Dividing wall columns for natural gas liquefaction plants

In order to meet current carbon dioxide emissions reduction challenges, natural gas processing and refining industries have to find the ways to minimize energy requirements of distillation operations. Building on foundations lied down in a preceding effort, this paper shows that this could be achieved in a cost-effective way in natural gas liquids fractionation plants and that a conventional demethanizer column combined with either a thermally coupled direct sequence of deethanizer and propane-butane recovery columns or a dividing wall column produces expected savings in capital and hot utilities costs as compared to conventional direct sequence, without any temperature penalty on cold utilities side. The choice between available options will largely depend on important process considerations that may differ for offshore and onshore plants to the extent depending on specific site requirements.