NOVELTY - Processing natural gas to generate longer-chain hydrocarbons, comprises reacting the methane to generate a mixture of carbon monoxide and hydrogen, and subjecting this mixture to Fischer-Tropsch synthesis to generate longer-chain hydrocarbons, where the longer-chain hydrocarbons from the Fischer-Tropsch synthesis are reacted with hydrogen in a compact catalytic reactor at a constant elevated temperature and an elevated pressure above 80 atm to perform hydrocracking. The reactor comprises a stack of plates bonded together and defining flow channels containing a removable catalyst insert.    USE - For processing natural gas to generate longer-chain hydrocarbons.    ADVANTAGE - The process uses reactors that provide short diffusion path lengths, so that the heat and mass transfer rates can be high and so the rates of chemical reactions can be high. The reactor can provide a high power density. The process enables a small and lightweight plant to be used for hydrocracking, leading to a hydrocarbon product, which is more valuable and easier to store and transport.    DETAILED DESCRIPTION - Processing natural gas to generate longer-chain hydrocarbons, comprises reacting the methane to generate a mixture of carbon monoxide and hydrogen, and subjecting the mixture to Fischer-Tropsch synthesis to generate longer-chain hydrocarbons, where the longer-chain hydrocarbons from the Fischer-Tropsch synthesis are reacted with hydrogen in a compact catalytic reactor at a constant elevated temperature and an elevated pressure above 80 atm to perform hydrocracking. The reactor comprises a stack of plates bonded together and defining flow channels for the hydrocracking reaction alternating in the stack with flow channels for heat removal. The flow channels for the hydrocracking reaction contain a removable catalyst insert with a metal substrate.    An INDEPENDENT CLAIM is also included for a plant for performing the inventive process, comprising compact catalytic reactor(s) for hydrocracking comprising a stack of plates defining flow channels for reactants and for a coolant arranged alternately in the stack, the plates being bonded together, and the flow channels for the hydrocracking reaction containing catalyst inserts that define parallel flow paths for the reactant gases and comprise a catalyst for the hydrocracking reaction.    DESCRIPTION OF DRAWING(S) - The figure shows graphically the range of chain lengths produced by the Fischer-Tropsch synthesis.