Tail denitration and in-furnace combustion combined optimization system and control method thereof

Abstract

The invention relates to the technical field of in-furnace combustion and tail denitration, and discloses a tail denitration and in-furnace combustion combined optimization system and a control method thereof. The tail denitration and in-furnace combustion combined optimization system comprises a boiler internally provided with a secondary air opening, multiple layers of combustors arranged in the boiler at intervals, an economizer communicated with the boiler, a denitration device, a desulfurization device and a purified flue gas detection piece. The denitration device comprises a denitration inlet detection assembly for detecting the concentrations of O2 and CO in flue gas in different areas, an injection assembly capable of injecting NH3 into the flue gas, a denitration catalytic assembly, and a denitration outlet detection assembly used for detecting the concentrations of NOx and NH3 in the flue gas in different areas. The desulfurization device is arranged at the downstream of the denitration device, and the purified flue gas detection piece is arranged at an outlet of the desulfurization device. According to the tail denitration and in-furnace combustion combined optimization system disclosed by the invention, the combustion efficiency of the boiler is improved, the concentration of NOx in the flue gas is reduced, and the probability of ash deposition and corrosion of downstream equipment is reduced.

Description

technical field [0001] The invention relates to the technical field of tail denitrification combined with furnace combustion, in particular to an optimization system and a control method for tail denitrification combined with furnace combustion. Background technique [0002] In order to ensure that the boiler NOx emissions meet the standards, it is generally necessary to equip a denitrification device, which uses NH 3 Reduction of NOx, reducing NOx to N which is harmless to the environment 2 and H 2 O. In the actual operation of the denitrification device, the amount of ammonia injection is particularly important. Increasing the amount of ammonia injection is beneficial to reduce the NOx concentration of the flue gas, but the escape of ammonia will increase, which will cause downstream equipment (such as air preheater, dust collector, etc.) etc.) fouling and corrosion. The existing denitrification device only controls the total amount of ammonia injection, and cannot adj...

AI Technical Summary

Problems solved by technology

[0004] On the one hand, as the capacity of the unit increases, the cross-sectional area of ​​the flue increases, and the unevenness of the flue gas concentration distribution along the width direction of the flue increases. Inhomogeneous, if the local combustion oxygen is low, the incomplete combustion loss in the corresponding area will increase sharply, causing the CO concentration in the flue gas to increase sharply, thereby reducing the combustion efficiency of the boiler; if the local combustion oxygen is high , the NOx concentration generated in the corresponding area rises sharply again, so a single NOx concentration measuring point cannot represent the actual NOx production amount, resulting in excessive ammonia injection by the denitrification device;

[0005] On the other hand, frequent changes in the power generation load of the unit cause frequent changes in the coal supply and air supply volume. The low-oxygen environment required for low-nitrogen combustion in the furnace cannot last when the coal supply and air supply volume change, resulting in NOx formation The amount of ammonia fluctuates greatly, and the delay of the denitrification device itself makes the amount of ammonia injection unable to respond in real time to the amount of NOx generated, resulting in excessive environmental assessment and increased ammonia injection amount

Images