STUDY EFFECT OF PARTICLE SIZE DISTRIBUTION OF FUEL TO UNBURNED CARBON QUANTITY IN FLY ASH AT CFB BOILER PLTU PELTAR

• Main Author: MAYA LUCIANA (NIM: 23115305), GITA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/27552
• Institution: Institut Teknologi Bandung

CFB boiler is the current technology in combustion system of steam power plant (PLTU) which has higher combustion efficiency. Although CFB boiler has utilized, fly ash from boiler PLTU PELTAR still has high unburned carbon content is 21.12%. A high content of unburned carbon in the fly ash, have financial impact on PLTU because cost of fuel increase due to incomplete combustion. There is one of operational problem faced by PLTU PELTAR, is hard to control distribution particles size of fuel that goes into the boiler. Particles size of fuel are not suitable to design would influence the burning time of particles inside of boiler. Unburned carbon in fly ash caused by the burned out time of the fuel particles longer than the residence time of the fuel particles in the boiler. <br /> <br /> This study discussed about effect of five variation of cut diameter particles size of fuel toward quantity of unburned carbon in fly ash CFB boiler of PLTU PELTAR. Moreover, this study also included cyclone simulation using CFD to determined cyclone performance. The performance of the cyclone shows the ability of the cyclone to recirculate the unburned coal particles but has been exited from the boiler continuously back to the bottom of the boiler therefore could decrease concentration of unburned carbon in fly ash. The output of CFD simulation show that the total efficiency of PLTU PELTAR cyclone for the five variations of cut diameter of the fuel particles is 72%. The percentage of unburned carbon in fly ash could be determined by comparing the time of particles burned out with the travel time of the unfiltered particles by the cyclone to ESP. The results of this study show that the distribution of particle with cut diameter 1.5 mm, 2.5 mm, 3.5 mm, 4.5 mm and 5.5 mm have unburned carbon content in fly ash of 5.98%, 8.52%, 11.32%, 13.53%, and 15.30% respectively. By using extrapolation method, cut diameter of coal particles that enter into boiler PLTU PELTAR when the content of unburned carbon in fly ash equal to 21.12% is 7.5 mm.