BOILER DRUM MODELLING, LEVEL CONTROL SYSTEM AND SIMULATOR DESIGN AT PLTU JERANJANG UNIT III

• Main Author: Satrio Rachman, Arief
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/44852
• Institution: Institut Teknologi Bandung

Level control on boiler drum is an important part of coal power plant’s control system. Level condition has to be controlled so it doesn’t pass off the operation limit. Power plant’s process will be stopped if level pass off the operation’s range value. Level is difficult to be contrrolled manually because there are shrink and swell phenomena that occur inside drum boiler. Shrink and swell phenomena caused by non minimum phase characteristic of the boiler. This research is focus on designing the model of boiler drum operation and designing PID control for drum level control system of Jeranjang Unit III coal power plant. Model of boiler drum is designed by breaking down global mass and global energy balance equation. Final form of the model is state-space equation with state variables: pressure (P), water volume under water surface (Vwt), steam volume in the drum (Vsd), and steam quality ( ). Variables that manipulated are steam mass flowrate (qs) and feedwater mass flowrate (qf). Controlled variables are water level ( ) and pressure (P). Heat rate (Q) is inputted as disturbance. The validated model is simulated by 1 element control and 2 element control method. 1 Element Control can stabilize system from 10% step change of Q and keep the value of feedwater mass flowrate in operation range value (31-33.33 kg/s). But when the value of steam mass flowrate (qs) is decreased, 1 Element Control cannot keep the level stability in operation range value (-50 mm – 50 mm). Level instability from steam mass flowrate change is caused by increment of drum pressure value. Drum pressure’s increment causes condensation of the vapor in downcomer so water level shrink. 2 Element Control is needed for controlling the level from steam’s mass flowrate change. On 2 Element Control, pressure and level are controlled at spesific value by changing the value of feedwater and steam massflow rate.