Molecular Level Separation Model for Heavy Petroleum Supercritical Fluid
Extraction Process
Suoqi Zhao ([email protected])*†, Linzhou Zhang†, Zhen Hou‡, Triveni Billa‡,
Scott R Horton‡, Michael T Klein*‡, Zhiming Xu†, Quan Shi† Xuewen Sun and
Chunming Xu†
†
State Key Laboratory of Heavy Oil Processing, China University of Petroleum,
Beijing 102249, China
‡
Department of Chemical and Biomolecular Engineering and the Energy Institute
University of Delaware, Newark, Delaware 19716, United States
Abstract
The increasing content of heavy petroleum resource forms challenges for refineries
around the world. The upgrading of heavy petroleum is problematic due to its high
content of heteroatom species and metallic compounds. The removal of
contaminates will promote the processability of feedstock and quality of products.
During the last decade, supercritical fluid extraction (SFE) technology have been
developed to separate heavy petroleum into various fractions with distinct properties.
It facilitates the selective processing of different fraction to achieve maximum
utilization of the heavy petroleum resource.
The processability of the derived SFE fraction is determined by its property and
molecular composition. Understanding molecular composition variation with different
operation conditions (e.g., extracting pressure) is crucial for SFE technology
development. In previous work, we develop a quantitative molecular composition
model for heavy petroleum (Energy & Fuels, 2014, 28(3) 1736-1749). It covers
hydrocarbons and heteroatom species and the thermodynamic properties of each
molecule were calculated using group contribution method. Here, we report a
molecular level separation model for SFE process using composition model as input.
To reduce the model complexity, the separation process was calculated in terms of
limited number of thermodynamic pseudocomponents. A rigorous reversible lumping
method was developed to map the molecular composition to pseudocomponent
composition. The molecular level information is retained by the moleculepseudocomponent transformation. The heavy petroleum SFE process was modeled
and the molecular composition of derived fractions at different operating condition
was predicted.