S-IRCLE

The Vietnamese biogas sector is characterized by high hydrogen sulfide (H2S) concentrations in the biogas, leading to health impacts and inefficient gas usage due to corrosion. The S-IRCLE project aimed to meet the demand for efficient, effective, and durable biogas filters with a smart and reusable small adsorber. Compared to short-lived existing Systems, the small adsorber should be able to automatically regenerate the filter material during operation to filter more sulfur. After use, the charged filter material is then to be used as sulfur fertilizer.

The S-IRCLE project adressed the further development and testing of a small adsorber to capture H2S from Vietnam's domestic biogas plants and sulfur fertilizer development from loaded filter material.

Therefore, a small adsorber prototype was further developed and extended to include automated regeneration. Subsequently, field tests were conducted with at least three small-scale biogas plants in northern Vietnam and supervised by the local company eGreen. After one year of operation, the small-scale adsorbers were dismantled and the tests were evaluated.

Parallel to this, two plant trials were conducted. One trial served to determine the sulfur release as a function of the grain size of the filter material (FerroSorp®). The second plant trial served as an effect test of three prototype fertilizer mixtures. The plants and soils were analyzed and evaluated after the trials in laboratories of the TU Berlin.

In addition, a survey on the Vietnamese waste disposal and recycling system was developed and conducted by the Hanoi University of Science and Technology (HUST) in Vietnam.

Data from the small adsorber field trials, the plant trials, the survey on the Vietnamese waste disposal and recycling system, and a tool to determine recyclability were incorporated into material flow analyses of small biogas plants with small adsorbers as well as reference systems. Based on these analyses, the environmental impacts of the S-IRCLE approach were quantified and evaluated.

As part of the project, a biogas workshop with local stakeholders and an international scientific conference was organized.