This utility model relates to the field of bio-
jet fuel technology, specifically a selective collection device for isomeric fractions of bio-
jet fuel. The device includes a housing, a rotating
assembly, and a tube rack. The bottom of the rotating
assembly is located inside one end of the housing, and the end of the tube rack away from the rotating
assembly is connected to the housing. This assembly, consisting of the housing, rotating assembly, and tube rack, provides a continuous collection device for isomeric fractions of bio-
jet fuel. Through a step-by-step rotation, test tubes used for collecting the fractions pass sequentially below the
discharge end of the tube rack. Simultaneously, the device actively lifts the test tubes being collected, bringing the tube opening closer to the
discharge end of the fraction, thus reducing the likelihood of external interference during the fraction's descent into the
test tube and improving the reliability of fraction collection.