The Regression Model for the Evaluation of the Quality Parameters for Pellets

In Latvia no European legislation concerning the quality of the production of pellets is adopted. Since the market is not regulated by any governmental regulations, biofuel testing is not compulsory. This aspect leads to the situation when pellets of various qualities are available on the market. The main objective of this paper is to compare the characteristics of the pellets which are produced in various regions of Latvia. The second goal is to elaborate a regression model which describes the influence of the independent aspects (physical parameters, price, trading form, transportation distance etc.) on the pellet quality. The quality parameters for the solid biofuels were determined accordingly to the methods described in the Technical Specifications of the European Commission for Standardization. The regression model for the pellet quality has been implemented using the software STATGRAPHICS Centurion 16.1.15. The results of the research emphasize that the physical parameters of the pellets change in a wide range. Three regression models were built in order to describe the influence of the various parameters on the indicator (price per net calorific value) and on the mechanical quality of the pellets. The fitted Models were described by the regression equation given in the paper