| 摘要 |
<p>The present invention is related to a method for preventing the formation of NH4HSO4 during the noncatalytic reduction of nitric oxide by ammonia or ammonia precursors in combustion effluents. The present invention is also related to a method for preventing the formation of H2SO4 in the absence of ammonia or its precursors. The formation of these corrosive substances is extremely detrimental. NH4HSO4 formation is a limitation upon the usefulness of nitric oxide reduction processes, particularly in boilers, furnaces, and other combustion devices. The formation of H2SO4 limits effective heat recovery in combustion equipment. The present invention specifically teaches the use of methanol to reduce SO3 in the effluent stream to SO2. The noncatalytic reduction of SO3 by methanol is selective in that a large fraction of the SO3 is converted to SO2, while on a percentage basis very little oxygen is consumed. In addition, the process of the present invention allows the amount of methanol to be limited such that significant amounts of carbon monoxide are not produced and emitted with the effluent stream. By eliminating SO3, the formation of NH4HSO4 and H2SO4 can be blocked. The present invention teaches contacting the methanol with the combustion effluent at a temperature ranging from approximately 500 DEG C to about 950 DEG C in order to assure proper operation of the process. It is also important to limit the reaction time used so that the carbon monoxide produced by the methanol oxidation is not itself oxidized to carbon dioxide.</p> |
