高温高压下异丙醇-水汽液平衡的计算

Calculation of VLE equilibria of isopropanol-water system at high temperature and high pressure

为提高高温高压条件下异丙醇-水汽液平衡计算精度,汽相采用PRSV方程,液相采用NRTL方程,对方程参数进行拟合。经数据拟合得到异丙醇和水PRSV方程的特性Kappa值为0.238和-0.064 1,二元相互作用参数k12和k21分别为-0.072 4和-0.151 8。以Kelvin为单位时,5参数NRTL方程参数A12、B12、A21、B21和α分别为-1.666 4、800.692、1.052 43、515.751和0.511 9。按以上方程及参数,可以准确计算常压到2.0 MPa或82℃到200℃异丙醇-水体系相平衡。

PRSV and NRTL equations are applied in vapor and liquid phase calculations. Equation parameters are regressed from VLE data to increase phase equilibrium prediction precision. PRSV equation characteristic parameters （kappa） for isopropanol and water are 0.238 and -0.064 1, binary parameters, k12 and k21, are -0.072 4 and -0.151 8 respectively. The five NRTL equation parameters, A^e, B12 ,A21. B21 and a,, for isopropanol-water system are -1.666 4, 800.692, 1.052 43, 515.751 and 0.511 9 ,respectively. The unit for B12 and B21 is Kelvin. Isopropanol-water VLE phase equilibrium between atmosphere and 2.0 MPa or between 82 ℃ and 200℃ can be accurately calculated by NRTL equation with the above parameters when vapor non-ideality is treated with proper equations.