For details see:
From his description:
The new TLUD barrel burner is an improvement over the crude, rough-cut barrel Brad Rush and I made at 4 Oaks Farm in the winter. Most upgrades were to improve air flow up through the burn barrel, and up the chimney. These were successful, and this new equipment performed significantly better, evidenced by faster, hotter burns, and the gas flare contained inside the chimney.
The new barrel has a removable lid, making it easier and faster to load and unload. The one-piece barrel we used at 4 Oaks Farm was loaded through an 8-inch chimney hole in the top, and emptied through the same hole. The lid is permanently attached to the first length of chimney, making it secure against strong winds, safer to remove, with tighter air seal at the lid-chimney junction.