High temperature sulfur burner

No,yso, High temperature at burner for thermal NO,j Higher content of sulfur in fuel or flue gas desulfurizing plant failure Environmental impact, acid tain, pollution... 

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. 

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)...

Free, or corrosive, sulfur in an appreciable amount could result in corrosive action on the metallic components of an appliance. Corrosive action is of particular significance in the case of pressure burner vaporizing tubes that operate at high temperatures. The usual test applied in this connection is the corrosion (copper strip) test (ASTM D-130, ASTM D-849, IP 154). 

Spent Acid or Burning. Burners for spent acid or hydrogen sulfide are generally similar to those used for elemental sulfur. There are, however, a few critical differences. Special types of nozzles are required both for H2S, a gaseous fuel, and for the corrosive and viscous spent acids. In a few cases, spent acids maybe so viscous that only a spinning cup can satisfactorily atomize them. Because combustion of H2S is highly exothermic, carehil design is necessary to avoid excessive temperatures. 

Relatively high (typically 980—1200°C) temperatures are required to decompose spent acids at reasonable burner retention times. Temperatures depend on the type of spent acid. A wide variety of spent acids can be processed in this way, but costs escalate rapidly when the sulfuric acid concentration in spent acid (impurity-free basis) falls below about 75%. A few relatively uncontaminated spent acids can be reused without decomposition by evaporating the excess water in concentrators, or by mixing in fresh sulfuric acid of high concentration. Weak spent acids are frequently concentrated by evaporation prior to decomposition. 

The bed temperature in the burner is of the order of 590 to 650°C (1095 to 1200°F), and any excess coke that is not removed as part of the burning is periodically removed from the burner. The coke yield from the process may be as little as 1.2 or as high as 1.7 times the carbon residue of the feedstock. As with delayed coking, the fluid coking process is capable of producing liquid products with substantially lower sulfur contents than the feedstock (Table 7-14), but part of the sulfur in the feedstock is concentrated in the coke. There is elimination of sulfur into the gaseous products but uses for the coke depend very much upon the amount of feedstock sulfur. 

To enable them to serve as a replacement fuel in oil-burning installations, COM are usually prepared from a bituminous coal of medium to high volatility and low ash content, since oil burners have only limited capability for ash removal. To minimize ash deposition and fouling problems, it is also desirable that the feed coal be low in moisture and have a moderate-to-high ash fusion temperature (the temperature of initial deformation) (Table 14.10). A low-sulfur content is also required to maintain the low-sulfur emissions of the oil fuels being replaced. 

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