Apparatus and method for controllably carrying out chemical reactions

The invention relates to a method for carrying out a chemical reaction in a controllable manner in a reactor having several reaction tubes, said reaction tubes having several electrically heatable tube sections, an electrical connection being provided which is connected to at least one of the tube sections in each case in a current input region, at least one connecting element is provided in the current output region, and each of the tube sections is connected to a connecting element, the chemical reaction being one of the following reactions: steam cracking, steam reforming, dry reforming, propane dehydrogenation, reaction with hydrocarbons, which is carried out at least partially above 500 DEG C. The method comprises: directing a process fluid through one or more reaction tubes; providing a number of variable voltages at the number of power connectors, where the number of voltages are provided as phases of the multi-phase alternating voltage such that at least one connecting element forms a star point; sett