Method for separating C2+-hydrocarbons or C3+-hydrocarbons from a hydrocarbon-rich fraction

Described herein is a method for separating C2+-hydrocarbons or C3+-hydrocarbons from a hydrocarbon-rich fraction is described, whereby the separation is carried out in a rectification fractionation. The rectification fractionation is provided with at least three heating circuits via which intermediate fractions are drawn off from rectification fractionation, partially evaporated and fed back again to rectification fractionation. In the method, removal of the intermediate fraction circulating in the heating circuit located at the highest temperature level is at least temporarily interrupted. During this interruption, a partial stream of a bottom fraction from the rectification fractionation is partially evaporated against an external medium and is fed as a bottom heating to the rectification fractionation. Also during this interruption, the two additional intermediate fractions, in each case at the temperature level at which the intermediate fraction circulating in the heating circuit located at the next-higher temperature level was partially evaporated, are partially evaporated.