Partial pressure effect

Because water will be present in this system, and is assumed immiscible with the other components, it will exert its own vapor pressure. This situation is similar to many systems where the liquid to be flashed enters below its dew point, and hence requires the use of steam to heat (sensible + latent) as well as steam for the partial pressure effect... 

Deactivation Energy, Kcal/mole Fraction of ZSM-5 in inventory Catalyst Inventory, tons Deactivation Rate Constant Pre-Exponential Term of Kp Water Partial Pressure Effect Makeup Rate of Base Catalyst, tons/min Makeup Rate of ZSM-5 Catalyst, tons/min Motor Clear Octane Number Base Motor Octane Number Deactivation Order... 

Fio. 52. Pore size and hydrogen partial pressure effects on residuum catalyst stability (Nielsen ei at., 1981). 

A negative partial pressure effect was observed in the oxidation of all the hydrocarbons. The potential decreases by about 70 mv per decade increase of pressure at constant current density. At constant potential, 8 log i/0 pH = 0.5. The usual Arrhenius temperature dependence was observed with an apparent activation energy of 22 kcal mole at the reversible potential, calculated by extrapolation from the Tafel region. Radiotracer studies showed that adsorption isotherm is Langmuirian, and that high coverages are obtained in the potential and concentration range studied. 

Fig. 8.2 H2S partial pressure effect on equilibrium, calculated using Gaseq (Chemical equilibria in perfect gases)...

Orozco EO, Vrinat M (1998) Kinetics of dibenzothiophene hydrodesulfurization over M0S2 supported catalysts modelization of the H2S partial pressure effect. Appl Catal Gen 170 195-206... 

The above relations of anode overpotential (Eqs. 8.15a and 8.15b) and cathode overpotential (Eqs. 8.16a and 8.16b) only employ the partial pressure effect of gases. A lot of previous works on the electrode kinetics have been done with a coin type single cell, which had a geometric electrode area of about 3 cm. They were carried out with a very low gas utilization that was sufficient to neglect the gas-phase mass-transfer effect. The low utilization, however, was far from the actual condition where the anode utilization is normally over 70%. In addition, the performance of MCEC depends on the gas flow rate even in the 100 cm class single cell as shown in Fig. 8.3. To investigate the flow rate effect in the MCFC, the inert gas step addition (ISA) method has been developed [22], ISA can vary the utilization without changing gas compositions, and thus the flow rate effect could be analyzed. 

The performance of a HT-PEMFC depends mainly on the amount of phosphoric acid in the polymer membrane and in the porous catalyst layer as well as on the temperature. Furthermore, it is well known that phosphoric acid dehydrates at low water vapour partial pressure and rehydrates with increasing partial pressure, effects which can be observed in HT-PEMFCs under operating conditions [1, 2]. The composition change of phosphoric acid results in a variation of the ionic conductivity as well as of the viscosity. 

An example of partial pressure effects may be described by calculation of the first endothermic kaolinite reaction. Using Arens specific heat data for kaolinite and calcined kaolinite, 0.201 and 0.428 cal/gm/°C, respectively, and molar heat capacities of 51.1 and 75.0 cal/mole/°C, respectively, the evolution of two moles of water requires another 18.0 cal/mole/°C and the AC, is calculated to be 60 cal/mole/°C. For observed peak shifts at 545 and 620°C (heating rates of 6 and 10°C per min) and a heat of decomposition of 200cal/gm the preceding equation may be partially evaluated ... 

Similar findings of partial pressure effects have also been noted by other researchers (Younesi et al 2005). However, a critical analysis of partial pressure effects on key gas substrate enzymes has not been undertaken. This work will provide aitical information towards developing a predictive model that can be nsed to understand how carbon dioxide partial pressure affeets formate dehydrogenase (FDH), which is one of the three gas-substrate enzymes. 

Hurst KM, Lewis RS. 2010. Carbon monoxide partial pressure effects on the metabolic process of syngas fermentation. Biochemical Engineering 48 159-165. 

Carrier distillation involves the recycling of the overhead product so that its carrying or partial-pressure effect can reduce the vaporization temperature. The process has been developed by the Lummus Company. Figure 7-20 shows features of the process, and Fig. 7-21 indicates the reduction in boiling point that may occur. According to Fig. 7-21, the amounts of material vaporized at 700°F are... 

Top Temperature. The temperature at the top of the tower must be just high enough to allow complete vaporization of the overhead product. A lower temperature will condense a part of the desired overhead product and incorporate it in the first side-draw product, and a higher temperature will cause the inclusion of high-boiling materials which are not desired in the overhead product. If the top of the tower is at atmospheric pressure and no steam is used, the 100 per cent point of the equilibrium vaporization curve of the overhead product is the top temperature. Such a rimple case is seldom encountered, and hence the top temperature at 760 mm must be corrected for the tower pressure and for the partial-pressure effect of steam or gas. 

In the condensation zone, the temperature may be computed with accuracy by means of the equilibrium condensation curve (Examples 4-5 and 4-6) of the oil vapor, corrected for the total pressure within the condenser and for the partial-pressure effect of the steam. In some... 

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