NUMERICAL SIMULATION OF THE PULVERIZED COAL RICH/LEAN BURNER IN THE UTILITY BOILERS

The present paper describes the numerical investigation for a newly developed pulverized coal rich/lean burner used in the utility boilers. The mechanism of the rich/lean separation process of the pulverized coal are analyzed and the effect of the height of the baffle body and the different particle sizes on the separation efficiency are considered. It is concluded that the burner is applicable in industry.

Influence of the Type of the Pulverized Coal Concentrator on the Operation of a Tangential Fired Boiler with Horizontal Bias Combustion

In this paper, the problems of combustion instability and high-temperature corrosion of pulverized coal fired boiler are investigated by numerical simulation and analysis of the momentum moment. Elbow and twisting plate type of burners are used in the boiler, and the reverse moment of momentum is formed at the outlet of the fuel-rich side of the burner. The momentum moment in the boiler is opposite to the designed tangential circle, and the tangential circle in the boiler is reversed rotation. The reverse moment of momentum at the burner outlet can be eliminated by using louver horizontal bias pulverized coal burner, while the problems of combustion instability and high-temperature corrosion of the boiler are solved, and the combustion efficiency is improved. Accordingly,economic benefit is obviously got.

Numerical simulation of bituminous coal combustion in a fullscale tiny-oil ignition burner： Influence of excess air ratio

The progression of ignition was numerically simulated with the aim of realizing a full-scale tiny-oil ignition burner that is identical to the burner used in an 800 MWe utility boiler. The numerical simulations were conducted for four excess air ratios, 0.56, 0.75, 0.98 and 1.14 （corresponding to primary air velocities of 17, 23, 30 and 35 m/s, respectively）, which were chosen because they had been used previously in practical experiments. The numerical simulations agreed well with the experimental results, which demonstrate the suitability of the model used in the calculations. The gas temperatures were high along the center line of the burner for the four excess air ratios. The flame spread to the bumer wall and the high- temperature region was enlarged in the radial direction along the primary air flow direction. The O2 concentrations for the four excess air ratios were 0.5%, 1.1%, 0.9% and 3.0% at the exit of the second combustion chamber. The CO peak concentration was very high with values of 7.9%, 9.9%, 11.3% and 10.6% for the four excess air ratios at the exit of the second combustion chamber.

Study on the Effect of the Side Secondary Air Velocity on the Aerodynamic Field in a Tangentially Fired Furnace with HBC-SSA Burner

The present paper has compared a group of furnace aerodynamic fields at different velocities of side secondary air （SSA） in a test model of 420t/h utility boiler, applying Horizontal Bias Combustion Pulverized Coal Burner with Side Secondary Air （HBC-SSA Burner）. Experimental results show that, when the ram pressure ratio of side secondary air （SSA） to primary air （PA） （p2s..v2s2./p1v12） is between 1.0-2.4, the furnace aerodynamic field only varies slightly. The relative rotational diameters （φ/L） in the burner domain are moderate and the furnace is in good fullness. When p2sv2s2/p1v12 is beyond 4, φ/L is so large that the stream sweeps water-cooled wall and rotates strongly in the furnace. Therefore, slagging and high temperature corrosion of tube metal will be formed on the water-cooled wall in actual operation. This investigation provides the basis for the application of this new type burner. In addition, numerical simulations are conducted, and some defects in the numerical simulation are also pointed out and analyzed in this paper.