Carbon dioxide equilibrium

Ocean disposal of C02 five injection scenarios. (From Butler, J.N., Carbon Dioxide Equilibria and Their Applications, Lewis Publisher, Michigan, 1991. With permission.)... 

Herczeg, A.C., and Hesslein, R.H. (1984) Determination of hydrogen ion concentration in softwater lakes using carbon dioxide equilibria. Geochim. Cosmochim. Acta 48, 837-845. 

Butler, J.N. Carbon Dioxide Equilibria and Their Applications Lewis Publisher Chelsea, MI, 1991. 

The equipment is branded as the AQA total and uses a special three-dimensional electrode to produce specific current-voltage impulses to the electrically conductive particles, resulting in a local displacement of the hardness-carbon dioxide equilibrium. 

Diffusion coefficients can be estimated with the aid of the mathematical description of the diffusion of carbon dioxide from the paint film (Scheme II). Film thickness, saturation concentration and carbon dioxide equilibrium concentration are known. The emission curves of carbon dioxide calculated by the model have been fitted with the actual emission curves in Figure 7. In this case carbon dioxide is not formed chemically. 

At 800° C. reaction (2) appears to proceed slowly in either direction, while (1) is very rapid. The fact that the degree of dissociation in (1) is. independent of the amounts of carbon dioxide and carbon disulphide present, shows that carbon monoxide and sulphur are primary products of the decomposition of carbonyl sulphide and are not formed secondarily from the carbon dioxide and carbon disulphide. At temperatures below 400° C. decomposition according to equation (1) is not evident, while at 900° C. it reaches a maximum (64 per cent.) reaction (2) reaches a maximum at about 600° C., at which point 43 per cent, of the carbonyl sulphide is decomposed in this way and 16 per cent, according to reaction (1). The carbon monoxide equilibrium depends upon the pressure, whilst the carbon dioxide equilibrium does not. Nearly all the reactions involved in the thermal decomposition of carbonyl sulphide depend greatly on catalytic influences. Quartz is a pronounced catalyst for reaction (2), but has little influence on reaction (1). Carbonyl sulphide is comparatively rapidly decomposed in quartz vessels, but is stable when kept in glass apparatus. The viscosity of gaseous carbonyl sulphide is as follows x... 

Lemon oil-carbon dioxide equilibrium was measured at 303. 308, and 313 K and in the pressure range of 4 to 9 MPa. Below 6 MPa, there was insufficient lemon oil in the vapor phase to obtain good samples for analysis. Above 9.0 MPa at 313 K, above 7.8 MPa at 308 K, and above 7.4 MPa at 303 K, the system exhibited a single phase. Nine experiments provided two-phase, vapor-liquid equilibrium data... 

Calcium carbonate-calcium oxide-carbon dioxide equilibrium. 

Similarly, the selectivity ratios of O2/N2, as obtained from their respective uptake curves (Figures 14 - 17), are shown in Table 3. The adsorption capacity for O2 and N2 is lower than for the carbon dioxide equilibrium capacity, with low selectivity ratios of 1.0 to 2.2. Selectivity improved slightly at low burn-off values but still the results indicated poor kinetic separation effects. The kinetic diameters of CO2, CH4, O2 and N2 are 3.3, 3.8, 3.46 and 3.64 A respectively. Hence, the CO2 molecule, being the smallest of all, could be quickly and preferentially adsorbed in the activated carbon pore structure, over the largest methane molecule. However the kinetic diameters of O2 and N2 differ only slightly, which makes their separation difficult in the existing activated carbons from raw lignite. Such separation would require the preparation of a product... 

Calcium carbonate precipitation is caused by a shift toward carbonates in the carbonate-bicarbonate-carbon-dioxide equilibrium. When the equilibrium shifts in the other direction, the precipitate goes back into solution. Since there is usually considerable delay between the establishment of an equilibrium and the precipitation or dissolution of calcium carbonate, unstable conditions exist in which water will precipitate or dissolve calcium carbonate on standing. 

To achieve the full utilization of carbon (4 electrons per atom) requires an electrochemical reaction producing only CO2. For this to occur, it is necessary to polarize the carbon anode by at least the difference between the open circuit potential and the carbon/carbon dioxide equilibrium potential (1.02 V), i.e. by about 0.10 V at 750°C. This lowers the electrode potential into the range where evolution of CO2 is possible. 

