The influence of parameters variability on biomass selection for energy use

Abstract

Background: Biomass selection integrates heterogeneous variables such as fuel composition, fuel morphology and operating conditions. One important challenge in fuel selection field is to determine the influence of each individual variable in the combustion process to obtain the most efficient energy.

Methods: This paper investigates an optimization design of different combustion parameters for biomass combustion in fixed-bed counter-current boiler. A new application of error propagation theory (EPT) and grey relational analysis (GRA) has been proposed to analyse the combined effect of the most influential variables in the operating conditions; i.e. the ignition mass flux and the maximum temperature. This methodology combines the GRA to rank the alternatives and EPT to compute input measurement uncertainty propagation through the subsequent computing operations.

Results: The behaviour of seven biomasses [i.e. brassica pellet, poplar pellet, refuse-derived fuel pellet, wood pellets, almond shell and olive stone] that are readily available in Spain, in southern Europe, was analysed. The results presented are based on 43 experimental tests with these fuels.

Conclusions: This paper proposes a new tool based on grey relational analysis and error propagation theory, for making quick and easy decisions regarding fuel performance. The main advantages of this new tool are its simplicity, versatility and reliability, which have been verified by comparing obtained results with other studies. The influence of operational parameters and fuel properties were analysed. The results showed that air supply injected on the bed basis and size particle are the most influenced variables on the combustion.