Sulfur dioxide simultaneous removal

Lime (portlandite) spray dryers are often used to remove sulfur dioxide from flue gases at coal combustion facilities. Calcium in the spray and flyash may also simultaneously remove arsenic. The resulting arsenic-bearing flyash and calcium sulfites and sulfates are then collected in baghouses or with electrostatic... 

R.J. Walker, C.J. Drummond and J.M. Ekmann, Evaluation of Advanced Separation Techniques for Application to Flue Gas Cleanup Processes for the Simultaneous Removal of Sulfur Dioxide and Nitrogen Oxides, Department of Energy Report, DE85102227 (May, 1985). 

Spray drying has become increasingly important in recent years as an alternative to wet scrubbing for sulfur dioxide control. In the spray dryer the sulfur-containing flue gas is contacted with a fine mist of an aqueous solution or a slurry of an alkali (typically Ca(0H)2 or soda ash). The sulfur dioxide is then absorbed in the water droplets and neutralized by the alkali. Simultaneously, the thermal energy of the gas evaporates the water in the droplets to produce a dry powdered product. After leaving the spray dryer the dry products, including the fly ash, are removed with collection equipment such as fabric filters or electrostatic precipitators. 

Squires, A.M. Pfeffer, R, (1970) Panel bed filters for simultaneous removal of fly ash and sulfur dioxide 1. Introduction. J. Air Pollut. Control Assoc. 20, 534-538. 

Venturi scrubbers are designed on the basis of the venturi flow-metering device. The flow channel is narrowed down so that the velocity will greatly increase at the throat. Then, as in the flow-metering device the flow channel widens ouf. For ease of fabricalion venturi scrubbers are designed with a rectangular cross section. The absorption fluid is injected into the Venturi at the throat where the velocity is the greatest. For particulate removal plain water could be used. As in the plate columns discussed above, for the simultaneous removal of particulate matter and sulfur dioxide, soda ash or caustic soda slurries could be used for absorption of the gas. Venturis are frequently used in conjunction with plate towers. They also serve as stand-alone removal devices in some cases. 

Asanuma, H., et al.. Adsorption of nitrogen monoxide by the chelate resin-immobilized iron(ll) complex and its application for simultaneous removal of nitrogen monoxide and sulfur dioxide. Ind. Eng. Chem. Res., 29( 11). 2267-2272(1990). 

The CNG process removes sulfurous compounds, trace contaminants, and carbon dioxide from medium to high pressure gas streams containing substantial amounts of carbon dioxide. Process features include 1) absorption of sulfurous compounds and trace contaminants with pure liquid carbon dioxide, 2) regeneration of pure carbon dioxide with simultaneous concentration of hydrogen sulfide and trace contaminants by triple-point crystallization, and 3) absorption of carbon dioxide with a slurry of organic liquid containing solid carbon dioxide. These process features utilize unique properties of carbon dioxide, and enable small driving forces for heat and mass transfer, small absorbent flows, and relatively small process equipment. 

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