A promising way to substitute fossil fuels for production of not only electricity and heat, but also fuels for transportation and synthetic chemicals is steam gasification of biogenous feedstocks in a dual fluidized bed (DFB). The principle of this technology is the separation of combustion and gasification into two reactors. Bed material, nowadays, olivine, circulates between those reactors and acts both as heat carrier and catalyst. Interactions between biomass ash and bed material leading to layer formation on the surface of bed particles have been observed in the past. It was found that layer formation can have different consequences on the process. On the one hand, enrichment of ash components on the surface of bed particles can lead to agglomeration. On the other hand, Ca-rich layers showed a high catalytic activity towards tar reduction in DFB gasification. Beside olivine no other suitable bed material for DFB gasification has been identified so far. Alternative bed materials could lead to an economical improvement of the process due to various reasons, e.g. finding an heavy-metal free bed material would lead to a reduction of deposition costs of the biomass ash. Furthermore, when installing DFB gasifiers in other regions locally available materials could be used as bed materials which would improve the economics of the operation. In this work, three major aspects of the interaction between bed materials and biomass ash have been addressed. First, the influence of bed particle layers on possible alternative materials on the tendency toward agglomeration and deposit build-up in industrial-scale DFB gasification. Second, the catalytic activity of different layered bed particles regarding the reduction of undesirable tars. And third, the identification of mechanisms underlying layer formation on different bed particles. It was found that the admixing of foreign matter from biomass feedstock (e.g. quartz) into the olivine bed leads to increased deposit build-up due to enrichment of undesired compounds in the combustion reactor. Furthermore, promising characteristics regarding the thermal stability of its layer have been observed for K-feldspar, a possible candidate for an alternative bed material. In addition, it could be proven that once a Ca-rich layer has formed, even non-catalytic materials, such as e.g. quartz, develop a satisfying catalytic activity. Steam reforming of different tar model compounds has been performed as well as the water-gas-shift reaction. All experiments showed a similar trend proving the comparably high catalytic activity of the Ca-rich layer. Pure CaO, used as benchmark material for the highest catalytic activity reachable for layered particles, showed promising catalytic properties for DFB gasification. A layer formation mechanism for olivine was proposed and compared to the already known mechanism of layer formation on quartz. It was shown, that layer formation on olivine is based on a fundamentally different mechanism, where a solid-solid reaction leads to the substitution of Mg2+ and Fe2+ ions in the crystal structure of olivine with Ca2+ from the biomass ash. Due to this incorporation of Ca2+ into the crystal structure of olivine the bed materials keeps its low tendency toward agglomeration even during layer build-up. Thus, an alternative bed material should follow a similar layer formation mechanism than that of olivine. Such similarities were found for K-feldspar, however, more detailed research is yet needed to verify these fist observations. Finally, an outlook of future research fields regarding the interaction of biomass ash and bed material is given.