Project FeKat: Knowledge-based development of iron oxides for desulphurisation and exhaust gas treatment in CO2-neutral biomethane engines (Duration: 07/2018-08/2020)

A new research project on the knowledge-based development of iron oxides for desulphurisation and exhaust gas treatment in CO2-neutral biogas engines started on July 1st, 2018. The research project is financed by subsidies from the Sächsische AufbauBank (SAB) and the European Union and is carried out in cooperation with the “DBI – Gastechnologisches Institut gGmbH Freiberg”. The objective is to ensure the future CO2-neutral energy production from biogas using stationary lean-burn engines.

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

The "FeKat" research project has the objective to develope an economically sensible and technically efficient solution through the use of novel iron oxides. This approach includes the use of iron oxide for H2S adsorption directly in front 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.

Konzept zur technisch effizienten Reinigung von Biomethan und Abgas von Biomethanmotoren

Fig.: Concept for the technically efficient purification of biomethane and exhaust gas from biomethane engines

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

  • absorptive removal of sulphur components (subproject DBI-GTI), especially H2S, from biomethane, up to a content of 5 ppm. This efficiently counteracts damage to the engine and catalytic converter as well as engine emissions of SOx

as well as

  • oxidation of CH4 and CH2O (subproject TUBAF) in the exhaust gas of stationary lean-burn engines which are operated with the desulfurized biomethane. The novel oxidation catalyst will limit the emission of the two pollutant gases to a maximum of 80 ppm in accordance with the legal limits of TA Luft and will be active at common exhaust gas temperatures (450-500°C). As a result, a special control of the engine or purification stage is not necessary.