Method for operating a dehydrogenation reactor for the dehydrogenation of hydrocarbons wherein the dehydrogenation reactor comprises a potassium promoted iron oxide catalyst the hydrocarbons being dehydrogenated in contact with the catalyst, characterized in that carbon dioxide is introduced during a) start-up of the reactor, b) shut-down of the reactor, and c) steaming procedures, characterized in that - the method comprises the following steps during start-up (a): i. heating the reactor to a first temperature by a recirculating gas stream comprising nitrogen, ii. heating the reactor to a second temperature by introducing steam, and optionally continuing nitrogen recirculation along with the steam, iii. optionally, checking for leaks, and iv. heating the reactor to a third temperature and stopping carbon dioxide introduction before introducing the hydrocarbon, wherein the carbon dioxide is introduced in step i) via the recirculating nitrogen gas stream and in steps ii) and iv) via the steam and optional recirculating nitrogen, - the method comprises the following steps during shut-down (b): i. stopping the introduction of hydrocarbons into the reactor, the reactor being at a third temperature, ii. cooling the reactor to a first temperature using a coolant gas comprising steam and optionally adding nitrogen and recirculating the nitrogen along with the steam, iii. cooling the reactor to a fourth temperature using a recirculating coolant gas comprising nitrogen, wherein the carbon dioxide is introduced in step ii) via the coolant gas comprising steam and optional recirculating nitrogen and in step iii) via the coolant gas comprising nitrogen, - the method comprises the following steps during steaming procedures (c) beginning from normal operation: i. stopping the introduction of hydrocarbons into the reactor, the reactor being at a third temperature ii. adjusting the reactor to and holding at a fifth temperature with steam and optionally adding nitrogen and recirculating the nitrogen, iii. adjusting the temperature to a third temperature and stopping the introduction of carbon dioxide before introducing the hydrocarbon, wherein the carbon dioxide is introduced in steps ii) and iii) via the steam and optional recirculating nitrogen, wherein the concentration of carbon dioxide in the steam is from 0.1 to 20 % by volume and the concentration of carbon dioxide in the nitrogen gas is from 2 to 50% by volume. a) start-up of the reactor, b) shut-down of the reactor, and c) steaming procedures, - the method comprises the following steps during start-up (a): i. heating the reactor to a first temperature by a recirculating gas stream comprising nitrogen, ii. heating the reactor to a second temperature by introducing steam, and optionally continuing nitrogen recirculation along with the steam, iii. optionally, checking for leaks, and iv. heating the reactor to a third temperature and stopping carbon dioxide introduction before introducing the hydrocarbon, i. heating the reactor to a first temperature by a recirculating gas stream comprising nitrogen, ii. heating the reactor to a second temperature by introducing steam, and optionally continuing nitrogen recirculation along with the steam, iii. optionally, checking for leaks, and iv. heating the reactor to a third temperature and stopping carbon dioxide introduction before introducing the hydrocarbon, - the method comprises the following steps during shut-down (b): i. stopping the introduction of hydrocarbons into the reactor, the reactor being at a third temperature, ii. cooling the reactor to a first temperature using a coolant gas comprising steam and optionally adding nitrogen and recirculating the nitrogen along with the steam, iii. cooling the reactor to a fourth temperature using a recirculating coolant gas comprising nitrogen, i. stopping the introduction of hydrocarbons into the reactor, the reactor being at a third temperature, ii. cooling the reactor to a first temperature using a coolant gas comprising steam and optionally adding nitrogen and recirculating the nitrogen along with the steam, iii. cooling the reactor to a fourth temperature using a recirculating coolant gas comprising nitrogen, - the method comprises the following steps during steaming procedures (c) beginning from normal operation: i. stopping the introduction of hydrocarbons into the reactor, the reactor being at a third temperature ii. adjusting the reactor to and holding at a fifth temperature with steam and optionally adding nitrogen and recirculating the nitrogen, iii. adjusting the temperature to a third temperature and stopping the introduction of carbon dioxide before introducing the hydrocarbon, i. stopping the introduction of hydrocarbons into the reactor, the reactor being at a third temperature ii. adjusting the reactor to and holding at a fifth temperature with steam and optionally adding nitrogen and recirculating the nitrogen, iii. adjusting the temperature to a third temperature and stopping the introduction of carbon dioxide before introducing the hydrocarbon,