Measurements of Decompression Wave Speed in Pure Carbon Dioxide and Comparison With Predictions by Equation of State

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
K. K. Botros ◽  
J. Geerligs ◽  
B. Rothwell ◽  
T. Robinson
Keyword(s):  
Carbon Dioxide ◽  
Large Scale ◽  
Wave Speed ◽  
Equations Of State ◽  
Initial Conditions ◽  
Thermodynamic Characteristics ◽  
Point Of View ◽  
Decompression Wave ◽  
Rapid Transients

Carbon dioxide capture and storage (CCS) is one of the technologies that have been proposed to reduce emissions of carbon dioxide (CO2) to the atmosphere. CCS will require the transportation of the CO2 from the “capture” locations to the “storage” locations via large-scale pipeline projects. One of the key requirements for the design and operation of pipelines in all jurisdictions is fracture control. Supercritical CO2 is a particularly challenging fluid from this point of view, because its thermodynamic characteristics are such that a very high driving force for fracture can be sustained for a long time. Even though CO2 is not flammable, it is an asphyxiating gas that is denser than air, and can collect in low-lying areas. Additionally, it is well known that any pipeline rupture, regardless of the nature of the fluid it is transporting, has a damaging reputational, commercial, logistic, and end user impact. Therefore, it is as important to control fracture in a CO2 pipeline as in one transporting a flammable fluid. With materials specified appropriately for the prevention of brittle failure, the key element is the control of propagating ductile (or tearing) fracture. The determination of the required toughness for the arrest of ductile fracture requires knowledge of the decompression behavior of the contained fluid, which in turn requires accurate knowledge of its thermodynamic characteristics along the decompression isentrope. While thermodynamic models based on appropriate EOS (equations of state) are available that will, in principle, allow determination of the decompression wave speed, they, in general, have not been fully validated for very rapid transients following a rupture. This paper presents experimental results of the decompression wave speed obtained from shock tube tests conducted on pure CO2 from different initial conditions, and comparison with predictions by models based on GERG-2008, Peng-Robinson, and BWRS equations of state (EOS). These tests were conducted as a baseline before introducing various impurities.

Measurements of Decompression Wave Speed in Binary Mixtures of Carbon Dioxide and Impurities

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
K. K. Botros ◽  
J. Geerligs ◽  
B. Rothwell ◽  
T. Robinson
Keyword(s):  
Binary Mixtures ◽  
Wave Speed ◽  
Equations Of State ◽  
Propagation Speed ◽  
Plateau Pressure ◽  
Wave Speeds ◽  
Decompression Wave ◽  
Arrest Toughness ◽  
Good Agreement

Shock tube tests were conducted on a number of binary CO2 mixtures with N2, O2, CH4, H2, CO, and Ar impurities, from a range of initial pressures and temperatures. This paper provides examples of results from these tests. The resulting decompression wave speeds are compared with predictions made utilizing different equations of state (EOS). It was found that, for the most part (except for binaries with H2), the GERG-2008 EOS shows much better performance than the Peng–Robinson (PR) EOS. All binaries showed a very long plateau in the decompression wave speed curves. It was also shown that tangency of the fracture propagation speed curve would normally occur on the pressure plateau, and hence, the accuracy of the calculated arrest toughness for pipelines transporting these binary mixtures is highly dependent on the accuracy of the predicted plateau pressure. Again, for the most part, GERG-2008 predictions of the plateau are in good agreement with the measurements in binary mixtures with N2, O2, and CH4. An example of the determination of pipeline material toughness required to arrest ductile fracture is presented, which shows that prediction by GERG-2008 is generally more conservative and is therefore recommended. However, both GERG-2008 and PR EOS show much worse performance for the other three binaries: CO2 + H2, CO2 + CO, and CO2 + Ar, with CO2 + H2 being the worst. This is likely due to the lack of experimental data for these three binary mixtures that were used in the development of these EOS.

