A flue exhaust flow calibration device and method based on porous probe

Abstract

The invention relates to the field of exhaust flow calibration, in particular to a flue exhaust flow calibration device and method based on a porous probe, comprising a length measuring rod and a rotating rod inserted into the radial center of the flue, one end of the length measuring rod is equipped with The worm gear and worm mechanism has a rotating shaft, and the length measuring rod and the rotating rod are connected through the rotating shaft; the rotating rod rotates in the flue with the rotating shaft as the center. The measurement process is as follows: select the sampling hole in the radial center of the flue, insert the length measuring rod and the rotating rod into the sampling hole, and judge the extending position of the length measuring rod and the rotating rod according to the scale on the length measuring rod; set the rotation of the rotating rod Step length and single-step dwell time, the measurement and control system collects the pressure signal of each porous probe; calculates the flue gas flow rate at each measurement point, and then calculates the current flue gas flow rate by area integration. The invention adopts the porous probe instead of the pitot tube as the measuring instrument, has a large measuring angle range and high accuracy, and can quickly complete the multi-point flow velocity measurement of the flue section.

Description

technical field [0001] The invention relates to the field of exhaust flow calibration, in particular to a flue exhaust flow calibration device and method based on a porous probe. Background technique [0002] At present, in the context of the growing demand for total energy in national economic development and the gradual increase in environmental protection efforts, government departments have become more and more stringent in controlling the total amount of polluting gases and greenhouse gas emissions. To ensure the smooth realization of emission control indicators, on the one hand, it is necessary to reduce the emission of polluting gases and greenhouse gases in terms of technology and control means, and on the other hand, to ensure the accuracy and reliability of measurement data. GB13223-2011 "Emission Standard of Air Pollutants for Thermal Power Plants" and "The Law of the People's Republic of China on the Prevention and Control of Air Pollution" put forward clear requ...

AI Technical Summary

Problems solved by technology

[0009] At present, most thermal power plants in China are limited by the site, the straight pipe section of the flue is relatively short, and there are various choke parts such as T-shaped pipes, L-shaped elbows, dampers, variable diameter pipes, etc., and the distribution of the exhaust flow field is uneven. , the flow is very chaotic

If the pitot tube is used for measurement, the same fixed position can only measure the flow velocity in a single direction. If the angle between the incoming flow direction and the pitot tube axis exceeds 5°, the measurement error of the pitot tube will increase rapidly, resulting in inaccurate flue gas flow measurement. precise

Furthermore, during the measurement process, the current method used is manual point-by-point measurement

As there are more and more thermal power plants with large units in China, most of the flue sizes are more than 4 meters high, some are more than 10 meters high, and the number of measuring points is often more than 60. The entire measurement process requires more than 2 sampling personnel. 1 hour of heavy labor, time-consuming and labor-intensive

[0010] This method usually requires that the straight pipe section upstream of the measurement section has a length of 6 times the flue diameter, but it is difficult to meet the actual situation. The length of the straight pipe section is not long enough to cause uneven distribution of the exhaust flow field and chaotic flow direction.

If the measurement is still carried out in the above way, it will inevitably lead to an uncontrollable increase in measurement error

On the other hand, the method of measuring the flow rate of the point is completely manual, the measurement time is long, the stability of the flue exhaust and the uncertainty caused by the human factors of the operator increase, and the reliability of the measurement results is also greatly reduced.

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