Pressure trapping

Pilot-operated valves have the advantage of allowing operations n the set point v/ith no leakage, and the set position is not affected by ba pressure. However, they will not function if the pilot fails. If the sens line fills with hydrates or solids, the valve will open at 25% over pressure trapped above the disc (usually the normal operating pre the vessel). For this reason they should be used with care in dirty vice and liquid service. They are used extensively offshore where all platform relief valves are tied into a single header because up to 5 back-pressure will not affect the valve capacity. 

The use of a U-tube sequence operated at less than 1 atm and temperatures below —78 °C. The use of such a reduced-pressure trap would allow lower trap temperatures without the collection of solid C02 and would also increase the superficial linear velocity of the gas as it passes through the trap. This type of a system appears feasible but was not investigated during this program because other concepts seemed to offer comparable or better collection efficiencies. 

Analyzer Cell General term used for the lower pressure trapped... 

Ethylene-copolymer melts generally have a vinyl acetate proportion of approx. 5 to 35% by weight, equivalent to a melt index of Ml216/i9o°c=2 to 500 g/10 min. The melt temperatures in the low-pressure trap range from 160 to 200 °C, depending on the viscosity of the melt. Depending on the polymerization and on the pressure in the low-pressure trap, the melt contains free vinyl acetate (approx. 4000 ppm) in addition to the known ethylene content of... 

Low-pressure trapped melts crystallize plagioclase, and it has been documented that the relatively much less abundant plagioclase-bearing abyssal peridotites are products of refertihzation by trapped melt (e.g., Dick, 1989). For this reason,... 

CT - chemical traps 120-150 mL of Silica Gel 60 (230/ ifOO mesh, EM Reagents, methanol-rinsed, activated at 110, 20 hours) in high pressure traps (prototypes, Adsorbents and Dessicants of America)... 

The configuration of the reactor for the supercritical-phase reaction was similar to that of a conventional pressurized fixed-bed flow reactor system. The only difference was that a vaporizer and an ice-cooled high pressure trap were set upstream and downstream of the reactor, respectively, as shown in Figure 4.8-1. To compare characteristic features of the gas-phase, liquid-phase and supercritical-phase reactions, all three kinds of reactions were conducted in the fixed bed reactor. The liquid-phase reaction was operated in a downflow-type trickle bed. The balance materials were nitrogen for the gas-phase reaction, and n-hexadecane and nitrogen for the liquid-phase reaction [15-17]. 

The SC methanol synthesis was performed in a conventional fixed-bed reactor where a vaporizer and an ice-cooled high-pressure trap were set upstream and downstream of the reactor, respectively, as shown in Fig. 1. The catalyst was loaded into the reactor, and then reduced at 493 K by 10% H2 diluted in He for 1 h. After the reduction, the reactors were adjusted to the reaction condition. The standard reaction conditions were as follows partial pressure of syngas (CO/CO2/H2/Ar 32/5/60/3) = 10 bar, catalyst weight of 0.50 g (20-40 mesh), W/Fsyngas of 10 g of cat. h. mol. Ar was an inner standard. Various alcohols were selected as the SC cataljdic fluid as shown in Table 1. In... 

Figure 5.14 Variation of the density of transverse cracks in cross-ply laminates produced by three manufacturing processes. The manufacturing process for the lowest curve (Plate 3) is the standard autoclave process (specified hy the manufacturer), while in Plate 2 vacuum was not applied, and Plate 1 was not consolidated by external pressure, trapping air between...

What about comparison between theory and experiment for those few systems in which lalxnatory values for or upper limits to radiative association rate coefficients are available Two systems - C " + Ho - and CH3" + H> - have been studied both by a low pressure ion trap method, in which is determined directly, and a higher pressure trap method, in which kj. is determined via extrapolation of a linear plot of k ff vs density to zero density. The results are shown in Table ni below along with theoretical phase space results derived from papers of both Herbst and Bates. The experiments utilize "normal" hydrogen, in which the cntho/para ratio is 3/1, so that the results do not pertain to the interstellar medium where H2 is thought to be in true tiiermodynamic equilibrium. In addition, care must be taken not to attempt to direct comparison with the published theoretical results on (Herbst 1982a) which utilizes sub-thermal excitation of Co-... 

The CH3 + H2 data from two different experiments are enigmatic. The low pressure ion trap experiment of Barlow, Dunn, and Schauer (I984a,b) has been claimed by Bates (1986d) to have the ions at an effective temperature much h her than the 13 K of the ambient gas. He deduced a stabilization rate kj. of 3.5(4) s T This value of k- leads to a radiative association rate kj. of 3(-13) cm s at 80 K, the temperature in the mgh pressure trap experiment of Gerlich and Kaefer (1988). However, the value of delennined by Gerlich and Kaefer (1988), again a preliminary value, is less than 3(-15) cm s which is almost two orders of magnitude lower. 

High-pressure traps discharge into low-pressure return ... 

The last bolts on the manway should be loosened and carefully spread open to ensure that there is no pressure trapped in the vessel. 

Schweikhard, L. Guan, S. H. Marshall, A. G. Quadrupolar excitation and colUsional cooling for axialization and high-pressure trapping of ions in Fourier-transform ion-cyclotron resonance mass-spectrometry. Int. J. Mass Spectrom. Ion Processes 1992, 120, 71-83. 

The blackbody infrared radiative dissociation (BIRD) technique can be considered as the reverse process of radiative association. At very low pressure, trapped ions (essentially in an ICR cell) are slowly dissociated by the blackbody radiation emitted by the walls of the ICR cell [127]. 

High Pressure Trapping with Subsequent Recovery by Solidification of the Carbon Dioxide... 

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