scholarly journals Stellar mass spectrum within massive collapsing clumps

2018 ◽  
Vol 611 ◽  
pp. A89 ◽  
Author(s):  
Yueh-Ning Lee ◽  
Patrick Hennebelle
Keyword(s):  
Large Scale ◽  
Equations Of State ◽  
Initial Conditions ◽  
Peak Position ◽  
Density Fluctuations ◽  
Initial Mass Function ◽  
Analytical Models ◽  
Numerical Resolution ◽  
Tidal Forces ◽  
The Imf

Context. Understanding the origin of the initial mass function (IMF) of stars is a major problem for the star formation process and beyond. Aim. We investigate the dependence of the peak of the IMF on the physics of the so-called first Larson core, which corresponds to the point where the dust becomes opaque to its own radiation. Methods. We performed numerical simulations of collapsing clouds of 1000 M⊙ for various gas equations of state (eos), paying great attention to the numerical resolution and convergence. The initial conditions of these numerical experiments are varied in the companion paper. We also develop analytical models that we compare to our numerical results. Results. When an isothermal eos is used, we show that the peak of the IMF shifts to lower masses with improved numerical resolution. When an adiabatic eos is employed, numerical convergence is obtained. The peak position varies with the eos, and using an analytical model to infer the mass of the first Larson core, we find that the peak position is about ten times its value. By analyzing the stability of nonlinear density fluctuations in the vicinity of a point mass and then summing over a reasonable density distribution, we find that tidal forces exert a strong stabilizing effect and likely lead to a preferential mass several times higher than that of the first Larson core. Conclusions. We propose that in a sufficiently massive and cold cloud, the peak of the IMF is determined by the thermodynamics of the high-density adiabatic gas as well as the stabilizing influence of tidal forces. The resulting characteristic mass is about ten times the mass of the first Larson core, which altogether leads to a few tenths of solar masses. Since these processes are not related to the large-scale physical conditions and to the environment, our results suggest a possible explanation for the apparent universality of the peak of the IMF.

Determination of Decompression Wave Speed in Rich Gas Mixtures

2008 ◽  
Vol 82 (5) ◽  
pp. 880-891 ◽  
Author(s):  
Kamal K. Botros ◽  
Wojciech Studzinski ◽  
John Geerligs ◽  
Alan Glover
Keyword(s):  
Wave Speed ◽  
Gas Mixtures ◽  
Decompression Wave

Measurement of Decompression Wave Speed in Rich Gas Mixtures at High Pressures (370 bars) Using a Specialized Rupture Tube

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
K. K. Botros ◽  
J. Geerligs ◽  
R. J. Eiber
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Wave Speed ◽  
High Pressures ◽  
Equations Of State ◽  
Gas Mixtures ◽  
Internal Diameter ◽  
Decompression Wave ◽  
Predicted Values ◽  
Fracture Arrest

Measurements of decompression wave speed in conventional and rich natural gas mixtures following rupture of a high-pressure pipe have been conducted. A high-pressure stainless steel rupture tube (internal diameter=38.1 mm and 42 m long) has been constructed and instrumented with 16 high frequency-response pressure transducers mounted very close to the rupture end and along the length of the tube to capture the pressure-time traces of the decompression wave. Tests were conducted for initial pressures of 33–37 MPa-a and a temperature range of 21–68°C. The experimentally determined decompression wave speeds were compared with both GASDECOM and PIPEDECOM predictions with and without nonequilibrium condensation delays at phase crossing. The interception points of the isentropes representing the decompression process with the corresponding phase envelope of each mixture were correlated with the respective plateaus observed in the decompression wave speed profiles. Additionally, speeds of sound in the undisturbed gas mixtures at the initial pressures and temperatures were compared with predictions by five equations of state, namely, BWRS, AGA-8, Peng–Robinson, Soave–Redlich–Kwong, and Groupe Européen de Recherches Gaziéres. The measured gas decompression curves were used to predict the fracture arrest toughness needed to assure fracture control in natural gas pipelines. The rupture tube test results have shown that the Charpy fracture arrest values predicted using GASEDCOM are within +7% (conservative) and −11% (nonconservative) of the rupture tube predicted values. Similarly, PIPEDECOM with no temperature delay provides fracture arrest values that are within +13% and −20% of the rupture tube predicted values, while PIPEDECOM with a 1°C temperature delay provides fracture arrest values that are within 0% and −20% of the rupture tube predicted values. Ideally, it would be better if the predicted values by the equations of state were above the rupture tube predicted values to make the predictions conservative but that was not always the case.

