Vapor- liquid equilibrium for the n-dodecane + phenol and n-hexadecane + phenol systems at 523 K and 573 K

Roshi Dahal,Petri Uusi-Kyyny,Juha-Pekka Pokki,Ville Alopaeus

doi:10.1016/j.fluid.2021.112991

Abstract

A continuous flow apparatus was applied to measure the phase equilibrium at 523 K and 573 K. The performance of the apparatus was analysed with the determination of vapor pressures of water at the temperatures (T = 453 K and 473 K). The measured water vapor pressures deviated from the literature values less than 1 %. Vapor pressures of n-dodecane, n-hexadecane and phenol were measured at the temperatures (T = 523–623 K) and, the bubble point pressures of n-dodecane + phenol and n-hexadecane + phenol were measured at the temperatures (T = 523 K and 573 K). The measured vapor pressures of the pure components were compared with the literature values. Relative vapor pressure deviated from the literature value less than 2 % for all the measured vapor pressures. The measured vapor pressures value in this work agreed well with the literature, which indicates that the measurement apparatus and the method can produce good-quality data. The measured bubble point pressures for the n-dodecane + phenol and n-hexadecane + phenol systems were modeled with Peng-Robinson and Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equations of state and Non-random Two-liquid (NRTL) activity coefficient model. The measured systems were at first modeled with Peng-Robinson and Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equations of state without binary interaction parameters. Additionally, the parameters were regressed to optimize the performance of the models. The NRTL activity coefficient model described the behaviour of the measured and the literature data better than the equations of state. Furthermore, the Peng-Robinson equation of state resulted in better predictions than PC-SAFT equation of state even without binary interaction parameters regression. Both equations of state modeled the phase equilibrium behaviour of the system well. The n-dodecane + phenol system showed azeotropic behaviour.

Highlights

The increasing energy demand and negative environmental impacts due to the use of fossil fuels have directed modern society to search and adopt renewable and sustainable energy sources
Vapor pressures of pure components phenol, water, nhexadecane and dodecane were measured with the continuous flow apparatus
The measured vapor pressures of phenol, nhexadecane and n-dodecane were compared with the values calculated from the DIPPR 101 equation [16], Pi/Pa = exp A + B/(T/K ) + C ln(T/K ) + D(T/K )E

Summary

Introduction

The increasing energy demand and negative environmental impacts due to the use of fossil fuels have directed modern society to search and adopt renewable and sustainable energy sources. The use of biomass as a renewable source and its energy conversion via fast pyrolysis has already undergone scale-up [1]. Chemical recycling of waste plastics via pyrolysis has been an interest of study [2,3]. The increasing production of plastics and low recycling rates have led to increment of plastic wastes [3], which shows that there is considerable scope of improvement. Produced from petroleum by-products, plastic polymers are rich in hydrocarbons [4]. Pyrolysis of plastics results in hydrocarbon rich oil with excellent fuel properties [5].

Methods

Results

Conclusion