An integrated, multi-scale modelling approach for the simulation of multiphase dispersion from accidental CO2 pipeline releases in realistic terrain

Abstract

The deployment of a complete carbon capture and storage chain requires a focus upon the hazards posed by the operation of pipelines transporting carbon dioxide (CO 2 ) at high pressure in a dense-phase (supercritical or liquid state). The consequences of an intentional or accidental release from such pipelines must be considered as an integral part of the design process. There are a number of unique challenges to modelling these releases due to the unusual phase-transition behaviour of CO 2 . Additionally, few experimental observations of large-scale CO 2 releases have been made, and the physics and thermochemistry involved are not fully understood. This work provides an overview of elements of the EC FP7CO2PipeHaz project, whose overall aim is to address these important and pressing issues, and to develop and validate mathematical models for multiphase discharge and dispersion from CO 2 pipelines. These are demonstrated here upon a full-scale pipeline release scenario, in which dense-phase CO 2 is released from a full-bore 36-inch pipeline rupture into a crater, and the resulting multiphase CO 2 plume disperses over complex terrain, featuring hills and valleys. This demonstration case is specifically designed to illustrate the integration of different models for the pipeline outflow, near-field and far-field dispersion.

Experimental investigation of the impact of liquid carbon dioxide injection on temperature in pulverized coal

“…conducted a series of experimental studies on different phase states of CO 2 releases, and profoundly discussed the possible presence of phase state and concentration distribution in discharge area. In addition, much research into the numerical simulation of LCO 2 release has been conducted . However, the current results failed to achieve an acceptable agreement with experiment as the complicated thermodynamic conditions during the simulation.…”

“…In addition, much research into the numerical simulation of LCO 2 release has been conducted. [25][26][27] However, the current results failed to achieve an acceptable agreement with experiment as the complicated thermodynamic conditions during the simulation. No matter analyzing phase transition behavior of CO 2 or evaluating environmental temperature variations through experimental or simulated method, the above research is of insufficient significance for our study.…”

Multi‐phase decompression modeling of CO2 pipelines

“…8,26 It was suspected that the discrepancies were introduced by the thermal equilibrium assumption in HEM. 10,31,36,37 Brown et al 10,31 proposed a two-phase transient flow model using HRM for simulating the flow following failure of a high-pressure CO 2 pipeline. Some researchers have proposed a Homogenous Relaxation Model (HRM).…”

“…In a few recent publications, CO 2 depressurization or dispersion considering non-equilibrium phase transition have been presented. 10,31,36,37 Brown et al 10,31 proposed a two-phase transient flow model using HRM for simulating the flow following failure of a high-pressure CO 2 pipeline. A 'relaxation time' was introduced during phase change, which was empirically determined by Angielczyk et al 30 based on tests involving the steady-state flow of CO 2 through a nozzle.…”

Validation of turbulence closures for the RANS modelling of under-expanded fluid releases

“…The ratio of the reservoir to atmospheric pressure defines whether a jet is moderately under-expanded (1.1 to 2.1) or highly under-expanded (>2.1), the structures displayed in the releases being dependent upon this classification. Such under-expanded jets have a very wide variety of engineering applications including rocket propulsion and maneuvering [2], fuel injection systems [3], and the assessment of consequences and risk assessment of industrial releases [4], in additional to natural occurrences such as during the rapid expansion of volcanic eruption. The ability to accurately predict the detailed structure of such flows requires an understanding and numerical representation of the interaction of turbulent mixing and compressibility effects due to associated phenomena.…”