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本文针对文献资料提供的饱和水蒸汽性质参数的离散型数据,利用曲线拟合的原理和回归方法,进行了计算机多项式拟合,建立了饱和水蒸汽某些对应参数的计算方程,给出了相应的相对误差和标准误差。 相似文献
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本文作者通过多年的合成氨工作实践,总结出一个简单的计算公式,运用该公式可以迅速,准确地计算出合成转化气、变换气中水蒸汽含量。文中介绍了通用计算公式的推导过程,使用说明,并列举实例与传统计算方法进行对比、说明它的准确性。 相似文献
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饱和水蒸汽压是冷却塔热力计算的基础参数之一,国内普遍采用的纪利公式不适于计算低温(小于0℃)条件下的饱和水蒸汽压.通过对多种计算公式的系统比较和分析,推荐了一种具有高准确度的计算公式(IAPWS R14-08(2011)公式),弥补了纪利公式的不足,为提高冷却塔热力计算的准确性奠定基础. 相似文献
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本文比较了文献中给出的由压力计算水蒸汽饱和温度的反算公式的计算准确性,包括Antoine方程和4个经验公式。在各自标明的适用范围内,由压力计算了水蒸汽的饱和温度,与水蒸汽热力性质表的数据作了比较,分析了各公式计算偏差大小。在各自的适用范围内,Antoine方程具有最好的计算准确度,且形式简单,使用方便,最适合工程应用;而一些形式简单的纯经验性公式,计算准确度不高,价值不大。文中最后给推荐意见,以便工程计算使用。 相似文献
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以近似数学模型计算饱和水及饱和水蒸汽特性参数,一般情况下,其相对误差可达到10~(-5)~10~(-7)水平。 相似文献
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介绍了最新的水和水蒸汽的性质国标标准"IAPWS1997工业公式",在Excel表格环境下,根据此公式利用Visual Basic语言编写计算水和水蒸汽性质的计算公式。在PC电脑下,可使用Excel表格计算水和水蒸汽的性质,计算化工过程的蒸汽平衡等等。 相似文献
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依据Chapman导热理论关于液体导热系数与粘度的关系,结合由Eyring反应速率理论及NRTL方程导出的液体粘度关联式,得到一个计算液体混合物导热系数的新型方程。经对18个二元体系和4个三元体系、1个四元体系共1646个数据点的检验,结果较为满意,与文献值或实测值相比总的平均误差仅为0.394%。 相似文献
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A thermodynamic analysis of steam reforming of glycerol using the stoichiometric method has been performed. Since the aim of this work is to study product distribution and coke formation in equilibrium, two different models have been proposed: (a) CO as primary product and (b) CO2 as primary product. Moreover, substantial information regarding the behavior of the different reactions could be acquired. Product distribution at equilibrium has been investigated in a broad range of conditions: temperature (600–1200 K), water‐to‐glycerol feed molar ratio (0:1–10:1), and pressure (1–9 atm). Glycerol conversion results completely over the whole range of the mentioned conditions. Consequently, product distribution at equilibrium is determined by water gas shift (WGS) and methanation or methane steam reforming reactions. Finally, high temperatures and a high water‐to‐glycerol feed molar ratio favor hydrogen production and decrease both methane and coke. 相似文献
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We investigated the heat of formation (ΔfH) of polynitrocubanes using density functional theory B3LYP and HF methods with 6‐31G*, 6‐311+G**, and cc‐pVDZ basis sets. The results indicate that ΔfH firstly decreases (nitro number m=0–2) and then increases (m=4–8) with each additional nitro group being introduced to the cubane skeleton. ΔfH of octanitrocubane is predicted to be 808.08 kJ mol−1 at the B3LYP/6‐311+G** level. The Gibbs free energy of formation (ΔfG) increases by about 40–60 kJ mol−1 with each nitro group being added to the cubane when the substituent number is fewer than 4, then ΔfG increases by about 100–110 kJ mol−1 with each additional group being attached to the cubic skeleton. Both the detonation velocity and the pressure for polynitrocubanes increase as the number of substituents increases. Detonation velocity and pressure of octanitrocubane are substantially larger than the famous widely used explosive cyclotetramethylenetetranitramine (HMX). 相似文献
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用SRK方程与PR方程求算双组分混合气体热力学性质 总被引:1,自引:0,他引:1
流体热力学性质的计算是化工热力学中的一类重要计算,立方型方程经常用于这类计算中。SRK方程与PR方程是在RK方程基础上发展而来的,具有比RK方程更好的计算精度。但现有教材中没有给出PR方程和SRK方程的剩余焓、剩余熵的计算公式,缺失了流体热力学性质计算的系统性。本文通过立方型状态方程的一般形式推导出PR方程和SRK方程的剩余焓、剩余熵的计算公式,利用Excel电子表格计算双组分混合气体的热力学性质。计算过程简捷明了,利于学生更好地理解混合物热力学性质的计算过程。 相似文献
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Slobodan?P.??erbanovi? Ivona?R.?Grguri? Mirjana?Lj.?Kijev?anin Aleksandar?Z.?Tasi? Bojan?D.?Djordjevi?
