Sulfur, burners

Pan and cascade burners are generally more limited ia flexibiHty and are useful only where low sulfur dioxide concentrations are desired. Gases from sulfur burners also contain small amounts of sulfur trioxide, hence the moisture content of the air used can be important ia achieving a corrosion-free operation. Continuous operation at temperatures above the condensation poiat of the product gases is advisable where exposure to steel (qv) surfaces is iavolved. Pressure atomiziag-spray burners, which are particularly suitable when high capacities are needed, are offered by the designers of sulfuric acid plants. 

The temperature of the gas leaving the sulfur burner is a good indication of SO2 concentration, even though the thermocouples employed for temperature measurement (qv) frequently read somewhat lower than the tme temperatures, because of radiation and convection errors. A temperature of 970°C corresponds to about 10.0 vol % SO2, 1050°C to 11.0 vol % SO2, and 1130°C to 12.0 vol % SO2. Other temperatures and concentrations are in similar proportion. 

Sulfur burners are normally operated at moderate pressures, in the range of 135.8—170.3 kPa (5—10 psig), using air suppHed by the main blower for the plant. 

Schwefel-natrium, -natron, n. sodium sulfide, -nickel, m. nickel sulfide, -niederschlag, m. precipitate of sulfur, precipitated sulfur, -ofen, m. sulfur burner, -oxyd, n. (any) sulfur oxide, -phosphor, m. (any) phosphorus sulfide, -probe, /. sulfur sample mercury sulfide, -quelle, /. sulfur spring, -rducherung, /. sulfur fumigation, -rubin, m. ruby sulfur, realgar, -salz, n. sulfur salt, thio salt, sulfo salt sulfate. 

The commercial production of stabilized liquid sulfur trioxide and the assessment of its advantages led to increased use [47-49]. Later development of specialized sulfur burners with catalytic conversion of sulfur dioxide to sulfur trioxide in air by vanadium pentoxide has established this method as an alternative to liquid sulfur trioxide. 

Fig. 4. Flow diagram of an S02 converter with periodic air flushing of the final catalyst stage and recycle of the air stream to the sulfur burner (in the diagram, air stripping of one of the final beds is shown). (Figure taken from Briggs et al., 1978, with permission of the authors.)...

The gas from the sulfur burner (problem 11-4), after reduction of I in a waste-heat boiler, enters a catalytic converter for oxidation of S02 to SO3 in several stages (see Figure 1.4). If the gas enters the converter at 700 K, calculate /so, and the temperature (T/K) of the gas at the end of the first stage, assuming the reaction is adiabatic and equilibrium is attained. Assume P = 1 bar. See Table 11.1 for data. 

Air-atmosphere furnaces, 22 290-291 Air atomization, in spray coating, 7 70-72 Air-atomizing sulfur burners, 23 659-660 Airbags, nylon, 19 766 Air-based balanced vinyl chloride process, 25 637, 640, 641, 645 Air-based ethylene oxidation, 20 643-646 Air bioremediation... 

Spinning basket reactor, 21 352, 353 Spinning-cup atomizers, 23 659 Spinning-cup sulfur burner, 23 660 Spinning machines, 19 749 Spinning processes, hollow-fiber, 16 7-12 Spinning pump, for olefin fiber extrusion, 11 231... 

Substitution-defect pigments, 79 405 Substitutive bromination, 4 343-344 Substoichiometric sulfur burners, 23 660 Substrate additions, in microbial transformations, 76 411—412 Substrate materials... 

Figure 2.4 A sulfur burner where sulfur and oxygen are burned at high temperatures to make sulfur dioxide. (Courtesy of Du Pont, LaPorte, TX)...

This exothermic process enables heat recovery in many places after the sulfur burner, after the converter pass, and after the absorption towers. The waste heat can be used to generate steam for heating. A plant operating at 10% SO2 feed and at a conversion rate of 99.7% SO2 to SO3 has a stack gas... 

Sulfur dioxide is manufactured mostly by combustion of sulfur or its iron sulfide mineral, pyrite, FeS2, in air. The flame temperatures for such combustion of sulfur in the air are usually in the range 1,200 to 1,600°C. Many types of sulfur burners are available and are used to produce sulfur dioxide. They include rotary-kiln, spray, spinning-cup and air-atomizing sulfur burners. Selection and design of burners depend on quality of sulfur to be burned, and rate and concentration of sulfur dioxide to be generated. Pyrites or other metal sulfides may be burned in air in fluid-bed roasters to form sulfur dioxide. 

For leaner sulfur streams, several techniques have been suggested to provide the heat balance. Among them are 1) use of oxygen rather than air for combustion, 2) addition of hydrocarbon or other fuel species to the sulfur burner section to provide heat,... 

Contact process. This process has been in use for about 100 years and involves the use of a sulfur burner, dust remover, gas cooling exchanger, water scrubber, gas absorber, and contaminant remover. The first step in the process is the formation of sulfur dioxide, either by burning sulfur... 

The gas stream from a sulfur burner consists of 15 mole percent S02, 20 mole percent 02, and 65 mole percent N2. The gas stream at atmospheric pressure and 480°C enters a catalytic converter where 90 percent of the S02 is further oxidized to SO,. On the basis of 1 mol of gas entering, how much heat must be removed from the converter so that the product gases leave at 480°C ... 

JO The gas stream from a sulfur burner is composed of 15-mol-% S02,20-mol-% 02, and 65- N2. This gas stream at 1 bar and 480°C enters a catalytic converter, where the S02 is further oxi to S03. Assuming that the reaction reaches equilibrium, how much heat must be removed from converter to maintain isothermal conditions Base youT answer on 1 mol of entering gas. 

---