Combustion Characteristic Experiment And Optimization On Supercritical And Ultra Supercritical Unit Boiler

With supercritical (SC) and ultra supercritical (USC) power unit main/reheat steam parameters increase, the unit thermal efficiency being improved than the national average, which have a significant effect on energy conservation and environmental improvement. Construction of thermal power plants in the future will mainly develop high efficiency and high parameters of SC and USC power unit.Due to introduction of technology on domestic coal sources considered inadequate, thereby leading to malignant slagging and combustion instability problems in boiler. In addition, original design of boiler is fuel ignition, after the introduction of technology, in order to save oil, change the burner to oilless ignition and fuel ignition share, all this need to optimize SC and USC power unit boiler combustion. Papers about this research study on combustion characteristics and ation of the object main contents are as follows.600MW supercritical LNASB combustion swirl burner boiler was predicted by numerical simulation test anduse the actual industrial test to vertify and analysis. To solve boiler coking in malignant as a starting point, the influence of secondary swirling intensity and air flow on the distribution of temperature and flow field were studied. The influence of mode on the burner to the powder and secondary changes on NOx formation in the furnace were studied. Air force field, temperature field and NOx formation characteristics on the burner original structure and the improvement scheme are compared and analyzed.The numerical simulation test combined with actual industrial test, combustion instability phenomena on a1000MW ultra-supercritical units HT-NR3burner hedge hydrocyclone combustion boiler are studied, the original structure of burner and three improving programs were compared.The numerical simulation test and actual industry experiment had shown as follows, the extended corner was impacted obviously by the external secondary air. The recirculation zone is hardly affected by the inner secondary air. Increasing the flow and swirling intensity of the inner secondary air could make the flame deviation and adherence. The inner secondary air have a great influence on NOx, when the inner secondary air is off, NOX in the furnace exit fell by22%. The recirculation zone root distance increased with the center air speed,the temperature of burner nozzle increased with central air exit significantly, the flame from the nozzle distance on burner center powder feeding can be increased effectively.1000MW ultra-supercritical units HT-NR3burner Conclusions are drawn as follows, when the Secondary outlet expanding angle and the axial length are large, the flame shape is short and wide, effluent concentrations of NOx is low, Coal combustion is unstable when the quality of coal is bad.When the Secondary outlet expanding angle is small and the axial length is short, combustion stability of coal center rich and original structure about burner are both increased, NOx emission is not increased obviously. The combustion stability could effectively increase when the axial length of secondary expanding outlet was reduced to1/2, NOx emission is not improved obviously, which was the best improvement program.The combustion process of a1000MW ultra supercritical dual tangential circle boiler was numerically studied and in the actual industrial experiment study. The influence of the nozzle structure and the primary and secondary air velocity on the distributions of thermal flow and temperature field was studied. The flow field and temperature field with the burners of being improved structure were compared with the original ones.The primary and secondary air velocity have a greatimpact on the thermal flow within the burner's combustion area. Diameter of the tangent circle decreases with the increasing of primary air velocity but increases with the increasing of secondary air velocity. In the shape of the burner nozzle under the same circumstances, increasing the dimension of the primary air nozzle can increase the rigidity of the flame. For different burner jet structure and arrangement, NOx generation and distribution performance is different correspondingly, while the NOx emission change is unobvious for different boiler design schemes. As flow area of the primary coal powder tube jet is enlarged by100%, that is, the coal feeding is increased by20%, temperature around the burner zone rises significantly and NOx generation also increases. When there arranged one layer of auxiliary air from the burner undersurface, the combustion characteristic is promoted and NOx generation increases lightly.