A fractionation system for removing heavy hydrocarbons in a gas stream, comprising: a feed gas inlet, as a bottom section a stripping section, and as a top section a rectification section, wherein the feed gas inlet is in a position adjacent both the stripping section and the rectification section; the feed gas inlet configured to introduce a feed gas stream through it; the stripping section configured to receive a predominantly liquid phase of the feed gas stream; and the rectification section comprising a co-current contacting system (600; 421a-c) configured to receive a predominantly vapor phase of the feed gas stream, the co-current contacting system comprising: a compact contacting bundle disposed within a vessel that forms a unitary pressure boundary, the compact contacting bundle including a plurality of substantially parallel contacting units (608a-n), each of the plurality of contacting units (608a-n) having a droplet generator (612a-n) and a mass transfer section, each droplet generator (612a-n) configured to generate droplets from a liquid and to disperse the droplets into a gas stream, and each mass transfer section configured to provide a mixed, two-phase flow having a vapor phase and a liquid phase, and a separation system configured to separate the vapor phase from the liquid phase; and an inlet manifold configured to distribute the liquid to each droplet generator (612a-n) of the plurality of contacting units (608a-n); wherein the system is configured such that a concentration of heavy hydrocarbons in the vapor phase provided by each mass transfer section of the plurality of contacting units (608a-n) is lower than a concentration of heavy hydrocarbons in the liquid phase provided by each mass transfer section of the plurality of contacting units (608a-n). a feed gas inlet, as a bottom section a stripping section, and as a top section a rectification section, wherein the feed gas inlet is in a position adjacent both the stripping section and the rectification section; the feed gas inlet configured to introduce a feed gas stream through it; the stripping section configured to receive a predominantly liquid phase of the feed gas stream; and the rectification section comprising a co-current contacting system (600; 421a-c) configured to receive a predominantly vapor phase of the feed gas stream, the co-current contacting system comprising: a compact contacting bundle disposed within a vessel that forms a unitary pressure boundary, the compact contacting bundle including a plurality of substantially parallel contacting units (608a-n), each of the plurality of contacting units (608a-n) having a droplet generator (612a-n) and a mass transfer section, each droplet generator (612a-n) configured to generate droplets from a liquid and to disperse the droplets into a gas stream, and each mass transfer section configured to provide a mixed, two-phase flow having a vapor phase and a liquid phase, and a separation system configured to separate the vapor phase from the liquid phase; and an inlet manifold configured to distribute the liquid to each droplet generator (612a-n) of the plurality of contacting units (608a-n); a compact contacting bundle disposed within a vessel that forms a unitary pressure boundary, the compact contacting bundle including a plurality of substantially parallel contacting units (608a-n), each of the plurality of contacting units (608a-n) having a droplet generator (612a-n) and a mass transfer section, each droplet generator (612a-n) configured to generate droplets from a liquid and to disperse the droplets into a gas stream, and each mass transfer section configured to provide a mixed, two-phase flow having a vapor phase and a liquid phase, and a separation system configured to separate the vapor phase from the liquid phase; and a droplet generator (612a-n) and a mass transfer section, each droplet generator (612a-n) configured to generate droplets from a liquid and to disperse the droplets into a gas stream, and each mass transfer section configured to provide a mixed, two-phase flow having a vapor phase and a liquid phase, and a separation system configured to separate the vapor phase from the liquid phase; and an inlet manifold configured to distribute the liquid to each droplet generator (612a-n) of the plurality of contacting units (608a-n); wherein the system is configured such that a concentration of heavy hydrocarbons in the vapor phase provided by each mass transfer section of the plurality of contacting units (608a-n) is lower than a concentration of heavy hydrocarbons in the liquid phase provided by each mass transfer section of the plurality of contacting units (608a-n).