Power Plant Boiler Primary Air Pulverized Coal Concentration In The System

Measuring of pulverized coal concentration in primary air is very important to thesafe and economic operation of boilers. The movement of pulverized coal is verycomplex gas-particle two-phase flow in the primary air. Measuring of pulverized coalconcentration is always one of the problems of engineering along, also is the conundrumwhich the engineers and technicians are dedicated to solve. A kind of new method—thesound velocity method which measures pulverized coal concentration is putted forwardin this paper. The model of which the concentration of coal powders is measured by thesound velocity method, is built up in this paper. Based on analyse of the actual workstatus, the applied function between the concentration of solid phase and the spread timeof the sound is given. Designing and building an experiment set, the applied function isalso validated by the experiment. The theoretical analyse and experiment resultsdemonstrate that the sound velocity method can be used to measure the solid phaseconcentration of the gas-particle two-phase flow. When pulverized coal concentration inprimary air is on-line to measure, the sound velocity method has advantages inpreventing the pollution of sensors and being wearable.This paper discusses measuring system of pulverized coal concentration in primaryair which is developed according to the sound velocity method. The measuring systemhardware is divided into the driving circuit of sensor, the receiving circuit of sensor, thecollection circuit of temperature and the processing system of microprocessor. Theprocessing system of microprocessor adopts TI MSP430F449 processor as CUP. Thispaper describes the concrete design methods and attentive questions of parts of circuits,gives the corresponding schematic circuit diagram, and designs the PCB of wholemeasure system. The measuring system software is developed under IAR EmbeddedWorkbench, which adopts the modularization design method. The measuring systemcarries on the soft and hardware adjustment, which passes verification to meet theapplied request in the laboratory.