Phase Equilibria of Pyrolysis Oil Components and Distillation of Pyrolysis Oil Containing Styrene

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Journal Title
Journal ISSN
Volume Title
School of Chemical Technology | Doctoral thesis (article-based) | Defence date: 2023-10-20
Date
2023
Major/Subject
Mcode
Degree programme
Language
en
Pages
72 + app. 73
Series
Aalto University publication series DOCTORAL THESES, 153/2023
Abstract
  This thesis focuses on vapor-liquid and liquid-liquid-(liquid) equilibrium measurements of a few selected model components of pyrolysis oil and their mixtures. The vapor-liquid equilibrium of phenol – dodecane/hexadecane systems was measured at temperatures 523 – 573 K. Similarly, the vapor-liquid equilibrium of styrene – toluene/alpha-methylstyrene systems was measured at lower pressure range of 20 – 40 kPa. In this study, the phenol – dodecane system showed azeotropic behavior at the temperature range of 393 – 573 K. The ideal behavior of styrene – toluene/alpha-methylstyrene systems was observed at the pressure range of 20 – 40 kPa as the calculated activity coefficients were very close to unity. The applied thermodynamic models Peng-Robinson (PR), Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) and Non-Random Two-Liquid–Redlich-Kwong (NRTL-RK) correlated very well with the experimental data. The model parameters were also regressed from the experimental data. The liquid-liquid equilibrium of binary and ternary systems of water – phenol – dodecane/hexadecane were measured with the analytical and the cloud point detection methods at 298 – 353 K. The two and three liquid phases were studied for the ternary systems. The Non-Random Two-Liquid (NRTL) activity coefficient model described the phase behavior very well. The results from the three-liquid phase decanter model were comparable with the experimental three-liquid phase data. Further, the purification of polystyrene pyrolysis oil to a pure styrene monomer was carried out by employing a batch distillation unit at 99 mbar condenser pressure. It was important to perform the batch distillations at lower pressures to minimize the risk of polymerization in the distillation column. Five batches of distillate fractions were obtained. The purity of the styrene monomer in the distillate fraction was 99.94 wt.%. This grade of styrene monomer was suitable for further polymerization and subsequent production of latex or other polymers. The experimental distillation and the proposed continuous distillation model show a possibility of scale-up of the process where styrene monomer can be obtained with a high purity.
Description
Supervising professor
Alopaeus, Ville, Prof., Aalto University, Department of Chemical and Metallurgical Engineering, Finland
Thesis advisor
Uusi-Kyyny, Petri, Dr., Aalto University, Finland
Pokki, Juha-Pekka, Dr., Aalto University, Finland
Keywords
phenol, hydrocarbons, two-liquid phases, three-liquid phases, spline fit, decanter model, polystyrene pyrolysis oil, ideal system, batch distillation, short-path distillation, styrene monomer
Other note
Parts
  • [Publication 1]: Dahal, Roshi; Uusi-Kyyny, Petri; Pokki, Juha-Pekka; Alopaeus, Ville. Vapor-liquid equilibrium for the n-dodecane + phenol and n-hexadecane +phenol systems at 523 K and 573 K. Fluid Phase Equilibria, volume 537, 2021, issue 112991. ISSN: 0378-3812.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202103312646
    DOI: 10.1016/j.fluid.2021.112991 View at publisher
  • [Publication 2]: Dahal, Roshi; Uusi-Kyyny, Petri; Pokki, Juha-Pekka; Alopaeus, Ville. Liquid-liquid equilibria in binary and ternary systems of phenol + ydrocarbons (n-dodecane or n-hexadecane) and water + phenol + hydrocabons (n-dodecane or n-hexadecane) at temperatures between 298 K and 353 K. Fluid Phase Equilibria, volume 556, 2022, issue 113402.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202202161897
    DOI: 10.1016/j.fluid.2022.113402 View at publisher
  • [Publication 3]: Dahal, Roshi; Uusi-Kyyny, Petri; Pokki, Juha-Pekka; Alopaeus, Ville. Isobaric Vapor-Liquid Equilibrium of the Binary Mixtures Toluene + Styrene and Styrene + α–Methylstyrene. Journal of Chemical Engineering Data, volume 68(3), 2023, pages 654-663.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202303292637
    DOI: 10.1021/acs.jced.2c00662 View at publisher
  • [Publication 4]: Dahal, Roshi; Uusi-Kyyny, Petri; Pokki, Juha-Pekka; Ohra-aho, Taina; Alopaeus, Ville. Conceptual design of a distillation process for the separation of styrene monomer from polystyrene pyrolysis oil: experiment and simulation. Chemical Engineering Research and Design, volume 195, 2023, pages 65-75.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202308014566
    DOI: 10.1016/j.cherd.2023.05.039 View at publisher
Citation