Abstract: An apparatus for carrying out a chemical reaction in a process fluid includes a reactor comprising one or more reaction tubes which have a number of electrically heatable tube segments which are connected to one another by an electrically conductive star bridge, and at least one power source configured to provide a multiphase alternating current with N phases to N phase lines at a predetermined voltage. N is an integer greater than or equal to 2. For each of the at least one power source, a number of power connections is provided, each of which is connected to at least one of the tube segments and to one of the phase lines of the power source. In the at least one power source, a star point is formed at which the phase lines of the power source are connected, wherein the star point is not connected to a ground connection.

Abstract: A method for regulatedly carrying out a chemical reaction in a reactor having reaction tubes which have a number of electrically heatable tube sections, wherein power connections are provided, which are each connected to at least one of the tube sections, wherein at least one connecting element is provided and each of the tube sections is connected to the connecting element. The method comprises conducting a process fluid through the one or more reaction tubes, providing several variable voltages at the several power connections, wherein the several voltages are provided as phases of a multiphase AC voltage so that the at least one connecting element forms a star point, setting the one or more voltages; detecting one or more measured values corresponding to one or more measured variables; changing the several set voltages so that the detected measured values correspond to predetermined values or value ranges of the measured variables.