A system and method for integrated heavy hydrocarbon removal in a liquefaction system having a lean natural gas source. An economizer located between a main cryogenic heat exchanger and a reflux drum is provided to cool an overhead vapor stream against a partially condensed stream. In addition, pressure of the natural gas feed stream is maintained into a scrub column. A pressure drop is provided by a valve located between the economizer and the reflux drum on a partially condensed stream withdrawn from the cold end of the warm section of the main cryogenic heat exchanger.