Bio-Acrylic Acid Production from Glucose (Single-Step Process)

The process under analysis comprises three major sections: (1) Fermentation; (2) Product Treatment and Purification; and (3) Components Recovery.

Fermentation. Fermentation media is prepared by mixing glucose, corn steep liquor and water recovered downstream, and fed to agitated fermentors. The pH control is made by addition of make-up and recycled sodium carbonate. The fermentation broth is centrifugated to separate cells and other suspended solids. The supernatant of the centrifugation, containing sodium acrylate, is sent to Liquid-Liquid Extraction, while the retentate is partially recycled to the fermentors, with the remainder being disposed.

Product Treatment and Purification. The sodium acrylate solution from Cells Separation is sent to L-L Extraction, where it is contacted in countercurrent flow with an extractant solvent. An aqueous phase containing sodium bicarbonate and residual sodium acrylate is directed to Sodium Carbonate (Na2CO3) tegeneration. An organic phase containing the extractant and acrylic acid is passed through a flash unit to remove most of the dissolved carbon dioxide (CO2), and then routed to Water Removal Column. In this column, water is removed, and a bottom product is sent to the Acrylic Acid Column. Glacial acrylic acid (99.7 wt.% purity) is obtained as the column overhead, while the extractant solvent is recovered from the bottom and routed to back extraction.

Components Recovery. In back extraction, the solvent is contacted in countercurrent with hot water, obtaining two phases: an aqueous phase containing impurities and unconverted glucose, disposed as wastewater, and an organic phase containing the solvent, sent to CO2 Compression and Absorption. Part of the carbon dioxide streams released throughout the process is also fed to this area. The solution formed is used as the extractant in the liquid-liquid extraction. The sodium bicarbonate solution from L-L Extraction is decomposed at high temperatures in the Na2CO3 Regeneration, producing carbon dioxide and dissolved sodium carbonate. The solution is passed through a sequence of evaporation steps for partial water removal and recycled as a neutralization component in the fermentation process.