If there are 3 identical cylindrical structures, with a combined total of 72 rooms, then each individual cylindrical structure contains 72/3=<<72/3=24>>24 rooms.
In each 24-room cylindrical structure, there are 24-12-7=<<24-12-7=5>>5 kitchens.
Thus, the entire, three-cylinder space station contains a total of 3*5=<<3*5=15>>15 kitchens.
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