Abstract

Fructose is a monosaccharide of great interest to industries. The easiest way to produce crystalline fructose from its aqueous solution is adding ethanol to the solution, which narrows the large metastable zone width and reduces the solution viscosity and the fructose solubility in water, increasing yields of crystallization. Studies in the literature though are limited to those of solubility, kinetics, and characterization of product, not including economic or environmental effects. This study addresses steps to integrate the whole productive system. A thermal analysis of the solution showed that exposing the solution to temperatures equal or above 104 °C has adverse effects on crystallization and should be avoided. The experimental study also showed that using 90 wt.% ethanol aqueous solution leads to the best yields and a well-defined morphology of fructose crystals – yields of 97%, roundness of 7.25 and mean size of 95.00 µm in the best experiment. However, the cost of ethanol represents almost 80% of the gross income of the plant, if ethanol is not recycled. An integrated system is then proposed considering the separation and reuse of ethanol and mother-liquor. Among those evaluated, the optimal operating conditions conducts to a minimal cost of 99.40 US$/tonne of fructose, which has a value of 796 US$/tonne.

摘要

果糖是工业界非常感兴趣的一种单糖。从水溶液中生产结晶果糖最简单的方法是在溶液中加入乙醇，这样可以缩小较大的亚稳区宽度，降低溶液粘度和果糖在水中的溶解度，从而提高结晶产率。然而，文献中的研究仅限于溶解度、动力学和产品表征，不包括经济或环境影响。本研究提出了整合整个生产系统的步骤。溶液的热分析表明，将溶液暴露在等于或高于 104 °C 的温度下会对结晶产生不利影响，应避免。实验研究还表明，使用 90 wt. % 乙醇水溶液导致最佳的产率和明确的果糖晶体形态 - 在最佳实验中，产率为 97%，圆度为 7.25，平均尺寸为 95.00 µm。然而，如果乙醇不被回收，乙醇的成本几乎占工厂总收入的 80%。然后提出了考虑乙醇和母液的分离和再利用的集成系统。在这些评估中，最佳操作条件下果糖的最低成本为 99.40 美元/吨，其价值为 796 美元/吨。然后提出了考虑乙醇和母液的分离和再利用的集成系统。在这些评估中，最佳操作条件下果糖的最低成本为 99.40 美元/吨，其价值为 796 美元/吨。然后提出了考虑乙醇和母液的分离和再利用的集成系统。在这些评估中，最佳操作条件下果糖的最低成本为 99.40 美元/吨，其价值为 796 美元/吨。