Measurements of Decompression Wave Speed in Simulated Anthropogenic Carbon Dioxide Mixtures Containing Hydrogen

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
K. K. Botros ◽  
J. Geerligs ◽  
B. Rothwell ◽  
T. Robinson
Keyword(s):  
Carbon Dioxide ◽  
Shock Tube ◽  
Phase Boundary ◽  
Ductile Fracture ◽  
Critical Point ◽  
Wave Speed ◽  
Plateau Pressure ◽  
Boundary Crossing ◽  
Decompression Wave ◽  
The Impact

In order to determine the material fracture resistance necessary to provide adequate control of ductile fracture propagation in a pipeline, a knowledge of the decompression wave speed following the quasi-instantaneous formation of an unstable, full-bore rupture is necessary. The thermodynamic and fluid dynamics background of such calculations is understood, but predictions based on specific equations of state (EOS) need to be validated against experimental measurements. A program of tests has been conducted using a specially constructed shock tube to determine the impact of impurities on the decompression wave speed in carbon dioxide (CO2), so that the results can be compared to two existing theoretical models. In this paper, data and analysis results are presented for three shock tube tests involving anthropogenic CO2 mixtures containing hydrogen as the primary impurity. The first mixture was intended to represent a typical scenario of precombustion carbon capture and storage (CCS) technology, where typically the concentration of CO2 is around 95–97% (mole). The second mixture represents a worst case scenario of this technology with high level of impurities (with CO2 concentration around 85%). The third test represents a typical chemical-looping combustion process. It was found that the extent of the plateau on the decompression wave speed curves in these tests depends on the location of the phase boundary crossing along the bubble-point curve. The closer the phase boundary crossing to the critical point, the shorter the plateau. This is primarily due to the change in magnitude of the drop in the speed of sound at phase boundary crossing. For the most part, the predictions of the plateau pressure by both of the EOS that were evaluated, GERG-2008 and Peng–Robinson (PR), are in good agreement with measurements by the shock tube. This by no means reflects overall good performance of either EOS, but was rather due to the fact that the isentropes intersected the phase envelope near the critical point, or that the concentration of H2 was relatively low, either in absolute terms or relative to other impurity constituents. Hence, its influence in causing inaccurate prediction of the plateau pressure is lessened. An example of pipeline material toughness required to arrest ductile fracture is presented which shows that predictions by GERG-2008 are more conservative and are therefore recommended.

scholarly journals Approach to the Proecological Distribution of the Traffic Flow on the Transport Network from the Point of View of Carbon Dioxide

2020 ◽  
Vol 12 (17) ◽  
pp. 6936 ◽  
Author(s):  
Piotr Gołębiowski ◽  
Jolanta Żak ◽  
Ilona Jacyna-Gołda
Keyword(s):  
Carbon Dioxide ◽  
Traffic Flow ◽  
Carbon Dioxide Emissions ◽  
Ecological Footprint ◽  
Optimization Problem ◽  
Real Data ◽  
Point Of View ◽  
Total Carbon ◽  
Microsoft Excel

