甲醇专用状态方程的研究

A Helmholtz Equation of State for Methanol

本文在广泛搜集现有文献中甲醇各项热物性实验数据的基础上,开发出以Helmholtz自由能为显式、以温度密度为自变量的新的甲醇状态方程。该方程可适用于温度在176~710 K,压力不高于5000 MPa,密度不大于70 mol/I的区间。方程计算饱和液密度的不确定度在430 K以下为0.4%,430 K以上为0.6%。方程计算密度的不确定度在压0.1MPa以下区域为1%,100 MPa以上区域为3%,0.1 MPa与100 MPa之间为5%,而靠近临界点处达到10%。力程计算饱和蒸汽压的不确定度为2%。经分析,方程趋势合理,这表明方程在极高或极低的温度和压力下具有合理的外推性。

The equation of state for methanol is developed based on the experimental data in literature using the Helmholtz energy as the fundamental property with independent variables of density and temperature.The equation of state could be used in the temperature range of 176~710 K with the pressures up to 5000 MPa and the density less than 70 mol/L.The uncertainty in saturated liquid density is 0.4%under 430 K and increases to 0.6%above 430 K.The uncertainties in density are 1%in liquid region under 0.1 MPa,3%above 100 MPa and 5%in the range between 0.1 MPa and100 MPa.The uncertainty of equation of state is 2%when calculate the saturated vapor pressure.The behavior of the equation of state is reasonable within the region of validity and at higher and lower temperatures and pressures.