Test Research On The Method Of Coal Particle Concentration Measuring

Nowadays, most of the boilers which are used in domestic or international large-and-middle scale power plants are pulverized coal fired boilers. To these boilers, the pulverized coal concentration in pulverized coal blast pipes, is a very important parameter, it could influence the pulverized coal concentration inside of the boiler, and influence the burning state inside of the boiler. Especially, the modernized large-scale boiler, widely adopts the multilevel foursquare spraying technology. If the pulverized coal concentration of the spraying pulverized coal from each layer differs largely and controls incapably, it would be easy to cause the ultra warm phenomenon of water-cooling wall, which is a potential safety hazard. For this reason, we must carry on accurate measuring and monitoring online. But, because the mixed-phase flow of pulverized coal and air is a two-phase flow, it is very difficult to measure accurately online. So, it is very necessary to find one accurate measurement, which could improve boiler burn stability, economy and dependability. Whereas, domestic and international experiments and researches on measurement of pulverized coal concentration, have put forward much measurement schemes. For example, reaction electric potential measurement, microwave measurement, capacitance measurement, ultrasonic measurement, laser measurement, etc. Each method has its merit, shortcoming and suitable condition, and none of them can be perfect. In this paper, I would mainly explain the capacitance measurement of pulverized coal concentration, including its principle, merit, shortcoming, and so on. And we put up an experiment stand, then, on this experiment stand, we would do some experiment study on several main factors of pulverized coal concentration measuring and do some data analysis. Then, we could have drawn these conclusions: Air blower will not influence the result of the test basically; Following the different pulverized coal concentration, we could deserved to reach one voltage signal, thus could realize the calibrating between the pulverized coal concentration and the voltage signal; The higher moisture having in the pulverized coal, the heavier impact on voltage signal, and can revise through correcting coefficient; The larger size of the pulverized coal particle, the heavier voltage signal is, and can revise through correcting coefficient, too.