共查询到20条相似文献,搜索用时 93 毫秒
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在集热型或温室一集热混合型干燥装置中加入贮热单元便构成贮热型太阳能谷物干燥装置。图1是一种强迫循环组合式贮热型太阳能谷物干燥装置,它采用石头作为贮热元件。白天日光充足时,打开阀门8,关闭阀门9,风机将集热器中的空气吹入干燥室,同时通过集热器底部的孔板将热传到放有石头的贮热室, 相似文献
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影响微波干燥各因素的分析及实验研究 总被引:5,自引:0,他引:5
影响微波干燥各因素的分析及实验研究范红途,刘雅琴江苏省南京市节能技术服务中心,东南大学一、前言微波用于干燥是自本世纪60年代开始的一种新的干燥方式,它具有穿透性强、选择性吸收、势惯性小、便于控制的优点以外,还具有杀菌作用,并且干燥速率要比纯对流干燥速... 相似文献
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一谷物太阳能干燥 1 贮热型太阳能谷物干燥 在集热型或温室-集热混合型干燥装置中加入贮热单元便构成贮热型太阳能谷物干燥装置.图1是一种强迫循环组合式贮热型太阳能谷物干燥装置,它采用石头作为贮热元件.白天日光充足时,打开阀门8,关闭阀门9,风机将集热器中的空气吹入干燥室,同时通过集热器底部的孔板将热传到放有石头的贮热室,对石头进行加热,蓄积多余的太阳能. 相似文献
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干燥转轮除湿器的新数学模型与RDCS程序 总被引:4,自引:2,他引:4
发展了干燥转轮除湿器的数学模型。控制方程中除考虑周向对流项{平和上士及非定常项上L和运二外,还增加了吸附剂中的热扩散项\共和外关及质量扩散项于共和才知。新编RDCS程序,采用松驰迭代法求解离散方程组。空间差分涉及对流和扩散两种不同的传热、传质形式,对流项采用一阶迎风差分格式,扩散项采用中心差分格式。时间差分可根据需要采用显格式、全隐格式或其它半隐格式。将RDCS与国外除湿器的数值计算结果和为数不多的实验数据作了比较。结果表明,RDCS的精度更高,适用范围更广。新建立的数学模型能更全面地反映干燥转轮中经历的传热、传质过程的物理本质。 相似文献
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一般地,煤收到基的全水分M,应该高于空气干基水分Msd。然而,由于煤全水分的国家标准分析方法不够完善。造成部分煤化较高的年老煤出现全水分Mi低于空气干燥基水分Mad的相反结果;进而,将引出一系列的诸如发热量、工业分析、元素分析结果各种基换算的反常的错误结果,为此,本文进行了简单的原因分析,并提出了妥善解决该问题的办法。 相似文献
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热泵粮食种子干燥装置研制 总被引:1,自引:0,他引:1
谷物种子的干燥处理一种是自然通风干燥.摊晒法:另一件是人工烘干处理.即热风干燥法。这里介绍一种与常现热风干燥不同的热泵除湿干燥法.它的优点主要是保证谷种的干燥质量和节约能源。本文取材于1994年1月热泵粮食种子干燥装置研制的鉴定文件.它总结了该装置研制、设计的过程和主要技术参数。 相似文献
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该在现有除氧器动态数学模型的基础上考虑除氧器汽侧空间,抽汽管道泡空间,及连续排污扩容器来汽量,除氧器储水量及除氧器热惯性可变等因素,建立更为完善的除氧器动态数学模型和动态压力降的计算方法,并编制了电算程序,该程序能够进行多工况,多因素模拟计算。 相似文献
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简要介绍了喷雾流化干燥系统,并用计算费用法对其进行了优化设计,通过比较发现优化设计能够降低能耗、运行费用及系统的总投资。 相似文献
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A mathematical model is presented that can be used to study the heat and mass transfer mechanisms that determine the dynamic behavior of the primary and secondary drying stages of spray freeze drying (freeze drying of particle based materials) in trays and in vials on trays. Simulation results indicate that particle based materials require longer primary drying times than solution based materials (conventional freeze drying) due to (a) reductions in the heat and mass transfer capabilities of particle based materials, and (b) the development of a secondary porous dried layer near the surface of the lower heating plate during the primary drying stage of the spray freeze drying process. The results of spray freeze drying for the systems studied in this work indicate that the drying rate during the primary drying stage increases as (i) the product height decreases, (ii) the particle diameter increases, and (iii) the value of the packing porosity increases. The mathematical model presented in this work is considered to offer a necessary and essential capability that could be used for the design, optimization, and control of the spray freeze drying process as well as of a process involving the drying of frozen particles in packed beds. 相似文献
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Narges Banaeian 《Energy》2011,36(8):5394-5402
The aims of this study are determining the energy use, qualitative analyzing of energy flow and also investigating energy efficiency by Data Envelopment Analysis (DEA) in corn production of Iran during a seven years period. Results indicated that the average of total energy input increased from 40.98 GJ ha−1 in 2001 to 63.64 GJ ha−1 in the year of 2007. Similarly, the average of total output energy rose from 89.03 to 107.54 GJ ha−1 in the same years, respectively. Also the results showed that average energy use efficiency, energy productivity, specific energy and net energy gain in the studied period was 2.59, 0.17 kg MJ−1, 7.24 MJ kg−1 and 51.34 GJ ha−1, respectively. DEA considered the yield (kg ha−1) as output and three major energy inputs; fertilizers, diesel fuel and machinery as input of 10 provinces in each year. Findings revealed that average energy efficiency score was 90.26%. There is impermanent trend in growth of energy efficiency in corn production of Iran, which needed to further analysis in future studies to realize relevant fluctuations in corn farming. 相似文献
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玉米秸秆预处理对厌氧发酵制氢影响的研究 总被引:3,自引:0,他引:3
为提高玉米秸秆的产氢能力,实验研究了蒸汽爆破预处理、硫酸预处理、氢氧化钠预处理、盐酸预处理和酸化(碱化)气爆预处理5种预处理方法对玉米秸秆发酵产氢能力的影响。结果表明,预处理可以将秸秆中相当一部分纤维素和半纤维素水解生成还原糖,其中质量分数为0.8%的H2SO4酸化汽爆预处理对秸秆的水解效果最好。在固-液比1∶10、H2SO4质量分数0.8%、保持微沸状态30min的处理条件下,秸秆的糖含量达到最大值24.57%,最大氢气产量为141mL/g。 相似文献
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H.Stephen LeeWallace W. Carr Haskell W. BeckhamJohannes Leisen 《International Journal of Heat and Mass Transfer》2002,45(2):357-366
A transient two-dimensional mathematical model is developed to simulate the through-air drying process for tufted textile materials. The heat and mass transfer in a cylindrical porous medium and the air flowing around it are analyzed separately. First, thermal and mass circuits are used to analyze the simultaneous heat and mass transfer within the porous medium. Then, the equations of the conservation of mass and energy are written for the drying medium. The resulting system of three non-linear differential equations is numerically solved by an implicit finite difference method. The numerical solutions are compared with experimental drying results obtained using magnetic resonance imaging (MRI) and a laboratory through-air dryer (LTAD). 相似文献