Operating diagram absorption

The criterion for a reaction being effectively irreversible with respect to the absorption of a gas is that the concentration of the unreacted gas in the solution [e.g., NH3(a )] is so small that its partial pressure at the interface is much less than the partial pressure of the absorbing gas [e.g., NH3(g)] in the gas phase. When this criterion is satisfied, the interfacial mole fraction of the absorbing gas y, can be considered to be zero. This obviates the need for an equilibrium line or an x-y operating diagram. 

The limestone dual alkali technology consists of four distinct operations SO2 absorption, absorbent regeneration, waste solids dewatering, and raw materials storage and feed preparation. A typical process flow diagram is shown in Figure 1. 

Operating diagram for countercurrent cascades (a) adsorption (b) absorption. 

The Operating Diagram for Gas Absorption with a Reactive Solvent... 

The thermal efficiency of the process (QE) should be compared with a thermodynamically ideal Carnot cycle, which can be done by comparing the respective indicator diagrams. These show the variation of temperamre, volume and pressure in the combustion chamber during the operating cycle. In the Carnot cycle one mole of gas is subjected to alternate isothermal and adiabatic compression or expansion at two temperatures. By die first law of thermodynamics the isothermal work done on (compression) or by the gas (expansion) is accompanied by the absorption or evolution of heat (Figure 2.2). 

They are usually joined along the 110 plane of the lattice of the face-centered salt crystal, although we have not shown them this way (The 100 plane is illustrated in the diagram). Note that each vacancy has captured an electron in response to the charge-compensation mechanism which is operative for all defect reactions. In this case, it is the anion which is affected whereas in the "F-center", it was the cation which was affected (see equation 3.2.8. given above). These associated, negatively-charged, vacancies have quite different absorption properties than that of the F-center. 

Some commercially available detectors have a number of detection modes built into a single unit. Fig. 2.4o is a diagram of the detector used in the Perkin Elmer 3D system, which combines uv absorption, fluorescence and conductivity detection. The uv function is a fixed wavelength (254 nm) detector, and the fluorescence function can monitor emission above 280 nm, based on excitation at 254 nm. The metal inlet and outlet tubes act as the electrodes in the conductance cell. The detection modes can be operated independently or simultaneously, using a multichannel recorder. In the conductivity mode, using NaCl, a linear range of 103 and a noise equivalent concentration of 5 x 10 8 g cm-3 have been obtained. 

Fig. 14.2 Block diagram illustrating wave absorption (d) collisional or colli-the operation of EDL (a) energy flows sionless dumping (e) collisional excita-from a MW source into the plasma tion of atoms and ions followed by...

A typical diagram for the complete absorption of pentane and heavier components is shown in Fig. 14-11. The oil used as solvent is assumed to be solute-free (i.e., X2 = 0), and the key component, butane, was identified as that component absorbed in appreciable amounts whose equilibrium line is most nearly parallel to the operating lines (i.e., the K value for butane is approximately equal to... 

Four theoretical trays have been stepped off for the key component (butane) on Fig. 14-11, and are seen to give a recovery of 75 percent of the butane. The operating lines for the other components have been drawn with the same slope and placed so as to give approximately the same number of theoretical trays. Figure 14-11 shows that equilibrium is easily achieved in fewer than four theoretical trays and that for the heavier components nearly complete recovery is obtained in four theoretical trays. The diagram also shows that absorption of the light components takes place in the upper part of the tower, and the final recovery of the heavier components takes place in the lower section of the tower. 

The following diagram shows the operation cycle of a Carnot refrigerator. The refrigerator operates between 25°C(7 2) and -10°C(7 1) and step 2 involves heat absorption of500J. 

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