Use of a fractionation system for removing heavy hydrocarbons in a gas stream, comprising: a feed gas inlet configured to introduce a feed gas stream through it; a stripping section configured to receive a predominantly liquid phase of the feed gas stream; and first and second co-current contacting systems located in-line within a pipe, the first co-current contacting system configured to receive a predominantly vapor phase of the feed gas stream, each of the first and second co-current contacting systems comprising: a co-current contactor including a droplet generator (208, 428a, 612a-n) and a mass transfer section , the droplet generator (208, 428a, 612a-n) configured to generate droplets from a liquid and to disperse the droplets into a gas stream , and the 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; wherein the system is configured such that the vapor phase of the co-current contactor in the first co-current contacting system comprises the gas stream for the co-current contactor in the second co-current contacting system , and wherein the system is configured such that the liquid phase of the co-current contactor in the second co-current contacting system comprises the liquid from which droplets are generated in the co-current contactor of the first co-current contacting system . a feed gas inlet configured to introduce a feed gas stream through it; a stripping section configured to receive a predominantly liquid phase of the feed gas stream; and first and second co-current contacting systems located in-line within a pipe, the first co-current contacting system configured to receive a predominantly vapor phase of the feed gas stream, each of the first and second co-current contacting systems comprising: a co-current contactor including a droplet generator (208, 428a, 612a-n) and a mass transfer section , the droplet generator (208, 428a, 612a-n) configured to generate droplets from a liquid and to disperse the droplets into a gas stream , and the 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; a co-current contactor including a droplet generator (208, 428a, 612a-n) and a mass transfer section , the droplet generator (208, 428a, 612a-n) configured to generate droplets from a liquid and to disperse the droplets into a gas stream , and the 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; wherein the system is configured such that the vapor phase of the co-current contactor in the first co-current contacting system comprises the gas stream for the co-current contactor in the second co-current contacting system , and wherein the system is configured such that the liquid phase of the co-current contactor in the second co-current contacting system comprises the liquid from which droplets are generated in the co-current contactor of the first co-current contacting system . <EOS>