Method for producing hydrogen cyanide in a particulate heat exchanger circulated as a moving fluidized bed

A process for continuously preparing hydrogen cyanide by reacting ammonia with at least one hydrocarbon, the process comprising bringing a reaction gas mixture comprising the ammonia and the at least one hydrocarbon to reaction temperature in a transported fluidized bed by through indirect heating by contact with a particulate heat transferrer, wherein

• the particulate heat transferrer is conducted cyclically in the transported fluidized bed,
• the particulate heat transferrer is heated in an ascending transport stream, and
• the particulate heat transferrer is contacted with the reaction gas mixture in a descending transport stream.