(8c) New Insights on Fixed-Bed Reactor Dynamics Via Real-Time Distributed Temperature Sensing

Fuel syntheses from green hydrogen and carbon dioxide (CH₄, CH₃OH, Jet Fuel) are key process steps in future Power-to-X applications. In order to perform fuel synthesis on a large production scale at low cost, the catalytic fixed-bed reactor is the favored technical solution. Changing market environments and volatile process inputs (e.g., if renewable energies are involved) currently demand reactors that perform well not only at a fixed nominal load but also under varying partial loads (load flexibility). However, it is often unclear how load changes are to be performed, how much time the load change requires, and whether there is a risk of any damage.

In order to answer these questions, profound knowledge on the entire reactor’s state during static and transient operation is essential but often inaccessible within conventional applications. We will present an industrial scale reactor setup equipped with high-definition distributed temperature sensing (DTS). This technology allows for up to 6500 simultaneous and minimally invasive temperature measurements along the 2 m packed-bed at sampling rates of 25 Hz. With this innovative analytical tool, we will provide a look inside fixed-bed reactors under static and dynamic conditions (see Fig. 1). Beyond that, we will showcase reactor load changes, start-ups, shut-downs, and outline future challenges for load-flexible reactor operation (e.g., model-based state estimation and control, catalyst degradation, reactor runaway).

Figure 1 Cool-down perturbation of an industrial-scale reactor for carbon dioxide methanation – a comparison between measured (by DTS) and predicted (by model) temperature profile.