Enhanced process control of trickle-bed reactors for biomethanation by vertical profiling directed by hydrogen microsensor monitoring

Abstract

Biomethanation is an emerging Power-to-X technology enabling CO2 valorisation to produce biomethane using renewable H2. A promising reactor for facilitating biomethanation is the trickle bed reactor (TBR), however, these bioreactors are conventionally operated with a black-box approach, where the system is solely described by the input and output characteristics. This study employed a novel approach for process surveillance of internal dynamics in TBRs by installing multiple H2 microsensors along its vertical axis. The H2 microsensor monitoring was demonstrated for 135 days in a TBR integrated into a full-scale biogas plant. Despite achieving an overall CH4 productivity of 12.6 L L-1 d-1, the vertical positioning of microsensors revealed a clear zonation with CH4 productivity zones reaching 54.8 L L-1 d-1 and enabled early warning detection of deteriorating process performance days before detecting it in the product gas. Thus, vertically positioned microsensors present a promising solution for securing process stability.