Power-to-X gas desulfurization technology: Demonstration and parameter analysis

In this work an electroscrubber has been used to remove hydrogen sulfide (H₂S) from biogas. This was done by applying electricity and Power-to-X principles in a scrubbing process. The process is adaptable, scalable and does not consume chemicals. The process uses chlorine to oxidize H₂S and remove it from the gas. The chlorine is regenerated electrochemically. Simultaneously, hydrogen is produced.

This work describes a demonstration campaign at a biogas plant, where an initial parameter study has been performed.

Four experimental campaigns were performed. The first campaign concerned the identification of a single steady state.

The second campaign investigated the relationship between applied electrical current and H₂S removal. The removal of hydrogen sulfide was seen to depend linearly on the electrical current. This means that the process can easily be adapted to changing H₂S levels.

The third campaign explored the influence of solvent flow on the process. The solvent flow through the scrubber tower was found to have no significant impact on the process performance.

The fourth campaign investigated the impact of the gas flow on the process. It was found that the process efficiency decreased as the gas flow increased.

Across all experiments the mean process efficiency was 32.7 % and a mean power consumption of 16.84 kWh/kg H₂S was observed, which fits well with earlier achieved laboratory results. Calculating the cost of the removal gives a price of 3.09 €/kg H₂S. This price is competitive with currently used technologies.