The technical characteristics of DLNC denitrification ultra-low emission system are mainly manifested in:
1）. Highlight deep ultra-low nitrogen combustion skills
The difference between deep low nitrogen combustion technology and ordinary low nitrogen combustion lies in its depth and efficiency, with a denitration efficiency of up to 70% in the furnace under the premise of firm combustion of the boiler.
2）. The principle of combining the two
Adhere to the combination of deep low nitrogen combustion and SNCR efficiency improvement, and the combination of deep ultra-low nitrogen combustion and SNCR efficiency improvement must achieve ultra-low emissions of flue gas denitrification. It is impossible to achieve ultra-low emissions of flue gas denitrification by working alone.
The exaggerated low bed temperature and low oxygen content correspond to low nitrogen combustion flue gas denitrification emissions. Although the emission value is very low, it is based on the premise of sacrificing the combustion efficiency of the boiler and sacrificing the SNCR without reaction. Ultimately, the ultra-low emission request cannot be achieved, and the owner does not agree. It is difficult for the owner to take over.
3）. Balancing three aspects
Deep low oxygen and low temperature combustion:
It is necessary to take into account that the bed temperature meets the SNCR reaction temperature window, so that SNCR can perform immersion dyeing abnormally;
To balance the bed temperature and oxygen content to meet the planned combustion efficiency of the boiler;
We need to take into account the impact on desulfurization and oxygenation inside the furnace.
After the low nitrogen combustion transformation, the combustion share in the upper part of the furnace will increase, and the difference between the flue gas temperature at the furnace inlet and the bed temperature will be very small, which is more conducive to achieving the temperature window and complete combustion of fly ash required by SNCR in the later stage.
When the load is low, the SNCR middle spray gun is used to ensure the temperature window requested by the SNCR, and at the same time, the oxygen content in this temperature window area is sufficient, so that the efficiency of the SNCR is high.
4）. Four evenly distributed
Uniform fluidization.
Evenly scatter coal.
Uniformity of material and oxygen content in flue gas.
Uniform implantation of returned materials.
After four uniform processes, the temperature uniformity of the material and flue gas is achieved. The purpose of temperature uniformity is to eliminate the peak nitrate caused by low temperature in the department and achieve an ideal low nitrogen temperature environment of 880-940 ℃.
The uniform oxygen supply in the department has maintained a low nitrogen environment in the dense phase zone of the furnace, restoring a revitalizing atmosphere.
5）. Five mouth renovation
Hood air outlet.
Secondary air outlet.
Coal inlet.
Coal blowing vents.
Return port.
After the above five port renovation processes, the department's oxygen enrichment has been eliminated, the general oxygen enrichment has been reduced, the department's oxygen deficiency has been eliminated, and the department's low temperature has been eliminated.
6）. Six types of cycles
Internal circulation.
External circulation.
Bottom slag recycling.
Fly ash recycling.
Smoke is circulating.
Heat recycling.
Through the above six cycles of the process, the achievement of solving the serious impact of excessively high or low bed temperature on the ultra-low emission effect of flue gas denitrification under high and low loads of the boiler has been achieved.
