Sulfur burning composition

In order to explore composition modulation of the final stage of a converter further, Briggs et al. (1978) added a second integral reactor, also holding about 30 g of the vanadia catalyst. With the preconverter in place, this system was operated on a typical feed from sulfur burning, with a S02 02 N2 composition in vol% of 10.8 15.2 74, and from a smelter effluent with a composition of 8.0 6.2 85.8. The cycled beds of vanadia catalyst were held in a fluidized sand bath at 401°C for the former feed and at 405°C for the latter one. The space velocity for both the air and the S03/S02 mixture was about 24 min 1 (STP). Table II summarizes the experimental results for the cycle periods tested. 

S02 emitted from the modulated bed goes through a minimum after switching to the S03/S02 mixture. Lowest values are obtained 2 min after the composition change for the sulfur burning feed and they are about 8% of the steady-state emission, whereas for the smelter effluent feed, the lowest emission is about 13% of the steady-state value. Evidently, a cycle period of 4 to 5 min would be optimum for the conditions used, yielding a performance some 10% better than that shown at r = 10 in Table II. 

The composition and temperature of sulfur burning s product gas are controlled by adjusting the sulfur burning furnace s ... 

Sulfur burning s product gas composition and temperature are readily controlled by adjusting the sulfur furnace s input air/input sulfur ratio. Replacement of some of the input air with oxygen gives the process independent 02/S02, temperature and volume control. 

Table 7.1. Compositions of furnace offgases and catalyst bed feed gases. Sulfur burning gases don t change. Metallurgical and waste acid decomposition furnace offgases lose S03 and H20(g). The SO3 is removed during water scrubbing. The H20(g) is removed during condensation and dehydration. ...

Gas source and composition, volume% Sulfur burning furnace Metallurgical furnaces Waste acid decomposition furnace... 

Fig. 21.1. Heat transfer flowsheet for single contact, sulfur burning sulfuric acid plant. It is simpler than industrial plants, which nearly always have 4 catalyst beds rather than 3. The gaseous product is cool, S03 rich gas, ready for H2S04 making. The heat transfer product is superheated steam. All calculations in this chapter are based on this figure s feed gas composition and catalyst bed input gas temperatures. All bed pressures are 1.2 bar. The catalyst bed output gas temperatures are the intercept temperatures calculated in Sections 12.2, 15.2 and 16.3.

Gases produced contain about 6% SO2 but the composition is not constant. Hence, there is an additional sulfur burning furnace to maintain thennal stability in... 

The problem statement is as follows. We use sulfur as raw material for the production of sulfuric acid. After burning the sulfur, the composition that we feed to the converter can be seen in Table 4.1. 

The design of a lead smelter depends to a significant extent on the nature of the feed materials processed, particularly the grade of the concentrates. In simple terms this is due to the large possible variation in the sulfur to lead ratio in feed materials and hence the size of the sinter plant required, which is dictated by the sulfur burning capacity. Usually lead sinter has a relatively common lead composition at around 45 per cent and hence the lead blast furnace sizing is not so critically dependent on the nature of the feed. For this reason the cost estimates provided are based on a standard concentrate feed of 60 per cent Pb and 20 per cent S content. Capacity is standardised at 100 000 tonnes per annum (t/a) lead production, representing the median capacity smelter. 

Sulfur burning s product gas composition and temperature are readily controlled by adjusting the sulfur furnace s input air/input sulfur ratio. 

Steady operation and control of catalyst bed temperatures result in lower acid plant SO2 emissions. This is relatively easy for sulfur burning acid plants, but much more challenging for metallurgical acid plants, especially those treating Peirce-Smith converter gases that are intermittent and highly variable in terms of flow and composition. 

The ordinary burning of sulfur produces SO2. This is the hrst step in the manufacture of sulfuric acid. The second step oxidizes SO2 to SO3 in a gas-solid catalytic reactor. The catalyst increases the reaction rate but does not change the equilibrium compositions in the gas phase. 

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