Design & Implementation of process control loop for Boiler Steam Pressure using Programmable Logic Controller

Abstract

The boiler is necessary equipment used in industries in almost all process and power plants to generate steam for the generation of electricity via steam turbines. The auto control is very important to ensure the boilers security and stability. To obtain high efficiency power plant operation, it is very much necessary to efficiently control one of the critical parameter of boiler like steam pressure. High steam pressure and temperature are the necessary conditions for achieving high efficiency of the power plant. Stable and smooth steam pressure is a necessary condition for high quality steam temperature and turbine control. Steam pressure has to be measured and critically monitored for reliable and safe operation of the generation unit. Steam pressure is a key variable that indicates the state of balance between the supply and demand for steam. Therefore, by controlling the steam pressure, one can establish a balance between the demand for steam and the supply of steam. In this thesis, Prototype of a small boiler system is implemented using most widely used industrial automation control equipments in order to control all parameters digitally instead of manually. Interfacing it with or controlling the parameters using Siemens 400 PLC which provides the conceptual basis for implementation of PLC technology in boiler systems. The Siemens 400 PLC accepts the outputs from 2 transmitters i.e. flow transmitter and pressure transmitter incorporated within the boiler, evaluate them using PLC based PID controller FB 41 functional block for the pressure controller or feedback controller and generate appropriate signals which will ultimately be used to turn on or terminate the heating element or furnace. Thesis work also covers the analysis which has been done to validate the prototype of boiler system (real system) with the ideal system. The analysis will come up with the mathematical model and will be analysed with MATLAB and SIMULINK software named as "Analysis of Boiler lab kit simulation". Hence, Hardware named as "Boiler Lab kit" a real boiler system has been successfully implemented using fully integrated industrial automated devices interfaced with PLC to make the process control system fully automated. Also in addition, simulator named as "Analysis of boiler lab kit simulation" has been developed using Matlab-Simulink software to make the model i.e. real system valid with the ideal system.