Global Hydrogen Balance

All of these methods require the use of analytical equipment unfortunately, such equipments are not always available in the refineries. Alternatively, the hydrogen content can be estimated by the empirical correlations reported in Table 12.10. 

Empirical Correlations to Estimate the Hydrogen Content in Petroleum Fractions Authors 

Developed with 247 aviation fuels and 84 pure hydrocarbons 

Developed with 33 different FCC feedstocks Developed for jet fuels with aniline points in the range 

The oldest and simplest approach Derived from data on jet fuels 

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Table 12.12 shows the operating conditions for the different experiments conducted at bench-scale. Some feedstocks were prepared by blending various streams as indicated in the table. Table 12.13 describes the catalysts used in the experiments. Table 12.14 reports the characterization of the feed and product for each hydrotreating test. Global mass balances for all experiments showed an error lower than 0.8%, while the global hydrogen balances presented an error lower than 1%. Therefore, the experimental data obtained from the HDT of petroleum fractions can reliably be used to determine the hydrogen consumption. 

The global hydrogen balance requires experimental ultimate analyses to determine hydrogen consumption hence, it is rarely reported by refineries, and they... 

FIGURE 12.8 Hydrogen consumption by global hydrogen balance with experimental data. 

Figure 12.9 shows a comparison of the experimental hydrogen consumption and that determined from the global hydrogen balance using correlations to calculate the hydrogen content in liquid streams. 

Figure 4-13 shows an example from a three-dimensional model simulation of the global atmospheric sulfur balance (Feichter et al, 1996). The model had a grid resolution of about 500 km in the horizontal and on average 1 km in the vertical. The chemical scheme of the model included emissions of dimethyl sulfide (DMS) from the oceans and SO2 from industrial processes and volcanoes. Atmospheric DMS is oxidized by the hydroxyl radical to form SO2, which, in turn, is further oxidized to sulfuric acid and sulfates by reaction with either hydroxyl radical in the gas phase or with hydrogen peroxide or ozone in cloud droplets. Both SO2 and aerosol sulfate are removed from the atmosphere by dry and wet deposition processes. The reasonable agreement between the simulated and observed wet deposition of sulfate indicates that the most important processes affecting the atmospheric sulfur balance have been adequately treated in the model. 

After closing the material and heat balances, we will examine the potential environmental impact (PEI) of the design. The basic information is the stream report. Table 5.16 shows material- and heat-balance data for a fresh feed of 150kmol/h phenol and 350kmol/h hydrogen, in total 14822.5kg/h. The products are cyclohexanone 9618.9 and 5017.9 cyclohexanol in the molar ratio 2 1. After simulation it is found that the amount of waste is 150.6 kg/h lights and 80 kg/h heavies. These data lead to a global yield of raw materials of 98.75%. 

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