Method for testing ammonia escape of flue gas denitrification system

Abstract

The invention provides a method for testing ammonia escape of a flue gas denitrification system. The method includes: collecting flue dust in flue gas of an outlet flue of an air preheater, mixing the flue dust with water, and controlling the water-to-dust ratio and the pH (potential of hydrogen) value of solution to achieve accurate measurement of ammonia content in flue dust; and collecting gas in the outlet flue of the air preheater, detecting to obtain gaseous ammonia content in the gas, and obtaining a detection result of ammonia escape of the flue gas denitrification system according to the solid-state ammonia content in the flue dust and the gaseous ammonia content in the gas. The method detects the gaseous ammonia mixed in the flue gas after ammonia escape, as well as detects the solid-state ammonia absorbed on the flue dust, the water-to-dust ratio is controlled to be (10-100): 1 while the pH value of the solution is controlled to be 6.0-6.8 during solid-state ammonia detection, and accordingly the obtained detection result can show ammonia escape of the flue gas denitrification system more accurately and truly, and further the method is more conducive to directing of production processes.

Description

technical field [0001] The invention relates to the technical field of denitrification systems for coal-fired boilers, in particular to a method for detecting ammonia escape in a flue gas denitrification system. Background technique [0002] With the development of my country's electric power industry, NOx emissions are increasing day by day. As we all know, NOx pollution can form acid rain, photochemical smog, and destroy the ecological environment. Its impact has attracted more and more attention and attention. With the improvement of my country's emission standards, coal-fired generating units basically require the installation of SCR (selective catalytic reduction) flue gas denitrification devices to reduce NOx emissions. [0003] The principle of SCR flue gas denitrification is: under the action of a catalyst, ammonia is injected into the flue gas, and NO x catalytic reduction to N 2 and H 2 O, because it is impossible to achieve 100% uniform mixing of the injected a...

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Problems solved by technology

[0007] The study of the present invention shows that when using this test method to test the ammonia escape of the flue gas denitrification system, due to the uneven matching of the injected ammonia and the NOx in the flue gas, the distribution of the ammonia escape at the outlet of the denitrification system is relatively uneven, but because the heating gun It is difficult to splice. For portability and transportation, it can only be made within 2m. However, the cross-section of the outlet flue of the denitrification system is relatively large, generally larger than 5m×5m, so it is impossible to uniformly distribute the test on the entire cross-section of the outlet flue of the denitrification system. resulting in a lack of representativeness of the test results

; and in order to prevent the dust in the flue gas from entering the absorption bottle, it is necessary to install a filter device at the head of the flue gas collection pipe. During the process of extraction and collection, a certain amount of smoke dust will accumulate in the filter device. In the device, ammonia in the flue gas will be adsorbed, resulting in sampling loss, so that the obtained test results cannot reflect the real ammonia escape situation

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