SELECTIVE NON-CATALYTIC REDUCTION SYSTEM

Abstract: The aim of this thesis is to develop a Selective Non-Catalytic Reduction (SNCR) system which is based on a control system to keep NOx emissions from combustion by maximum 27 kg/h urea consumption and then perform commissioning on the site. The NOx value in the combustion is around 220 mg/Nm3 under 100% laud. The SNCR system will decrease the NOx value in the combustion till around 180-190 mg/Nm3 . The system injects the amount of urea directly into the combustion which creates chemical reaction and as a result of NOx decreases. The system will consist of a storage tank, pump module for reduction agent (PMR), standardized pump module for softened water (PMW), pump module for filling (PMF), two injectors and a cabinet for control and management (CMM). The control system made of PLC (Siemens) intelligence and a HMI (CitectSCADA) for local operation. The system is a closed-loop control system where it gets signals continuously from NOx analyzer in the combustion and PID controller the process variables and injecting amount of urea to keep the NOx under set point. The HMI provides a robust capability for visualization controls the entire system. The communication with the modules is performed via bus cables from the control and management cabinet. The communication between the control system and the plant is done via Profibus. The supervision and daily operation can be done both from the operator panel and in the control room. The SNCR system has been installed successfully and the system manage to reduce the NOx value from 220 mg/Nm3 till around 190 mg/Nm3 by around 21.7 kg/h urea consumption.