Closing pressure

The repressurization step returns the adsorber to feed pressure and completes the steps of a PSA cycle. Pressurization is carried out with product and/or feed. Pressurizing with product is done countercurrent to adsorption so that purging of the product end continues indeed it may be merely a continuation of the purge step but with the bed exit valve closed. Pressurizing with feed cocurrent to adsorption in effect begins adsorption without producing any product. 

Because at higher latitudes the coriolis force deflects wind to a greater extent than in the tropics, winds become much more zonal (flow parallel to lines of latitude). Also in contrast to the persistent circulation of the tropics, the mid-latitude circulations are quite transient. There are large temperature contrasts, and temperature may vary abruptly over relatively short distances (frontal zones). In these regions of large temperature contrast, potential energy is frequently released and converted into kinetic energy as wind. Near the surface there are many closed pressure sys-... 

Another feature of the centrifugal is its ability to admit or extract flow to or from the main flow stream, at relatively close pressure intervals, by means of strategically located nozzles. These flows are referred to as side-... 

Conventional Safety Relief Valve - A conventional safety relief valve is a closed-bonnet pressure relief valve that has the bonnet vented to the discharge side of the valve and is therefore unbalanced. The performance characteristics, i.e., opening pressure, closing pressure, lift and relieving capacity, are directly affected by changes of the back pressure on the valve. 

This valve provides an internal design (usually bellows) above/on the seating disk in the huddling chamber that minimizes the effect of backpressure on the performance of the valve (opening pressure, closing pressure and relieving capacity) [35]. See figures 7-4, 7-6, and 7-6A. 

Closing Pressure the pressure established as decreasing inlet pressures when the disk of the valve seats and there is no further tendency to open or close. 

J. Pressure ventilated large induction or synchronous motors A Pressure Ventilated motor requires a closed pressure system to force filtered air or nitrogen into the motor casing (housing) to avoid corrosive or explosive conditions internally. Constance reference 56 describes some of the details of such a system also see Ecker et al. [69]. 

False. The behaviour of stirred bioreactors does not resemble closely pressure-cycle fermentors at any scale. 

A boiler is a device for heating water or other liquids and is most commonly constructed as a closed pressure vessel, containing a furnace area, purpose-designed heat transfer surface areas, and other functional components. 

Khadilkar and Rebeiro have investigated a new method [107] that overcomes all these problems and is far safer. The authors used closed pressure reactor [108], with no apparent loss of yield. The microwave reactor used for these reactions has a possibility for recording temperature and pressure during irradiation. For example, 1-bu-tyl-3-methylimidazolium chloride was isolated in 91% yield in 24 min [109] at 150 °C and 57 psig was the maximum pressure reached. 

Closed vessel microwave digestion for bones, teeth, hair, and soil Specially designed closed pressurized Teflon vessels may be used for microwave digestion. Teflon is transparent to microwaves, which enhances the effect of the acids by raising the temperature and pressure within the vessel. In addition the closed vessels will retain any volatile components (e.g., Si) in solution. It must, however, be emphasized that any sealed vessels must only be heated if they have been designed for the purpose. Examples of applications include Kingston and Walter (1992), Baldwin et al. (1994), Sheppard et al. (1994), and Tamba et al. (1994). 

The source of these compounds is varied. The butanes are found naturally in crude oils and natural gas. They, plus the olefins, are products of various refinery processes and of olefins plants. They are separated by fractionation, except for butadiene and isobutylene, which are sometimes recovered by extractive distillation. They all vaporize at room temperature, so they are handled in closed, pressurized systems.. 

Due to its stability and water-solubility sodium tetraphenylborate is a particularly convenient starting material for such reactions. Several halogenated heterocycles were phenylated with NaBPlu in aqueous solution with [Pd(OAc)2] catalyst under microwave irradiation (Scheme 6.13) [36]. All reactions were mn under argon in Teflon-closed pressure tubes. It is not easy to compare these results to those of thermal reactions, since the temperature of the irradiated samples is not known precisely. Nevertheless, the microwave method is certainly very effective since 8-12 min irradiation at 100-160 W power allowed the isolation of 60-85 % phenylated products. 

Effect of the initial depressuring rate on the closed pressure relief system and flare... 

In sizing depressuring valves, it should be assumed that heater burners are shut-off, reboilers are shutdown, and normal flow in the vessel has ceased. Vapor depressuring valves should be designed such that the initial, instantaneous depressuring flow rates do not exceed the capacity of the closed pressure relief system and the flare. 

Aqueous methylamine (64 ml, 33.2 mmol) was added to 1,1 -bis(diphenylphospino) 2,2 -bis(a-acetoxyethyl)ferrocene (403 mg, 0.55 mmol) in isopropanol (5 ml) and the reaction mixture was stirred in a closed pressure ampoule at 90°C for 66 hours. After evaporation in vacuo, the residue was dissolved in ethyl acetate/heptane 1 1 and extracted with 10% aqueous citric acid. The aqueous phase was washed with ethyl acetate/heptane 1 1, basified with 2N NaOH basic and... 

The closing pressure for the mold for making uniform foams may be obtained by knowing precisely how the volume of this gel depends on temperature and pressure. 

This arrangement is used as follows in the procedure described above, the force on the sample surface is always equal to that applied by the load over the entire range of pressures and temperatures used in this investigation. The volume, temperature, and pressure behavior over the entire range of temperature and pressure can be determined from the measurements made with this arrangement. With the steel sleeve, g, the closing pressure, PB, can now be determined directly, as that pressure which barely suffices to relieve the force off pistons, fi and fi, by sleeve, g. 

In Figure 6 the broken lines show the experimentally determined closing pressure. Ps, vs. temperature. 

Figure 6. The relationship of the closing pressure, P8, to the temperature for various degrees of filling, /, of the testing space.

Figure 6 shows the relation of closing pressure, P8 to temperature at various degrees of filling. The isochores are not indicated below 400 atm. since the values obtained were only poorly reproducible below this pressure. It can be seen clearly in Figure 6 that, if the test space is 90% filled at 20° C., the specimen will completely fill the space by thermal expansion by the time it reaches 160° C. 

Figure 7 presents in concise form the relation between closing pressures, P8, and three practically important parameters, the filling factor,/, the specific volume,... 

Figure 7. The relationship of the closing pressure, Pt, to the degree of filling, f, to the specific weight, a, and to the specific volume Va at various temperatures.

The closing pressure, in Figure 6 can be determined from the volume changes in Figures 4 and 5, in relation to the volume of the steel sleeve. A constant... 

As shown above, the most important quantity in making foamed plastics (16) is the closing pressure. In the discussion below, the pressure is understood to be that which must be applied to keep the volume of the specimen constant as the temperature is raised. In this way the closing pressure is expressed as the isochore of an equation of state. 

Equation 4 shows that in order to determine the closing pressure from differential data, it is necessary to know the compressibility over the entire range of pressure and temperature. If the system is in equilibrium, the following relation holds ... 

The practically important closing pressure is shown for various temperatures in relation to specific volume, specific weight, and filling factor. The filling factor is the relation between the volume of the specimen and the test space. 

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