### Abstract

Knowledge of hydrogen solubility in tall oil fractions is
important for designing hydrotreatment processes of these
complex nonedible biobased materials. Unfortunately
measurements of hydrogen solubility into these fractions
are missing in the literature. This work reports hydrogen
solubility measured in four tall oil fractions between
373 and 597 K and at pressures from 5 to 10 MPa. Three of
the fractions were distilled tall oil fractions their
resin acids contents are respectively 2, 20 and 23 in
mass-%. Additionally one fraction was a crude tall oil
(CTO) sample containing sterols as the main neutral
fraction. Measurements were performed using a continuous
flow synthetic isothermal and isobaric method based on
the visual observation of the bubble point. Composition
of the flow was changed step-wise for the bubble point
composition determination. We assume that the tall oil
fractions did not react during measurements, based on the
composition analysis performed before and after the
measurements. Additionally the densities of the fractions
were measured at atmospheric pressure from 293.15 to
323.15 K. A Henry's law model was developed for the
distilled tall oil fractions describing the solubility
with an absolute average deviation of 2.1%. Inputs of the
solubility model are temperature, total pressure and the
density of the oil at 323.15 K. The solubility of
hydrogen in the CTO sample can be described with the
developed model with an absolute average deviation of
3.4%. The solubility of hydrogen increases both with
increasing pressure and/or increasing temperature. The
more dense fractions of the tall oil exhibit lower
hydrogen solubility in comparison to the less dense
fractions. The increase in the density of a fraction
corresponds to an increased resin acid and sterol content
of the sample. Sterols and resin acids exhibit lower
hydrogen solubility in comparison to fatty acids.

Original language | English |
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Pages (from-to) | 15-20 |

Number of pages | 6 |

Journal | The Journal of Chemical Thermodynamics |

Volume | 105 |

DOIs | |

Publication status | Published - 1 Feb 2017 |

MoE publication type | A1 Journal article-refereed |

### Keywords

- fatty acid
- hydrogen solubility
- measurement
- resin acid
- tall oil
- Measurement

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## Cite this

Uusi-Kyyny, P., Pakkanen, M., Linnekoski, J., & Alopaeus, V. (2017). Hydrogen solubility measurements of analyzed tall oil fractions and a solubility model.

*The Journal of Chemical Thermodynamics*,*105*, 15-20. https://doi.org/10.1016/j.jct.2016.10.008