A device and a method are provided for reacting a starting material in at least two reactors connected to each other, including the reacting of the starting material in a first reactor to a first product, removing the first product from the first reactor using a jet pump, wherein a negative pressure zone of the jet pump is operationally connected to the first reactor, so that the first product of the first reactor moves through the negative pressure zone in a propulsion jet of a propulsion medium of the jet pump, conducting the propulsion medium having the first product into a second reactor, wherein the first product is allowed to react into a second product, separating the second product from the propulsion medium and discharging the separated second product.

A method is provided for the pyrolysis or thermolysis of a fluid or fluidized starting material in a tube bundle reactor including a plurality of heatable reactor tubes. The method includes feeding the starting material to the tube bundle reactor at one end by at least one supply line; wherein the supply line has several pressure reduction units which enable a positive pressure before the starting material is introduced into individual reactor tubes of the tube bundle reactor and a negative pressure inside the reactor tubes. The pressure reduction units control a substantially equal inflow of the starting material into individual reactor tubes and the reactor tubes are heated to a decomposition temperature of the starting material in at least one primary section. The starting material is pyrolyzed or thermolyzed and a pyrolysis or thermolysis product is obtained.