Improvements in or relating to monitoring of fischer-tropsch chemical reactors

A method for detecting poisoning of a catalyst in a reaction chamber, the method comprising:

• a) operating a main reactor, comprising the reaction chamber containing the catalyst, by passing feedstock gas through the reaction chamber to contact the catalyst to produce reaction products from reaction of the feedstock gas in the presence of the catalyst;
• b) simultaneously operating a reaction testing module by passing feedstock gas through at least one test reactor of the reaction testing module, each test reactor comprising a reaction chamber containing catalyst;
• and
• c) using an analyser to determine a level of catalytic activity of the catalyst within the at least one test reactor by analysis of gas exiting or derived from the reaction chamber of the at least one test reactor and/or analysis of the catalyst of the at least one test reactor,
• wherein the main reactor is a Fischer Tropsch reactor containing a Fischer Tropsch catalyst.