Numerical simulation study on load up characteristic of 350 MW circulating fluidized bed boiler

With the large-scale grid connection of new energy sources, CFB units are facing the technical challenges of deep peaking and rapid load ramping. In this study, the low load peaking characteristics of a 350 MW supercritical CFB boiler were numerically simulated using Barracuda software based on the Euler-Lagrange model. The results show that the bed temperature rises from 779 °C to 830 °C in 6.9 min from 35% load to 50% load, with a temperature increase rate of about 7.4 °C•min<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>. To improve the load response rate of the CFB boiler, the numerical simulation investigates the fast peaking of the composite combustion of the PC-CFB (Pulverized Coal-Circulating Fluidized Bed), which is the most effective way to improve the load response rate of the CFB boiler. Bed) composite combustion fast peaking performance, using the advantages of fast PC coal combustion speed and high burnout rate to enhance the load regulation ability of CFB unit. It is found that the injection of PC coal into the secondary air outlet can significantly increase the load increase rate. When mixing PC1 with 20% calorific value, the bed temperature increase rate increased to 9.83 °C•min<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>, and when mixing PC2 with high calorific value and high volatile content, the bed temperature increase rate increased to 13.95 °C•min<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>.