A process for hydrogenating a Fischer-Tropsch (“FT”) wax includes placing hydrogenation catalyst particles within a low-temperature hydrogenation reactor having a mixing sub-system and a vent at the top for excess hydrogen, placing the FT wax at a low temperature up to a predetermined level within the low-temperature, hydrogenation reactor, leaving a vapor space above the predetermined level, adding hydrogen under a desired pressure into the low-temperature hydrogenation reactor, mixing the input FT wax, the hydrogen gas and the hydrogenating catalyst particles together to create a mixture using the mixing subsystem and continuing the mixing until the FT wax has hydrogenated, stopping the mixing to allow the hydrogenation catalyst particles to settle, and removing an hydrogenated FT wax with residual hydrogenating catalyst particles from the low-temperature hydrogenation reactor. The hydrogenated FT wax may be filtered and subjected to vacuum distillation. Other embodiments are also disclosed.