Membrane separation is a new separation technology that appeared in the early 20th century and rose rapidly after the 1960s. Membrane separation technology not only has the functions of separation, concentration, purification and refining, but also has the characteristics of high efficiency, energy saving, environmental protection, molecular filtration, simple filtration process and easy control. Therefore, it has been widely used in food, medicine, biology, environmental protection, chemical industry, metallurgy, energy, petroleum, water treatment, electronics, bionics and other fields, and has produced huge economic and social benefits. It has become one of the most important means in separation science. Membrane separation differs from traditional filtration in that membrane separation can be carried out on a molecular scale, and this process is a physical process that does not require phase changes and the addition of additives.
In the traditional crystalline glucose production process, a large amount of crystallization mother liquor will be produced, and the direct sales price of the mother liquor is affected by the relationship between supply and demand, which is generally not economical. Therefore, membrane separation technology is used for the treatment of crystalline glucose mother liquor to solve this problem.
The viscosity of the glucose mother liquor is high, and it is not easy to separate directly into the membrane separation equipment, so a certain amount of water needs to be added before entering the membrane system. During the membrane separation process, since the oligosaccharides above disaccharides are trapped, the permeation volume is continuously reduced, so it is necessary to add water to wash the glucose on the trapped side through the membrane.
Nanofiltration dialysate is almost colorless, in order to remove trace pigments, it is more appropriate to use resin to decolorize. The color of the nanofiltration concentrate is darker, and activated carbon can be used for decolorization. After that, the concentrate and the dialysate are both concentrated by their respective evaporators to reach a dry matter content of 75%. The former can be used as maltose syrup product with high DE value or mixed with maltose syrup. The latter produces crystalline glucose through crystallization, which improves the extraction rate of the whole production process of crystalline glucose.
1) Technical requirements for concentrated water treatment. According to the actual situation, if the enterprise has an integrated sewage treatment system, the membrane separation and concentrated water can be integrated into the integrated sewage treatment system for treatment; if not, a biochemical treatment system can be independently designed to combine with chemical cleaning wastewater, media filters and activated carbon filtration. The backwash wastewater is collected together for treatment.
2) Process flow of concentrated water treatment. The concentrated water treatment process can adopt the coagulation sedimentation and contact oxidation treatment process.