Two Element Boiler Drum Level Control Using PLC

Abstract

The main concern to develop this hardware is for lab kit and for employees training. In this thesis study of the all field instrument,different control stategy and IMC(internal model control) based pid tuning method. Boiler is the main component in generating steam in thermal power generation units and its control is very important. The thermal efficiency of a steam generator is s the ratio of the heat transferred to the water(steam) to the heat input with the fuel. One of the goals associated with the operation, maintenance, and control of a boiler is to maximize its thermal effciency. Feedwater control is the regulation of water to the boiler drum.so we had made prototype boiler by integrating all field instrument and for PLC(programmabla logic controller) is used for controlling purpose.PLC is from Siemens 400 series,which is multi processor PLC.it is also used as PLC based DCS sys-tem.now a days PLC based DCS is more popular in industry. A method of controlling level of with one element is induce swell and shrink because they give false indication to the PID controller,so further improvement is two element control a mass flow rate signal (corrected for density) is used to control the feedwater flow, giving immediate corrections to feedwater demand in response to load changes.in two element feedforward controller is needed,feedforward controller wants perfact modelling then it can make perfact controller.this thesis has modelling by mass balance and energy balance of feed water. In this thesis validation of modelling with practical system.this thesis point to the boiler drum level and boiler drum pressure process,this two process we consider as mimo(multi input multi output) process and we will analysis and design of whole process boiler drum level control and boiler drum pressure control.