Urs Corporation

Aecom Technical Services, Inc.

Sterling Michael Gray

James B Jarvis

Steven Kosler

James David Colley

Finely atomized alkaline sorbent salt solutions are injected into a hot flue gas stream to remove SO. Flash evaporation of the droplets produces very fine dried sorbent particles, which react efficiently with SOin the flue gas. The liquid sorbent may be sodium carbonate, sodium hydroxide, sodium sulfite, potassium carbonate, potassium hydroxide or the like. In a coal-fired boiler, the liquid sorbent may be injected after the economizer section, where the flue gas temperature is below 850&#xb0; F., and upstream of a particulate collection device. The dried sorbent particles react with SOand then are removed from the flue gas stream in the particulate collection device, producing a cleaned flue gas stream.

Process for removing SO2 from flue gases using liquid sorbent injection

A flue gas desulfurization unit is converted from operating with lime or magnesium enhanced lime under inhibited oxidation into a unit that operates using limestone under inhibited oxidation conditions. A ball mill grinding unit may be installed to crush the limestone thereby producing a suspended slurry of fine limestone particles which is pumped to the reaction vessel. When installed, the ball mill may be installed in the process immediately downstream of the existing slaking equipment. The suspended solution may be maintained at a pH in the range of 3.0 to 6.5, optimally at approximately 5.0 to increase the dissolution rate of the limestone reagent produced by the ball mill. The post-conversion process may also require the addition of organic acids and oxidation inhibitors to achieve better SOremoval from the flue gas.

Method for converting lime-based wet flue gas desulfurization systems to limestone-based systems

Processes and methods exist for decreasing emissions of mercury upon combustion of fossil fuels such as coal. Halide salts can be effective when used at locations where they are thermally decomposed to form reactive halogen species, or in combination with an adsorbent material such as activated carbon. Halide salts, such as calcium bromide and sodium bromide, are not typically used at locations downstream of the economizer, where the temperature is typically below around 500&#xb0; C., because these salts are non-thermolabile and do not decompose to produce reactive halogen species. However, in flue gas streams that certain flue gas constituents, such as sulfur trioxide or sulfuric acid, reactive halogen species can be produced via chemical reaction. These species react with elemental mercury through various means to form an oxidized form of mercury that is more easily captured in downstream pollution control devices such as particulate control devices or SOscrubbers.

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Austin, TX, United States of America

Sterling Michael Gray