Pipeline powdered coal particle size measuring device and measuring method

Abstract

The invention relates to a digital holographic technique, and aims to provide a pipeline powdered coal particle size measuring device and a measuring method. The method comprises the following steps: sampling a gas in a powdered coal conveying pipeline by a sampling nozzle, mixing clean air with the sampled gas to form a mixed gas, and taking the mixed gas as a sample to be delivered into a diluting chamber; combining a laser with a spatial filter to generate collimated laser, and projecting the collimated laser to a CCD camera by virtue of a laser channel of the diluting chamber; and processing a holographic image acquired by the CCD camera to obtain concentration and particle size distribution information of the measured sample, and then obtaining concentration and particle size distribution data of the powdered coal in the sampled gas according to a dilution ratio of the measured sample. By use of the device and the method provided by the invention, online quantitative measurement on the particle size and the concentration of the powdered coal in a pipeline can be achieved at the same time. The device is easy to operate and has a relatively high automation degree, and the measurement process does not need artificial interference; and by virtue of computer calculation, a measurement result close to reality can be given, manpower and material resources are saved, and daily running monitoring and maintenance work of coal-fired boiler equipment are facilitated.

Description

technical field [0001] The invention relates to a digital holographic technology, in particular to an on-line measurement device and method for measuring particle diameters of pulverized coal particles in external pipelines based on laser illumination and CCD camera image recording. Background technique [0002] Coal in thermal power plants usually needs to be pulverized into pulverized coal by using a coal mill. Because the pulverized coal has good combustion characteristics, the finer the pulverized coal particles, the easier it is to catch fire and burn completely, which can reduce the loss of incomplete combustion. In addition, the finer the particles, the easier it is to respond to the air flow, the fuel distribution in the furnace is uniform, and the combustion is stable, which is conducive to adjusting the instability of combustion in the furnace and the uneven distribution of flames, and the heat loss is small. However, the smaller the pulverized coal particles are,...

AI Technical Summary

Problems solved by technology

At present, the coal powder particle size measurement method commonly used in thermal power plants is mainly the sampling measurement method. The coal powder needs to be sampled from the pipeline and sieved through sieves with different apertures to obtain the mass fraction of coal powder with different particle sizes. The particle size distribution of pulverized coal, the sampling measurement method described has complicated operation steps and low real-time performance, which cannot meet the needs of real-time adjustment of coal mills; the existing online measurement technology mainly includes the optical pulse method, which uses pulverized coal to pass through the measurement area The pulsation of the optical signal caused by the inverse measurement of the pulverized coal particle size according to the Mie scattering theory, but the method can only measure the average particle size of the pulverized coal particle size, and cannot quantitatively measure the particle size distribution of the pulverized coal, which cannot meet the economical and efficient requirements of thermal power plants. running requirements

Images