Abstract:

Xylitol is an important sugar alcohol widely used as sweetener. A processing route to remove the residual acid from xylose hydrolyzed solution in industrial production of xylitol is the acid hydrolysis method. Conventional neutralization method with lime has many drawbacks such as high energy consumption, large consumption of chemicals and environmental pollution. To achieve a clean production of xylitol, a self-resemble electrodialysis stack was used for selective removal of residue acid. The influences of current density on the removal ratio of residue acid and recovery ratio of xylose were investigated. The residue acid removal rate was higher than 99% and xylose recovery rate reached 84.9% at a current density of 30 mA·cm^-2. The total energy consumption for xylose hydrolyzed solution was 179 kW·h·t^-1 and the deacidification process cost was estimated to be 139 ￥·t^-1, indicating economic and ecological advantages of this technology. Thus the electrodialysis is a very promising technology for production of xylitol.

Key words: membrane, separation, desalination, electrodialysis, xylitol

摘要：

木糖醇作为一种可作为甜味剂的糖醇具有广泛的应用前景。目前工业上酸水解法制备木糖醇的过程中需要一个脱除水解液中的残酸的工艺步骤。传统的残酸去除方法为饱和石灰水中和法,存在能耗高、消耗的化学试剂多、污染大等缺点。为实验木糖醇的清洁生产,本文采用自我组装的电渗析装置对木糖水解液中的残酸进行了选择性的去除,考察了操作电流对残酸去除及木糖得率的影响。结果表明,当操作电流为30 mA·cm^-2时,电渗析过程对残酸的去除率大于99%,其木糖的得率为84.9%,电渗析工艺处理木糖水解液的能耗为179 kW·h·t^-1,脱酸工序成本为每吨母液139元,具有良好的经济效益和环境效益。由此可见,电渗析工艺在木糖醇酸水解法制备过程中具有广泛的应用前景。

关键词: 膜, 分离, 脱盐, 电渗析, 木糖醇