Design of the scales for the power boiler fuel feeding system based on the process identification G. Bialic*, M. Zmarzly**, R. Stanislawski*** Department of Electrical Engineering Automatic Control and Computer Science, Opole University of Technology, 31 K. Sosnkowskiego St., PL45-272, Opole, Poland *(bialic@sprinter.com.pl) ** (marcin@zmarzly.com.pl) ***(r.stanislawski@po.opole.pl) Abstract: In the paper the mathematical modeling methods were employed to solve the problem of fuel mass estimation supplied to the power generating boiler grid. It was shown that popular polynomial and neural network based identification algorithms can be used to measure amount of fuel supplied to the boiler combustion chamber. Furthermore the original conception and exemplary realization of the mass stream measuring system was presented. 1. INTRODUCTION The fuel feeding system usually cause a lot of problems during designing and operating processes of the power generating boiler (Rataj et al., 2005; Rataj et al., 2004). The weak point is poor quality of the control system responsible for the fuel feeding. To improve the control performance it is essential to measure the amount of fuel supplied to the combustion chamber with high accuracy. Therefore in cooperation with SEFAKO S.A. one of the largest manufacturers of power generating boilers in Poland the conception and design of the scales for the fuel feeding system was prepared. As a result the physical model of the scales was built and equipped in electronic and computer measurement system based on the force gauge. Numerous pieces of research, aggregated measuring data series and mathematical analysis let authors to work out the mathematical model of the system which enable graduation of the device. The paper is organized as follows. In Section II the physical model of the measuring device and the data acquisition system were presented. In section III the mathematical model of the system was determined. In section IV results of process identification and model validation using the prototype device were illustrated. In section V the achievement and direction of further research were summarized. 2. PHYSICAL MODEL OF THE DEVICE The conception of the system (Fig. 1) is based on the force measurement transferred axially by means of measuring movable plate assembled directly under the grid of boiler. The mass stream moving along the plate cause its rotation and next pressure on the tensometer sensor. Microprocessor based measuring amplifier calculates the amount of fuel on the basis of identified mathematical model of process. Further the data are transmitted via industrial communication interface to the visualization and control systems. Fig. 1. The conception of the scales for power generating boiler fuel feeding system In order to verify above presented conception the physical model of the fuel feeding system for power generating boiler made by SEFAKO was prepared. This prototype solution was connected with the dedicated measurement system to make the data acquisition for the mathematical analysis possible. The measurement position (Fig. 2) consist of movable measurement plate (1) where the fuel is delivered. The plate has the permanent connection with tensometer sensor (2) and transfers the stream of the fuel mass to the force indicated by the gauge. The fuel sliding down the plate falls to the container placed on the electronic weigher graduated in grams (3). The measuring signals were transferred by the