Efficiency Increase of Secondary DeNOx Systems for Cleaning of Flue Gas Produced in Combustion Processes

摘要

Due strict legislation providing for emission limits and increasing charges forrnemissions, their producers are forced to implement new technologies and methodsrnwhich decrease amount of released emissions as low as possible. Nitrogen oxides (NO_x)rnare mostly eliminated using the method of selective non-catalytic reduction (SNCR) andrnselective catalytic reduction (SCR). A commonly presented efficiency of NO_x reductionrnfor flue gas cleaning systems using SNCR ranges from 40 to 70 % and 90 to 94 % forrncleaning systems using SCR. There are several ways of increasing efficiency of flue gasrncleaning systems which mostly depend on economical financial balance. Basic methodsrnof efficiency increase include:rn1. rearrangement of operating conditions of current technologiesrn2. rearrangement of existing technological equipmentrn3. implementation of brand new technologies totally different from originalrntechnology (most commonly replacement of SNCR system for SCR system)rn4. supplementing existing technology with a new one and thus increasing itsrnefficiencyrnThis paper presents possibility to increase efficiency of SNCR system usingrncombination with SCR catalytic filtration or SCR fixed bed catalytic reactor to the valuernreaching 98 %. Possibilities of both options will be given in example for potentialrnapplication at a municipal solid waste (MSW) incineration plant with waste processingrncapacity of 15 t/h.