Denitration uniformity measurement optimizing system and method under fluctuating loads

Abstract

The invention relates to a denitration uniformity measurement optimizing system and method under fluctuating loads. The system comprises two flue inlets formed in a side A and a side B respectively and two SCR reactors arranged between two flue outlets, remote control adjusting doors (4) are formed between the two flue inlets and the two SCR reactors, grid method tour measuring devices (2) are arranged between the two flue outlets and the two SCR reactors, reference point calibration loops (3) are arranged between the two flue outlets and the two grid method tour measuring devices, and a uniformity analysis control system (1) is further arranged and connected with the remote control adjusting doors (4), the reference point calibration loops (3) and the grid method tour measuring devices (2) separately. According to the system and method, through the reference point calibration loops, the deviation influence of NOx overall fluctuation is removed, through the uniformity measurement result, the relative amplitude of NOx values at different position points is accurately reflected, and misjudgment and wrong adjustment caused by the influence of fluctuation are avoided.

Description

technical field [0001] The invention belongs to the technical field of energy and environment engineering control, and relates to a performance optimization system and method for an SCR denitrification device of a coal-fired boiler, and in particular to an automatic measurement optimization system and method for uniformity of nitrogen oxide concentration at a denitrification outlet under fluctuating loads . Background technique [0002] Large coal-fired boilers such as thermal power plants have installed selective catalytic reduction (SCR) denitrification devices in order to meet the environmental protection and ultra-low emission requirements of nitrogen oxides (NOx). By injecting ammonia into the flue gas, ammonia and The nitrogen oxides in the flue gas react under the action of the catalyst, so that the concentration of nitrogen oxides at the outlet of the SCR denitration reactor is lower than the design value. [0003] The SCR denitrification system needs to be well con...

AI Technical Summary

Problems solved by technology

[0006] One is manual detection and adjustment, low work efficiency and high cost

Manual detection and adjustment must rely on professionals, the timeliness of adjustment cannot be guaranteed, and the test adjustment takes a long time and labor costs are high

[0007] Second, the existing technology does not consider the overall fluctuation of NOx at the denitrification outlet, and there are large errors in the uniformity analysis results

During the normal operation of the unit, the NOx at the SCR outlet is fluctuating, and the average value of NOx is 35mg / m 3 Around, fluctuation range ±10mg / m 3 Left and right, the fluctuation frequency is about once every 5 minutes. The overall fluctuation of NOx will cause great interference to the judgment of the relative measurement value of each point, and even cause misjudgment

[0008] The third is that the existing technology analyzes and adjusts the distribution of the opening of the ammonia injection door by numerically simulating the distribution of the flow field. Due to frequent changes in the state of the field equipment, the simplified numerical simulation boundary conditions deviate greatly from the actual situation, and the leveling effect of the ammonia injection cannot be guaranteed.

[0009] Fourth, the existing technology needs to measure the entrance and exit of the SCR. There are many measuring meters, the equipment system is complicated, the equipment investment is high, and the maintenance workload is large.

However, this invention only provides an optimal control method and system for the total amount of ammonia injection, and does not involve the technical problem of how to solve the spatial optimization distribution of the amount of ammonia injection, nor does it involve the technical problem of how to solve the uniformity of nitrogen oxide concentration at the denitrification outlet. Therefore, it is still necessary to improve the above-mentioned technical defects in the existing SCR reactor outlet NOx uniformity automatic measurement system and method.

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