Double channel thick and light pulverized coal burner structureDate: 2019-07-18 Views:
After the structure of the dual-channel thick and light pulverized coal burner is determined, its operation adjustment in the fan grinding direct blowing system mainly depends on the waist wind.Therefore, the effect of waist wind on the running characteristics of burner is emphatically examined in the actual operation of boiler. Meanwhile, the ignition start, stable combustion capacity under low load and NOx emission performance of boiler after adopting dual-channel thick and light pulverized coal burner are also tested comprehensively.
Half open waist wind in the burner nozzle has an extreme point, indicating that from this point on the atmosphere from oxidation to reductibility, will be part of the NOx reduction has been generated, and fully open state coal has been burning under the condition of oxygen, NOx has been increasing.
Under the waist wind opening degree, the root temperature of the channel under the burner decreases from 570℃ to 210℃ with the waist wind being turned off to on, and the ignition condition becomes worse.Under various working conditions, the temperature gradually increases along the axis direction of the burner. At the nozzle, the temperature is as high as 700℃ when the waist wind is fully turned off, which can realize stable combustion of most coals.
While the temperature under the waist wind full open only 350℃, 350℃ difference between the two.Along the axial distance of the burner, when the waist wind is half open or fully open, the O2 content decreases and the CO2 content increases.From the burner in the temperature distribution under different wind around the waist, the dual channel shade combustion pulverized coal burner with shades and stationary combustion chamber, and by adjusting the (turn down/off) the waist wind fire conditions, improving pulverized coal and air flow easily ignited after cast in pulverized coal, pulverized coal because of stable ignition in time, improve the degree of burnout, increase to the heating furnace, thus sped up the boiler start-up speed, shorten the boiler start-up time, saving oil.
NOx production changes correspondingly, do not open the waist wind NOx production between 20~50ppm;The NOx production amount of half-open and full-open waist wind is between 40 and 170ppm.By integrating the flue gas temperature near the exit of the burner stable combustion chamber and the distribution characteristics of various components in the flue gas, it is well reflected that the waist wind has a good adjustment characteristic to the backflow area of the burner, and the size of the waist wind also has a great impact on NOx generation.
When the wind close around the waist, O2, CO2 almost unchanged, O2 volume maintained at below 9%, CO2 at more than 10%, indicating that a large number of flue gas had been back to the burner under channel nozzle, pulverized coal has been here can fully open burning wind half at the waist and is apart from the stationary combustion chamber nozzle outside near 50 mm and 200 mm, O2, CO2 didn't appear obvious turning point, a significant drop in O2 and CO2 rising rapidly, then fire, quickly outside is 500 mm from stationary combustion chamber nozzle when fitted.