A new research project for the knowledge-based development of iron oxides for desulphurization and exhaust gas purification in CO₂-neutral biogas engines started on 01.07.2018. The research project is funded by the Sächsische Aufbaubank (SAB) and the European Union. In cooperation with the DBI - Gastechnologisches Institut gGmbH Freiberg, the new project aims to secure future CO₂-neutral energy generation from biogas using stationary lean-burn engines.

Biomethane is increasingly being used as a fuel for generating electricity and heat, for example in decentralized combined heat and power plants for residential and commercial buildings. Combined heat and power plants are generally operated with gas engines in the 2kW to 1500kW output classes and efficiencies of up to around 95%. When using biomethane, however, its relatively high H₂S content (up to 30ppm) is problematic, leading to damage to the engine and the emission of environmentally harmful sulphur dioxide (SO₂). Furthermore, biomethane combustion results in increased emissions of toxic formaldehyde (CH₂O), while unburned methane (CH₄) contributes significantly to the greenhouse effect (factor 25 compared to CO₂). It is therefore essential to desulphurize the biomethane and clean the exhaust gas of formaldehyde and methane to ensure CO₂-neutral energy production in the long term.

The "FeKat" research project aims to develop an economically viable and technically efficient solution through the use of innovative iron oxides. This solution involves the use of iron oxide for H₂S adsorption directly upstream of the engine and the use of an iron oxide catalyst for the simultaneous oxidation of CH₂O and CH₄ in the exhaust gas of stationary gas engines.

The scientific and technical objective of the project is therefore the development of highly efficient iron oxide materials for the

• adsorptive removal of sulphur components (sub-project DBI-GTI), in particular H₂S, from biomethane, down to a content of 5ppm - thus efficiently counteracting damage to the engine and exhaust catalytic converter as well as engine emissions of SO_x

and the

• catalyzed oxidation of CH₄ and CH₂O (sub-project TUBAF) in the exhaust gas of stationary lean-burn engines that are operated with the desulphurized biomethane. The innovative oxidation catalyst is intended to limit the emission of the two harmful gases to a maximum of 80ppm in accordance with the legal requirements of "TA Luft" and be active at common exhaust gas temperatures (450 - 500°C). As a result, no special regulation of the engine or cleaning stage is required.