Purge Curve

The temperature-compensated HFR is then essentially indicative of membrane water content only, and the temperature dependence is removed from actually measured HFR data. 

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Figure 14. Stages of purge curve, (reproduced with permission from Tajiri et al.33)...

However, the concentration of impurity in the recycle is varied as shown in Fig. 8.5, so each component cost shows a family of curves when plotted against reactor conversion. Reactor cost (capital only) increases as before with increasing conversion (see Fig. 8.5a). Separation and recycle costs decrease as before (see Fig. 8.56). Figure 8.5c shows the cost of the heat exchanger network and utilities to again decrease with increasing conversion. In Fig. 8.5d, the purge... 

The startup speed and temperature acceleration curves as shown in Figure 19-2 are one such safety measure. If the temperature or speed are not reached in a certain time span from ignition, the turbine will be shutdown. In the early days when these acceleration and temperature curves were not used, the fuel, which was not ignited, was carried from the combustor and then deposited at the first or second turbine nozzle, where the fuel combusted which resulted in the burnout of the turbine nozzles. After an aborted start the turbine must be fully purged of any fuel before the next start is attempted. To achieve the purge of any fuel residual from the turbine, there must be about seven times the turbine volume of air that must be exhausted before combustion is once again attempted. 

Fig. 10 shows the curves for the canister weight and the amount of vapor removed for the example canister during a purge event. In this case, the canister is being purged with an air stream flowing at a rate of about 22.6 liters per minute for a total of 15 minutes. The curves show that the n-butane desorption rate is initially quite rapid, and then it levels out at a lower rate. 

Fig. 10. Purging (desorption) curves for the N-butane in a one liter canister...

Effects of performance changes, 201-203 Head curve for single pump, 198 Relations between head, horsepower, capacity and speed, 200 Temperature rise 207-209 Viscosity corrections, 203-207 Purging, flare stack systems, 535 Reciprocating pumps, 215—219 Flow patterns, 219 Specification form, 219 Relief areas, 437 External fires, 451, 453 Sizing, 434, 436... 

Figure 8.9 Polarization curves for a PtSn/C catalyst recorded by a rotating disk electrode in 0.5 M H2SO4 saturated with either pure hydrogen, a H2/2% CO mixture, and pure CO (the arrow points to the onset of CO oxidation) at 60 °C with 1 mV/s and 2500 rev/min the dashed curve is the cyclic voltammogram (in arbitrary units) in an argon-purged solution at 60 °C with 50 mV/s. (Reprinted with permission from Aienz etal. [2005]. Copyright 2005. Elsevier.)...

Fig.9. Loading and breakthrough curves Fig. 10. Purging (desorption) curves for the in a one liter canister, 40 g/hr N-butane N-butane in a one liter canister feed rate...

If, as illustrated in figure 12.6, the isothermal starting lines of the various curves do not coincide, then A< >o, A< cai, and Aheat transfer change between runs, for example, due to a variation in the purge gas flow or the fact that it is virtually impossible to relocate the crucible containing the sample exactly in the position used for the calibrant run (normally the reference crucible remains in place throughout a series of runs). Note that a similar correction should have been used in the computation of heat flow or area quantities if, in the example of figure 12.4, the isothermal baselines of the main experiment and the zero line were not coincident. 

TPD-NH3 curves were obtained in a temperature range of 120 to 600°C, at a rate of 15°C/min. The adsorption of ammonia onto the sample was carried out at 25°C. Subsequently, the removal of ammonia was performed at 500 or 550°C for 1 h by purging air or pure nitrogen. Blank runs were carried out under the same conditions but with no NH3 adsorbed. The TPD-NH3 curves were obtained after subtraction of the blank run. 

Absorption test starts with purging process as well as evacuation and then system is thermally stabilized under vacuum. Subsequently, hydrogen at desired absorption pressure is admitted into the system and by observing the pressure decreasing as a function of time, the kinetic curve is registered. 

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