Hydrocarbon Removal

The impurities usually found in raw hydrogen are CO2, CO, N2, H2O, CH, and higher hydrocarbons. Removal of these impurities by shift catalysis, H2S and CO2 removal, and the pressure-swing adsorption (PSA) process have been described (vide supra). Traces of oxygen in electrolytic hydrogen are usually removed on a palladium or platinum catalyst at room temperature. 

Liquid hydrocarbons removed from the production stream but not from oil refining... 

Poppendieck, D.G., Loehr, R.C. and Webster, M.T., Predicting hydrocarbon removal from thermally enhanced soil vapor extraction systems. 2. Field study, J. Hazard. Mater., 69, 95-109, 1999. 

More recently Miron and Lee (1962) analysed the hydrocarbons removed from strong acid catalysts in some detail, and suggested unsaturated cyclic structures. These structures contain from one to five five-membered rings with various methyl and alkenyl substituents and a minimum of two double bonds per molecule. However, during their drowning procedures, as the acid is diluted, considerable polymerization occurs. This conclusion is based on work by Hodge (1963), who showed that cyclopentenyl cations are rapidly destroyed by alkylation at 10 m concentrations in 35% H2SO4. 

In AAC technologies, water is exposed to an AAC material, and metals in the water are adsorbed by the material. AAC systems can be designed and built as stand-alone units or integrated to work efficiently in concert with complementary water treatment systems designed for hydrocarbon removal, pH control, particulate removal, or electrodialysis. AAC systems can tolerate hard water (calcium and magnesium) and high temperatures (up to 200°F) without a decrease in performance. 

The EiAD technology is only marginally effective for hydrocarbon removal. 

Case A. Transfer of hydrocarbon from water to hydrocarbon. The transfer of a hydrocarbon solute of surface area A from water to hydrocarbon removes the hydrocarbon-water interface (w = — yHc/w) and creates a hydrocarbon-vacuum and a water-vacuum interface (w = yHC + yw) formation of a cavity in the hydrocarbon solvent creates a hydrocarbon-vacuum interface (w = ync) transfer of the hydrocarbon solute to the hydrocarbon, and collapse of the water-vacuum cavity, loses two hydrocarbon-vacuum surfaces and a water-vacuum surface (w = — 2yHC — yw). The free energy of transfer, AGtrans, is given by A X Sw i.e.,... 

Volatile non-adducting impurities e.g. ILtSi, R2Zn and hydrocarbons, removed in vacuo at low to moderate temperature. 

Compressed air source, -10 psi, with water and hydrocarbon traps (e.g., Model 75-45 Purge Gas Dryer for FTIR and Model A963-000 Trace Hydrocarbon Remover, both available from Balston)... 

Fig. 1. Effect of Pb level on hydrocarbon removal (Oilead free A 0.5, Ckl.5, 0 3 g Pb/gal). [From Weaver (79).] (Reprinted with permission of the Society of Automotive Engineers.)...

Figure 8 Cumulative gasoline-equivalent hydrocarbon removal...

A quantitative comparison of the kinetics of hydrocarbon removal based on the changes in band intensities was not attempted. Extracting quantitative... 

Terminal alkynes are much more acidic than other hydrocarbons. Removal of an... 

Zheng, Z. Obbard, J. P. (2002). Polycyclic aromatic hydrocarbon removal from soil by surfactant solubilization and Phanerochaete chrysosporium oxidation. Journal of Environmental Quality, 31, 1842-7. 

Although the Pt/Rh catalyst generally retains good efficiency for hydrocarbon control, it is desirable to enhance the efficiency of catalysts for hydrocarbon removal in the light of the severe future U.S. hydrocarbon standards. Developments in palladium catalyst technology have resulted in a significant improvement in hydrocarbon control. These catalysts will see application in close-coupled converter systems, either as a single palladium catalyst or as a palladium catalyst in combination with rhodium [9] and in some... 

Unfortunately there is an aging problem for PTMSP, resulting in deterioration of its transport properties with time. As shown in Figure 9.16, permeability decreased by one order of magnimde during the first 3 months, whereupon permeability stabilized. Selectivity remained stable during this period. But even the aged PTMSP is still a viable alternative to mbbery polymers for heavy hydrocarbon removal. 

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