SCR outlet flue cross section nitric oxide and oxygen concentration online monitoring method and system

Abstract

The invention discloses an SCR outlet flue cross section nitric oxide and oxygen concentration online monitoring method and system. The monitoring method comprises the steps that multiple flue gas sampling measuring points are arranged on the measuring cross section according to a grid and divided into a path A and a path B, when monitoring analysis is conducted, flue gas sampling monitoring analysis is conducted on one of the flue gas sampling measuring points on the path A, extraction and discharge are conducted on one of the flue gas sampling measuring points on the path B, after monitoring analysis on the path A is finished, monitoring analysis is conducted on flue gas of the flue gas sampling measuring point subjected to flue gas extraction and discharge on the path B, and meanwhile flue gas extraction and discharge of the flue gas sampling measuring point which is not monitored is conducted on the path A, in this way, the flue gas sampling measuring points of the two paths are subjected to flue gas sampling monitoring and flue gas extraction and discharge alternately. The monitoring system is simplified in structure and low in cost, and online measurement of concentration field distribution of NOx and O2 in SCR outlet flue gas can be effectively achieved.

Description

technical field [0001] The invention relates to the flue gas denitrification technology of thermal power plants in the field of environmental protection technology, in particular to a NO x and O 2 On-line monitoring method and system of concentration field. Background technique [0002] Selective Catalytic Reduction (SCR) denitrification technology is widely used in domestic coal-fired power plants due to its high efficiency and good selectivity. According to the my country Electricity Council, as of the end of the "Twelfth Five-Year Plan", the total installed capacity of SCR denitrification units in China has reached 750 million kilowatts, accounting for 87% of the total installed capacity of thermal power. SCR denitrification technology uses ammonia gas to reduce NO in the flue gas to non-toxic and pollution-free N under the action of a catalyst in a specific temperature range (320~420°C). 2 and water vapor to remove NO x the goal of. [0003] The ammonia injection sy...

AI Technical Summary

Problems solved by technology

Use the flue gas sampling pump to draw the flue gas at the measuring point to the flue gas analyzer through a flue gas sampling pipe several meters long, so that the point-by-point measurement is performed until all the measuring points are measured; and when switching the measuring point for measurement, all It is necessary to connect and disconnect the sampling pipe and the flue gas analyzer. In this way, it often takes several minutes to complete the measurement of a measuring point, and it often takes several hours to complete the measurement of all the measuring points of a section. When the tester In many cases, the cumulative time consumed is even longer, which makes the test work efficiency very low and seriously affects the progress of performance tests and adjustment tests.

In addition, the measurement environment of the flue at the outlet of the SCR reactor is high temperature and high dust. The smoke and dust entering the flue gas sampling pipe are easy to deposit and agglomerate. When the test takes a long time, the sampling pipe will be blocked, which will affect the smooth progress of the test work. Accuracy of Test Results

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