Methods and systems to separate hydrocarbon mixtures such as natural gas into light and heavy components

The present invention integrates adsorption and liquefaction techniques to separate hydrocarbon feed mixtures into light and heavy components. A feed is partially liquefied in two or more stages. A first stage occurs at higher pressure. A second stage occurs at lower pressure. At each stage, gas and liquid components are separated. The separated heavy components resulting from liquefaction provide a purified natural gas liquid product. The separated gas components may be further processed and/or handled to provide purified natural gas. Heavy streams resulting from the further processing of the separated gas streams may be recycled and incorporated into the feed mixture. By using separate liquefaction stages at different pressures to favor C1 and then C2 separation from the heavy stream, a natural gas liquid product with high C3+ purity results.