Monitoring the Bed Material Activation in the GoBiGas-Gasifier

Other conference contribution, 2015

The GoBiGas-plant was constructed by Göteborg Energi AB to produce 20MW of bio-methane though gasification of biomass. The gasifier is a dual fluidized bed gasifier and one of the major hurdles during the commissioning of the plant was to control and limit the amount of tar produced from the gasifier. The yield of tar was efficiently decreased by adding potassium to activate the olivine used as bed material. However, the activation is not permanent and must be maintained and for this purpose, the aim of this work was to develop a method for monitoring the bed material activation. A clear correlation between the concentration of CH4 and the total yield of tar was found and is therefore used to regulate the amount of potassium added to the process to keep the olivine active and avoid tar related problems. With a CH4 concentration of 9% or less, tar related problems are avoided in the GoBiGas-plant however, this correlation is plant specific. To generalize the method a syngas modulus was defined and implemented to monitor the fuel conversion in the process (and thereby the activation of the bed material), and to simplify the optimization of the gasifier by reducing the need for time-consuming tar analysis.