Oxidation of sulfur dioxide

Adsorption of sulfur dioxide and its oxidation to snlfnr trioxide or snlfuric acid is an interesting way to remove snlfnr dioxide from fine gases (see Chapter 6). 

The snlfnric acid formed remains in the pores of the activated carbon and blocks access to the reactive snrface. It is usually removed by cyclic heat treatment at temperatures above 700 K SO2 (in a more concentrated form) and CO2 + CO are released in the reaction. 

Evidence for a role of incorporated nitrogen in the carbon catalysts was presented when Mochida et al. found very high activity in SO2 conversion by heat-treated ACFs produced from PAN [100,112-115], Such ACFs have nitrogen contents of 4 to 10%, depending on the heat treatment temperature. A continuous removal of SO2 from a synthetic flue gas could be achieved by addition of excess H2O to the flue gas and allowing the more dilute H2SO4 to flow down from the vertically aligned catalyst bed [112,113], It was shown that pitch-based ACFs 

Many authors correlated the SO2 adsorption capacity with the basic centers on the carbon surface [107,108,116,118-120]. However, it has been pointed out that more SO2 was adsorbed than corresponded to the basic centers [102]. This is not surprising since the surface basic sites are quite weak, and SO2 is not a strong acid. Also, no good correlation of SO2 conversion per square meter of surface or nitrogen content was found. The correlation was much better with the N-6 content [108]. It was also reported that the SO2 oxidation capacity increased with increasing N-6 and N-Q contents [118-121]. 

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Oxidation of sulfur dioxide in aqueous solution, as in clouds, can be catalyzed synergistically by iron and manganese (225). Ammonia can be used to scmb sulfur dioxide from gas streams in the presence of air. The product is largely ammonium sulfate formed by oxidation in the absence of any catalyst (226). The oxidation of SO2 catalyzed by nitrogen oxides was important in the eady processes for manufacture of sulfuric acid (qv). Sulfur dioxide reacts with chlorine or bromine forming sulfuryl chloride or bromide [507-16 ]. 

The anaerobic reaction of sulfur dioxide with aqueous ammonia produces a solution of ammonium sulfite [10192-30-0]. This reaction proceeds efficientiy, even with a gas stream containing as Httie as 1 wt % sulfur dioxide. The sulfur dioxide can be regenerated at a high concentration by acidulation or by stream stripping of the ammonium sulfite solution, or the sulfite can be made to precipitate and the ammonia recovered by addition of lime (243). The process can also be modified to produce ammonium sulfate for use as fertili2er (244) (see Fertilizers). In a variant of this process, the use of electron-beam radiation cataly2es the oxidation of sulfur dioxide in the presence of ammonia to form ammonium sulfate (245). 

Vanadium pentoxide, VjOj, is used as a eatalyst in the oxidation of sulfur dioxide. The meehanism involves oxidation-reduetion of V2O5 that exists on the support at operating eonditions in the molten state. The meehanism of reaetion is ... 

Heal content, 110. 116 change (luring a reaction, 110 of a substance, 109 Heat of combustion of diamond, 122 graphite, 122 hydrazine, 47 hydrogen, 40 methane, 123 Heat of formation, 113 Heat of reaction, 135 between elements, table, 112 oxidation of HC1, 160 oxidation of sulfur dioxide, 161 predicting, 112 Heat of reaction to form ammonia, 112 Br atoms, 290 carbon dioxide, 112 carbon monoxide, 112 Cl atoms, 290 CO + Hi, 110 ethane, 112 F atoms, 290 H atoms, 274 hydrogen chloride, 160 hydrogen iodide, 112 iron(Ill) oxide, 162 Li atoms, 290 Li + Br, 290 Li + F, 290 Na + Cl, 290 NHs products, 114 Na atoms, 290 NO, 112 NOj, 112... 

Gasoline normally contains 0.04% by weight of sulfur, which is oxidized into sulfur dioxide in the engine. Automobiles contribute about 2% of manmade sources of sulfur in the air. It has been reported recently that oxidation catalysts may accelerate the oxidation of sulfur dioxide to sulfates, which is a more serious respiratory hazard than sulfur dioxide. It may be necessary to reduce the sulfur in gasoline. 

Additionally, the vanadium acts as a catalyst for the oxidation of sulfur dioxide (S02) to sulfur trioxide (S03). Consequently, the S03 content of the furnace gases increases from perhaps 10 ppm to 30 ppm or more. At 30 ppm S03, the dew point of the sulfuric acid generated is high enough to saturate the air heater, and this unit rapidly corrodes (typically within 1-2 years). To prevent this corrosion, the S03 content in the flue gas stream must be below 7 ppm. 

