Development Of SCR Electronic Control System For Gas Generator Set

With the promotion of the national energy structure reform since the 12th Five-Year Plan,gas-fired generating units have been put into use in a large scale in the form of distributed energy generation,relying on the diversity of fuel acquisition.However,with the emission regulations restricting the emission of NOx from gas-fired generating units,it is very important to develop an exhaust gas treatment system suitable for gas-fired generating units.In this paper,the selective catalytic reduction(SCR)technology with urea solution as reductant is selected as the scheme of tail gas treatment.SCR electronic control system is developed for 40 gas generating units in a gas power plant.The main research contents include:Firstly,based on the emission requirements of gas-fired generating units in "Air Pollutant Emission Standards for Thermal Power Plants" and some methods and regulations,combined with the characteristics of gas-fired generating units,the design objectives and overall scheme of SCR electronic control system are determined,and the main equipment of SCR system is selected and designed.Secondly,the project design incorporates 10 gas-fired generator flue gas pipelines into one main flue gas pipeline,sharing a set of SCR and waste heat boiler system to achieve denitrification and waste heat recovery functions.In order to verify whether the overall pressure difference of the flue gas main pipe,the temperature regulation effect of the thermostat and the decomposition of urea solution can meet the design requirements,a three-dimensional simulation model of the flue gas main pipe,SCR reactor and waste heat boiler system is established according to the engineering design scheme,and various indexes are simulated and verified.The results show that the design can meet the requirements.Subsequently,through the analysis of the working principle of SCR electronic control system,the software and hardware architecture of SCR electronic control unit is built.Based on PLC and HMI controller,SCR electronic control unit hardware is developed.Communication module,urea solution preparation module,fault detection module,injection control module and upper computer software including operation interface,alarm interface and debugging interface are compiled.After the installation of the whole system,the debugging of hardware and software has been completed on the spot.After testing,the controllers,sensors and actuators of SCR electronic control system can achieve automation according to the preset control strategy.Finally,the performance of SCR denitrification is tested.The test results show that the SCR electronic control system designed in this paper can control the concentration of NOx in the flue gas of the gas generator set below 100 mg/m_and achieve the system design goal.