Development of a New Method for Investigation of the Ash Melting Behavior in the Fluidized Bed Conversion Processes

Abstract

The suitability of woody biomass for thermochemical conversion process using fluidized bed technology has already been successfully demonstrated in the last decades. However in lower-rank biomass (e.g. crops and agriculture residues), the ash-forming matter differs from the one in the woody biomass and can cause operational problems such as agglomeration, sintering, fouling, or eventually total defluidization of the fluidized bed. These problems are common for both – combustion and gasifying reactors. Hence the understanding of the ash behavior, as well as creating of a reliable method for the prediction of the ash melting in the fluidized bed is necessary. Several methods such as the ash fusion test, the compression- strength- based test or the controlled fluidization bed agglomeration test can be used to determine the ash melting temperature in the fluidized bed. However none of the test takes into account the influence of the local overheating caused by burning char particles. The following paper focuses on developing a new reliable method to investigate the ash behavior in the fluidized bed.