Direct White Sugar Production: optimization and chemical regeneration of fixed-bed activated carbon adsorbers
Master of Science in Biological and Agricultural Engineering (MSBAE)
Biological and Agricultural Engineering
A system for the direct production of white sugar from clarified sugar cane juice in a raw sugar factory has been developed at the Audubon Sugar Institute. This Direct White Sugar Production (DWiSP) system employs a series of columns packed with adsorbent media. Activated carbon is used in the first column(s) as a filter and bulk decolorizer. Ion exchange resins are then used to remove ash and remaining color. Batch testing was performed in order to determine equilibrium parameters. An analytical model was utilized in conjunction with column loading tests to determine dynamic characteristics of the carbon adsorber for use in determining design parameters. Ion exchange columns were investigated to determine deashing and decolorization properties. The use of hydrogen peroxide pretreatment was also investigated. Chemical regeneration of carbon was also investigated. Batch test indicated a decrease in the carbon's adsorptive capacity when the feed was pretreated. Column tests indicated that residence time has a significant effect on carbon column performance and film mass transfer was related to superficial velocity as is described in previous work. The ion exchange system performed consistently over seven cycles and was able to produce a low color, low ash product for approximately 15 bed volumes, after which exhaustion set in rapidly. Exhaustion was indicated by a sharp increase in conductivity of the final column product. Evaluation of a New Regeneration Process (NRP) for chemical regeneration of carbon showed it to be effective in returning the carbon to 70-85% of its virgin capacity. The NRP solution was also compared to a regenerant solution of sodium hydroxide. The NRP solution was twice as effective as a 2% sodium hydroxide solution, but costs more than twice as much.
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Cortes, Raul Alejandro, "Direct White Sugar Production: optimization and chemical regeneration of fixed-bed activated carbon adsorbers" (2007). LSU Master's Theses. 3921.