1、 Overview of pulverized coal sampler
Tag Pulverized coal sampler It is widely used in 1000MW, 600MW and below units. Taige coal sampler adopts compressed air purging and air extractor for sampling, which avoids the problem of sampling port blockage and is easy to sample. The rate of sampling is controlled by controlling the pressure of the compressed air. In this way, a more accurate, representative and constant velocity pulverized coal fineness value can be obtained.
Due to the wear of equipment and the change of coal type, the fineness of pulverized coal will change greatly, which will affect the economic operation of the boiler. Therefore, according to the results of regular sampling and testing of pulverized coal fineness, as the basis for timely using the opening of the deflecting door of the whole separator and damaging the equipment components, there are 4-8 coal pipes directly leading to the burner at the separator outlet of the medium speed coal mill. The pulverized coal fineness of each pulverized coal pipe is quite different. The accurate pulverized coal fineness value can be calculated only by calibrating the pulverized coal sample taken by the multi-point constant velocity sampling device installed on the pulverized coal pipe.
2 Working principle of pulverized coal sampler
? 1. According to the principle of back blowing jet, the pumping rate can be adjusted arbitrarily. It is suitable for the pulverizer with 2-inch plug. The flow rate of pulverized coal is 18-50 MGS, the temperature is 75-95 ℃, the pressure is above 0.8 MPa, and the flow rate is more than 20 cubic meters per hour. At the same time, the four samples are completed at one time on the circular area. The synchronous accuracy of the samples is ensured by adjusting the rotating device The valve size is used to control the phenomenon of pulverized coal injection in pipeline, which ensures the safety of operators.
2. Equal ring area sampling. When the sampling gun pushes the pulverized coal pipe, it runs through the whole diameter. According to the equal ring area algorithm, the closer to the pipe wall, the greater the pulverized coal throughput and the longer the residence time. The pulverized coal gas flow near the pipe center is small and the residence time is shortened. The pulverized coal gas flow rate in the pipe core can be regarded as 0. Practice has proved that the coal powder sampling is the most representative according to the equal ring area method. As shown in the figure
3, isokinetic Pulverized coal sampling In order to accurately measure the concentration of gas-solid two-phase flow and make the solid particle sample representative, the direct sampling of gas-solid two-phase flow must be carried out under the condition of constant velocity. When the sampling speed is not the same as that of the sampling probe, the sampling speed can be adjusted at the same speed as the sampling probe.