Research On The Process And No_x Emission Technology In The Tower Furnace Of Lignite Fired Boiler

China’s lignite resources is rich, and has a high moisture, high ash, low calorific value and other characteristics, so the lignite is mainly used for burning power generation. Supercritical unit is the mature and advanced power generation technology, has become the preferred technology in the clean and efficient use of coal, tower type boiler due to the different with other types of furnace flue structure, with small footprint, no smoke to, the flue gas flow field uniformity, and therefore more suitable for the combustion of lignite. The actual reform case based by the lignite fired supercritical unit tower boiler furnace process numerical simulation, preliminary analysis of the furnace combustion process and the key parameters of nitrogen oxide emission effect.With the help of fluent to simulate the Jiutai of Jilin supercritical tower furnace furnace single octagonal chamber tangentially fired boiler, boiler BMCR condition and part of the test data as the basis of burning ember wind rate, three groups of burner pulling space and burning ember wind the different layers of the open closed on furnace temperature field, furnace group concentration, coke burning ember and NOx; and select burning ember wind rate and burner spacing between distance the two effects on the NOx factors were analyzed with multiple regression analysis, find out influence factors and nitrogen oxides regression analysis expression. Research shows that: the burnout wind rate increase to reduce NOx, but the combustion in the furnace influence; burner spacing pull is beneficial to the NOx emission, but the gap caused by the general assembly exports of coke quality fraction increased and cold ash hopper at elevated temperature; in three layer burnout wind, compact structure than loosely type structure to reduce NOx effect is good, and even on the three layer structure is open three layer structure, reduce NOx emission effect is good, equivalent to burning ember wind shift.Finally, the regression analysis expressions show that burning ember wind rate and NOx emissions showed an exponential, and burner distance and NOx to choose the second correlation, and practical experience are basically consistent, selected 400 MW load measured value and the predicted value of contrast, error is less than 10%, It is good prediction, For the boiler design, modification and operation has certain guiding significance.