Method for cracking hydrocarbons

A method for transitioning from a first process cracking a first hydrocarbon feed to a second process cracking a second hydrocarbon feed, wherein:

• a) the first process comprises
• a. passing the first hydrocarbon feed to a reactant tube which reactant tube comprises a first zone and a second zone, downstream of the first zone, each zone comprising one or more electrically heated sections,
• b. heating the first hydrocarbon feed in the first zone in the one or more electrically heated sections to vaporise the hydrocarbon feed, and
• c. heating the vaporised first hydrocarbon feed in the second zone in the one or more electrically heated sections to crack the hydrocarbon feed,
• b) the transitioning comprises stopping the passing of the first hydrocarbon feed to the reactant tube and starting a feeding of the second hydrocarbon feed to the same reactant tube,
• wherein the second hydrocarbon feed is analysed, and electrical energy provided to the one or more electrically heated sections in the first zone and electrical energy provided to the one or more electrically heated sections in the second zone is adjusted during the transitioning based on results of the analysis.