Hydrogen mixing ratio

In the platforming process (Fig. 1), the feedstock is usually a straight-run, thermally cracked, catalytically cracked, or hydrocracked C6 to 200°C naphtha. The feed is first hydrotreated to remove sulfur, nitrogen, or oxygen compounds that would foul the catalyst, and also to remove olefins present in cracked naphthas. The hydrotreated feed is then mixed with recycled hydrogen and preheated to 495 to 525°C at pressures of 116 to 725 psi (0.8 to 5 MPa). Typical hydrogen charge ratios of 4000 to 8000 standard cubic feet per barrel (scf/bbl) of feed are necessary. 

Active hydrogen Viscosity, cP, Mix ratio, pph Curing conditions ... 

Curing agent Type Active hydrogen equivalent weight Viscosity, cP, at 25 °C Mix ratio, pph (DGEBA EEW 185) Curing conditions comments Supplier... 

The relatively weak line strengths for hydrogen peroxide limits the detection of hydrogen peroxide to 100 pptv for 5 min integration times. Measurements made with this system showed that the HbOa mixing ratios in rural and ambient air is generally above this detection limit. 

Molecular hydrogen is assumed to be well mixed in the troposphere, with a mixing ratio of 0.4 to 0.6 ppm [Junge (128) and Scholz, Ehhalt, Heidt, and Martell (219)]. Koyama (142) found that swamps and paddies are very small natural sources. Levy (153) proposed both an atmospheric source (photodissociation of formaldehyde) and an atmospheric sink (oxidation by hydroxyl radical). From daily average number densities for the hydroxyl radical and a daily average hydrogen production rate,... 

Fig. 8. Vertical distribution of molecular oxygen (Oj) mixing ratio in prebiological paleo-atmosphere. Calculations for molecular hydrogen (Hj) = 17 ppmv, carbon dioxide (CO2) = 280 ppmv, and three different solar ultraviolet fluxes.

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