Gas at atmospheric pressure

In summary, starting with 105°F gas at atmospheric pressure, the theoretical work necessary to liquify one pound of methane is 510.8 Btu or 352 hp/MMcfd. The simplified liquefaction process, as illustrated, uses a turboexpander/compressor and a small propane refrigeration unit. The 41.25% efficiency breaks down as follows one-fourth contributed by the turboexpander/compressor at 35.8% efficiency one-sixteenth contributed by the mechanical propane refrigeration unit at 43% efficiency, at a moderate temperature where its efficiency is high and a large fraction—eleven-sixteenths—contributed at 58.2% efficiency by compression and Joule-Thomson condensation energy. 

In a centrifugal compressor, air or gas at atmospheric pressure enters the eye of the impeller. As the impeller rotates, the gas is accelerated by the rotating element within the confined space that is created by the volute of the compressor s casing. The gas is compressed as more gas is forced into the volute by the impeller blades. The pressure of the gas increases as it is pushed through the reduced free space within the volute. 

L. Seglin Was this conclusion sensitive to the purification system you are using or did you just exclude that Did you assume you had gas at atmospheric pressure or at some higher pressure ... 

A novel reactor for pyrolysis of a PE melt stirred by bubbles of flowing nitrogen gas at atmospheric pressure permits uniform temperature depolymerisation. Sweep-gas experiments at temperatures 370-410 C allowed pyrolysis products to be collected separately as reactor residue (solidified PE melt), condensed vapour, and uncondensed gas products. MWDs determined by GPC indicated that random scission and repolymerisation (crosslinking) broadened the polymer-melt MWD. 19 refs. USA... 

How many collisions occur, roughly, in a liter of gas at atmospheric pressure, and what fraction of these collisions will normally give rise to a reaction (assuming commonly applied reaction temperatures and barrier energies) ... 

Since hydrogen sulfide exists as a gas at atmospheric pressure, partitioning to the air is likely to occur after environmental releases. However, the compound is also soluble in oil and water, and therefore, may partition to surface waters, groundwaters, or moist soils, and subsequently travel great distances. In addition, sorption of hydrogen sulfide from air onto soils (Cihacek and Bremner 1993) and plant foliage (DeKoketal. 1983, 1988, 1991) may occur. 

Fixed systems are classified in the manner they are stored. Low pressure 2,068 kPa (300 psi) or high pressure 5,860 kPa (850 psi) systems can be specified. Low pressure systems are normally provided when the quantity of agent required exceeds 907 kgs (2,000 lbs ). Protection of electronic or electrical hazards usually requires a design concentration of 50% by volume. NFPA 12 provides a table specifying the exact concentration requirements for specific hazards. As a guide, 0.45 kgs (1 lb.) of CO2 liquid may be considered to produce 0.23 cubic meters (8 cu. ft. ) of free gas at atmospheric pressure. 

Data for the uncatalyzed polycondensation from STA (simultaneous TGA/DTA) experiments under high-flow inert gas at atmospheric pressure [8] are shown in Figure 2.28. These data also demonstrate the dependency of the overall polycondensation rate on the polymer film thickness. 

In the TRAPI experiment, the new ions that are formed immediately after each X-ray pulse are often of greatest interest. Later in time, these relatively energetic ions will be converted to more stable terminal ions by unavoidable reactions with common buffer gas impurities (primarily water). Because ions are lost relatively slowly at atmospheric pressure, these terminal ions can persist in time over many pulse cycles (25 to 50 X-ray pulses are applied per second) while the fast decay curves of the more energetic ions are monitored after each pulse. In this way, for example, the rate of the reaction of NJ with added Oj was determined from the observed time dependence of the Nj ion in nitrogen buffer gas at atmospheric pressure during the first 300 (is after each X-ray pulse. 

Figure 4, Structure of a series of alkyl bromides and the rate constants (1 O " cm s ) for the IM reaction of each compound with the chloride ion, determined by the photodetachment-modulated electron capture detector (PDM-ECD) in 10% argon-inmethane buffer gas at atmospheric pressure and 125 °C. ...

Figure 7. (A) Reaction-modified IMS spectrum for the reaction of Cl" with CHjBr in nitrogen buffer gas at atmospheric pressure and 125 °C with 1.95 x 10 mole-cules/cm of CHjBr in the drift gas. (B) Mass-analyzed IMS spectra of the Cl" and Br" ions under identical reaction conditions. ...

Figure 13. Reaction-modified IMS spectra for the reactions of chioride ion with (A) n-butylbromideand (B) /-propylbromide in nitrogen buffer gas at atmospheric pressure and 125 °C. The concentrations (molecules/cm ) of the alkylbromide added to the drift gas are indicated. The peaks at drift times greater than 0.050 seconds are due to impurities formed in the ion source and do not affect the kinetic measurements of interest.

However, the sohd density is approximately 1000 times the density of a gas at atmospheric pressure, and molecules in gases and liquids have much higher drSusivities than in solids. Therefore, the reacting boundary (I or R) moves very slowly compared to the motion of gas molecules to and from the boundary, and we can assume that concentration profiles near this boundary remain in steady state while we calculate the steady-state concentration profiles in the reaction... 

A sample, referred to as H2G, was treated in-situ with flowing hydrogen gas at atmospheric pressure and room temperature. 

When the mean free path is approximately the same as the channel diameter, as with coarse powders at reduced gas pressures or fine powders with the gas at atmospheric pressures, the gas will behave as though there were slippage at the channel walls. This occurs because collisions between molecules rebounding from a wall and the flowing molecules occur uniformly across the diameter of the channel. Therefore, there appears to be no preferential retardation of flow near the channel wall when compared to the center of the channel. 

Propane can be stored as liquid in pressurized (approximately 15 atmospheres) storage tanks and/or at cold temperatures and vaporizes to a gas at atmospheric pressure and normal temperatures. This makes it possible to store a large volume of propane as a liquid in a relatively small volume propane as a vapor occupies 270 times the volume of propane in liquid form. This makes liquid propane an ideal fuel for transport and storage until needed. 

The negative sign indicates that heat flows in the direction of negative temperature gradient, namely, from warmer to colder points. Some examples of the approximate values of thermal conductivity (kcalh m °C ) at 20 °C are 330 for copper, 0.513 for liquid water, and 0.022 for oxygen gas at atmospheric pressure. Values of thermal conductivity generally increase with increasing temperature. 

The total gas sample during an experiment, usually between 100 and 200 liters, was collected in a bag made from a roll of Polythene tubing sealed at each end and fitted with an inlet nozzle. The Polythene tube, when lying flat, was 1 ft. wide, and when it was filled with 100 liters of gas at atmospheric pressure, it produced a cylindrical bag about 10 ft. long. Only a very small pressure difference was required between the inside and the outside of the bag for filling and emptying. 

Figure 6-7 may be used to obtain the viscosities of the usual constituents of natural gas at atmospheric pressure for use in Equation 6-16.4... 

Interstitial volume. Vj (Vg). The volume occupied by the mobile phase (carrier gas) in a packed column. This volume does not include the volumes external to the packed section, i.e., volume of sample injector and volume of the detector. In GC it corresponds to the volume which would be occupied by the carrier gas at atmospheric pressure and zero flowrate in the packed section of the column. 

Electrospray mass spectroscopy (EMS) is the mass spectroscopy of gaseous ions produced by electrospraying into a suitable gas at atmospheric pressure a dilute solution containing as solute the macromolecules in question. (Although the use of other gases is possible, we have obtained our best results with nitrogen gas.) Although the technique is... 

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