A comparison of the performances of two different approaches of cubic equations of state models, based on a classical van
der Waals and mixing rules incorporating theG
E
equation, was carried out for correlation of Vapor-Liquid Equilibria (VLE), HE and C
P
E
data alone, and simultaneous correlation of VLE+HE, VLE+C
P
E
, HE +C
P
E
and VLE+HE +C
P
E
data for the diethers (1,4-dioxane or 1,3-dioxolane) with n-alkane systems. For all calculations the Peng-Robinson-Stryjek-Vera
cubic equation of state (PRSV CEOS) was used. A family of mixing rules for the PRSV CEOS based on the Modified van der Waals
one-fluid mixing rule (MvdW1) and two well-known CEOS/GE mixing rules (MHV1 and MHV2), was considered. The NRTL equation, as the GE model with linear or reciprocal temperature dependent parameters, was incorporated in the CEOS/GE models. The results obtained by the CEOS/GE models exhibit significant improvement in comparison to the MvdW1 models. 相似文献
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采用连续式蒸汽爆破装置对含水量分别为20%、30%、40%及50%的棉秆皮纤维进行预处理,并制备预处理后棉秆皮纤维填充量分别为20%、30%、40%及50%的聚丁二酸丁二醇酯(PBS)/棉秆皮纤维复合材料标准拉伸样条。从外观形态、扫描电镜观察方面分析棉秆皮纤维含水量对其蒸汽爆破改性效果的影响;通过扫描电镜观察分析复合材料拉伸断面形貌,从拉伸强度、拉伸模量及断裂伸长率三方面研究了连续式蒸汽爆破对PBS/棉秆皮纤维复合材料拉伸性能的影响。结果表明,连续式蒸汽爆破预处理方法能有效改善棉秆皮纤维与PBS基体的界面黏结;爆破前纤维含水量及爆破后纤维填充量对PBS/棉秆皮纤维复合材料拉伸性能起决定性作用;综合考虑,当爆破前纤维含水量为40%、爆破后纤维填充量为40%时,PBS/棉秆皮纤维复合材料拉伸性能最佳。 相似文献
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水蒸汽对四丙氟橡胶性能的影响 总被引:3,自引:0,他引:3
就四丙氟橡胶TP-2/DCP-TAIC体系做了耐280℃×480h水蒸汽实验,结果表明,其硫化胶的性能保持率较高,体积变化在60%~30%。 相似文献
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Steam reforming of methanol in fixed‐bed and hybrid reactors, namely, traditional fixed‐bed reactor (FBR1), fixed‐bed reactor with H2‐selective membrane (FBR2), and fixed‐bed reactor with CO2 adsorption (FBR3) is thermodynamically analyzed. The performance of these reactors is compared in terms of quality and quantity of H2 production for fuel cell application. In FBR2 and FBR3, the contents of undesired products CO, CH4, and carbon are highly reduced. 相似文献