Process of removing heat

A method of starting up an exothermic reaction in a start-up reactor comprised in a reaction train, said method comprising

• a) providing multiple reaction trains each comprising at least one reactor;
• b) providing a common coolant circulation system which comprises a single common reservoir comprising a first coolant which is fed into each reaction train except the reaction train comprising the start-up reactor in which the exothermic reaction is to be started up;
• c) providing a second coolant circulation system associated with a second coolant reservoir comprising a second coolant which is fed into the reaction train comprising the start-up reactor;
• d) increasing the pressure in the start-up reactor to a desired reaction pressure;
• e) feeding a reactant feedstream into the reaction train comprising the start-up reactor;
• f) running the process until the operating conditions of the start-up reactor are such that the coolant exiting the start-up reactor may be reintroduced to the common coolant circulation system;
• and
• g) stopping the feed of the second coolant to the reaction train comprising the start-up reactor while simultaneously initiating a feed of the first coolant to the reaction train comprising the start-up reactor;
• h) redirecting the first coolant from the reaction train comprising the start-up reactor to the single common reservoir.