Separating device and separating method

The invention provides a separating device and a separating method for separating each component of a hydrocarbon mixture. The separating device comprises a debutanizer and a demethanation device, wherein the debutanizer is used for separating C4 components and heavier hydrocarbon fractions; the debutanizer comprises a C4 component outlet for outputting the C4 component; the demethanation device is used for separating a mixture containing a C2 component and lighter fractions; the demethanation device comprises an absorbent inlet for introducing an absorbent of absorbing the C2 component; and the absorbent inlet and the C4 component outlet are communicated to introduce the C4 component into the demethanation device as the absorbent. By applying the technical scheme disclosed by the invention, an extra absorbent is prevented from being added to the separating device, a recycling link of the absorbent is avoided, and energy consumption of the separating device is reduced.