Condensation of olefins in fischer tropsch tail gas
AssigneeChevron U.S.A. Inc.
InventorsDennis J. O'Rear, Stephen J. Miller
Life of this patent
Estimating the term…
Abstract
Light olefins including LPG contained in unreacted tail gas from a Fischer-Tropsch process are catalytically condensed using an acidic oligomerization/aromatization catalyst to form higher molecular weight C5+ products. Thus, C3-C4 olefins are readily separated from the tail gas and upgraded to more valuable products. In one embodiment, the condensation is conducted on a mixed gas stream of fresh synthesis gas and tail gas from a Fischer-Tropsch process. In another embodiment, the condensation is conducted on a syngas feed to a Fischer-Tropsch reactor and removes a significant portion of catalytically poisonous nitrogen compounds.
Claims25
A process which comprises reacting syngas gas in a generator, reacting syngas in a Fischer-Tropsch reactor, recovering a product stream containing C5+ hydrocarbons and a tail gas fraction containing C2-C4 olefins from the Fischer-Tropsch reactor, forwarding at least a portion of the tail gas fraction to an oligomerization/aromatization reaction zone containing an acidic catalyst, recovering C5+ hydrocarbon products and unreacted syngas therefrom, recycling at least a portion of the unreacted syngas to the syngas generator.
A process which comprises producing syngas in a generator, reacting said syngas in a Fischer-Tropsch reaction zone to produce hydrocarbonaceous products, recovering a tail gas fraction containing C2-C4 olefins from the Fischer-Tropsch reaction zone, treating at least part of the tail gas fraction with an acidic oligomerization/aromatization catalyst, recovering a product stream containing C5+ hydrocarbons and a tail gas fraction, recycling a portion of the treated tail gas fraction to the syngas generator, and recycling a portion of the treated tail gas fraction to the Fischer-Tropsch reaction zone.
A process which comprises reacting a feed mixture comprising CH4, O2 and H2O in a syngas generator, forwarding the syngas so obtained to an oligomerization/aromatization zone containing an acidic catalyst to produce a C5+ product and a lighter syngas fraction, forwarding the lighter syngas fraction to a Fischer-Tropsch reaction zone, recovering C5+ products and a tail gas fraction and recycling at least a portion of the tail gas fraction to the said feed mixture.
Dependencies are inferred from the claim text.