Thermo Plant220t/h Gas Boiler DCS Control Systerm

The boiler is one of the important equipments of thermal power plants. It has thesecharacteristics. The first is the Multi-variable input or output. The second is the strongly nonlinear.And the third is without the characteristics of the self-constant. So the factors that affect itscombustion are very complex.In recent years,the level of the boiler’s combustion and conformity hasbeen significantly improved, with the continuously developing of the boiler’s controltechnology.This is of great significance for the Power plants to save energy, to i mprove combustionefficiency and to raise the level of automation and control.In this paper, I regard Thermo Plant220t/h gas boiler as the research object. Since the boiler’smain fuel is blast furnace gas,so it is generally different from coal-fired boilers.This also led to theunique position of the automatic detection and control system.The control system uses theFOXBORO Corporation’s the I/A series DCS control system, It can automatically control theDrum level, drum pressure, superheated steam temperature and combustion.In this paper, based on the Brief introduction of#8Boiler DCS control system’s controlideology, structure and principles.Focus on the following two points. design a gas-fired boiler’sdrum level control, the control of furnace pressure and steam pressure and temperature controlsystem design the#8boiler’s the main monitor screen, the historical curve, alarm curve and toachieve dynamic monitoring of the Site environmental data by using of the Configurationsoftware,according to the Thermo Plant#8boiler process’s requirements of the computer controlsystem. Program of thesis focus on the of combustion optimization control carried out research, inthe analysis the ratio Control System of Cascade, single cross-on the limiting control system and thethe basis of of the dual-cross limiting control system, focus of analyzes the by the dual-crosslimiting model, air-fuel ratio two freedom degrees to find the optimal controller and flow controllercombustion optimization algorithm.The basic idea of the two degree of freedom optimization is toachieve the tracking control for Air-fuel ratio, by Using the value of the zirconia oxygen analyzermeasured the oxygen content of flue. It is using gas heat value of the instrument measured gascalorific value of the deviation factor of fuzzy controller feedforward control. On this basis,I putforward the pairs of cross-limiting control system.It can effectively solve the combustionoptimization problem. Finally is to be a simulation on gas-fired boiler combustion control systerm.