Study the phenomenon of slagging and fouling Low Rank Coal (LRC) at boiler Unit 1-4 Suralaya Steam Power Plant by Computational Fluid Dynamic (CFD) modeling

• Main Author: Hanafi Nur Rifa'i, Moch
• Format: Theses
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/38835
• Institution: Institut Teknologi Bandung

Boiler Units 1-4 Suralaya power plant was designed using the Bukit Asam coal (subbitumous) are classified as high caloric coal. Because of the limited supply of this kind of coal, sometimes feeding the powerplant with Low Rank Coal (LRC) has higher risk of slagging and fouling. A research was then conducted to study the phenomenon of slagging and fouling on the use of the LRC using Computational Fluid Dynamics (CFD) Construction of 400 MW boiler Unit 1-4 with dimension of 18.06 x62.6 x 12.8 m is symetrically modeled and meshed by Gambit 2.4.16. Waterwall, superheater, reheater is defined as a wall. Total burners are 35 and each simplified by 2 (two) inlets of pulverized coal and Secondary Air. Fluent 6.3.26 is used for running the model in Probality Density Function (pdf) with calorific value of each Bukit Asam (BA) and the LRC is 5147 and 4589 kCal/Kg. Calculation of radiation used model P1. Modelling was carried out with 2 models : BA coal-HQLV and LRC (LQHV-NGR). Specification of the hardware used is Windows 7 Ultimate, intel i7-730 processor, RAM 4 GHz and 750 GB 6000 rpm hard drive. CFD computational results show that temperature maximum of the HQLV model is 1150 K (877oC) was lower than 921oC commissioning data, with the furnace exit temperature in around of 900oC. It is due to lower calorific value than coal used in commissioning test (5245 kCal/Kg) and radiation error of P1 model. Leaving the gas velocity is 5.9 m/s lower than data of commissioning 11.3 m/s. HQLV and LQHV-NGR show that combustion has reached temperature combustion of 1020oC that means LQHV has reached Ash Melting Temperature (AMT). Combination of temperature AMT reached and Low gas velocity in lower zone result the moving of potential slagging in burner. It can be in accordance with the actual conditions on site that the slagging LRC occurs in the vicinity of the burner