Nitrogen material balance

As shown in Table II, in the presence of polymer, the enclosed nitrous oxide is completely consumed during irradiation. In the place of nitrous oxide, nitrogen and water are formed. The yield of nitrogen or water corresponds stoichiometrically to the loss of nitrous oxide. A large G value, about 2000, is given for the disappearance of nitrous oxide. Estimation of the G value is based on the assumption that the available energy for the consumption is only that absorbed directly by the gas dissolved in the polymer solid. The G values for the formation of water and nitrogen should be equal to 2000. Moreover, the summation of the amount of the excess formation of crosslinks and unsaturation becomes stoichiometrically almost equal to the loss of nitrous oxide, as shown in Table III. The equation of material balance of nitrous oxide, therefore, should be written as follows ... 

Husain and Norrish215 obtained a measurement of k5 in the isothermal flash photolysis of nitrogen dioxide at room temperature. Their calculations depend on knowing the concentrations of N02, N03, NO, and O obtained by calibration of photographic plates and material balance and on knowing the value of the rate constant for the reaction... 

The SRC-II liquid was obtained from the Pittsburg and Midway Coal Mining Co. The liquid was produced from Material Balance Run No. 77 SR-12 on coal from the Pittsburg seam from Consol s Blacksville No. 2 Mine in West Virginia. The middle (177-288° C) and heavy (288-454°C) distillates were blended to the same ratio as produced by the material balance run, e.g., 75.5 percent middle distillate and 24.5 percent heavy distillate. The feed contained 0.23 wt-pct sulfur, 1.06 wt-pct nitrogen and 3.29 wt-pct oxygen and boiled between 185 and 380° C (5-95 percent) by simulated distillation. 

Set up the material balance and calculate the composition and quantity of the flue gas. Convert to a mass basis because it is always true (unless there is a conversion between mass and energy) that from a mass standpoint the input equals the output plus the accumulation. In the present problem, there is no accumulation. The output (the flue gas) includes nitrogen from the air and from the natural gas, plus the 15 percent excess oxygen, plus the reaction products, namely, 0.40 mol/s C02 and 2(0.40) = 0.80 mol/s water. 

The interstage flow could also be calculated from material balance considerations at the top end of the system. When no product is being withdrawn, the mg. atoms of 4-f and 2+ nitrogen leaving as waste must be equal to the total feed flow L/ in mg. atom N/minute as NO2 or N2O4. The mg. atoms N/minute of 2-f nitrogen as NO in the waste stream is then Lf(l — x ) which must be equal to the 4-f nitrogen that entered the refluxer and was reduced to NO thus. 

Inorganic particulate nitrate products would be added if it were necessary to complete the material balance to account for nitrogen (36). 

Acetone (denoted as Ac) is partially condensed out of a gas stream containing 66.9 mole% acetone vapor and the balance nitrogen. Process specifications and material balance calculations lead to the flov/chart shown below. 

Nitrogen oxides—primarily nitric oxide (NO) and nitrogen dioxide (NO2)—are formed during the combustion of fossil fuels with air. Table I shows source estimates developed for EPA. These estimates of pollutant emission rates are based on emission factors developed by past stacksampling data, material balances, and engineering appraisals of other sources similar to the listed sources. 

Material balances can be made for a wide variety of materials, at many scales orsize for the system and-in-various-degrees of-complication. To Qbtain a perspective as to the scope of material balances, examine Figs. 2.3 and 2.4. Figure 2.3 illustrates a world-scale set of mass balances for nitrogen for different systems, while Fig. 2.4 shows a flowsheet for a chemical plant that includes both mass and energy flows. 

From a mass balance on nitrogen (N) as well as on non-nitrogen material (NNM) the following has been found ... 

As was seen in Figure 4, Table I shows that about 12% of the nitrogen fed at this stoichiometry was converted to hydrogen cyanide. Ninety-nine percent of the methane fed was converted to the gaseous products hydrogen and acetylene and also to an unmeasured small quantity of solid product which deposited on the wall. The minor disparity between the nitrogen and carbon material balances indicates the small fraction of material which was lost from the reaction zone to deposition on the reactor walls. 

The adsorbent was Linde Molecular Sieve 5A pellets 1.6 mm in diameter and 3-4 mm long. The dry weight of the molecular sieves was 508.7 grams. The feed was composed of mixtures of SO2 in nitrogen of specified concentrations that were prepared in advance and stored in pressure cylinders. The SO2 concentration in the effluent was measured continuously by a thermal conductivity cell that was recalibrated after every few runs. The estimated accuracy of the measured S02 concentration was within 1.5%. The SO2 material balance was checked for many runs by absorbing the SO2 from the effluent gas in an NaOH solution. The agreement was better than 5% in all cases. The accuracy of the pressure measurement at the outlet of the bed was within 15 mm Hg and that of the temperature in the bed was within 0.25°C. The reproducibility of duplicate runs was better than 5%. 

Essentially all of the conversion of 650°F plus bottom material to transportation fuel occurs in the hydrotreating step. Table II compares the overall material balance and yield and nitrogen levels obtained at Toledo with original pilot plant results. These data indicate that the denitrification activity of the catalyst was consistent with prior results, however the apparent yield structure was different. The differences in yields are attributed to two factors (1)... 

Check safety valve bypasses and drains for leakage. Place yom hand on the downstream side of each to find if these are warm. Leakage will affect the material balance. If it cannot be prevented, check if it can be estimated from flare or vent header analysis for certain components. Adjust the nitrogen flow to the flare or vent header accordingly. 

The quantity of adsorbed nitrogen may be obtained by material balance for the time during which it was being removed from the flowing stream. For the data from Run 3, it is estimated that the nitrogen content of 5.8 ft of hydrogen was adsorbed, i.e., 0.0765 g N2/g of catalyst. 

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