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

TL;DR: In this article, the authors present a simulation of a pipeline release scenario, in which dense-phase CO2 is released from a full-bore 36-in. pipeline, and the resulting multiphase CO2 plume disperses over complex terrain, featuring hills and valleys.

About: This article is published in International Journal of Greenhouse Gas Control.The article was published on 2014-08-01 and is currently open access. It has received 43 citations till now. The article focuses on the topics: Pipeline transport & Pipeline (software).

Summary

Summary

• There is emerging evidence to suggest that the growing incidence of endometrial cancer in several Western countries is due to an upward trend in the diagnosis of the clinically aggressive, non-endometrioid endometrial cancers (Clarke 2019; Faber 2017; Urick 2019).
• An ideal endometrial cancer screening test should be easy to perform and interpret, reliable and accurate, with few false positives and false negatives.
• Where necessary, the authors will contact study authors to confirm inclusion eligibility, to provide data required for the development of 2 x 2 tables or to provide further information needed for risk of bias assessment.
• Review eligiblity criteria   Study characteristics Inclusion criteria Exclusion criteria Population Asymptomatic women in the general population.
• Published by John Wiley & Sons, Ltd. 23 Cochrane Library Trusted evidence.

Frequently asked questions

Q1. What are the contributions mentioned in the paper "An integrated, multi-scale modelling approach for the simulation of multiphase dispersion from accidental co2 pipeline releases in realistic terrain" ?

This work provides an overview of elements of the EC FP7 CO2PipeHaz 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 CO2 pipelines. 

Q2. What are the future works mentioned in the paper "An integrated, multi-scale modelling approach for the simulation of multiphase dispersion from accidental co2 pipeline releases in realistic terrain" ?

In the future, it would be useful to further validate this integrated modelling approach against publicly-available datasets, particularly those involving releases of dense-phase CO concentrations. In view of the fact that most routine pipeline risk assessments will be carried out using integral or other phenomenological models that assume dispersion over flat terrain, it would be useful to use the models demonstrated here to determine under what set of conditions such models might provide unreliable results. Finally, from an emergency-planning perspective, it would be useful to further develop and validate models that are able to predict the extent of the visible CO2 plume, as well as its extent in terms of its instantaneous hazardous CO2 concentrations. 

Q3. How many sensors were distributed along the centre-line axis of the jet?

In the flow field, the instrumentation consisted of twenty-six, radially distributed thermocouples, and six oxygen depletion sensors distributed along the centre-line axis of the jet. 

Q4. What is the key to the prediction of accidental CO2?

Accurate and efficient prediction of thermodynamic properties of pure CO2 and its mixtures with non-condensable gases of interest to CCS is key to successful modelling of accidental CO2Tsangaris et al., 2013releases from pressurised transportation pipelines. 

Q5. Why is the flow interaction expected to be minimal?

It should be noted that the due to the length of the pipeline and the closure time of the valves used, the interaction of the flow with boundary conditions is expected to be minimal. 

Q6. What is the temperature of CO2 at atmospheric pressure?

As pure CO2, its triple-point pressure and temperature are 5.18 bar and 216.55 K respectively, and at atmospheric pressure CO2 exists in either a solid or gaseous state, with a sublimation temperature of 194.25 K. 

Q7. What is the effect of a pipeline failure on the flow of CO2?

given thatthe transportation of CO2 will undoubtedly occur at high pressure, this means that the nearisentropic expansion resulting from a pipeline failure will likely induce two-phase flow. 

Q8. How was the process of sublimation simulated?

The process of sublimation was simulated using the standard evaporation model, with suitable Antoine equation coefficients for solid CO2 sublimation. 

Q9. What is the way to determine the dispersion characteristics of a pipeline?

In view of the fact that most routine pipeline risk assessments will be carried out using integral or other phenomenological models that assume dispersion over flat terrain, it would be useful to use the models demonstrated here to determine under what set of conditions such models might provide unreliable results. 

Q10. Why is the CO2 cloud smaller than the steady-state release CFX simulations?

Owing to the finite total mass discharge, the CO2 cloud is notably smaller than that predicted by the steady-state release CFX simulations. 

Q11. What equations caused stability problems when using the PC-SAFT equation of state?

In this case only the PR and SRK equations were used as the larger diameter caused stability problems when using the PC-SAFT equation of state. 

Q12. What is the inviscid version of the overall model?

The inviscid version of the overall model is presented in detailelsewhere ( ) and the method considered here is extended for the turbulent closure of the fluid-flow equations detailed in the previous section. 

Q13. What is the symmetrical left boundary at y=15 m?

As previously mentioned, the uppermost boundary at y=15 m is also symmetric, and represents the companion jet release in a symmetrical full-bore release scenario. 

Q14. How can the authors investigate the effect of the terrain on the dispersion characteristics of a pipeline?

It should be possible to investigate this matter by varying inputs (e.g. pipeline release rate, wind speed, terrain height differences) to the type of models presented here to investigate under what combination of conditions the results deviate significantly from those of more pragmatic modelling approaches.