초록 ▼

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 formation of this sticky and corrosive substance inside combustion units is an extreme limitation upon

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 formation of this sticky and corrosive substance inside combustion units is an extreme limitation upon the usefulness of nitric oxide reduction processes, particularly in boilers, furnaces, and other combustion devices. 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. The present invention contacts the methanol with the combustion effluent at a temperature ranging from approximately 500°C. to about 950°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.

대표청구항 ▼

A process for minimizing the formation of NH4HSO4 in a combustion effluent having NO, at least 1 ppm SO3, and at least 1 ppm ammonia, the process comprising the step of contacting the combustion effluents with methanol, in an amount such that the mole ratio of the methanol to the sum of NO and SO3 i

A process for minimizing the formation of NH4HSO4 in a combustion effluent having NO, at least 1 ppm SO3, and at least 1 ppm ammonia, the process comprising the step of contacting the combustion effluents with methanol, in an amount such that the mole ratio of the methanol to the sum of NO and SO3 is in the range of from about 0.8 to about 2.0, at a temperature in the range from about 500°C. to about 950°C., said methanol reducing the SO3 in the combustion effluent to SO2, thereby minimizing the formation of NH4HSO4.