Tilman J. Schildhauer

High-Temperature Sulfur Removal from Biomass-Derived Synthesis Gas over Bifunctional Molybdenum Catalysts

The removal of sulfur species from the biomass‐derived producer gas after gasification is required to protect downstream catalysts. Finding suitable materials for high‐temperature desulfurization is one of the main challenges for the improvement in the efficiency of catalytic biomass conversion. The biomass‐derived producer gas usually contains not only H2S but also organic sulfur species such as thiophene (C4H4S), which cannot be removed by most sorbent materials. Herein, we explored Al2O3‐supported molybdenum catalysts as bifunctional materials for the removal of H2S and catalytic conversion of C4H4S at high temperatures. By using X‐ray absorption spectroscopy under reaction conditions, we show that H2S is removed through the sulfidation of MoO3. C4H4S is catalytically converted over MoO2 to MoS2 and hydrocarbon species. The subsequent oxidation of MoS2 to MoO3 and SO2 regenerates the material and allows the sequestration of sulfur from the gas stream. Furthermore, the negative effect of steam on sulfur removal is shown to be caused by competitive adsorption with sulfur species. These findings show the possibility of the high‐temperature desulfurization of biomass‐derived gas for catalytic conversion, for instance, to synthetic natural gas.

Reactors for Catalytic Methanation in the Conversion of Biomass to Synthetic Natural Gas (SNG).

Production of Synthetic Natural Gas (SNG) from biomass is an important step to decouple the use of bioenergy from the biomass production with respect to both time and place. While anaerobic digestion of wet biomass is a state-of-the art process, wood gasification to producer gas followed by gas cleaning and methanation has only just entered the demonstration scale. Power-to-Gas applications using biogas from biomass fermentation or producer gas from wood gasification as carbon oxide source are under development. Due to the importance of the (catalytic) methanation step in the production of SNG from dry biomass or within Power-to-Gas applications, the specific challenges of this step and the developed reactor types are discussed in this review.

Measurement, monitoring and control of fluidized bed combustion and gasification

Abstract: The measurement of hydrodynamic phenomena in a fluidized bed for monitoring and control is important, yet difficult. Difficulties arise due to the bed’s opaque nature, chemically aggressive environment, and/or mechanical wear of solids. This chapter briefly reviews several measurement techniques, such as tomography, radiography, optical and capacitance probing. We will focus on pressure (fluctuation) measurements, since this is the only technique that is routinely applied in industrial practice. Pressure fluctuations can give information on dynamic changes in the voidage distribution of a fluidized bed when analyzed with statistical time series methods. The chapter ends with a discussion of the industrial application of monitoring and measurement techniques.

Synthetic Natural Gas from Coal, Dry Biomass, and Power-to-Gas Applications

Due to the increasing integration of stochastic renewable sources like photovoltaics and wind energy into the electricity generation, the demand for balancing the electricity supply and the demand over spatial and temporal distances is increasing. For the future, even the seasonal storage of electricity may be necessary. Here, the production of Synthetic Natural Gas (SNG) from domestic resources such as biomass and coal can play an important role. Moreover, in times where the electricity production from renewables exceeds the actual demand in the electricity grid (a situation that today occasionally is observed in Central Europe and is expected to be more common in future), producing SNG could utilise the excess electricity instead of curtailing photovoltaics or wind turbines.