Properties of Carbon Dioxide

Thermodynamic properties were reviewed by Angus et al. (1976) and tables of thermodynamic properties were constructed. Vukalovich and Altunin (1968) reviewed both the thermodynamic and transport properties. These are similar to the Steam Tables (Haar et al., 1984), which should be familiar to most engineers. The latest tables for the thermodynamic properties of C02 are those of Span and Wagner (1996). 

The physical properties of saturated vapor carbon dioxide are listed in table 2.2 and those for the saturated liquid are in table 2.3. The 

°C) Vapor Pressure (MPa) Density (kg/m3) Heat Capacity (kJ/kg-K) Viscosity (cp) Thermal Conduct. (W/m-K) 

Here are a few comments on the values in the tables. First, the density of liquid carbon dioxide is only slightly less than water. At the temperatures listed in the table, carbon dioxide is fairly compressible since it is near the critical temperature. Under pressure, carbon dioxide can become more dense than water. 

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During the nineteenth century the growth of thermodynamics and the development of the kinetic theory marked the beginning of an era in which the physical sciences were given a quantitative foundation. In the laboratory, extensive researches were carried out to determine the effects of pressure and temperature on the rates of chemical reactions and to measure the physical properties of matter. Work on the critical properties of carbon dioxide and on the continuity of state by van der Waals provided the stimulus for accurate measurements on the compressibiUty of gases and Hquids at what, in 1885, was a surprisingly high pressure of 300 MPa (- 3,000 atmor 43,500 psi). This pressure was not exceeded until about 1912. 

Available data on the thermodynamic and transport properties of carbon dioxide have been reviewed and tables compiled giving specific volume, enthalpy, and entropy values for carbon dioxide at temperatures from 255 K to 1088 K and at pressures from atmospheric to 27,600 kPa (4,000 psia). Diagrams of compressibiHty factor, specific heat at constant pressure, specific heat at constant volume, specific heat ratio, velocity of sound in carbon dioxide, viscosity, and thermal conductivity have also been prepared (5). 

The following tables of properties of carbon dioxide are available enthalpy, entropy, and heat capacity at 0 and 5 MPa (0 and 50 atm, respectively) from 273 to 1273 K pressure—volume product (PV), enthalpy, and isobaric heat capacity (C from 373 to 1273 K at pressures from 5 to 140 MPa (50-1,400 atm) (14). 

Self-Test 4.17B The properties of carbon dioxide gas are well known in the bottled beverage industry. In an industrial process, a tank of volume 100. I. at 20.°C contains 20. mol C02. Use the data in Table 4.5 and the van der Waals equation to estimate the pressure in the tank. 

Kho, Y.W., Conrad, D.C. and Knutson, B.L. (2003) Phase equilibria and thermophysical properties of carbon dioxide-expanded fluorinated solvents. Fluid Phase Equilibria, 206 (1-2), 179-193. 

Quan Z, Min J, Zhou Q, Xie D, Liu J, Wang X, Zhao X, Wang F (2003) Synthesis and properties of carbon dioxide-epoxides coplymers from rare earth metal catalyst. Macromol Symp 195 281-286... 

Vlahakis, J.G., Chen, H.-S., Suwandi, M.S., Barduhn, A.J., The growth rate of ice crystals properties of carbon dioxide hydrate, a review properties of 51 gas hydrates, Syracuse U. Research and Development report 830, prepared for U S. Department of the Interior, November (1972). 

Optical properties of carbon dioxide, hydrogen sulfide, nitrogen, and water have not been considered, ft Author s estimate of status of studies in comparison with potential use by industry expressed on a probability scale extending from 0 to 10. 

Self-Test 4.15B The properties of carbon dioxide gas, COz, are intensively studied in the bottled beverage industry. In an industrial process,... 

A. 0. Rankine found that the mols. of nitrous oxide and carbon dioxide behave physically as if they had the same size, shape, and electronic structure. I. Langmuir compared the physical properties of carbon dioxide and of nitrous oxide, and the similarity was attributed to a like electronic structure—vide 4. 27, 4, Fig. 30. G. Kirsch made observations on the electronic structure of the molecule and M. L. Huggins made estimates of the interatomic distances. 

When carbon dioxide is poured from a gas jar on to a burning candle the candle goes out. What properties of carbon dioxide does this experiment show ... 

The CNG process removes sulfurous compounds, trace contaminants, and carbon dioxide from medium to high pressure gas streams containing substantial amounts of carbon dioxide. Process features include 1) absorption of sulfurous compounds and trace contaminants with pure liquid carbon dioxide, 2) regeneration of pure carbon dioxide with simultaneous concentration of hydrogen sulfide and trace contaminants by triple-point crystallization, and 3) absorption of carbon dioxide with a slurry of organic liquid containing solid carbon dioxide. These process features utilize unique properties of carbon dioxide, and enable small driving forces for heat and mass transfer, small absorbent flows, and relatively small process equipment. 

Properties of carbon dioxide. Carbon dioxide is a colorless, odorless gas, which does not support combustion and which is about 1.5 times as heavy as air. Under a pressure of 1 atm, the pure gas solidifies at -78.47°C. At room temperature and at atmospheric pressure, carbon dioxide dissolves in water to the extent of about 1 volume of gas to 1 volume of water. With increasing pressure, the solubility increases in accordance with Henry s law until a pressure of about 6 atm is reached, after which the increase in solubility is less pronounced. 

The good electron acceptor property of carbon dioxide can be used for the hydrodimerization to oxalic acid 4. Electrolysis is performed in an undivided cell using zinc as sacrificial electrode material. The reported electrolysis data are 6 mA/cm2 with 12 mM NBu4+BF4 in DMF. The current efficiency for the formation of oxalic acid is stated to be 60%. Unfortunately, no further details are currently available about this particular process (Lehmann and Dunach, 2009, personal communication). 

Carbon dioxide has a vapour pressure of about 50 bar at room temperature. It is therefore more difficult to handle, and it can only be pumped as a liquid when it is cooled down to sub-ambient temperatures. However, carbon dioxide is non-flammable and non-toxic, which makes it very attractive from a practical point of view. Also, the critical properties of carbon dioxide are very mild. 

The model used combines two equations of state and an excess function. It has been already developed to represent the thermodynamic properties of carbon dioxide-hydrocarbons mixtures [1]. 

U. Sievers, Thermodynamic Properties of Carbon Dioxide, Fortschr.-Ber. VD1-Z., Reihe 6, No. 155, VDl-Verlag, Dusseldorf, 1984. 

R. A. Alberty. Standard transformed formation properties of carbon dioxide in aqueous solutions at specified pH. J. Phys. Chem., 99 11028-11034, 1995. 

A new chart was developed for use with acid gas mixtures. It is based on the well-known properties of carbon dioxide, but it should be reasonably accurate for mixtures of C02+H2S. The new chart is shown in figure 2.3. 

As was mentioned earlier, the properties of carbon dioxide have been studied thoroughly. Thus it is relatively easy to construct a diagram that shows the viscosity of pure C02 over a wide range of pressure and temperature. Figure 2.5 is such a diagram, which shows the range of temperature and pressure of interest to acid gas injection. The curve labeled 0 MPa is the same as the low pressure viscosity shown in figure 2.4. 

Vukalovich, M.P. and V.V. Altunin. 1968. Thermophysical properties of carbon dioxide. London Collet s Publishers, Ltd. Translated by D.S. Gaunt. 

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