Hydraulic and thermal calculation model of supercritical CO2 steady-state transportation
Author of the article:PENG Shiyao1, JIA Qiyun2, LI Qifu1, LU Jianxin2, XIE Naiya2, WANG Wuchang2, QIAN Haonan2, LIU Luoqi1, HU Qihui2
Author's Workplace:1. PipeChina Research Institute of Science and Technology, Tianjin, 300457, China; 2. College of Pipeline and Civil Engineering, China University of Petroleum (East China)// Shandong Key Laboratory of Oil & Gas Storage and Transportation Safety, Shandong, Qingdao, 266580, China
Key Words: Supercritical CO2 pipeline; Steady state; Hydraulic and thermal; Numerical simulation
Abstract:
Supercritical
CO2 pipeline transportation is an important link in Carbon Capture, Utilization
and Storage(CCUS). Given the significant differences in hydraulic and thermal
characteristics between supercritical CO2 and its gaseous and liquid states, it
is necessary to develop a hydraulic and thermal calculation model tailored for
supercritical CO2 in order to meet the process design requirements of the
actual CO2 pipeline. This model aims to satisfy the process design requirements
of actual CO2 pipeline and provide theoretical support for the selection of
design parameters and optimization of pipeline scheme. In this study, we have
developed a model based on the three conservation equations for the steady-state operation of the pipeline, which take into
account elevation differences. Drawing upon phase equilibrium experiments, we
selected an appropriate equation of state to calculate the physical property
parameters for both pure and impurity-laden CO2.
The numerical solution was obtained using the fourth-order Runge-Kutta
method, with an adaptive step size control implemented in C++ to accurately
capture the effects of elevation changes. The accuracy of the model was
rigorously verified through experimental validation and by comparing its
predictions with those of the OLGA software, confirming its high precision.
Utilizing the established model, we investigated the effects of impurity
content and types on the pressure drop and temperature drop during the steady-state transportation process of CO2 pipelines.
Findings revealed that among the seven components tested—O2,
N2, H2O, CO, Ar, H2, and CH4—the presence of impurities
generally followed the same trend in affecting temperature drop data, with
negligible impact observed. Notably, the H2O component was found to reduce
pressure drop, whereas the remaining six impurities were shown to increase it
to varying degrees. The influence of these impurities on pressure drop was
ranked as follows:H2>CO>N2>CH4>O2>Ar. In conclusion, the study
underscores the critical role of considering elevation differences in the
steadystate
transportation calculations for supercritical CO2 pipelines. Additionally,
attention should also be paid to the effects of impurity components on
temperature and pressure.