| Down-fired boiler is designed to use anthracite, lean coal as a fuel which has a low level of volatile. There are a range of issue such as serious slagging, high carbon content in fly ash, high NOx emissions in most of down-fired boilers in China power plant, which are constructed through the introduction of technology. Therefore HIT invents the technology called'Many ejection and Staged Combustion"used in down-fired boiler. For the down-fired boiler which utilizes the DC-slot type burner, Shutter which is used to enrich the pulverized coal in primary air is one of key factors which can realize the effect of"many ejected, staged combustion"in the down-fired boiler.According to the shutters involved in the down-fired boiler with 660MW and 350MW respectively, using Fluent software, doing numerical simulation of both shutter by single-phase and two-phase simulation model. Comtrasting the results of the two experiments, it comprehensively show that: Numerical simulation can not only qualitative analysis velocity field of the shutter , but also in the velocity distribution its result and the result measured in the experiment with cold station are close to each other, the simulation method has a huge advantage of analysising and predicting result of experiment.According to the shutter of the power plant with 660MW load of single utility, adopt the principle of similar mode to establish the relevant cold-state experiment system according to the proportion of 1:2.5. The shutter separation has 5 vanes, because it has been designed deeply, it is only verified the performance. The result measured in experiment shows that: In the condition that all vane's angle are 30°,the rich-fuel flow of shutter separation accounts for 42%, other than 50% of design value; When adjusting the first and second vane's angle of the shutter separator, the ratio of the rich-fuel flow in the shutter separator has a fluctuations between 40% and 44%; Ajusting the angle of he first and second vane on shuttle has a finity influence on its performance, the second has the more obvious effect; 15 m/s is the best in the choice to flow velocity.According to the burner system of the power plant with 350MW load of single utility, the shutter separator is designed to used in the system of burner in shutter. Because it hasn't been designed deeply in geometry dimension, its experiment focus on the field of performance optimization after establishing the cold-state similar experiment system. The experiment device is established according to the proportion of 1:2.5. Do some research on the influence of performance with ratio of block, the angle of vane in shutter and vane default, the result shows that: The ratio of block in shutter separator has the most huge influence on the performance of the shutter; The shutter in the condition that the ratio of the block is 0.72, all vane's angle are maintained at 30°and the second and third vane in the shutter are set to adjustable vane under has the most optimal performance. |
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