US 6,642,281 B1 · Fischer-tropsch process

Abstract

There is provided an improved system and process for the catalytic hydrogenation of carbon monoxide to form a mixture of hydrocarbons utilizing a plurality of reactors in series. Synthesis gas entering the system under pressure is partially converted in at least one initial stage reactor and the effluent therefrom introduced into a final stage reactor. In the at least one initial stage reactor, a portion of the catalyst is continuously or periodically removed with some hydrocarbons and treated to renew, or renew and enhance it, and returned. The treatment comprises reducing the hydrocarbon context of the withdrawn mixture, heating to a temperature above at least one of the metals in the catalyst thereby forming a melt, removing any slag forming on the melt, cooling the melt and reducing the particle size of the resulting solid to a fine powder of renewed catalyst. The renewed catalyst may be treated to further enhance its properties by slurry low temperature oxidation or passivated before being returned to the at least one initial stage reactor. The final stage reactor, which has a catalyst of the same type or differing from that in the at least one initial stage reactor, receives a feed therefrom having a substantially reduced level of impurities, thereby enhancing the efficiency and longevity of the catalyst contained therein. The system can further employ at least one intermediate stage reactor configured so that all stages are operably connected in series and all reactors with a given stage are operably connected in parallel.

Claims14

Dependent claims

A process for the catalytic hydrogenation of carbon monoxide to form a mixture of hydrocarbons in a plurality of reactors operably connected in series comprising introducing a feed gas comprising carbon monoxide and hydrogen into at least one initial stage reactor and introducing the effluent therefrom into a final stage reactor so that unconverted feed gas is reacted therein, wherein the catalyst in the at least one initial stage reactor is a Dispersed Metal Catalyst (DAM) and is not immobilized, said catalyst comprising one or one or more members selected from the group consisting of Group VIII metals and copper and the catalyst in the final stage reactor is the same as or different from that in the initial stage reactor, said process additionally including the steps of:

a) withdrawing a mixture comprising hydrocarbons and a portion of said catalyst from the at least one initial stage reactor during operation thereof:
b) treating said catalyst mixture to reduce the hydrocarbon content thereof;
c) heating the resulting mixture in a non-oxidizing atmosphere to a temperature above the melting temperature of at least one of said metals thereby substantially removing non-metallic impurities therefrom and forming a slag of any refractory metal oxides therein on the resulting melt;
d) removing the slag, if present;
e) cooling the melt to solidify it;
f) treating the solid to reduce the particle size thereof to a fine powder of renewed catalyst;
and
g) returning at least a portion of the catalyst to said at least one initial stage reactor.

5 more elements

Dependencies are inferred from the claim text.

Fischer-tropsch process

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Fischer-tropsch process

Life of this patent

Abstract

Claims14