The Experimental Study Of Low Contaminant Combustion Characteristics In The Imported 410t/h CFB Boiler

The project on the imported PYROFLOW 410t/h Circulating Fluidized Bed (CFB) boiler in GaoBa Power Plant played the demonstrated role. The study and analysis on the basic design method and structure of the imported PYROFLOW 410t/h CFB boiler, the anatomy on the key technologies and the contrast between native CFB and the foreign CFB provided the technical references for the improvement of this CFB boiler.In this paper, the author tested and researched the low contaminant combustion characteristics of the imported PYROFLOW 410t/h CFB boiler in GaoBa Power Plant in NeiJiang. The research contents include the thermal characteristic, the desulfuration and the control of NOX exhaust. In the thermal characteristic test, the coal characteristic, the surplus air coefficient, the bed temperature and pressure, the oxygen consistence in the furnace, the flux of fly ash recycle, the characteristic of adjusting zenith during the various load and low load, the startup and stop characteristic and the returning load characteristic are researched. In the desulfuration and NOx exhaust control test, the factors that effect desulfuration efficiency are researched, which include the coal and limestone granularity, the air rate, the bed pressure, the oxygen consistence in the furnace and the flux of fly ash recycle. Finally, the factors that effect NOx exhaust are analyzed, which include the combustion temperature, the combustion ways and the desulfuration reagent. The study shows that:The boiler combustion is good when the operation status is normal. However, when the burning coal characteristic is inferior, and the boiler often operates in low load, so some problems will occur. The bed temperature will be lower, the burnable components in fly ash will be higher and the distribution of oxygen consistence in furnace will be asymmetry. The main measures available include: l)For the given coal category, reducing as possible as the regular small coal particles to enter the second pulverizer; 2)For the conditions of furnace, enhancing the mixing between coal and bed materials, increasing the air flux through the front wall while decreasing the air flux through the rear wall, improving the penetrability of secondary air and increasing the bed temperature; 3)do the thermal calculation using a complete set of imported mature technology; 4)using the fluidizing technics of dense phase in the upper furnace and thin phase in the lower furnace; 5)regulating the rate of the first and the secondary air to ensure the evenly burning in furnace; 6)after the continuous 12 hour operation under lower loading, arranging 4 hour operation under 80MW higher loading.The desulfuration efficiency and NOx exhaust control are both good, which can satisfy theenvironment protection. But the various effect factors need to be synthetically analyzed, then the desulfuration and NOx subtraction efficiency can be increased, at the same time, the boiler combustion can be also improved.At last, on the basis of the conclusion of the test and study, combining the practical condition in the GaoBa Power Plant, the author put forward some helpful opinions and suggestions, which can settle the problem in the process of the boiler operation and optimize the boiler operation.