Temperature-Dependent Factors in LC
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Figures 5.1 (a) and (b) show isothermal and nonisothermal cases, respectively. It is observe in Figure 5.1(a) that, on neglecting the enthalpy of adsorption, no change in temperature profile can be seen. Whereas, in Figure 5.1(b), the enthalpy of adsorption significantly affected the temperature profile without any change in the concentration profile. Moreover, it is notice that before the maximum value of concentration adsorption is taking place which produces a considerable rise in the temperature. On the other hand, desorption of concentration drops the temperature to the lowest value. Afterwards, the temperature attains its reference value.
Figures 5.2 and 5.3 show the concentration and temperature profiles at different values of ¢HA. It can be observed that analytical solutions for linearized isotherm and numerical solutions of HR-FVS for nonlinear isotherm start deviating from each other when the magnitude of enthalpy of adsorption, j¢HAj, is increased from 5 kJ=mol to 40 kJ=mol. These results clearly endorse our assumptions used for the linearization of isotherm.
Figures 5.4 (a) and (b) are representing the effects of inlet temperature on concentration and temperature profiles. In Figure 5.4 (a), it seen that the adsorption peak of the temperature rises due to hot injection and desorption peak diminishes. On the other hand, in Figure 5.4 (b), the desorption peak of temperature further reduces due to cold sample injection (lower from ambient temperature) and adsorption peak diminishes.
Temperature-Dependent Factors in LC
Figures 5.6 (a) and (b) show the effects of both inlet temperature and the ratio of specific heat. It observe that the adsorption and desorption coupling seen in Figure 5.5 remain the same. However, in Figure 5.6(a), an increase in inlet temperature enhances the desorption without affecting adsorption. While, in Figure 5.6(b), the overall temperature of the column enhances adsorption with no change in desorption.
Effect of adsorption enthalpy on (HETP) curve
Effect of these HETP curve has been shown in Figure 5.8. It can be observe that the concentration and temperature HETP curve increase when the magnitude of enthalpy of adsorption, j¢HAj, is increases from 10 kJ=mol to 60 kJ=mol. It is notice that the column efficiency is decreasing by increasing the enthalpy of adsorption due to significant temperature rise.
Effect of adsorption enthalpy on concentration and temperature moments
Figures 5.9 and 5.10 represent comparisons of analytical moments of concentration and temperature for different enthalpies of adsorption in the case of Tinj > Tref .
Figures 5.11 and 5.12 represent comparisons of analytical moments of concentration
and temperature for different enthalpies of adsorption in the case of Tinj < Tref .