Numerical study of heat transfer and stress-strain on 2 joints and 3 joints soot-blower lance tube at 600 MW power plant

Reliability on lance tube Soot-blower thickness and grade material, then overhung mechanical strength are very important for cleanliness of tube bank boiler 600 MW. Proper Operation and maintenance very effected for soot- blower system reliability. Objective of this research are knowing heat transfer characteristics of lance tube, thermal stress due to high temperature flue gas, and lance tube overhung mechanical stress. During soot-blowing there are area possibility of permanent deflection happened that showing plastic deformation and should avoided. This research is started with 3D geometry modeling, meshing and determine boundary condition with computational Fluid Dynamic software; Specify boundary and continuum types (steam flow, steam inlet temperature, steam density, maximum Heat flux into lance tube soot-blower). then steady temperature distribution is obtained. After that conduct finite element analysis (FEA) geometry modeling, meshing, define structural boundary types where load model are thermal stress, overhung mechanical stress, and stress due to steam jet, then solve. Material selecting is critical to lance tube reliability on radiation zone or super-heater platen area. CFD Simulation results are temperature distributions along lance tube body. For reliable condition, temperature distributions is kept in between 560°C until 650°C (According to ASME BPV Chapter II Section D). the maximum temperature of lance tube temperature is 751K near the nozzle of lance tube soot-blower. Creep-fatigue damage mechanism are two major problem on lance tube soot-blower system. Then FEA shows 3 joints is produce less stress-strain than 2 joints lance tube soot-blower.