Simulated moving bed chromatographic separation

Claim 1

In a method for the separation of an extract component from a raffinate component contained in a fluid feed stream in a simulated moving bed chromatographic separation train having a plurality of serially connected sorbent containing beds and means for recycling fluid through said train, wherein single extract and raffinate concentration profiles are established across the entire train which advance downstream in said train in the direction of recycle flow in response to the rate of recycle flow, wherein there are means for introducing or withdrawing fluid streams at spaced points along the train, wherein the feed stream is introduced into the train at a feed point, a raffinate rich stream is withdrawn at a second point downstream of said feed point, a desorbent stream is introduced at a third point downstream of said second point and an extract rich stream is withdrawn at a fourth point downstream of said third point, and wherein the points of introduction and withdrawal of said streams are periodically shifted downstream of said train in the direction of recycle flow in a series of timed steps in response to the downstream advancement of said concentration profiles within said train, the improvement which comprises: continuously recycling fluid through all of the sorbent beds in the train, dividing each of the timed steps into an active period and a rest period, introducing the feed and desorbent streams and withdrawing the raffinate and extract streams throughout the active period of each step, and ceasing the introduction and withdrawal of said streams throughout the rest period of each step.

Claim 7

A method for the simulated moving bed chromatographic separation of an extract component from a raffinate component contained in a fluid feed stream in a plurality of separate chromatographic separation trains, each of said trains including a plurality of serially connected sorbent containing beds, means for recycling fluid through all of the sorbent beds in said train, and means for introducing and withdrawing fluid streams at spaced points along the train, comprising: continuously recycling fluid in each of said trains to establish independent extract and raffinate concentration profiles across each of said trains which advance downstream in said trains in the direction of recycle flow in response to the rate of recycle flow in each of said trains, introducing the feed stream into a first of said trains at a feed point determined by said concentration profiles in said first train, withdrawing a raffinate rich stream from said first train at a second point downstream of said feed point, introducing a desorbent stream into said first train at a third point downstream of said second point and withdrawing and extract rich stream from said first train at a fourth point downstream of said third point, shifting the introduction of said feed and desorbent streams and the withdrawal of said raffinate rich and extract rich streams from said first train to a second of said trains while continuing the recycling of fluid in each of said trains, said feed stream being introduced at a feed point determined by the concentration profiles in said second train, said raffinate rich stream being withdrawn at a second point downstream of said feed point, said desorbent stream being introduced at a third point downstream of said second point and said extract rich stream being withdrawn at a fourth point downstream of said third point, shifting the introduction of said feed and desorbent streams and the withdrawal of said raffinate rich and extract rich streams to the next of said trains, the points of introduction and withdrawal of said streams being determined by the concentration profiles in said next train.

Claim 8

A method for the simulated moving bed chromatographic separation of an extract component from a raffinate component contained in a fluid feed stream in a plurality of separate chromatographic separation trains, each of said trains including a plurality of serially connected sorbent containing beds, means for recycling fluid through all of the sorbent beds in said train, and means for introducing and withdrawing fluid streams at spaced points along the train, comprising: continuously recycling fluid in each of said trains to establish independent extract and raffinate concentration profiles across each of said trains which advance downstream in said trains in the direction of recycle flow in response to the rate of recycle flow in each of said trains, introducing the feed stream into a first of said trains at a feed point determined by said concentration profiles in said first train, withdrawing a raffinate rich stream from said first train at a second point downstream of said feed point, introducing a desorbent stream into said first train at a third point downstream of said second point and withdrawing and extract rich stream from said first train at a fourth point downstream of said third point, shifting the introduction of said feed and desorbent streams and the withdrawal of said raffinate rich and extract rich streams from said first train to a second of said trains while continuing the recycling of fluid in each of said trains, said feed stream being introduced at a feed point determined by the concentration profiles in said second train, said raffinate rich stream being withdrawn at a second point downstream of said feed point, said desorbent stream being introduced at a third point downstream of said second point and said extract rich stream being withdrawn at a fourth point downstream of said third point, shifting the introduction of said feed and desorbent streams and the withdrawal of said raffinate rich and extract rich streams to the next of said trains, the points of introduction and withdrawal of said streams being determined by the concentration profiles in said next train.