CFD Model of a Pulverized Coal Fired Boiler

Keyword(s):  
Author(s):  
Mingyan Gu ◽  
Zumao Chen ◽  
Naresh K. Selvarasu ◽  
D. Huang ◽  
Pinakin Chaubal ◽  
...  

A three-dimensional multiphase CFD model using an Eulerian approach is developed to simulate the process of pulverized coal injection into a blast furnace. The model provides the detailed fields of fluid flow velocity, temperatures, and compositions, as well as coal mass distributions during the devolatilization and combustion of the coal. This paper focuses on coal devolatilization and combustion in the space before entering the raceway of the blast furnace. Parametric studies have been conducted to investigate the effect of coal properties and injection operations.


2014 ◽  
Vol 1010-1012 ◽  
pp. 847-855
Author(s):  
Ya Ming Liu ◽  
Fang Yong Li ◽  
Qi Sheng Xu

In this paper, a computational fluid dynamics (CFD) model of a 600 MW opposed swirling coal-fired utility boiler has been established to numerically study the NOx emission characteristics under different ratios of over fire air (OFA) and modes of in-service burner layers. The current CFD model had adopted a chemical percolation devolatilization (CPD) model and been validated by comparing the simulated results with the experimental data. The numerical simulation results show that, with increasing the ratio of OFA, the carbon content in fly-ash increase somewhat linearly and the NOx emission reduce significantly, and the OFA ratio of 30% is optimal with higher burnout of pulverized coal and lower NOx emission. The different in-service burner layer modes have different influences on the residence time of the pulverized-coal particles, effect of air staging in the burner region and flue gas temperature at the exit of the lower furnace. Stopping the upper burner layers can increases the residence time of the pulverized-coal particles, resulting in the reduction of the carbon content in the fly ash and the increase of the pulverized-coal burnout. The flue gas temperature at the exit of the lower furnace can also decrease, which would be helpful to reducing the slagging tendency on the surfaces of the platen superheaters.


Author(s):  
Gengxun Huang ◽  
Kenneth M. Bryden ◽  
Edmundo Vasquez ◽  
Ravikanth Avancha

Coal roping is a well-known phenomenon occurring in pneumatic transport of pulverized coal. In coal roping the majority of the coal is concentrated in a small portion of the transport piping cross section. This region of concentrated solid flow is created by a number of factors. For example, as the two phase flow of air and coal travels through an elbow or turn in the coal transport piping the centrifugal forces exerted on the coal concentrate the coal on the outside edge of the elbow. After the coal rope is formed these particles will tend to travel together. Coal roping upstream of a coal distributor (bifuractor) can create a significant imbalance in coal loading between in the split between the two branches. This can result in unbalance coal loading between burners and ununiform coal injection in plant burners. This can significantly impact plant performance and increase NOx production. This paper examines how CFD model can be used to understand common creation and breakup mechanisms of coal roping.


Sign in / Sign up

Export Citation Format

Share Document