SO2 production

FeS slurry absorbs SO2 product calcined producing S vapors which are condensed. 

CAAA Impact on Nonutility Power Producers. The SO2 and NO regulations being implemented as part of the CAAA of 1990 primarily target electric utiHty power plants. However, under Phase II of the CAAA, nonutiHty power producers will be requited to acquire emissions allowances for any SO2 being emitted from new faciHties. Although industrial emitters of SO2 and NO are not directly affected, the EPA did undertake a study to estimate what contribution industrial producers have on annual estimated SO2 production in the United States (10). The report found that annual industrial SO2 emissions would remain below the predeterrnined critical limit of 5.6 x 10 tons/yr until at least 2015 (10). Thus, the agency recommended no new controls for industrial SO2 emissions at this time. 

Currently, anthropogenic S02 production exceeds natural SO2 production by a factor of 3 (Bates et al. 1992), but the impact of the former on aerosol production is largely confined to industrialised areas of the Northern Hemisphere. The oceans, on the other hand, cover approximately 70% of the Earth s surface and much of this area is remote from man-made atmospheric contaminants. Consequently, the exchange of marine DMS is of high regional importance and may affect climate globally. Since the publication of a global inventory of DMS data by... 

At 298K our results demonstrate that reaction 1 in one atmosphere of air proceeds 70% via abstraction and 30% via (irreversible) addition. Photooxidation studies have been reported by Niki, et al. (18) and Hatakeyama and Akimoto (19), where 298K SO2 yields from OH initiated oxidation of CH3SCH3 were reported to be 22% and 21%, respectively. Large yields of methanesulfonic acid were observed in both studies. At present, there is insufficient information to allow SO2 production to be associated with either the abstraction... 

Reaction (20) is in disagreement with the findings of Halstead and Thrush that SO does not react rapidly with itself. However alternative paths for SO2 production can readily be imagined. In any case the value of the rate coefficient for reaction (28) does not depend on the subsequent reactions of the sulfur oxides with O, with themselves, or with other sulfur compounds. 

Both of these steps are energetically favorable and could satisfactorily account for the SO2 product. The mechanism is probably more complicated than indicated by (50) and (51) and may involve the aforementioned sulfur superoxide intermediate. 

With an increasing temperature the rate of H2S conversion In elemental sulfur, which is the most common reaction product, increased. The undesired side eflecl is an increase in the rate of SO2 production when temperature reached 445 K. This limits the application temperature due to secondary air pollution problems. An increase in the content of oxygen added to the gas stream significantly increases the conversion of H2S, as expected based on the mechanism of the reaction. With the oxy n content on the level of one time stoichiometric ratio the maximum conversion rate at 348 K is 80 % with a decrease to 40 % after 1000 minutes. When the content of oxygen is three times the stoichiometric ratio the initial conversion rate is almost 100 % and decreases to 86 % after 800 minutes. An increase in the flow rate and a decrease in the bed depth have also negative effect on the H2S conversion on activated carbon. With a three times increase in the flow rate the conversion rate can decrease even 40 % [67]. A similar effect is found when the bed depth decreases four times. The smallest alteration is observed with a decrease in pressure. When it decreases from 289 kPa to 104 kPa the initial conversion rate drops only 3 percent. 

Two additional lines of evidence link trends in the MTR data to coal combustion. The first is a comparison of temporal trends in IRM, Zn, and S with SO2 production in the US. This comparison is shown in Fig. 14. By far the dominant source of SO2 is fuel combustion (EPA, 2000). For the period from 1930 to about 1980, there is a close correspondence between SO2 production/combustion and reservoir geochemistry/mineralogy. In particular, SO2 production maxima during World War II (1945) and the period prior to the Clean Air Act of 1970 are mirrored by peaks in reservoir S and IRM. The correspondence between content of sedimentary trace elements and magnetite related to coal combustion with the source function for these constituents is consistent with a relation between the source and sink. 

TTie extraction of iron from Fe 2 leads to SO2 production and acid rain (see Section 17.6). 

Table 2.1. Sources of sulfur and SO2 for producing sulfuric acid (interpreted from Kitto, 2004a and Sander et al., 1984). Virtually all sulfur and SO2 production is involuntary, i.e. it is the byproduct of other processes.

Once the catalyst beds are hot, the SO2 production furnace is started and hot, clean, dry SO2 bearing gas is introduced into the catalytic converter. 

Equilibrium % SO2 oxidized increases slightly with increasing volume% O2 in feed gas. This is because a high volume% 02 volume% SO2 product pushes SO2 oxidation to the right, Eqn. 10.7. 

SO2 strength in industrial catalytic oxidation feed gas varies from 8 volume% to 12 volume%, Table 7.2. The strength depends mainly on the preceding SO2 production process. 

Cool sulfur dioxide must be recycled to the burner to lower the flame temperature below 1000 K so as not to damage the burner. The flowsheet and the temperatures of the different streams are given in Figure P2.30. For per lb mol of SO2 product, calculate the lb mol SO2 recycled and the pounds of steam produced. 

Catalytic oxidation of SO2 (production of H2SO4) 0.5-4 Emig and Wemm (2005)... 

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