供料区、压紧区、压实区、成型区的原料及压辊磨损前后期成型颗粒的组织进行微观形貌观察研究,对比不同阶段物料的微观形态。结果表明:随着压辊转动,散乱的物料方向变化明显,物料间相互填充,空隙减小。压实区物料主要发生弹性与塑性变形,微观结构被破坏,纤维层与层之间紧密胶合,方向形态基本稳定,以有序的排列进入成型孔。颗粒密度通过成型孔进一步增大,颗粒间结合得更加紧密。压辊磨损后期的成型颗粒纵横方向性较前期的混乱,同时生产效率降低、成型密度减小。研究结果旨在为生物质平模成型机优化设计提供理论参考。 相似文献
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There are several benefits of using the supercritical fluid microcellular injection molding process. One of the benefits of microcellular injection molding is that the dimensional stability can be improved. In this study, the mechanical properties of the material Polyamide(PA) 66 (glass fiber (G. F.) 33% wt.) and the dimensional stability of a microcellular injection molded gear shaft were investigated. L9 experimental tests based on Taguchi's method were performed and a Tokyo TF 40 gear experiment machine was used to measure gear profile and to determine the optimal process conditions. The gear diameter of the gear shaft molded by conventional and microcellular injection molding were compared. The results showed that dimensional stability was improved by microcellular injection molding. The microstructure of cells at the weld-line and flow end is clearly observed from the micrographs. 相似文献
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Yung-Kang Shen Chih-Yuan Chang Yu-Sheng Shen Sung-Chih Hsu Ming-Wei Wu 《International Communications in Heat and Mass Transfer》2008
Micro-injection molding is the most important technology in MEMS/NEMS industry for the necessary of scale, velocity and cost by the development of MEMS/NEMS industry and the innovation of MEMS/NEMS industry. It has the advantage of low cost, low interface and small volume in MEMS/NEMS industry. This paper emphasizes the analysis for microstructure of microlens arrays on micro-injection molding. The finite element simulation in a three-dimensional inertia-free, incompressible flow is presented. A control volume scheme with a fixed finite element mesh is employed to predict melt front advancement. The plastic material of microlens arrays is used for PMMA material. The results show the short shot on the filling stage of micro-injection molding. The results also indicate that the melt front first advance into the thickness direction of microlens arrays, and then it goes into the microstructure of microlens arrays. 相似文献
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The combustion behavior of biomass and biomass–coal blends under typical heating conditions was investigated. Thermogravimetric analyses were performed on bituminite coal, aspen strawdust and wheat straw used alone and blended with different coal weight ratios. The behavior of biomass fuels in the burning process (different rates of volatilization, char burning and heat production) was analyzed, and the effects of a cold molding procedure for wheat straw on the burning properties were investigated. In addition, the kinetic parameters for the thermal conversion of each fuel were determined. Cold molding led to easier firing, and 5% coal was identified as the ideal ratio to achieve similar heat release characteristics to strawdust. Such a mixed pellet fuel with burning characteristics similar to aspen wood can be produced to take advantage of the wide design basis for wood-fired boilers. 相似文献
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使用自制的微波热重分析装置,对压缩打包后的小麦和玉米秸秆进行了微波热解试验,考察了微波辐射下秸秆的热解特性和影响因素.使用气相色谱对气体产物进行了定性定量分析,考察了气体的热值,并与常规热解得到的气体产物进行了比较.结果表明:秸秆的微波热解过程可以划分为干燥、预热解、挥发份大量析出和炭化等4个阶段,物料种类和微波功率对热解过程具有重要影响.热解气体产物中主要成分为氢气、一氧化碳、二氧化碳、甲烷等.较高的氢气含量预示着秸秆微波热解可以用来生产富氢燃气,研究结果为生物质微波热解的工业应用提供了基础性数据. 相似文献
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A polymer–graphite composite bipolar plate of direct methanol fuel cell (DMFC) was fabricated by a compression molding method. The electrical conductivity and electrochemical behavior of the composite material under DMFC operating conditions were evaluated. The results show that the composite bipolar plate has a good electrical conductivity. Moreover, the through-plane conductivity of the composite material is higher than the in-plane one, which is ascribed to the anisotropic property of the composite bipolar plate resulted from the compression molding process. Corrosion tests show that the stable current density is below 10 μA cm−2 under both anode and cathode conditions of DMFC. The discharge test of the DMFC single cell also presents a satisfactory result. 相似文献
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Agglomeration is a major problem in straw combustion in a fluidized bed. This paper presents the results of rice straw combustion experiments carried out under different operating conditions in a bubble-fluidized bed (BFB). The influences of bed material size and type, feeding mode, temperature, and fluidization number on agglomeration were discussed, and the mode of alkali accumulation in the bed was analyzed. The results indicated that low bed temperature, short fuel in-bed residence time, high fluidization number, and small bed material particles are conducive to agglomeration prevention. Successful extended combustion in a small BFB and in a bench-scale circulating fluidized bed was carried out without agglomeration under selected parameters. This work suggests the possibility for combusting high-alkali straw using fluidization technology. 相似文献