Hydrocarbon absorber design

An excellent review of hydrocarbon absorber design is presented by Diab and Maddox. The simplest approach uses the design equations developed by Kremser and Souders and Brown and discussed in the preceding section for each individual component in the system. The application of this approach to multicomponent absorption is illustrated by this example from the GPSA Engineering Data Book ... 

A general, approximate, short-cut design procedure for adiabatic bubble tray absorbers has not been developed, although work has been done in the field of nonisothermal and multicomponent hydrocarbon absorbers. An analytical expression which will predict the recovery of each component provided the stripping factor, ie, the group is known for each component on each tray of the column has been developed (102). This requires knowledge... 

Generally, techniques for designing absorbers and strippers for multicomponent systems have been aimed at the recovery of light hydrocarbons from natural or refinery gas streams usir trqr towers. Numerous shortcut calculation methods have been developed to obviate the need for tedious tray-lqr-ttay calculations however, the importance of these techniques has declined sonrewhat because of (1) the advent of small powerful computers and (2) the use of low-temperature separation instead of oil absorption to recover light hydrocaitwns. As a result, the cahwlational techniques for multicomponent hydrocarbon absorbers are treated rather briefly in this section. 

In the standard method, the metal enclosure (called the air chamber) used to hold the hydrocarbon vapors is immersed in water before the test, then drained but not dried. This mode of operation, often designated as the wet bomb" is stipulated for all materials that are exclusively petroleum. But if the fuels contain alcohols or other organic products soluble in water, the apparatus must be dried in order that the vapors are not absorbed by the water on the walls. This technique is called the dry bomb" it results in RVP values higher by about 100 mbar for some oxygenated motor fuels. When examining the numerical results, it is thus important to know the technique employed. In any case, the dry bomb method is preferred. 

If I ever have to design an amine plant I will know, for example, that the temperature of the lean amine solution entering the absorber should be about 10°F higher than the inlet gas temperature to prevent hydrocarbon condensation and subsequent foaming, that the reboiler tube bundle should be placed on a slide about six inches above the bottom of the shell to provide good circulation, that about two percent of the total circulating flow should pass through the carbon towers, and many other necessary requirements. 

This process uses propylene carbonate as a physical solvent to remove CO2 and H2S. Propylene carbonate also removes C2+ hydrocarbons, COS, SO2, CS2, and H2O from the natural gas stream. Thus, in one step the natural gas can be sweetened and dehydrated to pipeline quality. In general, this process is used for bulk removal of CO2 and is not used to treat to less than 3% CO2, as may be required for pipeline quality gas. The system requires special design features, larger absorbers, and higher circulation rates to obtain pipeline quality and usually is not economically applicable for these outlet requirements. 

The v.ct glycol from the separator flows through a sock filter to remove. solids and a charcoal filter to absorb small amounts of hydrocarbons that may build up in the circulating glycol. Sock filters are normally designed for the removal of 5-micron solids. On units larger than 10 gpm... 

Rowland, C.H., Grens, E.A., II Design Absorbers Use Real Stages, Hydrocarbon Processing, Sept. 1971, p. 201. 

In cell culture, lycopene is a highly oxidizable nonpolar hydrocarbon supplied in an aqueous medium and is incubated at body temperature for 12-72 h. The amount of intact lycopene or its oxidation products delivered to and absorbed by various cell types is an important factor to keep in mind when evaluating the effects of lycopene on various cellular processes. Before reviewing cell culture studies designed to characterize the effects of lycopene on prostate cell biology, the characteristics of prominent prostate cell lines, and the stability and uptake of lycopene by various prostate cell lines are reviewed. 

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