Rich gas

Polymer Electrolyte Fuel Cell. The electrolyte in a PEFC is an ion-exchange (qv) membrane, a fluorinated sulfonic acid polymer, which is a proton conductor (see Membrane technology). The only Hquid present in this fuel cell is the product water thus corrosion problems are minimal. Water management in the membrane is critical for efficient performance. The fuel cell must operate under conditions where the by-product water does not evaporate faster than it is produced because the membrane must be hydrated to maintain acceptable proton conductivity. Because of the limitation on the operating temperature, usually less than 120°C, H2-rich gas having Htde or no (

Ammonium thiosulfate, stable as a solution, is produced ia the form of a 56—60% solution from ammonia and soHd sulfur or an H2S-rich gas stream or both soHd sulfur and H2S gas streams (68). As a result of avadabihty, only development of solutions for processing x-ray and color film and prints has been encouraged. The evolution of automatic processors to develop and print color reinforced the trend toward use of solutions. Most x-ray laboratories and automatic film and print processors require almost immediate results. 

The overhead temperatures of both the absorber and stripper are kept as low as possible to minimise solvent carryover. A temperature of about 311 K is typically used ia the high pressure absorber. The overhead temperature ia the stripper is set by the boiling poiat of the saturated complex solution and by the operating pressure of the stripper. At a stripping pressure of 0.166 MPa (1.7 atm), a temperature of 378 Kis used. The solvent-rich gas from the stripper is cooled to recover as much solvent as possible by condensation prior to the final aromatics-recovery section. Fiaal solvent recovery is accomphshed by adsorption on activated carbon (95). 

If the solute-rich gas entering the bottom of an absorption tower is cold, the liquid phase may be cooled somewhat by transfer of sensible heat to the gas. A much stronger cooling effect can occur when the solvent is volatile and the entering rich gas is not saturated with respeci to the solvent. It is possible to experience a condition in which... 

Temperature and Humidity of Rich Gas Cooling and consequent dehumidification of the feed gas to an absorption tower can be very beneficial. A high humidity (or relative saturation with solvent) limits the capacity of the gas phase to take up latent heat and therefore is unfavorable to absorption. Thus, dehumidification of the inlet gas prior to introducing it into the tower is worth considering in the design of gas absorbers with large heat effects. 

Table 26-26 hsts some of the main commercial methods used to generate nitrogen or nitrogen-rich gas. 

TABLE 26-26 Commercial Methods Used to Generate Nitrogen or Nitrogen-Rich Gas... 

Cryogenic processes using turboexpanders facilitate high levels of ethylene recovery from refinery gas while producing byproducts of hydrogen- and methane-rich gas. In a cryogenic process, most of the ethylene and almost all of the heavier components are liquified and ethylene is separated from this liquid. 

Edmister Method (1947). Briefly, the Edmister absorption method (1947) with a known rich gas going to a fixed tower is as follows ... 

Recently, Tanuma and Palnichenko [24] have reported a new form of carbon which they call Carbolite formed by quenching high temperature carbon vapour onto a metal substrate. Hexagonal Carbolite I was formed from an Ar-rich gas a rhombohedral form, Carbolite II, was formed from an Ar-Hj gas mixture. 

The Claus process consists of partial combustion of the hydrogen sulfide-rich gas stream (with one-third the stoichiometric quantity of air) and then reacting the resulting sulfur dioxide and unbumed hydrogen sulfide in the presence of a bauxite catalyst to produce elemental sulfur. Refer to the process flow diagram in Figure 7. 

Multistage porous diffuser contactors, which involve a single application of an ozone-rich gas stream and application of fresh ozone gas to second and subsequent stages with off-gases recycled to the first stage. Eductor-induced, ozone vacuum injector contactors, which include total... 

Packed-bed contactors, which include concurrent or countercurrent water/ozone-rich gas flow. 

Two-level diffuser contactors, which involve application of ozone-rich gas to the lower chamber. Lower chamber off-gases are applied to the upper chamber. Offgas treatment from contactors is an important consideration. Methods employed for off-gas treatment include dilution, destruction via granular activated carbon, thermal or catalytic destruction, and recycling. 

As vent collection systems normally contain vapor/air mixtures, they are inherently unsafe. They normally operate outside the flammable range, and precautions are taken to prevent them from entering it, but it is difficult to think of everything that might go wrong. For example, an explosion occurred in a system that collected flarmnable vapor and air from the vents on a number of tanks and fed the mixture into a furnace. The system was designed to run at 10% of the lower explosion limit, but when the system was isolated in error, the vapor concentration rose. When the flow was restored, a plug of rich gas was fed into the furnace, where it mixed with air and exploded [17]. Reference 34 describes ten other incidents. 

Mols of component in outlet gas/mol inlet rich gas Solve for Yu... 

The rich gas from the absorption operation is usually stripped of the desirable components and recycled back to the absorber (Figure 8-57). The stripping medium may be steam or a dry or inert gas (methane, nitrogen, carbon oxides—hydrogen, etc.). This depends upon the process application of the various components. 

The rich gas is known, the theoretical trays are fixed (or assumed and corresponding result obtained), the operating pressure and temperature can be fixed. 

Calculate the mols of each component absorbed by (Mol component in inlet rich gas) (Eai)... 

The total intercooler duty is the difference between the total heat in of the rich gas and lean oil and the total heat out of the off gas and rich oil all at the terminal calculated or design conditions. The total duty is often divided between several coolers placed to re-cool the oil as it passes down the column. If intercoolers are not used, then the absorption cannot meet the design terminal outlet conditions and the quantity of material absorbed will be reduced. If the intercooling is too great so as to sub-cool, then greater absorption may be achieved, but this can be controlled by the intercooler operation. 

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