Experimental Study And Numerical Simulation Of Combustion & Purging Process Of Oil And Gas Burners

With the adjustment of domestic energy structure, the rising up of prices of fuel oil, and the strictly requirements of cleaning environmental, as the key components of oil & gas boliers, burners especially gas burners will get rapid development in China in recent years.In the current oil to gas practical engineering problems, because of the boiler body structure doesn't do big changes, and liquid fuel and gas fuel composition and combustion characteristics different from each other, radiation strength and the flame shape will change. Heat distribution change inevitably lead to the boiler efficiency, steam pressure, exhaust temperature and so on a series of changes, it may affect the safe operation of the boiler, cause pipe explosion, etc. Therefore, detailed understanding furnace temperature changes, the safe operation of the boiler and pollutantion effect case by Fuel and wind change is very necessary.This paper aims at the present domestic widely running pot shell with oil and gas boiler, and widely used oil and gas burner in these boiler, the experimental and numerical simulation method are used to sturdy the effect of oil and gas burner parameters (load, hearth back pressure, excess air coefficient, etc.) on boiler burning field distribution flames in the furnace. Meanwhile, based on the FLUENT soft platform simulate the purging unsteady process of oil and gas burner, research the relationship of components and time in the boiler sweep with volume, the result can used for guiding the gas boiler transformation and the safe and economic operation of boilers is of great significance. Through the fuel gas burners combustion process of the experimental study and numerical simulation and purging transient numerical simulation, the following conclusions:1. Burner load in addition to directly affect chamber exports of furnace temperature level and flue gas temperature outside, still directly affects the flame size (length and diameter). Burner load increases, the chamber exports the smoke, and the flame temperature increase, size (the length and diameter) increased. Therefore, whether the fuel gas boiler design, modification or run, in the design of furnace or checking, besides should consider control heat load qv chamber volume outside the macroscopic thermodynamic parameters, consider the structure and burner flame furnace match in size, scope, load changes to the chamber of a stove or furnace burner flame directly, cannot fully spread heating scouring.2. Whether gas burner or oil burner, excess air coefficient increase inside-heater temperature level drops, flue gas temperature drop, the chamber exports. Relative to oil burner, flame size (gas burners for excessive length and diameter) are more sensitive, air coefficient, the greater the flame excess coefficient, the smaller the shorter in diameter. From ensuring complete combustion boiler heat loss and minimize the Angle of gas burners comprehensive consideration, coefficient of excess air should be as close as possible 1.0, oil burner is unfavorable exceed 1.1.3. pressure of furnace have great influence on gas burners but no influence on oil burner. Gas burners pressure of furnace improved, flame structure without major changes, but makes the combustion process, thus the chamber exports ahead of smoke temperature decrease.4.Through the simulation of furnace blowing is obtained that the difficulty of purging the furnace is related to structural complexity of burner and furnace. Purge should maintain proper air flow and maintain adequate purge time. Purge air flow and required approximately inversely proportional relationship between the minimum purge time5.Through contrast of the oil burner and the gas burner temperature field that because of the difference of radiation characteristic, in the same load, near the outlet section of the burner oil burner flame temperature higher than the gas flame, but Furnace exit section gas burner temperature is higher than oil burner temperature.Through contrast of experiment and numerical simulation, concluded that the experiment temperature change trend and numerical simulation of temperature change trend is consistent. The different of absolute value is mainly cased by measurement error and error of numerical simulation model. The conclusions can be used to oil-to-gas, boiler design, debugging and safe operation, operation norm formulation and have significance.