The present invention provides an improved process for removing heat from an exothermic reaction. In particular, the present invention provides a process wherein heat can be removed from multiple reaction trains using a common coolant system.

The present invention provides an improved process for removing heat from an exothermic reaction. In particular, the present invention provides a process wherein heat can be removed from multiple reaction trains using a common coolant system.

The invention relates to a method for start-up and operation of a Fischer-Tropsch reactor comprising the steps of: (a) providing a reactor with a fixed bed of reduced Fischer-Tropsch catalyst that comprises cobalt as catalytically active metal; (b) supplying a gaseous feed stream comprising carbon monoxide and hydrogen to the reactor, wherein the gaseous feed stream initially comprises a nitrogen-containing compound other than molecular nitrogen in an initial concentration in the range of from 0.1 to 50 ppmv based on the volume of the gaseous feed stream; (c) converting carbon monoxide and hydrogen supplied with the gaseous feed stream to the reactor into hydrocarbons at an initial reaction temperature, wherein the initial reaction temperature is set at a value of at least 200 C. and hydrocarbons are produced at a first yield; (d) maintaining the initial reaction temperature at the set value and maintaining the first yield by decreasing the concentration of the nitrogen-containing compound in the gaseous feed stream supplied to the reactor; (e) optionally increasing the reaction temperature after the concentration of the nitrogen-containing compound in the gaseous feed stream has decreased to a value below 100 ppbv.

The invention relates to a method for start-up and operation of a Fischer-Tropsch reactor comprising the steps of: (a) providing a reactor with a fixed bed of reduced Fischer-Tropsch catalyst that comprises cobalt as catalytically active metal; (b) supplying a gaseous feed stream comprising carbon monoxide and hydrogen to the reactor, wherein the gaseous feed stream initially comprises a nitrogen-containing compound other than molecular nitrogen in an initial concentration in the range of from 0.1 to 50 ppmv based on the volume of the gaseous feed stream; (c) converting carbon monoxide and hydrogen supplied with the gaseous feed stream to the reactor into hydrocarbons at an initial reaction temperature, wherein the initial reaction temperature is set at a value of at least 200 C. and hydrocarbons are produced at a first yield; (d) maintaining the initial reaction temperature at the set value and maintaining the first yield by decreasing the concentration of the nitrogen-containing compound in the gaseous feed stream supplied to the reactor; (e) optionally increasing the reaction temperature after the concentration of the nitrogen-containing compound in the gaseous feed stream has decreased to a value below 100 ppbv.

The present disclosure relates generally to processes for initiating Fischer-Tropsch synthesis. In particular, the application concerns a process for the initiation of Fischer-Tropsch synthesis, the process comprising: (i) providing the reaction zone with a temperature of no more than 140 C.; then (ii) purging the reaction zone with a purge gas comprising N.sub.2 at a pressure in the range of 2 barg to 10 barg; then (iii) contacting the catalyst in the reaction zone with a gaseous reaction mixture comprising H.sub.2 and CO in a ratio of between 1:1 and 3:1 at a pressure of no more than 20 barg and at a temperature of no more than 140 C.; then (iv) heating the reaction zone to a temperature of at least 200 C.; and (v) pressurizing the reaction zone to a pressure in the range of 30 barg and 45 barg.

A method is described for shutting down a Fischer-Tropsch reactor fed with a reactant gas mixture comprising a synthesis gas and a recycle gas recovered from the Fischer-Tropsch reactor in a synthesis loop, said Fischer-Tropsch reactor containing a Fischer-Tropsch catalyst cooled indirectly by a coolant under pressure, comprising the steps of: (a) depressurising the coolant to cool the reactant gas mixture to quench Fischer-Tropsch reactions taking place in the Fischer-Tropsch reactor, (b) stopping the synthesis gas feed to the Fischer-Tropsch reactor, and (c) maintaining circulation of the recycle gas through the Fischer-Tropsch reactor during steps (a) and (b) to remove heat from the Fischer-Tropsch reactor. The method safely facilitates a more rapid return to operating conditions than a full shut-down.