Nowadays, apart from travel time and cost, more and more attention is paid to ensuring that ecological footprint of the means of transport used for a journey is as small as possible. Therefore, it is reasonable to look for methods and solutions that will allow planning communication connections according to the principles of sustainable development. The aim of the article was to present mathematical model of the proecological distribution of traffic flow into a network, together with a determination of how the amount of emissions of harmful compounds for rail transport will be calculated (based on amount of energy necessary for movement, calculated on circumference of the wheels). The model has been verified on real data. The traffic flow was distributed over a selected communication route: Warszawa—Gdansk, where the criterion was minimization of total carbon dioxide emissions. An evolutionary method implemented in Microsoft Excel was used to solve the optimization problem. For the analysis of only the fastest connections, the railway one was the optimal from the point of view of the adopted criteria. After the train capacity was exceeded, air and car connections were loaded. Based on the research, a function that represents the amount of carbon dioxide emissions in the analyzed traffic route depending on the size of the traffic flow was developed.

scholarly journals Some thermal constants of solid and liquid carbon dioxide

1926 ◽  
Vol 111 (757) ◽  
pp. 224-244 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Latent Heat ◽  
Equations Of State ◽  
Direct Determination ◽  
Heat Of Fusion ◽  
Solid Carbon Dioxide ◽  
Specific Heats ◽  
Liquid Phases ◽  
The Subject

Carbon dioxide is a substance whose properties have been the subject of innumerable investigations. Particularly the pressure-volume-temperature relationships when in the gaseous and liquid phases have provided data for the basis of equations of state. The thermal properties are not so well known and an investigation of these is the purpose of the following paper. The actual measurements to be described deal with the direct determination of the latent heat of fusion, the latent heat of sublimation and the specific heats of the solid and liquid over the temperature range of 0°C. to —184°C. The experimental methods employed are of sufficient interest to warrant a detailed description. Since it was found that the specific heat of the solid carbon dioxide gave abnormally high results the expansion coefficient of the solid was measured.

Decompression Wave Speed in Rich Gas Mixtures at High Pressures (37 MPa) and Implications on Fracture Control Toughness Requirements in Pipeline Design

2010 ◽  
Author(s):  
K. K. Botros ◽  
J. Geerligs ◽  
R. J. Eiber
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Wave Speed ◽  
Equations Of State ◽  
Gas Mixtures ◽  
Internal Diameter ◽  
Decompression Wave ◽  
Fracture Control ◽  
Predicted Values ◽  
Fracture Arrest

Measurements of decompression wave speed in conventional and rich natural gas mixtures following rupture of a high-pressure pipe have been conducted. A high pressure stainless steel rupture tube (internal diameter = 38.1 mm, and 42 m long), has been constructed and instrumented with 16 high frequency-response pressure transducers mounted very close to the rupture end and along the length of the tube to capture the pressure-time traces of the decompression wave. Tests were conducted for initial pressures of 33–37 MPa-a and a temperature range of 21 to 68 °C. The experimentally determined decompression wave speeds were compared to both GASDECOM and PIPEDECOM predictions with and without non-equilibrium condensation delays at phase crossing. The interception points of the isentropes representing the decompression process with the corresponding phase envelope of each mixture were correlated to the respective plateaus observed in the decompression wave speed profiles. Additionally, speeds of sound in the undisturbed gas mixtures at the initial pressures and temperatures were compared to predictions by five equations of state, namely BWRS, AGA-8, Peng-Robinson, Soave-Redlich-Kwong, and GERG. The measured gas decompression curves were used to predict the fracture arrest toughness needed to assure fracture control in natural gas pipelines. The rupture tube test results have shown that the Charpy fracture arrest values predicted using GASEDCOM are within +7 (conservative) and −11% (non-conservative) of the rupture tube predicted values. Similarly, PIPEDECOM with no temperature delay provides fracture arrest values that are within +13 and −20% of the rupture tube predicted values, while PIPEDECOM with a 1 °C temperature delay provides fracture arrest values that are within 0 and −20% of the rupture tube predicted values. Ideally, it would be better if the predicted values by the equations of state were above the rupture tube predicted values to make the predictions conservative but that was not always the case.

Sign in / Sign up

Export Citation Format

Share Document