Study On Online Pulverized-coal Concentration For Power Plant By Soft-sensing Theory

In power plant, pulverized-coal concentration is an important parameter ofcombustion control, which has a great impact on the boiler’s safety and economy.Therefore, effective monitoring becomes necessary to pulverized-coal concentration, butpulverized-coal and wind mixture is typical of gas-solid fluid, whose movement processis very complex and theoretical basis still isn’t sound. Now, there are lots ofmeasurement methods of pulverized-coal, but they have some flaws, limiting theirmarketing. Studying on pulverized-coal also need a broader and deeper exploration.The concentration of pulverized-coal and wind’s mixture is from milling system’spipelines within. It belongs to an important parameter in gas-solid two-phase fluid. It’sdifficult to direct measure, and consided using soft-sensing to indirect measure.Soft-sensing theory has become mature and has had many modeling methods. Accordingto the specific questions and the actual situation, appropriate methods will be selected.This paper, through learning soft-sensing and multi-phase fluid theory, was used the totalpressure drop of the gas-solid two-phase fluid during conveying process to buildmechanism model by energy balance, and ultimately had got the mathematical model thatcomputed the pulverized-coal concentration by the total pressure drop.There were two methods to verify the new mathematical model in this paper. Firstly,it used relevant data, which was from writings that had been published, to computepulverized-coal concentration, and compare the results with the writings’. It was foundthat the results from the mathematical mode basically tallied with the writings’. Secondly,in a power plant, it was done further verification, and installed differential pressuretransmitter, and extracted the required date in the DCS system. Then, it computedpulverized-coal concentration by soft-sensing model, and comparative analysis theresults from electrostatic method that the power plant had have. By the comparison, theresults were still basically tally. Finally, both methods showed that soft-sensing model,which was established by the energy balance of the total pressure drop, was feasible andavailable.