Process for purification of EPA (eicosapentanoic acid) ethyl ester from fish oil

摘要

Disclosed is a process for extracting and purifying EPA (Eicosapentanoic acid) ethyl ester from a crude fish oil feedstock using a combination of novel esterification and simulated moving bed (SMB) techniques. Crude fish oil diluted in non-polar solvent is esterified with an acid and then transesterified with a base. Following washing, the non-polar phase is directly passed to an SMB zone, comprising a normal phase separation with a hydrophilic stationary phase agent and a non-polar/organic polar mobile phase desorbent to provide an enhanced omega-3 product, comprising EPA. In a further embodiment, the enhanced omega-3 product is passed to a second and third SMB zones operating in reverse phase using a hydrophobic stationary phase and a polar mobile phase desorbent. The process is useful for producing high purity EPA at purities in excess of 97 wt-% which are not economically recoverable by conventional distillation methods combined with conventional SMB configurations.

主权项

1. A process for recovering an enhanced omega-3 ester product from a crude fish oil comprising fatty acids of omega-3 fatty acids of eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) along with other unsaturated triglyceride species including at least one of docosapentanoic acid (DPA), stearadonic acid (SDA), alpha linolenic acid (ALA), gamma linolenic acid (GLA), linoleic acid (LIN) and oleic acid (OLE) and free fatty acids, said process comprising:
a. passing the crude fish oil to a solvent mixing zone and therein admixing the crude fish oil with a non-polar solvent to provide a fish oil/solvent mixture; b. passing the fish oil/solvent mixture to an esterification zone and therein subjecting the fish oil/solvent mixture to an esterification reaction in the presence of an ethanol stream and an acid catalyst stream comprising a mineral acid at effective esterification conditions to convert the free fatty acids to Fatty Acid Ethyl Esters (FAEE) to provide a non-polar esterification reaction effluent stream comprising non-polar solvent, fatty acids of omega-3 fatty acids of EPA or DHA or mixtures of EPA and DHA, and said unsaturated triglyceride species, and a polar esterification reaction phase comprising ethanol, water, the FAEE, and said mineral acid; c. admixing the non-polar esterification reaction effluent stream with a polar solvent stream to form a transesterification reaction feed stream and passing the transesterification feed stream to a transesterification zone and subjecting the transesterification feed stream to a transesterification reaction in the presence of a basic catalyst stream at effective transesterification reaction conditions to convert the fatty acids of omega-3 fatty acids of EPA or DHA to omega-3 fatty acid esters comprising EPA or DHA or mixtures of EPA and DHA, and to convert the unsaturated triglycerides to glycerol and to other fatty acid ethyl esters of LIN, OLE and at least one of DPA, SDA, ALA, and GLA to provide a two-phase transesterification reaction effluent stream; d. passing the two-phase transesterification reaction effluent stream to a wash/separation zone and therein washing the two-phase transesterification reaction effluent stream with water, stabilizing, and phase separating the two-phase transesterification reaction effluent stream to provide an aqueous phase stream comprising the polar solvent, water and glycerol, and a non-polar transesterification effluent stream comprising water, non-polar solvent, omega-3 fatty acid esters and said other fatty acid esters of LIN, OLE and at least one of DPA, SDA, ALA, and GLA; e. finishing the non-polar transesterification effluent stream to remove water in a finishing zone to provide a finished feed stream comprising non-polar solvent, omega-3 fatty acid esters and other fatty acid esters; f. passing the finished feed stream and a mobile phase desorbent to a normal phase simulated moving bed adsorption (SMB) zone, said normal phase SMB zone containing a hydrophilic stationary phase agent, said normal phase SMB zone comprising a plurality of adsorbent beds and operating in an effective normal phase cycle, said mobile phase desorbent comprising a non-polar solvent and an organic polar solvent in an effective normal phase solvent ratio to provide a first SMB extract stream, a primary SMB raffinate stream, and a secondary SMB raffinate stream a portion of which is recycled to provide at least a portion of the mobile phase desorbent, said SMB extract stream comprising non-polar solvent and omega-3 fatty acid esters and other fatty acid esters of at least one of DPA, SDA, ALA, and GLA and being essentially free of OLE and LIN, said primary SMB raffinate stream comprising non-polar solvent and fatty acid esters of OLE and LIN; g. passing the first SMB extract stream to a first extract solvent recovery zone and therein recovering the non-polar solvent to provide the enhanced omega-3 ester product comprising EPA or DHA or mixtures thereof being essentially free of OLE and LIN and having and EPA purity of greater than 97 wt-% EPA and a first SMB recovered solvent stream comprising the non-polar solvent, and passing the primary SMB raffinate stream to a raffinate solvent recovery zone and therein recovering the non-polar solvent to provide an SMB reject stream and a second SMB recovered solvent stream comprising the non-polar solvent and the polar organic solvent; and, h. returning at least a portion of the first SMB recovered solvent stream and the second SMB recovered solvent stream to be admixed with the mobile phase desorbent.