Operation Optimization And Control Of Ultralow Emission System Of Slime Fluidized Bed Boiler

Coal slime combustion for power generation is the most effective way to realize the resource utilization of coal slime.However,the SO₂,NO_x and soot particles produced in the combustion process will cause air pollution.With the continuous improvement of environmental protection requirements and pollutant emission control requirements,the ultra-low emission system of power plants is also facing increasing challenges during operation process.While ensuring the power generation,how to achieve the ultra-low and stable emission of pollutants and the economic operation of the ultra-low emission system has become an urgent problem to be solved.Therefore,this article has carried out research on the collaborative optimization operation and control of the ultra-low emission system of coal slime power plant,and hopes to obtain some research results.Based on reading and analyzing a large number of domestic and foreign related documents,this article has carried out the following work:（1）Based on the analysis of the pollutant generation and removal mechanism of the slime fluidized bed boiler,the current desulfurization and denitrification process methods are compared and analyzed.Also,the operation parameters and the realization of the DCS system of the ultra-low discharge system of the slime fluidized bed boiler are given.Firstly,the formation mechanism of SO₂and NO_x in the slime fluidized bed boiler is analyzed.Then,the three desulfurization mechanisms of wet,dry and semi-dry methods and the four denitration mechanisms of SCR,SNCR,SCR+SNCR and COA are compared and analyzed.Finally,the basic parameters of the boiler,the parameters of the inlet flue gas of the ultra-low emission device and the realization of the monitoring function under the DCS system of the coal slime power plant are introduced.（2）A strict mathematical model of desulfurization was established for the two-stage desulfurization process,and the cooperative operation optimization study of the two-stage desulfurization system was carried out with the goal of the lowest overall desulfurization operation cost.Firstly,the corresponding mathematical models are established for the coal slime combustion flue gas volume,boiler heat loss,two-stage desulfurization model,and the boiler thermal efficiency loss caused by limestone addition,through studying the synergistic mechanism and influencing factors of the two-stage desulfurization of the slime fluidized bed boiler.Then,based on the establishment of a strict mechanism model of the system,the simulation analysis and verification of several parameters affecting the SO₂concentration at the outlet of the slime fluidized bed boiler were carried out on the MATLAB platform.Finally,with the goal of minimizing the total cost of desulfurization,the cooperative optimization operation problems under different sulfur-based content are studied,and the best operation modes under relevant conditions are obtained through optimization.（3）In order to achieve better denitrification effect,the SNCR denitrification system is modeled and the predictive control technology is used to study the SNCR denitrification system control.Firstly,the various influencing factors of the denitrification system of the coal slime power plant are analyzed,and a better operating condition of the SNCR denitrification system is obtained.Then,based on the denitrification mechanism,the process equations affecting the denitrification efficiency,ammonia escape and the amount of ammonia injection in the furnace are established,and the pollutant generation prediction equation is established based on the pollutant generation mechanism.Finally,the accurate control model of SNCR is obtained through data identification,and its denitration control is studied by predictive control,and compared with conventional PID.The simulation results show that predictive control can achieve better dynamic performance and anti-interference ability than conventional PID in dynamic performance and anti-interference ability.（4）Aiming at the ultra-low emission system of slime fluidized bed boilers,a power plant monitoring software platform based on OPC communication has been developed.The platform accesses the DCS system server through OPC communication to obtain the data needed for desulfurization and denitrification monitoring.The object-oriented C#development language is used to design and realize the real-time monitoring,material consumption,fault alarm and other functions of the power plant desulfurization and denitration.It can also calculate related operating costs and other data based on model calculations,laying the foundation for subsequent collaborative optimization control.