共查询到19条相似文献,搜索用时 281 毫秒
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基于生物质秸秆加料的困难,对生物质秸秆物料在加料斗内的流动行为进行研究.在储料量为100kg的加料斗试验装置上,结合出料量分析和可视化观察,系统研究了物料特性、料位高度、螺旋轴转速及运转方式等因素对物料流动行为及出料速率的影响.结果表明,物料堆积密度大、含湿量高、物料易在加料斗内"搭桥",从而影响出料质量;原始料位高度直接影响出料速率,在同样螺旋转速下,料位高,出料快;料位低,出料慢,相同料位高度则出料速率基本一致;随着螺旋转速的提高,起始出料速率明显增加,随后增加缓慢;螺旋轴的运转方向对物料的堆积和流动具有不同的影响,正转压紧物料,不利于出料,反转疏松物料,出料更顺畅均匀. 相似文献
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对目前许多钢厂RH加料系统中存在的加料时间长、称量精度差的问题进行了详细的分析,并结合国内钢厂RH的使用情况和工程设计经验,对改善以上问题提出了一些优化建议,为RH加料系统的设计及使用提供参考. 相似文献
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生物质电厂上料系统和给料系统是生物质能发电工程的重要组成部分,其系统因工艺复杂、转点较多、设备选型多样化、日常维护不到位等问题导致输送系统故障率较高,而长期安全稳定运行关系到生物质发电厂的经济效益.通过介绍国内4家生物质发电厂上料和给料系统工艺,对比分析各厂上料和给料系统工艺特点及存在的问题.针对上料和给料系统的设计与运行提出了建议,并给出了简化输送系统的工艺方案,以供生物质发电厂上料系统和给料系统设计与运行管理人员参考. 相似文献
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针对传统生物质墙体存在集热蓄热差的热工问题,提出一种以太阳能为热源的集成管道生物质蓄热墙体,通过建立对比实验模型,分别测试墙体系统及室内物理环境参数,研究2种模型存在的热效率差异,并对实验组墙体系统进行供热性能分析。结果表明:所提出的集成管道生物质墙体系统具有良好的集热、蓄热性能;管道流系统循环控制策略应适应当地气象条件以优化系统供热效率;集成管道生物质蓄热墙节能率可达79.3%,经济效益明显,在生物质能与太阳能富集地区具有广泛应用前景。 相似文献
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扬州石化35t/h链条锅炉由于存在着煤种变化频繁以及现有分层布煤机构设计缺陷,不能适应各煤种热值及颗粒度的变化,导致锅炉燃烧不充分。为此,对落煤料仓、分层给煤装置和垄形平煤给煤装置进行改造。改造后,锅炉落煤料仓给煤闸板两边卡堵大煤块的现象基本消除,下煤顺畅;改进后的筛分板,其炉排煤层分层效果突出。大小煤块分布清晰,煤层疏松,过风阻力小;垄形平煤给煤机构的改造,使分层后的煤层形成平整垄形,平整煤层,透风均匀,耗风量降低,燃烧所需过剩空气“系数控制在较低的水平;垄形煤层使煤层和空气接触面积增加。燃烧工况好.达到了半沸腾燃烧效果,火床短、火焰稳定,炉渣含碳量降低。改造前后的数据比较显示,改造取得了较好的经济效益,年节约燃料费用约45万元,链条炉排锅炉对煤种的适应性增强,热效率可提高3个百分点。 相似文献
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推导了烟气在管内流动、均匀受热管壁的壁温计算公式,分析得出,影响壁温的主要因素是烟气温度和表面传热系数。降低管壁温度的有效方法是降低烟气温度,即在受热面前的高温烟气中混入冷烟气或冷空气,对降低壁温的两种方法进行了比较。研究了热风炉计算中过量空气系数、再循环系数的确定方法及热风炉对风温变化的适应性。 相似文献
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Modeling on heat and mass transfer in stored wheat during forced cooling ventilation 总被引:6,自引:0,他引:6
A mathematical model based on the theory of heat and mass transfer in porous media was developed to simulate the evolution of grain temperature and moisture content in a wheat storage bin during ventilation with cooling air at the constant temperature and humidity. Unlike the previous works on this aspect, the present work was not focused on cooling the stored grain by ventilation with ambient air, but with the refrigerated air. Validation was performed by comparing between predicted and measured grain temperature and grain moisture content for two cases. Predicted data were in reasonable good agreement with measured ones. The model and the parameter values used in the model are applicable for predicting temperature and moisture of stored grains under ventilation conditions. 相似文献
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Effect of design and operating parameters on the gasification process of biomass in a downdraft fixed bed: An experimental study 总被引:2,自引:0,他引:2
The main objective of this paper is to study the effect of design and operating parameters, mainly reactor geometry, equivalence ratio and biomass feeding rate, on the performance of the gasification process of biomass in a three air stage continuous fixed bed downdraft reactor. The gasification of corn straw was carried out in the gasifier under atmospheric pressure, using air as gasifying agent. The results demonstrated that due to the three stage of air supply, a high and uniform temperature was achieved in the oxidation and reduction zones for better tar cracking. The designing of both the air supply system and rotating grate avoided bridging and channeling. The gas composition and tar yield were affected by the parameters including equivalence ratio (ER) and biomass feeding rate. When biomass feeding rate was 7.5 kg/h and ER was 0.25–0.27, the product gas of the gasifier attained a good condition with lower heating value (LHV) about 5400 kJ/m3 and cold gas efficiency about 65%. An increase in equivalence ratio led to higher temperature which in turn resulted in lower tar yield which was only 0.52 g/Nm3 at ER = 0.32. Increasing biomass feeding rate led to higher biomass consumption rate and process temperature. However, excessively high feeding rate was unbeneficial for biomass gasification cracking and reforming reactions, which led to a decrease in H2 and CO concentrations and an increase in tar yield. When ER was 0.27, with an increase of biomass feeding rate from 5.8 kg/h to 9.3 kg/h, the lower heating value decreased from 5455.5 kJ/Nm3 to 5253.2 kJ/Nm3 and tar yield increased from 0.82 g/Nm3 to 2.78 g/Nm3. 相似文献
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生物质中热值气化装置设计与运行 总被引:5,自引:2,他引:5
从富氧气化的原理和特点出发,根据空气化的结果,讨论说明中热值气化装置的设计依据和参数计算方法,在试验运行的基础上,分析采用富样气化的中热值气化装置的优缺点,通过分析和试验表明,采用90%的富氧气化具有较理想的效果,其气体热值在10-12MJ/m^3之间,气化效率在70%以上,单位燃气的耗电量约0.075kWh/Nm^3,具有较好的经济性和实用性。 相似文献