In this dataset of 779 records, one assignee leads with 121 records, well ahead of the fifth-place company at 99 and the tenth-place company at 51, across a ranking of 100 companies. The leading positions are held by a mix of national energy companies and oil majors with long-running research programmes in gas-to-liquids conversion. Because the ranking counts patent families rather than raw filings, it is a fairer comparison across companies that file in different numbers of jurisdictions.

Filing activity peaked at 16 records in 2018 within this dataset and had not returned to that level by the 2022 midpoint, which shows zero. Recent-year momentum data for the leading assignees also shows zero filings in the latest tracked year across the board. Publication lags filing by roughly 18 months, so the very latest year is always undercounted, but the multi-year flattening pattern here looks like a genuine slowdown rather than a reporting artefact.

Hydrocarbon oils and refining processes (IPC class C10G) appear in 91.1% of the 779 records, and catalytic process claims (B01J) appear in 70.9%, showing that most patents sit at the overlap of process engineering and catalyst chemistry. Acyclic and carbocyclic compound claims (C07C) reach 32.5% of records, covering the hydrocarbon products themselves. Narrower classes like fuel gas purification and separation processes each account for under 5% of records, marking them as comparatively open ground.

US6060524A, assigned to Institut Francais du Petrole, claims a method for operating a slurry bubble column reactor where gas is injected near the bottom and liquid (and optionally solid) fractions are recirculated between the reactor's two ends at a controlled flow rate. Any new slurry-phase Fischer-Tropsch reactor design that recirculates liquid at or above the solids' sedimentation rate in this configuration should be checked against this claim specifically. It does not cover fixed-bed or fluidised-bed reactor designs, nor does it reach catalyst composition, so alternative reactor geometries or different recirculation control schemes are a starting point for designing around it.

The IPC composition data shows fuel gas purification (C10K, 3.7% of records), separation processes (B01D, 4.1%) and fuels/firelighters (C10L, 4.2%) are all filed at a fraction of the density seen in core refining and catalysis classes. These narrower branches, particularly around syngas ratio control and wax handling and separation trains, carry far fewer competing claims and are worth a dedicated prior-art search before committing to a filing strategy there. Co-assignee pairing data also suggests joint-development filings are concentrated among a small group, leaving room for independent filers in adjacent process steps.