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

A process for preparing a high purity EPA product from a crude fish oil comprising 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 filtered feed stream and a first stage 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 first stage mobile phase desorbent comprising a non-polar solvent and an organic polar solvent in an effective first stage solvent ratio to provide a first SMB extract stream, a first primary SMB raffinate stream, and a first secondary SMB raffinate stream which is recycled to provide at least a portion of the first stage mobile phase desorbent, said first SMB extract stream comprising non-polar solvent and omega-3 fatty acid esters and other fatty acid esters of at least one DPA, SDA, ALA, and GLA and being essentially free of OLE and LIN, said first 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 a first extract stream and a first SMB1 recovered solvent stream comprising the non-polar solvent, and passing the first primary raffinate stream to a first raffinate solvent recovery zone and therein recovering the non-polar solvent to provide a first SMB reject stream and a second SMB recovered solvent stream comprising the non-polar solvent the first extract solvent and admixing at least a portion of the first and second SMB recovered solvent stream with the first stage mobile phase desorbent;
• h. diluting the first extract stream with an effective amount of a polar solvent and counter-currently passing the diluted first extract stream and a second stage mobile phase desorbent to a first reverse phase simulated moving bed adsorption (SMB) zone, said first reverse phase SMB zone containing hydrophobic stationary phase agent, said first reverse phase SMB zone comprising a plurality of adsorbent beds and operating in an effective reverse phase cycle, said second stage mobile phase desorbent comprising a polar solvent and water in an effective second stage solvent ratio to provide a second SMB extract stream, a second primary SMB raffinate stream, and a second secondary SMB raffinate stream which is recycled to provide at least a portion of the second stage mobile phase desorbent, said second primary SMB raffinate stream comprising polar solvent and fatty acid esters of EPA, said second primary SMB raffinate stream comprising polar solvent and fatty acid ester of DHA, and other fatty acid esters of at least one DPA, SDA, ALA, and GLA;
• i. passing the second primary SMB raffinate stream to a second raffinate solvent recovery zone and therein recovering the polar solvent to provide a second raffinate stream and a first SMB2 recovered solvent stream comprising the polar solvent, and passing the second extract stream to a second extract solvent recovery zone and therein recovering the polar solvent to provide a second SMB reject stream and a second SMB2 recovered solvent stream comprising the non-polar solvent the first extract solvent;
• j. diluting the second raffinate stream with an effective amount of the polar solvent and counter-currently passing the diluted second raffinate stream and a third stage mobile phase desorbent to a third simulated moving bed (SMB) zone, said third SMB zone containing hydrophobic stationary phase agent, said third SMB zone comprising a plurality of adsorbent beds, said third stage mobile phase desorbent comprising a polar solvent and water in an effective third stage solvent ratio to provide a third SMB extract stream, a third primary SMB raffinate stream, and a third secondary SMB raffinate stream which is recycled to provide at least a portion of the third stage mobile phase desorbent, said third primary SMB raffinate stream comprising polar solvent and fatty acid esters of DHA and other fatty acid esters of at least one DPA, SDA, ALA, and GLA, said third SMB extract stream comprising polar solvent and fatty acid ester of EPA;
• and,
• k. passing the third primary SMB raffinate stream to a third raffinate solvent recovery zone and therein recovering the polar solvent to provide a third SMB reject stream and a first SMB3 recovered solvent stream comprising the polar solvent, and passing the third extract stream to a third extract solvent recovery zone and therein recovering the polar solvent to provide a high purity EPA product stream being essentially free of OLE and LIN having an EPA purity greater than 97 wt-% EPA and a second SMB3 recovered solvent stream comprising the polar solvent the first extract solvent.

A batch 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 through a chromatographic bed containing a hydrophilic silica adsorbent until a breakthrough of EPA occurred;
• g. terminating the passing of the finished feed stream to the chromatographic bed and passing a non-polar solvent to the chromatographic bed and collecting a raffinate stream comprising non-polar solvent and LIN and OLE;
• h. terminating the passing of the non-polar solvent to the chromatographic bed and passing a polar solvent to the chromatographic bed and collecting an extract stream;
• and,
• i. passing the extract stream to a polar solvent recovery zone to remove the polar solvent and recovering the enhanced omega-3 ester product, having an EPA purity greater than 97 wt-% EPA and being essentially free of LIN and OLE.