Other

Tate & Lyle Industries, Limited

The Western Sugar Company

Marc Hlavacek

Michael Donovan

Robert P Jansen

John C Williams

Gordon Walker

Richard C Reisig

Bimal Goculdas

Eric P Ekern

A process for producing sugar from beets includes the step of filtering a sucrose-containing feed juice, which has been obtained from macerated sugar beets, through a first ultrafiltration membrane that has a first molecular weight cutoff. This ultrafiltration step produces a first ultrafiltration permeate and a first ultrafiltration retentate. The first ultrafiltration permeate is filtered through a second ultrafiltration membrane that has a second molecular weight cutoff that is lower than the first molecular weight cutoff. This second ultrafiltration step produces a second ultrafiltration permeate and a second ultrafiltration retentate. The second ultrafiltration permeate is nanofiltered through a nanofiltration membrane, thereby producing a nanofiltration permeate and a nanofiltration retentate. The nanofiltration retentate has a higher concentration of sucrose on a dry solids basis than the feed juice in step (a), and can be used in evaporation and crystallization operations to produce crystals of white sugar. The process can optionally include ion exchange and/or electrodialysis purification steps, prior to or after the nanofiltration step. Recycle syrups can be treated with enzyme or a chromatographic separator to remove raffinose.

Sugar beet membrane filtration process

A nanofiltration process for obtaining sucrose uses a feed syrup, such as molasses, that comprises sucrose and no less than about 2% by weight invert sugars (on a dry solids basis). The nanofiltration produces a permeate and retentate. The nanofiltration permeate will comprise invert sugars that have passed from the feed through the nanofiltration membrane, and preferably will also comprise ash from the feed. The nanofiltration retentate has a higher concentration of sucrose and a lower concentration of invert sugars than the feed syrup. Sucrose can then be crystallized from the nanofiltration retentate. The reduction of the invert content in the syrup facilitates crystallization and thus enhances sucrose recovery.

Process for purification of low grade sugar syrups using nanofiltration

A process for producing sugar from beets includes the step of filtering a sucrose-containing feed juice, which has been obtained by diffusion from sliced sugar beets, through a first ultrafiltration membrane that has a first molecular weight cutoff. This ultrafiltration step produces a first ultrafiltration permeate and a first ultrafiltration retentate. The first ultrafiltration permeate is filtered through a second ultrafiltration membrane that has a second molecular weight cutoff that is lower than the first molecular weight cutoff. This second ultrafiltration step produces a second ultrafiltration permeate and a second ultrafiltration retentate. The second ultrafiltration permeate is nanofiltered through a nanofiltration membrane, thereby producing a nanofiltration permeate and a nanofiltration retentate. The nanofiltration retentate has a higher concentration of sucrose on a dry solids basis than the feed juice in step (a), and can be used in evaporation and crystallization operations to produce crystals of white sugar. The process can optionally include ion exchange and/or electrodialysis purification steps, prior to or after the nanofiltration step. Recycle syrups can be treated with enzyme or a chromatographic separator to remove raffinose.

A process for producing sugar from cane includes the step of filtering a sucrose-containing feed juice, which has been obtained from macerated sugar cane, through a first ultrafiltration membrane that has a first molecular weight cutoff. This ultrafiltration step produces a first ultrafiltration permeate and a first ultrafiltration retentate. The first ultrafiltration permeate is filtered through a second ultrafiltration membrane that has a second molecular weight cutoff that is lower than the first molecular weight cutoff. This second ultrafiltration step produces a second ultrafiltration permeate and a second ultrafiltration retentate. The second ultrafiltration permeate is nanofiltered through a nanofiltration membrane, thereby producing a nanofiltration permeate and a nanofiltration retentate. The nanofiltration retentate has a higher concentration of sucrose on a dry solids basis than the feed juice in step (a), and can be used in evaporation and crystallization operations to produce crystals of white sugar. The process can optionally include ion exchange and/or electrodialysis purification steps, prior to or after the nanofiltration step. Recycle syrups can be treated with a chromatographic separator to remove excess invert, ash and color.

Sugar cane membrane filtration process

A nanofiltration process for obtaining sucrose uses a feed syrup, such as molasses, that comprises sucrose and no less than about 3% by weight invert sugars (on a dry solids basis). The nanofiltration produces a permeate and retentate. The nanofiltration permeate will comprise invert sugars that have passed from the feed through the nanofiltration membrane, and preferably will also comprise ash from the feed. The nanofiltration retentate has a higher concentration of sucrose and a lower concentration of invert sugars than the feed syrup. Sucrose can then be crystallized from the nanofiltration retentate. The reduction of the invert content in the syrup facilitates crystallization and thus enhances sucrose recovery.

An efficient method for manufacturing a purified juice product from sugar beets. Untreated beet juice is initially prelimed using lime and CaCO.sub.3 to produce a prelimed juice product. Instead of subjecting the prelimed product to main liming and dual carbonation stages, the product is delivered to a porous filtration membrane which allows sugar molecules to pass therethrough which preventing the passage of solid matter and dissolved impurities. Optimum results are achieved if the prelimed product flows across the membrane from end to end. The membrane permeate is thereafter combined with CO.sub.2(g) in a single carbonation stage to remove dissolved lime. This step generates a purified juice product which can be processed to manufacture pure crystalline sugar. The membrane retentate can be combined with water and refiltered to collect residual sugar materials. The foregoing process uses less energy and raw materials (e.g. lime) compared with conventional methods.

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London, United Kingdom

Marc Hlavacek