Aim of the Fabio project is the determination of the adsorption capacity of filter material samples for the removal of hydrogen sulfide from raw biogas at large scale biogas plants and sewage treatment plants under practical conditions. A mobile pilot plant with two fixed-bed adsorbers will be operated onsite during two or three field tests using filter sands from water treatment plants as adsorbents.
Within the former research project „HiPur“ (DBU, Az: 34036/01-24) lab experiments were carried out with filter material samples from groundwater filtration plants to characterize their adsorption capacity with regard to the removal of hydrogen sulfide from biogas. Tests were carried out in small scale under lab conditions. 40% of the tested materials showed results comparable to those of commercially available adsorbents and therefore promised to be also competitive in larger scale.
The aim of the follow-up research project Fabio, described here, is to determine the applicability of such filter materials under real conditions within field tests at large scale biogas plants or sewage treatment plants. The project partner DBI developed a mobile pilot plant (Fig.1) which allows to carry out tests onsite with real biogas. The pilot plant is designed to monitor the influencing process parameters (i.e. temperature, volume flow, biogas composition) and allows the variation of operation conditions. Two adsorbent columns can be filled with different materials and can be operated under similar or different conditions. A comparison of moist and dried material will show, whether a pretreatment of the filter material will be required.
A survey among selected water suppliers operating ground water filtration plants will help to figure out the influencing parameters on the adsorption capacity of the filter materials. From a first evaluation of the results it can be said, that the presence of manganese in the process seems to have a positive effect on the adsorption capacity of the filter material, here especially the layers on the filter grains consisting of oxides of iron and manganese.
The project is subdivided in 9 working packages.
1. Characterization and analysis of future application fields.
2. Survey among water suppliers.
3. Screening of the most suitable materials in lab scale.
4. Choice of materials for the field tests.
5. Preparation of the mobile pilot plant for onsite field tests.
6. Field test I at a biogas plant within agricultural application.
7. Field test II at a municipal sewage gas plant or a dump gas plant.
8. Evaluation of the field test results with regard to the possible future reutilization of filter material.
9. Dimensioning of adsorbers for the future application at large scale biogas plants.
Manig, R.; Birkner, C.; Lipp, P.; Dammann, E.: Entschwefelung von Biogas mittels Filtersand. energie | wasser-praxis“ (Nr. 1/2021), S.44-48.