Abstract: A hydrocarbon wax product from a hydrocarbon synthesis slurry comprising liquid synthesis product and catalyst particles is purified by introducing a portion of hydrocarbon synthesis slurry from a hydrocarbon synthesis zone to a treatment zone in which a treatment gas contacts the hydrocarbon synthesis slurry. Hydrogen or a hydrogen-containing gas is useful as the treatment gas. The gas treatment removes impurities from the hydrocarbon wax portion of the hydrocarbon synthesis slurry. Purified wax product is separated and removed in situ via wax withdrawal means. This avoids or minimizes the need for further treating the wax product.

Abstract: A hydrocarbon wax product from a HCS slurry comprising liquid synthesis product and catalyst particles is purified by circulating the slurry from a synthesis zone with a first temperature through a treatment zone with a second temperature in which a hydrogen-containing treatment gas contacts the slurry. The gas treatment removes impurities from the hydrocarbon wax product and also removes catalyst de-activating species which may be present in the slurry. Purified wax product is separated and removed from the treated slurry via wax withdrawal means. This avoids or minimizes the need for further treating the wax product. Remaining treated slurry may be returned to the synthesis zone.

Abstract: A hydrocarbon wax product from a hydrocarbon synthesis slurry comprising liquid synthesis product and catalyst particles is purified by introducing a portion of hydrocarbon synthesis slurry from a hydrocarbon synthesis zone to a treatment zone in which a treatment gas contacts the hydrocarbon synthesis slurry. Hydrogen or a hydrogen-containing gas is useful as the treatment gas. The gas treatment removes impurities from the hydrocarbon wax portion of the hydrocarbon synthesis slurry. Purified wax product is separated and removed in situ via wax withdrawal means. This avoids or minimizes the need for further treating the wax product.

Abstract: A hydrocarbon wax product from a HCS slurry comprising liquid synthesis product and catalyst particles is purified by circulating the slurry from a synthesis zone with a first temperature through a treatment zone with a second temperature in which a hydrogen-containing treatment gas contacts the slurry. The gas treatment removes impurities from the hydrocarbon wax product and also removes catalyst de-activating species which may be present in the slurry. Purified wax product is separated and removed from the treated slurry via wax withdrawal means. This avoids or minimizes the need for further treating the wax product. Remaining treated slurry may be returned to the synthesis zone.

Abstract: A hydrocarbon synthesis (HCS) process wherein a Fischer-Tropsch reactor is operated to maximize the selectivity to 371° C.+ boiling fraction while minimizing the production of less valuable products such as light gases (C1-C4), naphtha and diesel fractions. Inventive modes of operation to offset the effects of catalyst deactivation and maximize selectivity to 371° C.+ boiling fraction are utilized including (a) reducing gas inlet velocity to maintain an optimal CO conversion level, (b) introducing additional active catalyst until a maximum loading is reached, and (c) increasing reactor temperature until productivity reaches a predetermined cut-off level.