The soda-ammonia process occurs in two main stages. First, brine is saturated with ammonia gas and this ammoniacal brine is then treated with carbon dioxide. The equilibrium... 

Section 19 9 Carbon dioxide and carbonic acid are m equilibrium m water Carbon dioxide IS the major component... 

Except as an index of respiration, carbon dioxide is seldom considered in fermentations but plays important roles. Its participation in carbonate equilibria affects pH removal of carbon dioxide by photosynthesis can force the pH above 10 in dense, well-illuminated algal cultures. Several biochemical reactions involve carbon dioxide, so their kinetics and equilibrium concentrations are dependent on gas concentrations, and metabolic rates of associated reactions may also change. Attempts to increase oxygen transfer rates by elevating pressure to get more driving force sometimes encounter poor process performance that might oe attributed to excessive dissolved carbon dioxide. 

CARBON DIOXIDE CAPACITY AT 25 C Molecular Sieve Type A Equilibrium 0818... 

The component reactions in eqn. (2) are very fast, and the system exists in equilibrium. Additional carbon dioxide entering the sea is thus quickly converted into anions, distributing carbon atoms between the dissolved gas phase, carbonate and bicarbonate ions. This storage capacity is clear when the apparent equilibrium constants for the two reactions in eqn. (2) are examined, namely... 

Cement mortar will be attacked by waters that have an excess of free carbon dioxide compared with that of waters that are in a lime-carbonic acid equilibrium. There is a two-step mechanism with a carbonization process according to... 

Example. A gas oil having a density of 0.84 grams per milliliter (37°AP1) is stored at 60°C (140°F) under a gas blanket of carbon dioxide (CO2) at a pressure of 1 atmosphere absolute. To estimate the amount of carbon dioxide dissolved in the gas oil at equilibrium, take the following steps ... 

Figure 4-4. Vapor-solid equilibrium constants o) for carbon dioxide, b) for hydrogen sulfide. (From Gas Processors Suppliers Association, Bngineerinq Data Book, 10th Edition.)...

K-factors for vapor-liquid equilibrium ratios are usually associated with various hydrocarbons and some common impurities as nitrogen, carbon dioxide, and hydrogen sulfide [48]. The K-factor is the equilibrium ratio of the mole fraction of a component in the vapor phase divided by the mole fraction of the same component in the liquid phase. K is generally considered a function of the mixture composition in which a specific component occurs, plus the temperature and pressure of the system at equilibrium. 

The most important property of the dissolved solids in fresh waters is whether or not they are such as to lead to the deposition of a protective film on the steel that will impede rusting. This is determined mainly by the amount of carbon dioxide dissolved in the water, so that the equilibrium between calcium carbonate, calcium bicarbonate and carbon dioxide, which has been studied by Tillmans and Heublein and others, is of fundamental significance. Since hard waters are more likely to deposit a protective calcareous scale than soft waters, they tend as a class to be less aggressive than these indeed, soft waters can often be rendered less corrosive by the simple expedient of treating them with lime (Section 2.3). 

The effect of pH on the corrosion of zinc has already been mentioned (p. 4.170). In the range of pH values from 5 -5 to 12, zinc is quite stable, and since most natural waters come within this range little difficulty is encountered in respect of pH. The pH does, however, affect the scale-forming properties of hard water (see Section 2.3 for a discussion of the Langelier index). If the pH is below the value at which the water is in equilibrium with calcium carbonate, the calcium carbonate will tend to dissolve rather than form a scale. The same effect is produced in the presence of considerable amounts of carbon dioxide, which also favours the dissolution of calcium carbonate. In addition, it is important to note that small amounts of metallic impurities (particularly copper) in the water can cause quite severe corrosion, and as little as 0-05 p.p.m. of copper in a domestic water system can be a source of considerable trouble with galvanised tanks and pipes. 

The oxidation rates in carbon monoxide (Fig. 5.12) are less than those for carbon dioxide. They increase steadily with temperature up to 800°C but then decrease markedly by a factor of 100 up to 1 000°C. The decrease in rate can be attributed to the beneficial factors operating at the higher temperatures with carbon dioxide and to the unfavourable thermodynamics for reaction 5.2 resulting in low equilibrium partial pressures of carbon dioxide. 

Table 21.22 Saturated solubilities of atmospheric gases in sea-water at various temperatures Concentrations of oxygen, nitrogen and carbon dioxide in equilibrium with 1 atm (lOI 325 N m ) of designated gas...

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