Paper details

Title:

The Influence of Volatile Alkali Species on Coating Formation in Biomass Fired Fluidized Beds

Author(s):

Gatternig, B., Hohenwarter, U., Schröttner, H., Karl, J.

Document(s):

Abstract:

The research in this paper focuses on the mechanisms leading to bed agglomeration in biomass fired fluidized bed combustion. This phenomenon is caused by low melting ash components and is responsible for the bed particles to stick together and the eventual disruption of the fluidization. An alkali containing ash layer is formed around the particles, which in turn acts as an adhesive for the agglomeration. This paper investigates one of the suggested effects leading to the creation of such layers, the influence of heterogeneous (gas/solid) chemical reactions. In chemical literature, this concept is described as chemical vapor transport (CVT) and has been thoroughly studied. A short summary of these studies is presented here, along with thermodynamical simulations of the proposed reactions under biomass combustion conditions. To validate the simulation results the L.A.P.I.S. (Labscale reactor for Agglomeration Prediction and In­situ detection of Sintering) setup was modified to reproduce CVT reactions between ash components and bed material. The considerations leading to this modification, as well as the results of first test runs are described in this paper. These experiments revealed no measurable deposition based on chemical transport, but some variation of the setup and process parameters is necessary in order to draw profound conclusions.

Keywords:

combustion, fluidized bed, fluidised bed, ash agglomeration, high ash biomass fuels

Topic:

Thermochemical conversion - Combustion and co-combustion

Subtopic:

Combustion and co-combustion for large utility and industrial scale applications

Event:

18th European Biomass Conference and Exhibition

Session:

VP2.4.18

Pages:

1167 - 1174

ISBN-13:

978-88-89407-56-1

ISBN-10:

88-89407-56-5

Paper DOI:

10.5071/18thEUBCE2010-VP2.4.18

Price:

FREE