Of expanding gas

Gas Cannons. The first cannons were small, crudely made cast metal pots shaped like a vase which fired iron darts. The invention of gun powder about the middle of the 13th century made possible the use of cannon to throw projectiles by use of expanding gas. 

Disadvantages of RESS are high ratios of gas/substance owing to the low solubility of the substance, high pressures (SC conditions) and sometimes temperatures difficult separation of (very) small particles from large volumes of expanded gas and supercritical solutions established discontinuously, and thus there is the requirement for large-volume pressurized equipment. 

In the earliest stage of foaming, the rising foam is a frothlike multiphase system of expanding gas cells surrounded by liquid phase which contains out-of-phase carbamic acid and arylamine carbamates which tend to stabilize the foam. At about the time disubstituted urea can be measured by infrared in the foam, the system achieves its maximum rate-of-rise. These highly polar species begin to "thicken" the system retarding the rate-of-rise. 

Pi is the initial pressure of the compressed gas (psia) Pj is the final pressure of expanded gas (psia)... 

A raised area, often dome shaped, resulting from (1) loss of adhesion between a coating or deposit and the base metal or (2) delamination under the pressure of expanding gas trapped in a metal in a near-sub-surface zone. Very small blisters may be called pinhead blisters or pepper blisters. 

Claude process A process similar to the Linde process for the liquefaction of air, except that additional cooling is produced by allowing the expanding gas to do external work. 

The previous equation is only valid as long as there is no compositional change of the gas between the subsurface and the surface. The value of E is typically in the order of 200, in other words the gas expands by a factor of around 200 from subsurface to surface conditions. The actual value of course depends upon both the gas composition and the reservoir temperature and pressure. Standard conditions of temperature and pressure are commonly defined as 60°F (298K) and one atmosphere (14.7 psia or 101.3 kPa), but may vary from location to location, and between gas sales contracts. 

The basic concepts of a gas-fluidized bed are illustrated in Figure 1. Gas velocity in fluidized beds is normally expressed as a superficial velocity, U, the gas velocity through the vessel assuming that the vessel is empty. At a low gas velocity, the soHds do not move. This constitutes a packed bed. As the gas velocity is increased, the pressure drop increases until the drag plus the buoyancy forces on the particle overcome its weight and any interparticle forces. At this point, the bed is said to be minimally fluidized, and this gas velocity is termed the minimum fluidization velocity, The bed expands slightly at this condition, and the particles are free to move about (Fig. lb). As the velocity is increased further, bubbles can form. The soHds movement is more turbulent, and the bed expands to accommodate the volume of the bubbles. 

During the period from 1950 to 1992, the worldwide proven reserves of natural gas increased at an average annual rate of approximately 6.7% (3—5). In this same period, worldwide production iacreased at an average annual rate of approximately 5.7% (5) so that the annual worldwide consumption of natural gas as of 1992 was equivalent to approximately 1.7% of the proven reserves. This suggests that the proven reserves, assuming the reserves could be deUvered to the existing world markets, could satisfy the requirements of this market for more than 50 years. However, world population is expected to iacrease and the demand for natural gas is expected to expand both ia areas that are heavily iadustrialized and ia areas where iadustrialization activities are underway. 

Condensable Hquids also are recovered from high pressure gas reservoirs by retrograde condensation. In this process, the high pressure fluid from the reservoir produces a Hquid phase on isothermal expansion. As the pressure decreases isotherm ally the quantity of the Hquid phase increases to a maximum and then decreases to disappearance. In the production of natural gas Hquids from these high pressure wells, the well fluids are expanded to produce the optimum amount of Hquid. The Hquid phase then is separated from the gas for further processing. The gas phase is used as a raw material for one of the other recovery processes, as fuel, or is recompressed and returned to the formation. 

---