Properties of air

The Catofin process, which was formerly the property of Air Products (Houdry Division), uses a proprietary chromium catalyst in a fixed-bed reactor operating under vacuum. There are actually multiple reactors operating in cycHc fashion. In sequence, these reactors process feed for about nine minutes and are then regenerated for nine minutes. The chromium catalyst is reduced from Cr to Cr during the regeneration cycle. 

FIG. 12-36 Psychrometric chart properties of air and water-vapor mixtures from 20 to 120 C, Catrier Corp. )... 

A problem with the overall approach for liquid mixtures is that suitable averages must be used when calculating B, although errors in B are partly offset by the logarithmic term in Eq. (1). It is also necessary to decide at what temperature the properties of air should be evaluated. In [66] it was suggested that Cp a and should be evaluated at the arithmetic mean of the... 

The physieal properties of air are given in Table 9.5. Air is a mixture of nitrogen, oxygen, argon. 

Common to all air cooled heat exchangers is the tube, through which the process fluid flows. To compensate for the poor heat transfer properties of air, which flows across the outside of the tube, and to reduce the overall dimensions of the heat exchanger, external fins are added to the outside of the tube. A wide variety of finned tube types are available for use in air cooled exchangers. These vary in geometry, materials, and methods of construction, which affect both air side thermal performance and air side pressure drop. In addition, particular... 

Computes thermodynamic properties of air, argon, carbon monoxide, carbon dioxide, hydrogen, nitrogen, oxygen, water vapor, and products of combustion for hydrocarbons. Computes all properties from any two independent properties. 

Computes properties of air-water vapor mixtures for HVAC, combustion, aerodynamic, and meteorological applications. Any two independent properties may be inpuicd by... 

The specific enthalpy (h ) of the room-air design condition is obtained from tables of the property of air or the psychrometric chart. 

Consider the pressure loss in a duct with straight, uniform cross-sectional area. The pressure loss is caused by friction. When different air sheets move against each other, friction is generated. The velocity and thermodynamic properties of air influence the friction. The duct wall has an overall roughness, which causes vortices to be formed with resulting friction in gas. The velocity has a pronounced effect in flow with low velocity, the vortices are small. Eor a straight duct the pressure loss Ap can be determined from... 

Psychrometric chart A chart constructed so that knowing any two air properties the remaining thermodynamic properties of air at that condition can be determined. 

SENSIBLE HEATING COOLING is represented by a horizontal line between the limits of the process. All the properties of air change except the moisture content. 

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