Infrared spectroscopy, 39, 69 Inorganic melts as electrolytes, 482 oxidation of sulfur dioxide, 482 Interface... 

Two successive stages in the industrial manufacture of sulfuric acid are the combustion of sulfur and the oxidation of sulfur dioxide to sulfur trioxide. From the standard reaction enthalpies... 

Example 4.5 Suppose the recycle reactor in Figure 4.2 is used to evaluate a catalyst for the manufacture of sulfuric acid. The catal5Tic step is the gas-phase oxidation of sulfur dioxide ... 

A platinum catalyst supported on AI2O3 is used for the oxidation of sulfur dioxide ... 

Oxidation of sulfur dioxide so2 - - o2 V205 or Pt S03 used in manufacture of oleum and sulfuric acid... 

Mathur and Thodos Chem. Eng. Sci., 21 (1191), 1966] used the initial rate approach to analyze the kinetics of the catalytic oxidation of sulfur dioxide. They summarized the most plausible rate controlling steps for the reaction as ... 

Olson, Schuler, and Smith (86) have studied the catalytic oxidation of sulfur dioxide in a differential fixed bed reactor. 

In Illustration 12.5, we considered the problem of estimating the concentration differences that exist between the bulk fluid and a catalyst used for the oxidation of sulfur dioxide. If the reported temperature is that of the bulk fluid, determine the external surface temperature corresponding to the conditions cited. Additional useful data are ... 

Vanadium pentoxide may be used as a catalyst for the oxidation of sulfur dioxide to sulfur trioxide. 

Eklund, R.B. (1956), The Rate of Oxidation of Sulfur Dioxide with a Commercial Vanadium Catalyst, Almgvist and Wik-sell, Stockholm. 

One of the steps in the prodnction of sulfuric acid involves the catalytic oxidation of sulfur dioxide. 

It is well known that ozone is quite soluble in water. Therefore, one expects that ozone absorption wi sulfur dioxide would contribute to significant oxidation of sulfur dioxide. Experiments of Penkett have shown that oxidation of sulfur dioxide in air at 7 ppb when absorbed in water droplets with ozone, which is present in surrounding air at 0.05 ppm, can be as large as 13%/h. Thus, foggy or cloudy air mixed with... 

Bufalini, M. Oxidation of sulfur dioxide in polluted atmospheres—A review. Environ. Sci. Technol. 5 685-700, 1971. 

Other substances decrease or annihilate, even in traces, the catalytic properties of iron. Such catalyst poisons had already been known as a nuisance in the catalytic oxidation of sulfur dioxide. With the ammonia catalysis several elements, particularly sulfur proved to be harmful, even in amounts of 4oo of one per cent. Chlorine, phosphorus and arsenic showed a similar behavior (30), just as certain metals, such as lead, tin and zinc. 

The principal use of Eq. (173) is in conjunction with a similar heat dispersion equation. Unfortunately, a system of coupled nonlinear partial differential equations then has to be solved, which is very difficult even with the aid of computers. In the oxidation of sulfur dioxide. Hall and Smith (HI) found relatively good agreement between theory and experiment near the center of the reactor. Their calculations were based on the heat-dispersion equation, and they did not take detailed mass dispersion into account. Baron (B2) later solved the mass and heat dispersion equations simultaneously by a novel graphical method, and found better agreement between his calculations and the data of Hall and Smith. 

In the upper atmosphere such oxidation of sulfur dioxide to its trioxide forming sulfuric acid or sulfate anion may occur at ambient temperature at a much slower rate in the presence of various free radicals. 

In the chamber process, nitric oxide catalyzes the oxidation of sulfur dioxide to trioxide ... 

The availability of hydrogen peroxide allows the direct oxidation of sulfur dioxide to sulfuric acid ... 

Carl Friedrich Plattner was bom in 1800 at Klein-Waltersdorf near Freiberg, was educated at the Freiberg School of Mines, and became a professor of metallurgy and blowpipe analysis there. He was a great master of the art and science of analytical chemistry, and applied the blowpipe even to quantitative analysis. He made many promising experiments on the oxidation of sulfur dioxide to the trioxide by means of catalysts. Before the work was completed, however, he was stricken with apoplexy, which terminated fatally in 1858 (68). When F lix Pisani (1831—1920) examined pollucite four years after the discovery of cesium, he found that Plattner had mistaken his cesium sulfate for a mixture of the sulfates of sodium and potassium (8, 37, 58). 

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