Sucrose is an important strategic material related to national economy and people's livelihood after grain, cotton and oil. However, due to the addition of chemicals as well as manual and batch operation, traditional refining method suffers from inferior and unstable product quality, food safety concerns, high operation and reagent costs, and serious environmental problems caused by solid waste.
The green production of sucrose by membrane technology is promising because the impurity removal, clarification, decolorization and concentration of sugarcane juice can be achieved only by physical separation. This technology has the advantages of not adding harmful substances, efficient, automatic and stable process, full utilization of by-products and product diversification.
However, due to the complex composition and high viscosity of sugarcane juice, it will cause severe membrane fouling and flux decline during the membrane separation process. Moreover, the commercial membranes have poor selectivity on pigments, sucrose and reducing sugar molecules, and thus it is difficult to increase the purity of sucrose. These technical limitations impede the application of membrane technology in sugar industry.
Researchers in the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences have conducted pilot-scale tests and systematic process optimization in a number of sugar mills in Guangdong and Guangxi provinces since 2014. Recently, in the IPE pilot plant located in Guangdong Guangken Sugar Co., Ltd., the continuous and stable operation of the integrated membrane filtration system is successfully achieved, and the first batch of white sugar refined by membrane technology in China is obtained.
This indicates that the technology roadmap of the integrated membrane technology for cane sugar production has been completely realized; the sugar industry may bid farewell to chemical auxiliary materials such as sulfur, phosphoric acid and lime to achieve pure physical process production, and completely eliminate the by-products such as sludge and molasses.
The novel membrane technology for sugar production is a milestone process technology that subverts the traditional carbonation and sulfiting methods used for more than 140 years worldwide.
This work was supported by the Key Research Program of Chinese Academy of Sciences.
Figure 1 Brief technology introduction and products exhibition (Image by LUO Jianquan et al.)
