Dynamic Operation of Fischer-Tropsch Reactors for Power-to-liquid Concepts: A Review

The Fischer-Tropsch synthesis (FTS) is considered as a power-to-X (PtX) storage concept for converting temporally available excess energy to fuels or chemical compounds without the need of fossil resources. Fluctuating energy supplies demand a load-flexible energy system and a dynamically operating FTS reactor might be beneficial compared to traditional steady-state operations which rely on expensive upstream buffer capacities. This review provides an overview of recent experimental and simulation studies dealing with dynamic FTS operation and summarizes the main findings. The results are presented the two categories, process intensification and PtX application. The review further discusses the experimentally difficult task of wide-ranging product characterization with a high temporal resolution. While dynamic reactor operation is often related to a complicated process control, which challenges a save and efficient reactor performance, the literature findings indicate that for dynamic FTS operation such concerns might not be as critical as assumed, at least within well-known boundaries. Researchers further agree that dynamic operation might be a tool for process intensification. Especially hydrogen pulsing seems to be a potentially beneficial operating technique to remove accumulated liquid products, restore initial catalyst activity and increase diesel-range productivity. The main challenge in this context is the prevention of high methane selectivity. A lucid future engineering goal seems to be the combination of the two applications: a robust and reliable FTS reactor in a PtX scenario that not only handles a fluctuating feed but uses such variations for process enhancement.