Process for producing propylene, comprising: - carrying out a process for propane dehydrogenation to obtain a first constituent mixture containing at least hydrogen, ethane, ethylene, propane and propylene, - carrying out a steam cracking process to obtain a second constituent mixture containing at least hydrogen, methane, ethane, ethylene, propane and propylene, - forming a first separation product containing at least predominantly propylene using at least a portion of the propylene of the first and of the second constituent mixture (A, B) and using one or more first separation steps, - forming a second separation product containing at least predominantly propane using at least a portion of the propane of the first and of the second constituent mixture (A, B) and using the first separation step or steps, - forming a third separation product containing at least predominantly ethylene using at least a portion of the ethylene of the first and of the second constituent mixture (A, B) and using one or more second separation steps, - forming a fourth separation product containing at least predominantly ethane using at least a portion of the ethane of the first and of the second constituent mixture (A, B) and using the second separation step or steps, and characterized in - that at least a portion of the first constituent mixture is subjected to one or more first pre-separation steps comprising a pressure increase and an at least partial removal of hydrogen to obtain a third constituent mixture, - that at least a portion of the second constituent mixture is subjected to one or more second pre-separation steps comprising a pressure increase, an at least partial removal of hydrogen and an at least partial removal of methane to obtain a fourth constituent mixture, and - that at least a portion of the third constituent mixture is subjected to the first separation step or steps together with at least a portion of the fourth constituent mixture. - carrying out a process for propane dehydrogenation to obtain a first constituent mixture containing at least hydrogen, ethane, ethylene, propane and propylene, - carrying out a steam cracking process to obtain a second constituent mixture containing at least hydrogen, methane, ethane, ethylene, propane and propylene, - forming a first separation product containing at least predominantly propylene using at least a portion of the propylene of the first and of the second constituent mixture (A, B) and using one or more first separation steps, - forming a second separation product containing at least predominantly propane using at least a portion of the propane of the first and of the second constituent mixture (A, B) and using the first separation step or steps, - forming a third separation product containing at least predominantly ethylene using at least a portion of the ethylene of the first and of the second constituent mixture (A, B) and using one or more second separation steps, - forming a fourth separation product containing at least predominantly ethane using at least a portion of the ethane of the first and of the second constituent mixture (A, B) and using the second separation step or steps, and characterized in - that at least a portion of the first constituent mixture is subjected to one or more first pre-separation steps comprising a pressure increase and an at least partial removal of hydrogen to obtain a third constituent mixture, - that at least a portion of the second constituent mixture is subjected to one or more second pre-separation steps comprising a pressure increase, an at least partial removal of hydrogen and an at least partial removal of methane to obtain a fourth constituent mixture, and - that at least a portion of the third constituent mixture is subjected to the first separation step or steps together with at least a portion of the fourth constituent mixture.