SYSTEM FOR AUTOMATIC CONTROL OVER PROCESS OF CLEANING OF COMBUSTION PRODUCTS FROM NITROGEN OXIDES WITH LIMITATION OF CONCENTRATION OF AMMONIA IN CLEANED GASES Russian patent published in 2000 - IPC

FIELD: automation of processes of chemical cleaning of combustion products from nitrogen oxides. SUBSTANCE: system include nonlinear elements that accounts for functional dependence between load and gross effluent of NO_x. It is placed between actuating controller of reagent feed and transducer of signal of load of boiler. Key correcting controller is connected via adder to transducer of signal of concentration of NO_x in cleaned gases and to nonlinear element. Source of additional correcting signal is manufactured in the form of additional correcting controller linked to transducer of concentration of NH₃ in cleaned gases. One input of two-position switch is connected to output of key correcting controller and its other input is linked to output of additional correcting controller, output of switch is connected to actuating controller. Switching-over element of switch is connected to relay element with one operational setting to connect additional correcting controller to actuating controller when concentration of NH₃ in cleaned gasses reached limiting value and to connect key correcting controller when concentration of NH₃ in cleaned gases decreases to permissible level. EFFECT: enhanced efficiency of automatic control over process of cleaning of combustion products from nitrogen oxide with effective limitation of overshoot of ammonia. 1 dwg