Online prediction of mass flow rate of solids in dense phase pneumatic conveying systems using multiple pressure transmitters and multivariate calibration

In many industries particulate materials are conveyed pneumatically, and it is both important and challenging to measure the mass flow rate of solids in a gas-solid mixture online.In this article we present some results from experiments carried out on a semi-industrial pneumatic conveying system located at the Department of Powder Science and Technology, Tel-Tek in Porsgrunn, Norway. We have successfully calibrated a regression model which relates the pressure distributions along the pipeline to the mass flow rate of powder. The method for mass flow rate estimation presented in this paper is based on multivariate calibration (chemometrics).Twenty-one pressure transmitters are distributed along the entire length of a pneumatic conveying system. The pressure samples from all transmitters constitute axial pressure distribution signatures, which in this study are used to calibrate a Partial Least Squares Regression model. When the Partial Least Squares Regression model is properly calibrated and validated, the model can be used to predict powder mass flow rate directly from new pressure signatures in the pneumatic conveying system used, under the same conditions of pressure and air flow.The results show that it is not necessary to use all the pressure transmitters available to predict mass flow rate. This paper presents promising results using only 5 pressure transmitters. Pressure transmitters are inexpensive, reliable and easy to use, and are widely used in the industry. This method has been tested with different values of pressure and air flow rates, with equally promising results. All prediction results are validated with independent data.