Ryan-Holmes distillation process

The Ryan-Holmes distillation process uses cryogenic distillation to remove acid gases from a gas stream. This process is applied to remove COi for LPG separation or where it is desired to produce COt at high pressure for reservoir injection. This complicated process is beyond the scope of this book. 

Ryan-Holmes A cryogenic extractive distillation process using liquid carbon dioxide, in which a light hydrocarbon is added in order to suppress the freezing of the carbon dioxide. Licensed by Process Systems International nine licenses had been granted by 1992. 

Chevron s Sacroc project (Parro, 1984 Schendel and Nolley, 1984) and Amoco s Central Mallet unit (100 MMscfd, 85% CO2) (Anon., 1985) used membranes. However, the Sacroc project predates the Ryan Holmes process, and Amoco was under contractual obligation to supply gas with NGL s still present to a downstream NGL extraction plant. Therefore in the mid-1980s, the market generally sustained the conclusion of Goddin (1982) that, when NGL was recovered, economics favored cryogenic distillation over the use of either membranes or amine treating in C02-flood EOR projects. 

The Ryan/Holmes processes represent a family of related techniques for recovering carbon dioxide and hydrocarbon liquids from carbon dioxide-rich gas streams. They are licensed by Process Systems International, Inc. The processes incorporate low-temperature distillation with a circulating natural gas liquid (NGL) additive. Their primary field of application has been in the processing of gas from enhanced oil recovery (EOR) projects. The technology has been described by Process Systems International, Inc. (1992) Wood et al. (1986) Ryan and O Brien (1986) Schaffert and Ryan (1985) and Ryan and Schaffert (1984). 

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