Research On Numerical Simulation Of The Combustion Process And Slagging Of A 600MW W-shaped Flame Boiler

With the rapid development of economics, energy source shortage was increasing,learning to use anthracite in power production efficiently becomes one of the important research directions in the future. In some countries, in order to burn low volatile coal such as anthracite, W-shaped flame boiler was used extensively. Although there are broad prospects for the development of the W-shaped flame boiler, some problems are also reflected such as slagging in lower furnace.In a 600 MW W-shaped flame boiler, the burning zone temperature was too high, so the side walls of the lower furnace ash was deposited heavily. A three-dimensional structure of the furnace was established and a mesh was produced with the help of Gambit. A various conditions numerical simulations of the combustion process were carried out. In order to validate the accuracy of the simulation, results of the simulation were compared with the experimental values. The main cause for the ash deposition on the side walls were analyzed based on the simulation results and the actual operational status: low pressure in the boiler makes the coal particles flows to the side walls and high temperature of the side walls make the ash deposition more serious.The optimized operation mode was simulation under various operating conditions,and the influence of the on or off of the fringe burners on the side walls slagging were studied. The velocity field, temperature field and component field under various conditions of combustion were simulated and analyzed. Results show that by cutting off the fringe burners, the coal particles around the side walls were substantially reduced, the temperature of the side walls was decreased, the reductive atmosphere has weakened substantially and then the side walls slagging was effectively alleviated.In order to alleviate the slagging in the boiler, refractory belt was partially disabled based on the structure characteristics of the system. Numerical simulation was carried out under various conditions before and after refractory belt reformation. The influence of area variations of refractory belt on the burning characteristic has been researched.Results show that the temperature of the side walls can be reduced and slagging can be alleviated by reducing the area of the refractory belt.