Combined SCR/SNCR process
July 26, 2019. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesCatalytic method for hydrolyzing urea Process for controlling nitrogen oxides in exhaust gases and apparatus therefor Apparatus for preheating combustion air, accompanied by simultaneous reduction of NOx contained in the flue gases Combined catalytic/non-catalytic process for nitrogen oxides reduction Selective hybrid NOx reduction process Multi-stage process for reducing the concentration of pollutants in an effluent Catalytic/non-catalytic combination process for nitrogen oxides reduction Control of NOx reduction in flue gas flows Process for the in-line hydrolysis of urea Transporting urea for quantitative conversion into ammonia InventorAssigneeApplicationNo. 360506 filed on 07/26/1999US Classes:423/239.1, Utilizing solid sorbent, catalyst, or reactant423/235Nitrogen or nitrogenous componentExaminersPrimary: Griffin, Steven P.Assistant: Medina, Maribel Attorney, Agent or FirmForeign Patent References
International ClassesB01J 008/00C01B 021/00 AbstractIn many situations where the maximum NOx reduction capabilities of conventional SCR systems are not necessary, and alternative SNCR systems may not economically provide desired NOx reduction, a staged SCR/SNCR system is believed to be the most appropriate solution available. By means of the present invention, a system has been developed for delivering NOx reduction agents from a common urea feedstock, when it appropriate to use combined NOx treatment stages (i.e. SNCR within the boiler followed by in-duct SCR and/or catalyzed air preheater elements). For the SNCR stage, the urea from the common feedstock is diluted prior to injection into the boiler and, for the SCR stage, the urea from the common feedstock is used to produce ammonia using hydrolysis. Urea solution which is not converted to ammonia in the SCR phase, is used for dilution of the solution being delivered to the SNCR system.Other References
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