Carbon dioxide water vapor content

Water stability is a major challenge that has to be overcome before metal organic framework can be used in removing carbon dioxide from flue gas. The core structure of MOF reacts with water vapor content in the flue gas leading to severe distortion of the structure and even failure. As a consequence, the physical structure of MOF is changed, e.g., reduction of porosity and surface area, etc. that decreases the capacity and selectivity for C02. Complete dehydration of flue gas increases the cost of separation. It is therefore essential for MOFs to exhibit stability in the presence of water up to certain extent [91]. 

Gas streams for the experimental reactor contained nitrogen, hydrogen, carbon monoxide, sulfur dioxide, and in some cases oxygen, from cylinders, which were blended to synthesize a mixture of reformed natural gas and a sulfur dioxide-bearing gas stream of the desired composition. The composition of this head gas stream was continuously monitored by an on-line process chromatograph. The mixed gas stream was saturated with water vapor at a controlled temperature and pressure to provide a water vapor content consistent with that in actual plant operation. 

Figure 11 -4. Water vapor content of saturated carbon dioxide-rich gas at lOO F. Ram Case etal. (1985). Reproduced with permission from Oii Gas Joumai, May 13,1985, copyright PennWeii Publishing Co.

Rework Example 3.3 for air and water, including the carbon dioxide in the air. How many variables are there How many equations In atmospheric air the carbon dioxide concentration changes slightly from place to place and time to time, but on the average, for dry air, the concentration is about 390 ppm. Assume that the ratio of mole fractions of CO2 to N2 is always 0.000,390/0.79, independent of the water vapor content of the air. 

The wet analysis assumes that the water vapor is present. The maximum theoretical carbon dioxide content is 9.66 per cent. The zirconia cell method of measuring oxygen is on the wet basis. 

The environmental problem of sulfur dioxide emission, as has been pointed out, is very much associated with sulfidic sources of metals, among which a peer example is copper production. In this context, it would be beneficial to describe the past and present approaches to copper smelting. In the past, copper metallurgy was dominated by reverberatory furnaces for smelting sulfidic copper concentrate to matte, followed by the use of Pierce-Smith converters to convert the matte into blister copper. The sulfur dioxide stream from the reverberatory furnaces is continuous but not rich in sulfur dioxide (about 1%) because it contains carbon dioxide and water vapor (products of fuel combustion), nitrogen from the air (used in the combustion of that fuel), and excess air. The gas is quite dilute and unworthy of economical conversion of its sulfur content into sulfuric acid. In the past, the course chosen was to construct stacks to disperse the gas into the atmosphere in order to minimize its adverse effects on the immediate surroundings. However, this is not an en-... 

The composition of the carrier gas containing the nitrogen oxides is another very important factor in NO removal. The influence of oxygen content in N2/02/N0 mixtures on the conversion of NO was investigated [26-28], The addition of water vapor [26,27,29-32], carbon dioxide [26,32] and hydrocarbons [27-35] was studied as well. 

Most of the available water content charts are applicable only to sweet lean natural gases, Moore, et al, (15) have developed a set of charts which are based on the Heidemann (8, 12) version of the SRK water prediction. The system used in this study contains nearly 6.0% carbon dioxide. The acid gases cause increased water solubility in the vapor phase. Our calculations simply verify these observations. 

Figure 7.10 Neon (solid lines) and argon (dashed) isotopic fractionations produced by diffusion-limited hydrogen escape from representative terrestrial atmospheres, as a function of its lifetime At. Three examples that differ in the amount of C02 present are shown. Each assumes 270 bars of water vapor (i.e., the mass of the present ocean). Carbon dioxide contents are 5, 10, and 20 bars. After Ozima and Zahnle (1993).

Carbon dioxide removal in ammonia plants is usually accomplished by organic or inorganic solvents with suitable activators and corrosion inhibitors. In a few circumstances, C02 is removed by pressure swing adsorption (PSA) (see Chapter 3). The removed C02 is sometimes vented to the atmosphere, but in many instances it is recovered for the production of urea and dry ice. Urea is the primary use of carbon dioxide and, in case of a natural gas feed, all of the C02 is consumed by the urea plant. This practice is especially significant since C02 is a proven greenhouse gas. Typically, 1.3 tons of C02/ton of NH3 is produced in a natural gas-based ammonia plant. The C02 vented to the atmosphere usually contains water vapor, dissolved gases from the absorber (e.g., H2, N2, CH4, CO, Ar), traces of hydrocarbons, and traces of solvent. Water wash trays in the top of the stripper and double condensation of the overhead help to minimize the amount of entrained solvent. The solvent reclaimer contents are neutralized with caustic before disposal. Waste may be burned in an incinerator with an afterburner and a scrubber to control NOx emissions. 

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